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Evelyn Smith

Comet ISON's  Sky Watch Journal offers the public a synopsis of the daily news on Comet ISON.

For additional up-to-date information about meteors, meteorites, and asteroids go to

• http://evelynelainesmith.blogspot.com/2013/11/comet-ison-dictionary.html

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• http://evelynelainesmith.blogspot.com/2013/03/meteors-meteorites-asteroids.html

Addendum: After ISON Disintegrates 

January 14, 2014

Dickinson, David. (2014, January  14).  A Possible Meteor Shower from Comet ISON?

Universe Today.  Retrieved from http://www.universetoday.com/108084/a-possible-meteor-shower-from-comet-ison/

“ISON could have one more trick up its cosmic sleeve –although it’s a big maybe — in the form of a meteor shower or (more likely) a brief uptick in meteor activity this week”, even though meteor showers are  impossible to predict accurately (Dickinson, 2014, January 14, para. 1 & 5).

Sky watchers should note that the night of January 15th into the 16th is the time to watch since Earth will cross the orbital plane of ISON’s path about 9 P.M. EST/2 UT. Some astrologers also speculate that dust from the comet might cause an increase in noctilucent, or night time,  dust cloud activity  (Dickinson, 2014, January 14, para. 6-7).

To look for possible “ISON-ids” look in the constellation of Leo near the +3.5 magnitude star Eta Leonis.  However, these meteors won’t be necessarily easy to spot since they will pass through Earth’s atmosphere with only a visible duration of less than a second.  Unfortunately, a full moon on Wednesday, January 15th, is in the constellation Gemini is just 32 degrees away from any possible sightings (Dickinson, 2014, January 14, para. 8-9).

No large debris from ISON is headed towards earth, only dust grains, although NASA Science News first predicted that Comet ISON’s orbit might generate a meteor shower as early as April 2013 (Dickinson, 2014, January 14, para. 10-11). The next scheduled meteor shower should occur on the night of April 21-22nd when the Spring Lyrids make their scheduled arrival.  On May 24th, debris from Comet 209P Linear should pass by Earth just as it did in 1803 in 1924 (Dickinson, 2014, January 14, para. 12). 

Stieber, Zachary.  (2014, January 12).  Comet ISON Update: Meteor Activity Possible on January 15. SPACE.  Epoch Times.  Retrieved from http://www.theepochtimes.com/n3/444877-comet-ison-update-meteor-activity-possible-on-january-15/

In a blog published January 9th, American Meteor Society’s Robert Lundsford predicted that meteor activity generated when Comet ISON was still an intact comet could reach earth on January 15th since when the comet was heading toward the sun, its orbit crossed the Earth’s orbit that the Earth, in turn, would reaches January 15th: http://www.amsmeteors.org/2014/01/meteor-activity-from-comet-ison/ (Stieber, 2014, January 14, para. 1-2).

Lundsford explains, “Comet ISON was producing a large amount of dust prior to its disintegration. Some feel that despite the distance that some of this dust may still reach earth” (Stieber, 2014, January 14, para. 3).  This debris could come in the form of either meteor showers or dust clouds.  Accordingly, Lundsford blogs that while the individual dust particles are too small to produce meteors large enough to be visible to the naked eye, sky watchers might catch a meteor display in the night sky in the constellation of Leo in the early morning hours, even though a full moon will be shining Wednesday night (Stieber, 2014, January 14, para. 5-8).

Paul Wiegart of the University of Western Ontario, however, earlier forecast that this shower might begin around January 12th (Stieber, 2014, January 14, para. 9-10). Even so, Wiegert also projected that they would be so small that they would dissolve in Earth’s upper atmosphere: “Instead of burning up in a flash of light, they will drift gently down to the Earth below” (Stiebert, 2014, January 14, para. 11-12).

This dust could produce icy notilucent clouds that glow electric-blue above the poles as it takes years “to settle out of the high atmosphere” (Stiebert, 2013, January 14, para. 13-14). Although ISON’s dust trail shouldn’t bother the International Space Station, even so, astronauts should look out for “possible anomalies” (Stiebert, 2014, January 14, para. 15). 

Sun-blown ISON comet remains harvested in Antarctic. (2014, January 14). RT. Retrieved from http://rt.com/news/ison-comet-dust-antarctic-568/

Searching for the “basic building blocks of life”, Russian scientists at the Vostok Antarctic Station plan to make three attempts to gather dust from Comet ISON first on Tuesday and Wednesday, then on Saturday, and finally in late January, according to Sergey Bulat from the St. Petersburg Institute of Nuclear Physics (Sun-blown, 2014, January 14, para. 1-2).

The scientists originally scheduled this mission for December, but they had to revise their plans when the comet disintegrated.  Bulat explains, “We expected the comet to survive and hoped to gather some large particulates in December. Now if we get something, it would be particulates from the coma [the major part of the head of a comet] and tail left when it was approaching the sun” (Sun-blown, 2014, January 14, para. 3-4).

Using five 15-square meter polyethylene canvases as comet-dust traps, the scientists will unroll them near the Vostok Station and thus hope to collect comet particles in the Antarctic since the air there is less polluted there than in more inhabited places.  After preserving the samples in inert argon gas, they will then ship them back to St. Petersburg for further research (Sun-blown, 2014, January 14, para. 5-6).

Bulat notes that the scientists are interested in particulates from Comet ISON that didn’t burn up in the atmosphere, “The fact that they did not experience heating is what makes them valuable” (Sun-blown, 2014, January 14, para. 7). 

If the researchers at the Eukaryotic Genetics Lab discover life’s building blocks, this would prove the panspermia hypothesis that comets and meteorites could have seeded life on earth.  Admittedly, however, finding any such particulates could be like winning the lottery (Sun-blown, 2014, January 14, para. 8-9).

If the dust hunters discover any of ISON’s dust particles, because the Earth’s current path “is far from overlapping” what ISON’s orbit was in early November when ISON crossed through it, and because a comet’s tail doesn’t just hang at the spot where it was blown, the particulates would have separated from the comet tens of thousands of years ago (Sun-blown, 2014, January 13, para. 9-11).

This study, however, is far from a wild goose chase since the scientists at the Vostok Antarctic Station are actually following an established tradition of studying comet dust.  For example, NASA’s Stardust robotic mission collected comet sample of Comet Wild 2 (Sun-blown, 2014, January 14, para. 13). 

January 12, 2014

Astronomy expert: Meteor likely in Upstate New York, but was it caused by Comet ISON?

Comet ISON.  (2014, January 12, 2014, updated January 13, 2014).   Central New York. Syracuse.com. Retrieved from http://www.syracuse.com/news/index.ssf/2014/01/astronomy_expert_meteor_likely_in_upstate_new_york_but_was_it_caused_by_comet_is.html

Oswego, NY – Even though meteors on average hit Earth seven times an hour every day, Scott Roby, Associate Professor of Astronomy and the Planetarium Director at the State University College at Oswego, believes that Upstate New Yorkers who either heard a loud sonic boom or saw a light streak across the sky Sunday evening most probably witnessed a meteor (Astronomy expert, 2014, January 12, para. 1-3).

Roby further explained that smaller debris creates a streak of light as it burns through the atmosphere while larger rocks generate enough light to be seen in the day time, sometimes leaving a smoke trail.  Traveling faster than the speed of sound, they also create a sonic boom.  Roby then acknowledged that a small chance might exist that these meteors could be remnants of Comet ISON; however, he also cautioned that random meteors hit Earth all the time (Astronomy  expert, 2014, January 12, para. 4-5). 

This speculation coincides with an Epoch Times article first published on Sunday that predicts a possibility of meteor activity generated by Earth passing Comet ISON’s path during early November.  Roby notes that while most astronomers suggest that Earth’s entry into this debris field will result in dust clouds only seen at night, a slim possibility exists that meteors might enter Earth’s atmosphere: “Comets are litterbugs. Whenever Earth passes through an old or new comet orbit, it can run into lots of rocks” (Astronomy expert, 2014, January 12, para. 6-8).

Since ice makes up the glue that holds comets together, Roby explains that "When they get near the sun, the ice evaporates and the rocks get left behind and stay in orbit" (Astronomy expert, 2014, January 12, para. 9).  Concluding that ISON’s demise needs to be further studied, Roby nevertheless admitted that “Random meteors could have caused this, or we could be lucky, and it could have been a piece of Comet ISON burning up in the sky” (Astronomy expert, 2014, January 12, para. 10-11).

December 30, 2013

King, Bob.  (2013, December 30).  Jan. 16 May Be Last Best Chance to Search for Comet ISON’s Remains.  Universe Today.  Retrieved from http://www.universetoday.com/107542/jan-16-may-be-last-best-chance-to-search-for-comet-isons-remains/

UPDATE Dec. 30 10 a.m. (CST):  Astrophotographer Hisayoshi Kato has taken a deep image of the Comet ISON, which appeared in the Constellation Draco on December 29 using a 180mm f/2.8 telephoto lens near the Mauna Loa Observatory in Hawaii at 11,000 feet.  Kato stacked five exposures to record what could be Comet ISON’S “incredibly diffuse and faint debris cloud . . . We’re talking as dim as it gets”  (King, 2013, December 30, para. 8).

The best hope for turning up a vestige of Comet ISON in a photographic search will be on January 16th, according to German amateur astronomer Uwe Pilz (King, 2013, December 30, para. 1).  At this point, earth will be crossing the debris left in the comet’s path, so bits of dust might possibly show up in time-exposure photos made through wide-field telescopes when the dust that Comet ISON has shed will possibly create a “visually compressed” bright band of rubble (King, 2013, December 30, para. 3).  Similarly, Comet C/2011L4 PanSTARRS brightened briefly when Earth crossed its orbital plane on May 27 (King, 2013, December 30, para. 4).  

Pilz has made a series of simulations of Comet ISON using his own comet tail program, presuming that ISON’s debris particles sizes of between 1 millimeters to 10 millimeters. Since ISON has remained invisible since perihelion, Pilz hypothesizes that the comet broke up into a smaller number of larger than average pieces than usual pieces that don’t reflect light as well as larger amounts of smaller dust particles (King, 2013, December 30, para. 5). So far [ except for Kato] no Earth-bound telescope has photographed any of ISON’s debris, and on January 16th, photographers will also face an additional obstacle because the full moon will make the task more difficult (King, 2013, December 30, para. 7).

December 23, 2013

Hoffman, Tony. (2013, December 23).  Comet ISON Wrap-up: It Fought the Sun and the Sun Won.  PC Magazine. Retrieved from http://www.pcmag.com/article2/0,2817,2428542,00.aspn

After Comet ISON emerged from its trip around the sun, astronomers were first unsure as to whether it had survived.   However, a few days later, they concluded that this much hyped comet had disintegrated (Hoffman, 2013, December 23, para. 1). Although ISON was supposed to be at its brightest in early December, “nothing of substance” resurfaced but a “faint smudge”, and when the Arecibo radio telescope and the Hubble Space Telescope looked for its remnants last week, they couldn’t detect any measurable fragments near the comet’s predicted position (Hoffman, 2013, December 23, para. 2).  Even so, observations by the Comet ISON Observing Campaign and more than a dozen spacecraft along the way helped Comet ISON became the most studied comet in history (Hoffman, 2013, December 23, para. 3).

Some Like It Hot: Astronomers classified Comet ISON as a “sungrazing comet” since its orbit took it to within less than a solar diameter of the sun’s surface.  Some sun grazers, like the Great Comet of 1680, have become very bright (Hoffman, 2013, December 23, para. 4).  However, what differentiated ISON from other such comets was that it originated from the Oort Cloud, having been most probably shoved out of its original orbit by the pull of a passing star (Hoffman, 2013, December 23, para. 5).  Some of these pristine comets, like Comet ISON, are relatively bright when they are far away from the sun since their outer frozen gases have yet to melt away.  After the gas cloud that they form expands, they “shut down” until they near the sun (Hoffman, 2013, December 23, para. 6).

The Promise, and the Hype: Comet ISON’s original magnitude along with its projected sun-grazing orbit around the sun led astronomers to predict that it might become a very bright comet, triggering overly optimistic forecasts that cast ISON in the role of the “Comet of the Century” particularly after scientists also verified that this was ISON’s first trip around the sun (Hoffman, 2013, December 23, para. 7-9).  Scientists, however, overestimated the size of the comet’s nucleus, which they inferred by its rate of outgassing:  Images taken by NASA’s Swift satellite and the Hubble Space Telescope in early 2013 suggested that the comet’s diameter was between 3 to 4 miles, but when the comet passed Mars in October, the Mars Reconnaissance Orbiter recorded data that inferred that its nucleus was only 500 yards across (Hoffman, 2013, December 23, para.10).  Similarly, in 2011, a small Kreutz sungrazer, C/2-11 W3 (Lovejoy), made an even closer approach to the sun than ISON (Hoffman, 2013, December 23, para. 11).

Breaking Up Is (Not So) Hard to Do: Although few astronomers believed that Comet Lovejoy would survive, that comet displayed a spectacular, long tail before it disintegrated.  Thus, comparing Comet Lovejoy and ISON left astronomers confused.  One hypothesis suggests that as a pristine comet ISON was much more of a conglomeration of less cohesive materials than Lovejoy, hardened by its previous trips around the sun (Hoffman, 2013, December 23, para. 12).

Incoming! Thanks to the “trove of data” that astronomers have collected on Comet ISON, they should more fully understand how new comets behave, and how all comets disintegrate when they come in contact with extreme physical forces (Hoffman, 2013, December 23, para. 13). Although Comet ISON disappointed both professional and amateur astronomers, once every decade a candidate worthy of the title “Great Comet” appears while “still pleasing comets”, appear, such as four comets that were visible to the unaided eye were visible in 2013 (Hoffman, 2013, December 14-15). 

December 20, 2013

King, Bob. (2013, December 20).  Hubble looks but finds no trace of Comet ISON.  Universe Today.  Retrieved from http://www.universetoday.com/107407/hubble-looks-but-finds-no-trace-of-comet-ison/

The Hubble Space Telescope didn’t pick up any traces down to the magnitude of 25 when it turned to Comet ISON’s predicted position on December 18.  This evidence--or rather the lack of any documented evidence of Comet ISON’s existence--indicates that any remaining fragments of the comet would now be smaller than 500 feet or 160 meters in diameter (King, 2013, December 20, para. 1).

Considering the possibility that the comet’s remains would follow a slightly different orbit, the Hubble also photographed two possible comet positions, still picking up no visible leftover debris.  Any fragments would have appeared in composite images, even as stars show up as faint streaks (King, 2013, December 20, para. 2-3).  

December 19, 2013

Allen, Kate. (2013, December 19). Comet ISON's last hurrah: shooting-stars in January, hopefully. The Star Blogs.com. Retrieved from
http://thestar.blogs.com/worlddaily/2013/12/astronomers-are-still-digging-through-the-data-from-comet-isons-nail-biting-and-ultimately-fatal-solar-pass-by-in-november.html

Karl Battams, one of the astronomers tracking ISON, predicts that Comet ISON’s dust passing through the Earth’s atmosphere may possibly produce a “shooting-star gallery” in January (Allen, 2013, December 19, para 2).  Battams explains that when ISON reached its perihelion it stopped emitting Lyman-Alpha photons, that indicate that sunlight is reacting with hydrogen, or that frozen ice still holds the nucleus of the comet together, so “all that remains of ISON is a dusty trail” (Allen, 2013, December 19, para. 3-4).  However, in mid-January, Earth’s orbit could pass through this trail, and any sand-grain size remnants of ISON that pass through the atmosphere will become shooting stars (Allen, 2013, December 19, para. 5). Meanwhile any sizeable remains of the comet will remain in their original orbit, taking them out of the solar system (Allen, 2013, December 19, para. 6).  

Battams, Karl. (2013, December 19).  What happens to ISON's remains? Space Daily.  Retrieved from http://www.spacedaily.com/reports/What_happens_to_ISONs_remains_999.html

Comet ISON definitely disintegrated upon its encounter with the sun and exists simply “as a dust cloud and some warm fuzzy memories” (Battams, 2013, December 19, para. 2).  Thus, the remains of ISON join the many dust clouds of comets that regularly pass through the solar system.  Even though Earth might pass through this dust in January 2014, this shouldn’t be any reason for alarm because 1) any remnants of ISON are reduced to about the size of about the size of a grain of sand that will burn up as shooting stars should they enter the earth’s atmosphere; 2) space is vast and empty just as comet tails are; and 3) Earth just passed through the Geminid meteor shower last weekend with no ill effects (Battams, 2013, December 19, para. 3-6). Additionally, any parts of ISON’s nucleus larger than a centimeter or meter that survived its fragmentation should continue to follow the same orbit an intact comet otherwise would have followed out of the inner solar system (Battams, 2013, December 19, para. 8).

December 16, 2013

Byrd, Deborah. (2013, December 16). Video: So long, Comet ISON.  Earth & Sky.  Retrieved from http://earthsky.org/space/video-so-long-comet-ison

The SOHO LASCO C3 one minute and 37 second, time-lapsed video provided in this link shows Comet ISON’s complete perihelion passage on November 28, 2013, thus confirming NASA’s  pronouncement that ISON is no longer a comet (Byrd,  2013, December 16, para. 1-2).  NASA now classifies ISON as “a traveling field of debris” that the Hubble Space Telescope should photograph on December 19, 2013 (Byrd, 2013, December 16, para. 4).  Karl Battams’ Tweeter feed, @Sungrazer Comets also notes that two bright Oort Cloud Comet should pass by in 2013—C/2012 K1 (LINEAR) and C/2103 A1 (Siding Spring) (Byrd, 2013, December 16, para. 5).    

December 11, 2013

Fire vs. ice: The science of ISON at perihelion. (2013, December 11). NASA/Goddard Space Flight Center.  ScienceDaily. Retrieved from http://www.sciencedaily.com­ /releases/2013/12/131211132908.htm

Remnants of Comet ISON dimming and dissolving didn’t disappoint researchers since their observations compiled a very large set of data as the December 10, 2013, meeting of the American Geophysical Union in San Francisco testifies.  This occasion gave astrophysicists the opportunity to describe how the comet lost mass before reaching perihelion and subsequently fragmented as it drew nearest the sun.  They also determined the chemical elements that made up the comet (Fire vs. ice, 2013, December 11, para. 2-3).

Naval Research Lab astrophysicist Karl Battams explains that Comet ISON was created when the planet were formed whereupon it circled the outer edge of the solar system as part of the Oort Cloud until something happened to jolt it out of its orbit and project it on a path that took it into the inner solar system (Fire vs. ice, 2013, December 11, para. 4-5).   When Russian astronomers spotted it in September 2012, and astronomers first mapped out its orbit, they discovered that its route would take it within 1.1 million miles of the sun’s surface.  Thus, both being a "sungrazer" and a pristine comet made Comet ISON a unique object of study for astronomers (Fire vs. ice, 2013, December 1, para. 6).

Thus, beginning around the first of October, NASA’s Mars Reconnaissance Observer (MRO), turned its HiRISE instruments to view ISON on its sweep by Mars, determining that its nucleus was a little over half a mile across or about the length of five or six football fields, making it possibly just large enough to survive its close trip around the sun (Fire vs. ice, 2013, December 11, para. 6-9).

As Comet ISON was circling the sun, Geraint Jones, a comet scientist at University College London’s Mullard Space Science Laboratory, studied the comet’s tails by comparing models of the dust tail to the observations made by NASA’s Solar Terrestrial Observatory (STEREO) and the European Space Agency/NASA Solar and Heliospheric Observatory (SOHO), establishing that the comet emitted very little dust after perihelion, thus implying that its nucleus had fragmented before its close encounter with the sun (Fire vs. ice, 2013, December 11, para. 10).

While the STEREO and SOHO satellites captured images of the Comet as it closed in on the sun, NASA’s Solar Dynamic Observatory (SDO) failed to do so on November 28, 2013, because SDO was looking for wavelengths of light that would indicate the presence of oxygen, which is usually very common in comets, according to Dean Pesnell, Project Scientist for SDO at NASA’s Goddard Space Flight Center.  Pesnell explains, “The fact that ISON did not show oxygen despite how close it came to the sun provides information about how high was the evaporation temperature of ISON’s material . . . This limits what it could have been made of” (Fire vs. ice, 2013, December 11, para. 11-12).  

When astronomers first caught sight of ISON, “it was relatively bright for a comet as such a great distance from the sun”, so they forecast that its magnitude might light up the night sky in December.  Although ISON’s break up dimmed their hopes, the data furnished by its journey will continue to enlighten the study of comets for years to come (Fire vs. ice, 2013, December 11, para. 13).  

Fuller-Wright, Liz. (2013, December 11).  Comet ISON now an ex-comet, says NASA. Christian Science Monitor.  http://www.csmonitor.com/Science/2013/1211/Comet-ISON-now-an-ex-comet-says-NASA

Even though remnants of Comet ISON briefly survived--in critical condition--after it scraped by the sun November 28th, NASA astronomers now confirm that ISON is a comet no more (Fuller-Wright, 2013, December 11, para.1). Although NASA’s Solar Terrestrial Relations Observatory as well as the European Space Agency/NASA Solar and Heliospheric Observatory were near enough to the comet to send back images of its auspicious journey, for several hours the satellite's instruments blocked these images from view (Fuller-Wright, 2013, December 11, para. 2).

The media first capitalized on ISON’s coming assignation when its early brightness gave false hope that it would become the “Comet of the Century”.   Coming from the Oort Cloud, it traveled through the inner solar system, and upon its buzzing by Mars, NASA’s HiRISE took pictures, while later as it crossed the orbits of the inner planets—all without living up to its billing— space-based and earth-bound telescopes documented its progress before it skirted the sun (Fuller-Wright, 2013, December 11, para. 3).

However, since ISON was lost from sight as it reached perihelion, scientists at first couldn’t tell what had happen to it (Fuller-Wright, 2013, December 11, para. 4-5).  But several hours later, a cloud of interstellar dust, “formerly known as ISON”, resurfaced on the other side of the sun (Fuller-Wright, 2013, December 11, para. 4-5).

Alas, not only did the comet “essentially erode to nothing”, but according to a senior research scientist at NASA’s Jet Propulsion Laboratory, Zdenek Sekanina, who had closely tracked the comet’s progress for months, it “had ceased to exist before it reached perihelion (Fuller-Wright, 2013, December 11, para. 6-8).

Sekanina explained that ISON went through four or five cycles of brightening and dimming, each cycle correlating with a specific frozen gas or mixture of gases sublimating, or thawing, from a frozen state into a liquid gas or liquid.  First, the comet's nucleus most probably expelled carbon monoxide or carbon dioxide before its frozen water begin to turn into water vapor about when ISON zoomed past Mars (Fuller-Wright, 2013, December 11, para. 9).

Come late October, the core of the comet’s head had started to fragment, fully exposing its interior to the sun's radiation, thus quickening its break up.  Then on November 21, instruments recorded a large increase of water vapor, signaling that the nucleus had broken apart (Fuller-Wright, 2013, December 11 para. 10).  

After all the water vapor and gases burned away, the comet began to feed on its solid fragments, and its dust started to burn in what Sekanina calls an “advanced phase of fragmentation” (Fuller-Wright, 2013, December 11, para. 11-12).

Therefore, sometime between 3.5 days of perihelion to within 3.5 hours of perihelion, all that remained of the nucleus fragmented, leaving nothing but dust behind.  So when nothing was left to change from a frozen state into a gas or vapor, ISON, or rather its inert dust, stopped being a comet (Fuller-Wright, 2013, December 11, para. 13-16).

Even so, the sun’s corona and gravity worked upon the still moving fragments of this “zombie comet”, sharpening its tip into an increasingly sharp needle composed of rocks and dust that were too large or dense to burn, showing that whatever was emerging from the nucleus’ remnant was coming together at its tip (Fuller-Wright, 2013, para. 17-19). Then one hour before ISON’s brush by the sun, scientists could make out a “very faint, narrow extension from the tip” as all that remained of its nucleus started to expel rock fragments ranging from a millimeter to many feet across (Fuller-Wright, 2013, para. 20-21).

Accordingly, even as ISON’s left overs started to flare up as they passed through a coronal mass ejection, Comet ISON was dead.  Even so, NASA scientists will continue to analyze the data its passage left them (Fuller-Wright, 2013, para. 22). 

Rest in pieces: Comet ISON officially dead, Sun chief suspect. (2013, December 11). Science.  Fox News.  Retrieved from http://www.foxnews.com/science/2013/12/11/rest-in-pieces-comet-ison/

WASHINGTON (AP) –Astronomers gathered in San Francisco at the annual American Geophysical Union conference  on Tuesday pronounced Comet ISON official dead, the victim of the sun’s gravity and solar radiation.  Naval Research Laboratory astronomer Karl Battams gave the valediction, “Sorry, everyone, Comet ISON is dead.  But its memory will live on” (Rest in pieces, 2013, December 11, para. 4).

Understandably, astronomers had hoped Comet ISON would survive its close brush with the sun as Comet Lovejoy did in 2012, giving backyard astronomers a naked eye view in early December.  But this pristine comet from the Oort Cloud didn’t survive its first trip around the sun perhaps because its radius was only approximately half a mile wide, smaller than researchers had first estimated (Rest in pieces, 2013, December 11, para. 5-8). For Battams, watching a dying ISON was “a process of heartbreak” (Rest in pieces, 2013, December 11, para. 9).

Sonnenberg, Max. (2013, December 11).  Comet ISON officially declared dead. The Space Reporter. Retrieved from http://thespacereporter.com/2013/12/comet-ison-officially-declared-dead/

At a meeting of the American Geophysical Union, Karl Battams, of the U.S. Naval Research Laboratory declared, “Comet ISON is dead; its memory will live on” (Sonnenberg, 2013, December 11, para. 1-2).  Even though remnants of ISON did survive its brush with the sun, observations by NASA’s solar laboratories confirmed that they rapidly dimmed.   However, this disintegration generated a massive collection of data for astronomers to analyze (Sonnenberg, 2013, December 11, para. 3-4).

During the AGU annual meeting, astronomers further expounded upon how the comet lost mass before reaching perihelion and most likely broke up during its close encounter.  Additionally, they explained how this fragmentation helped them learned what chemical elements made up the comet (Sonnenberg, 2013, December 11, para. 5).

 Astronomers will continue to study changes in the comet’s magnitude to determine its composition since different materials boil off at different temperatures (Sonnenberg, 2013, December 11, para. 6-7): Because Comet ISON was relatively bright for a comet so far from the sun when astronomers first discovered it in September 2013, many astronomers predicted that it would be visible to the naked eye during December. Although this “light show” was cut short when ISON broke apart, ISON’s disintegration left researchers with a tremendous amount of data to analyze (Sonnenberg, 2013, December 11, para. 8).  

Wall, Mike. (2013, December 11).  RIP Comet ISON: Scientists Declare Famous 'Sungrazer' Dead After Sun Encounter.  SPACE.com.  Retrieved from http://news.yahoo.com/rip-comet-ison-scientists-declare-famous-39-sungrazer-161011828.html

Astronomers have come to accept the reality that  Comet ISON's scattered cloud of dust has now spread out into deep space. Comet expert, Karl Battams has pronounced, “Comet ISON is dead; its memory will live on (Wall, 2013, December 11, para. 1-3).  

Comet ISON, a pristine comet from the Oort Cloud, incidentally skimmed just 684,000 miles, or 1.1. million kilometers from the surface of the sun on November 28th (Wall, 2013, December 11, para. 4). While astronomers  had hoped that Comet ISON would be visible to the naked eye during December, they did learn a lot about the comet’s chemical composition and structure by watching its gases boil away (Wall, 2013, December 11, para. 5-6).

However, observations indicate that the comet stopped emitting dust when it reached perihelion and then continued to grow fainter as it traveled away from the sun, according to Geraint Jones of University College London.  Although it briefly brightened for a few hours after perihelion, this may have been only “a consequence of orbital dynamics,” Jones explained (Wall, 2013, December 11, para. 7-8).

Most likely, ISON’s fragments spread out upon perihelion, with its more frontal wave of this debris speeding up relative to the dust fragments left behind, which would have caused ISON first to dim and then re-brighten as all the fragments  “clumped up again” on the other side of the sun (Wall, 2013, December 11, para. 9).

Recent observations by NASA’s Mars Reconnaissance Orbiter (MRO) also indicate that ISON’s nucleus measured only between 330 feet and 3,300 feet, or 100 to 1,000 meters, wide--a size that might have brought about its break up.  The principal investigator of MRO’s powerful HiRISE camera, Alfred McEwen of the University of Arizona, theorizes, “It was probably smaller than 600 meters in diameter”, adding that sun grazers of about half a kilometer or less ordinarily don’t survive" (Wall, 2013, December 11, para. 10-11).

While the astronomers have said their goodbyes to ISON, NASA space telescopes, including the Hubble Space Telescope and possibly Spitzer and Chandra, will be trained on the comet should it make a “miraculous” recovery (Wall, 2013, December 11, para. 12-13). 

December 6, 2013

No light show expected from Comet ISON. (2013, December 6).  Lifestyle. Kidspost. Washington Post. Retrieved from http://www.washingtonpost.com/lifestyle/kidspost/no-light-show-expected-from-comet-ison/2013/12/05/8853fa90-5c7f-11e3-be07-006c776266ed_story.html

NASA/Associated Press – Astronomers now agree that Comet ISON didn’t survive its intrusion into the sun’s corona, breaking into smaller pieces (No light, 2013, December 6, para. 1-3). The majority of researchers now believe that this rendezvous left only dust and debris (No light, 2013, December 6, para. 4).

Astrophysicist Karl Battams blogged Comet ISON’s obituary on Monday, and Physicist Alex Young  has told The Los Angeles Times that he was “pretty certain that it’s gone” (No Light, 2013, December 6, para. 5 & 7).  Young explained that while these remains would continue to travel along Comet ISON orbital path, the solar wind would eventually spread them out into space (No Light, 2013, December 6, para. 8).  Even so, NASA’s Hubble Telescope will search for whatever is left behind in mid-December (No Light, 2013, December 6, para. 9). 

December 5, 2013

Atkinson, Nancy.  (2013, December 5).  Is Anything Left of ISON? Spacecraft Continue to Monitor Comet’s Remains. Universe Today.  Retrieved from  http://www.universetoday.com/106976/is-anything-left-of-ison-spacecraft-continue-to-monitor-comets-remains/

High-resolution imagery taken by NASA’s STEREO spacecraft reveals some remaining remnants of Comet ISON.  But each day this debris releases less and less light, forcing Comet ISON’s Observing Campaign’s astrophysicist Karl Battams to admit, “If anything of ISON’s nucleus is left, it’s an inactive husk of a nucleus now . . . The comet remnant is fading fast in the STEREO data (Atkinson, 2013, December 5, para. 1).

Another CIOC astronomer, Casey Lisse, however, on December 4th suggested that a slimmed-down nucleus just might have survived:  Either observatories are picking up the comet’s tail emitting debris, or else “a sizable-nucleus-sized chunk” might have again started to expel gas and dust (Atkinson, 2013, December 5, para. 2).

Nevertheless, Lisse acknowledged that most astronomers give the comet a less than 10 percent chance of having survived.  Comet ISON’s nucleus now only has a 10 meter, or about 33 feet, radius, but some of the comets fragments might possibly measure 100 meters, or 328 feet, or larger.  This makes the debris large enough for astronomers to analyze, but not large enough for the naked eye to see in the December sky (Atkinson, 2013, December 5, para. 3). 

NASA space-based and earth-bound observatories will be on the lookout for these remains for the next few weeks.  If a much smaller nucleus is still emitting gas, the comet will display a much fainter comet and tail.  However, if a “stable and sizable” nucleus didn’t survive, the comet’s dust will scatter and dissolve into space (Atkinson, 2013, December 5, para. 5).

NASA’s STEREO spacecraft are using their camera to search for fragments, and its Infrared Telescope Facility in Honolulu, Hawaii, will use its spectroscopic telescope to search for the comet’s remnants. By next week, the recently launched MAVEN spacecraft may be looking for ISON’s leftovers, and from mid-to late December, the Hubble and Chandra observatories will be conduction deep space searches for the comet’s remains.  Finally, Spitzer will join this search in January 2014 (Atkinson, 2013, December 5, para. 6).

Even if these observatories detect a greatly reduced intact nucleus and tail, however, it won’t be visible from the third rock from the sun on December 26th, when Comet ISON comes its closest to Earth (Atkinson, 2013, December 7).  

Barnett, Amanda.   (2013, December 5). 5 latest things we know about Comet ISON. CNN.  Retrieved from http://www.cnn.com/2013/12/05/tech/comet-ison-dead-or-alive/index.html

Scientists expected Comet ISON to put on a spectacular show after it grazed the sun November 28, but instead the comet may now have turned to dust. Here is what astronomers know so far about ISON (Barnett, 2013, December 5, para. 1-2).

1. Is ISON dead? “Well, maybe”—after all, Karl Battams, an astrophysicists with the U.S. Naval Research Laboratory, wrote an obituary.  But even so, he acknowledged that everyone would have to wait for the Hubble Space Telescope to deliver the post mortem (Barnett, 2013, December 5, para. 3-4). Moreover, on Wednesday, December 4, 2013, NASA announced that its space telescopes will monitor ISON for the next three weeks just in case all that debris is obscuring a new smaller model of it (Barnett, 2013, December 5, para. 5).  Most authorities, however, believe that the sun destroyed 90 percent of the comet, leaving some of the nucleus (Barnett, 2013, December 5, para. 6)
2. What do we call ISON now? Battams refers to ISON as a “comet remnant” (Barnett, 2013, December 5, para. 7).
3. ISON wasn't a flop: Comet ISON not only became a “social media superstar”, but it also furnished scientists with lots of new data (Barnett, 2013, December 5, para. 8).
4. ISON won't be forgotten: More than 300 members of NASA’s Comet Ison Observing Campaign ISON, and many of these astronomers aren’t ready to accept its death.  CIOC founder, Padma Yanamandra-Fisher, explains, "I think the evidence shows that something catastrophic happened to the comet, but I don't think anyone is 100% sure…Ground-based observations and orbiting telescopic observations, such as Hubble Space Telescope, later in December are important" (Barnett, 2013, December 5, para. 10-11).
5. But wait, there's more! Comet watchers can currently enjoy looking for Comet Lovejoy, Comet Encke, and Comet LINEAR now visible in the night sky (Barnett, 2013, December 5, para. 2013). Barnett then posted a list of comet watching Websites.

Dietrich, Tamara. (2013, December 5). Comet ISON's gone, but local experts say its death wasn't in vain.  Chicago Tribune.  Retrieved from http://www.chicagotribune.com/topic/dp-nws-comet-ison-obit-20131205,0,1411876.story

Comet ISON’s destruction upon reaching its perihelion wasn’t in vain, according to experts: Robert Vold, an applied science professor at the College of William and Mary in Williamsburg, Virginia, acknowledges this debt, “This was a very unusual event . . .You don't see comets of this sort very often, so almost anything they do is scientifically interesting” (Dietrich, 2013, December 5, para. 1 & 3).

Astronomers are interested in ISON because it is a “pristine comet” straight from the Oort Cloud on the edge of the solar system where it was formed 4.5 billion years ago.  Although amateur Russian astronomers discovered it in September 2012, in the weeks before the comet’s approach to the sun, earth-bound astronomers and space-based telescopes are now organizing significant evidence about its chemical composition that will take several months to analyze. Professor Void hopes that the theories that result from this information will help astronomers hypothesize about the possibility of planets around other stars (Dietrich, 2013, December 5, para. 4-7).

Daniel Mazanek, a near-Earth object expert at NASA’s Langley Research Center, also notes that ISON’s break up offered additional  research opportunities in the coming years, “We’ve been able to observe it — get into the innermost parts of the comet's body, which in the long run could be very valuable (Dietrich, 2013, December 5, para. 8-10). Mazanek is fascinated with pristine comets like ISON because he theorizes that comets slamming into a young molten earth helped cool the planet when it first formed.  Some scientists also have theorized that comet impacts brought water to earth (Dietrich, 2013, December 5, para. 11-12). 

As for the near future, Mazanek forecasts that the Hubble Space Telescope might possibly pick up the remainders of Comet ISON in early January when the Earth’s orbit could pass through the tail of the comet—an event that also has a slim chance of bringing some meteor showers (Dietrich, 2013, December 5, para. 13-15). 

In October 2014, the next big event scheduled for NASA will be when Comet Siding Spring (C2013A1) will come within the orbit of Mars, so NASA is currently assessing what this will mean for the spacecraft orbiting that planet while it also plans to use the probes orbiting Mars as well as the two rovers on its surface to take photos (Dietrich, 2013, December 5, para. 16-17).  Vold also added that four "potentially interesting comets" and numerous small sun grazing ones will make their journey around the sun in the new year (Dietrich, 2013, December 5, para. 18).

Dance, Scott. (2013, December 5). As Comet ISON fizzles, catch Comet Lovejoy with binoculars.  Maryland Weather.  Baltimore Sun.  Retrieved from http://www.baltimoresun.com/news/weather/weather-blog/bal-wx-as-comet-ison-fizzles-catch-comet-lovejoy-with-binoculars-20131204,0,915475.story

 

As Comet ISON "fizzles", sky watchers using binoculars can watch Comet Lovejoy near the northeast horizon in the early morning.   Look first for the constellation Bootes and the bright star Arcturus to find the comet. Lovejoy came closest to earth on November 19th, but Comet ISON overshadowed its moves (Dance, 2013, December 5, para. 1-2).   

Astronomers at the Space Telescope Science Institute in Baltimore, however, plan to track Comet ISON once it moves away from the sun’s glare, hoping that its disintegration might reveal some clues about the makeup of the early universe (Dance, 2013, December 5, para. 3). Then astronomers will be able to estimate the size of the comet’s particles and calculate the speed of the comet’s disintegration (Dance, 2013, December 5, para. 4).

December 4, 2013

Lisse, Carey. (2013, NASA Begins Search For What Is Left Of Comet ISON. (2013, December 4). NASA.  Retrieved from http://www.nasa.gov/mission_pages/asteroids/comet_ison/index.html

NASA's Carey Lisse notes that its space-based telescopes may be seeing emission from the rubble and debris in Comet ISON’S tail, or their cameras may be making out comet activity beginning again in ISON’s nucleus (Lisse, 2013, December 4, para. 1).  Most authorities believe that there is a 90 percent probability that ISON is now destroyed.  But judging by the behavior of previous sun-grazing comet’s, a “sizeable” chunk of its nucleus may be left.  But for now, astronomers are waiting to receive the observations of NASA’s space-based observatories (Lisse, 2013, December 4, para. 1).

Always unpredictable, what remains of Comet ISON appeared first to spread and brighten and then to fade. This spreading light is most likely caused by the dust ISON discharged shortly before its perihelion (Lisse, 2013, December 4, para. 2). Again relying on precedent, NASA’s astronomers have seen sun-grazing comets like Lovejoy and Elenin in 2012 and Comet Kohoutek in 1973 break apart and disappear briefly  after they skimmed the sun before coming back in much smaller pieces (Lisse, 2013, December 4, para. 3). 

Twelve NASA spacecraft and the International Space Station have watched Comet ISON since two amateur Russian astronomers first spied it in September 2012.  During the next few weeks, NASA will rely on the data obtained from the observations of these spacecraft to confirm Comet ISON’s status:  If the images show nothing “sizable and stable” then the comet will disappear, but if they detect a nucleus, a much fainter comet and tail will have formed (Lisse, 2013, December 4, para. 4-8). 

NASA’S STEREO spacecraft camera will be searching for bright fragments this week, and NASA’s Infrared Telescope Facility in Honolulu, Hawaii, will be using its telescope to spectroscopically detect the comet.  The recently launched MAVEN spacecraft may also be able to detect ISON next week; and by mid-to late-December, the Hubble and Chandra space observatories will be conducting deep outer space searches for any debris. Then in early January 2014, Spitzer will start to look for ISON (Lisse, 2013, December 4, para. 9). 

However, if ISON acts like a much dissipated comet, it will be very hard to seefrom Earth when it reaches its closest approach to earth on December 26th (Lisse, 2013, December 5, para. 10).

 In the meanwhile, Comet ISON Observing Campaign will hold a post-perihelion workshop at the Johns Hopkins Applied Physics Laboratory on December 6th from 8:30 to 11:30 a.m. EST that can be seen at http://www.livestream.com/cometison (Lisse, 2013, December 4, para. 11).

For further details, go to http://www.isoncampain.org/ison-followup-meeting (Lisse, 2013, December 4, para. 11).

December 3, 2013

Chang, Jon M. (2013, December 3).  Comet ISON may be gone, but not forgotten to scientists.  ABC News.  Retrieved from http://abcnews.go.com/Technology/comet-ison-forgotten-scientists/story?id=21086382

Dean Pesnell, Project Scientist of NASA’s Solar Dynamics Observatory, acknowledges that science still has a lot to learn from the dead remains of Comet ISON (Chang, 2013, December 3, para. 2-3). Although the Solar and Heliospheric Observatory regularly coronagraphs sungrazing comets “every couple of days”, ISON was “unique” since it “originated from outside the solar system”, Pesnell explains (Chang, 2013, December 3, para.4). He also clarifies the reason for the original confusion as to whether the comet had survived its encounter with the sun: “There was a bright knot of material moving away from the sun . . . But people had to wait another day before they saw it wasn’t growing a tail” (Chang, 2013, December 3, para. 5).

 Pesnell speculates that ISON might have broken up even before it reached perihelion since all its water evaporated before this time, and without any of this ice to hold the comet together, it disintegrated.  Pesnell, therefore, likens ISON’s leftovers to a bee swarm—“It’s a bunch of pieces slowly drifting apart from each other” (Chang, 2013, December 3, para. 6-7). Studying these remains, however, can still help astronomers learn the composition of the comet (Chang, 2013, December 3, para. 8). 

Fazekas, Andrew.  (2013, December 3).  Top 5 Comet ISON Questions Answered.  National Geographic. Retrieved from http://newswatch.nationalgeographic.com/2013/12/03/top-5-comet-ison-questions-answered/

Fazekas has rounded you the top five questions readers have been asking about Comet ISON (2013, December 3, para. 1-3).

1)  How big was Comet ISON?

Comet ISON’s nucleus was around 2 to 4 miles, or 3.2 to 6.4 kilometers, across; however, the coma that surrounded the nucleus was 3,100 miles, or 4,989 kilometers across (Fazekas, 2013, December 3, para. 4-5).

2)  Will Earth pass through ISON’s remains?

The rubble that was Comet ISON will continue on its trajectory towards the outer solar system more than 39 million miles, or 63 kilometers away from Earth, but Earth’s orbit may take it into the dust clouds in the comet’s wake in early 2014. The Earth regularly passes through comet trails each year, so most likely no one will notice any difference other than perhaps seeing a handful of shooting stars (Fazekas, 2013, December 3, para. 6-10).

3)  Why did ISON not live up to its “comet of the century” billing?

Researchers theorize that the sun pulled Comet ISON’s nucleus apart and vaporized its frozen water and gases two days before the comet reached perihelion (Fazekas, 2013, December 3, para. 12).

4)  Any chance we can still see Comet ISON in the sky?

On December 2nd, earthbound sky watchers needed binoculars to view ISON’s debris cloud. As time goes on, this cloud of dust will further disperse, so less and less light will reflect off its dust grains. Thus, only experienced astrophotographers are going to have a ghost of a chance of capturing an image of the fading ex-comet (Fazekas, 2013, December 3, para. 13-15).

5)  What do astronomers hope to learn from Comet ISON?

Since ISON started its journey from the Oort Cloud on the outer edge of the solar system, astronomers expect to learn more about the chemical construction of the early solar system and thus indirectly discover what earth was like when it first formed (Fazekas, 2013, December 3, para. 16-17).

Rao, Joe. 2013, December 3.  Fate of Comet ISON Uncertain After Fiery Sun Encounter SPACE.com.  Retrieved from http://news.yahoo.com/fate-comet-ison-uncertain-fiery-sun-encounter-123029309.html

So “the celestial saga continues”, but like yesterday Comet ISON’s “fate is far from certain” (Rao, 2013, December 3, para. 1); or to hit replay--again, the reports of the comet’s death on Thursday of being “sun and done” were “premature”, but by Saturday, all that the spacecraft observatories was a diffuse cloud of dust (Rao, 2013, December 3, para. 2-4).

By Monday, December 2nd, NASA officials admitted that the comet had shrunk in size, but they still couldn’t tell whether what remained was “simply debris” or a “small nucleus of the original ball of ice” (Rao, 20103, December 3, para. 6).  Thus, they were questioning what these remains should look like should they reappear either as only the comet’s head, or coma, or “more likely just a tail” like the “Great Southern Comet of January 1887”(Rao, 2013, December 3, para. 7). Astrophysicist Karl Battams, after admitting that astronomers still don’t know whether ISON will be visible to the naked eye, admitted this won’t happen to the end of next week (9-12).

Anticipating this possibility, Rao has compiled a table for viewing Comet ISON in most northern temperate latitudes (2013, December 3, para. 13-17). Nevertheless, Rao does continue to prove one small item—astronomers and the reporters who cover astronomical events are adapt at punning and word play. 

December 2, 2013

Battams, Karl.  (2013, December 2).  In Memoriam. Comet ISON Observing Campaign (CIOC).  Retrieved from http://isoncampaign.org/karl/in-memoriam

Astrophysicist Karl Battams writes a clever tongue-in-cheek obituary for Comet C/2012 S1, Comet ISON,  4.5 billion BC—December 1, 2013—or there abouts--perhaps (2013, December 2, 2013, para. 1-3).

This is nicely balanced by a Comet ISON Observing Campaign has announced, “We are having an informal post-perihelion Comet ISON Workshop follow-up meeting on Dec 6, 2013” (http://isoncampaign.org/).  

Fuller-Wright, Liz. (2013, December 2). Did Comet ISON just ruin Christmas?  Christian Science Monitor.  Retrieved http://www.csmonitor.com/Science/2013/1202/Did-Comet-ISON-just-ruin-Christmas

Now that astronomers are questioning whether Comet ISON can still be classified as a comet, Fuller-Wright has written a comic poem that bears a resemblance to Clement Moore’s famous poem "A Visit from St. Nicholas" since the ISON’s debris will be closest to Earth on December 26 (2013, December 2, para. 1).  Readers will need to click on the Christian Science Monitor link above to read her entertaining doggerel in full, but the first, third, ad last stanzas deserve repeating:

'Twas the month before Christmas,

And all through the land,

Star-spotters were searching

For a comet so grand.

On SOHO! On STEREO!

On Earth-based observers!

But no glowing comet

Showed up on our servers.

We all held our breath

As it flew out of sight,

But we'll never see ISON

Light up a dark night.

To summarize:  NASA’s experts “are still uncertain about ISON’s fate, but by now it’s likely “only dust”, and whatever has survived won’t be visible to the naked eye.  As for all the hype, “ISON peaked early” (Fuller-Wright, 2013, December 2,  para. 3-5).

Mack, Eric. (2013, December 2).  Top Comet ISON watcher calls space rock officially DOA.  Cnet.com. Retrieved from http://news.cnet.com/8301-17938_105-57614223-1/top-comet-ison-watcher-calls-space-rock-officially-doa/

Mack notes that Karl Battams of the U.S. Naval Observatory has posted an obituary for ISON: “Tragically, on November 28, 2013, ISON’s tenacious ambition outweighed its ability, and our shining green candle in the solar wind began to burn out”, adding that NASA continues to investigate by ISON is “likely . . . only dust” (2013, December 2, para. 2 & 5).  Battams thus simultaneously provides an example of the literary trope known as personification, or endowing a non-living object with human traits, while evoking memories of Elton John’s tributes to Marilyn Monroe and Diana, Princess of Wales in the lyrics to “A Candle in the Wind”. 

Mack then goes on to give a play-by-play event of sightings of Comet ISON following its perihelion on Thursday: When solar observatories failed to find any images of ISON for several hours, astronomers concluded that the sun had vaporized it, but a few hours later, upon detecting images of a small nucleus, they retracted their original statement only later to pronounce ISON’s demise (Mack, 2013, December 2, para. 6-8).  Of course, Mack’s analysis runs counter to a Space.com report written by Joe Rao and posted on December 3rd that also attributes to Battams the admission that astronomers won’t know for certain whether the comet’s remains will be visible to the naked eye until sometime next week. 

MacRobert, Alan. (2013, December 2).  So It Ends for Comet ISON.  Sky and Telescope. Retrieved from http://www.skyandtelescope.com/news/So-It-Ends-for-Comet-ISON-234123671.html

Comet ISON turned out to be a “dud”, but in the meanwhile Web traffic “spiked through the roof” on Sky and Telescope’s Web page on November 27^th and November 28^th, and the Internet users’ “real-time” interest in science reached an all-time high thanks to the Comet ISON Observing Campaign team (MacRobert, 2013, December 2, para. 1-2).

To recap:  For most of 2013, Comet ISON “underperformed”, but from mid to late November its magnitude drastically brightened until just before Comet ISON skirted the sun’s corona, ISON’s coma brightened and flared to a -2 magnitude whereupon it shrank into “insignificance”.  Then upon reaching perihelion, Comet ISON failed to show before the Solar Dynamics Observatory’s extreme-ultra-violet cameras, or as MacRobert summarizes, “I was on the verge of titling an update “ISON Now ISOFF” (MacRobert, 2013, December 2, para. 3-6).   Then out from behind the sun came a headless stream of “dust and rubble” that revitalized long enough to make scientists wonder if Comet ISON would put on a big show after all before it steadily faded (MacRobert, 2013, December 2, para. 7-8). 

As of Monday, ISON’s “ghost” has a magnitude of +8 and is at least one-half° wide at its brightest part (MacRobert, 2013, December 2, para. 9). However, earth-bound astro-photographers as well as the Hubble Space Telescope may still manage to capture some faint images of the comet come mid-December (MacRobert, 2013, December 2, para. 12). 

P. S. -- The consolation prize: Comet Lovejoy (C/2013 R1) is now visible through binocular in the northeastern sky before dawn. 

December 1, 2013

Chang, Kenneth. (2013, December 1). Comet, thought dead but found alive, is now fading away, astronomers say. Space & Cosmos. New York Times.  Retrieved from http://www.nytimes.com/2013/12/02/us/comet-thought-dead-but-found-alive-is-now-fading-away-astronomers-say.html?partner=rss&emc=rss&_r=0

Last Thursday, Comet ISON vanished and then“blazed back to life”, but now it is fading from view.  Thus, the Associate Director for Science of the Heliophysics Division of the NASA Goddard Space Flight Center in Greenbelt, Maryland, C. Alex Young admitted, “I think for the most part it’s dead . . . The folks are finally pretty confident that’s the case” (Chang, 2013, December 1, para. 2).     

Comet ISON’s resurrection didn’t last long since by Sunday it was already so faint that experts predicted that its debris won’t be visible to the naked eye when it passes near Earth later this month.  After spending the weekend observing Comet ISON at the Kitt Peak National Observatory in Arizona, Karl Battans, who is an astrophysicist at the Naval Research Laboratory, noted, “I really don’t think there’s a whole lot left” (Chang, 2013, December 1, para. 5-6).  

According to Battams, Comet ISON most likely broke apart even before its closest approach to the sun, but after the comet had already rounded the sun, it was difficult to determine whether the comet at one time possessed a small nucleus that the sun has vaporized, for it could have just as easily have been a “cloud of dust (Chang, 2013, December 1, para. 7-9).  Analysis of Comet ISON’s journey will takes weeks and months to complete; and ironically, its disintegration will give scientists better information about its composition and clues as to how the planets formed than an intact comet could have done (Chang, 2013, December 1, para. 11). 

Fazekas, Andrew. (2013, December 1).  Ghost of Comet ISON fading fast.  Star Struck.  National Geographic.  Retrieved from http://newswatch.nationalgeographic.com/2013/12/01/ghost-of-comet-ison-fading-fast/

While Comet ISON’s revival on Thursday raised hopes that its brush with the sun might have only battered it, a missing nucleus proves that the sun’s corona has dealt ISON's nucleus a “fatal blow (Fazekas, 2013, December 1, para. 1-2).

ISON’s fate appeared to be in jeopardy when NASA’s Solar  Dynamics Observatory failed to send back any images as the comet passed within 683,000 miles, or 1.1 million kilometers of the sun’s surface—a mystery that led them to theorize that its nucleus might have broken apart when the sun evaporated the frozen gases within it (Fazekas, 2013, December 1, para. 3).

Several hours later, however, the Solar and Heliospheric Observatory began to document a brightened comet with a fan-shaped tail, but by late December 1st,  evidence begin to accumulate that Comet ISON had disintegrated,  and only a dust cloud remained since new satellite images showed it quickly dissolving (Fazekas, 2013, December 1, para. 4-5). 

Nevertheless, photographers and astronomers using binoculars or telescopes might be able to view the comet's debris before sunrise early in December.  The Hubble Space Telescope ans well as other satellites are--and will be--trying to photograph the comet’s remains as it heads back to the edge of the solar system (Fazelas, 2013, December 1, para. 8-9). 

Plait, Phil. (2013, December 1).  Comet ISON Post Mortem.  Bad Astronomy.  Slate.  Retrieved from http://www.slate.com/blogs/bad_astronomy/2013/12/01/comet_ison_post_mortem.html

As the remains of Comet ISON move away from the sun they are clearly dissipating, putting an end to the many twists and turns of the comet’s tale, for Comet ISON’s behavior puzzled scientists most particularly when it brightened unexpectedly before it approached the sun  (Plait, 2013, December 1, para. 2-3). 

Plait thus offers two videos that might explain what happened:  The first, his own, shows an image of ISON with no discernable nucleus while the second, a low resolution video taken by STEREO A, shows the emission of a sudden flash that might indicate the breaking apart of its nucleus.  At the conclusion of both videos, a cloud of debris “sweep around the comet” is visible. Hubble won’t be able to beam back images of the remains for several weeks(Plait, 2013, December 1, para. 5-8).

November 30, 2013

Boyle, Alan. (2013, November 30). Comet ISON's leftovers fade away, right before a satellite's eyes. Science. NBC News.  Retrieved from http://www.nbcnews.com/science/comet-isons-leftovers-fade-away-right-satellites-eyes-2D11674277

Astronomers can finally declare Comet ISON’s death since although remnants of the comet passed through the Solar and Heliospheric Observatory’s viewing field, the bright spot that remained grew increasingly dimmer (Boyle, 2013, November 30, para. 1-2). Astrophysicist Karl Battams of the Naval Research Laboratory Twittered, “I do think that something emerged from the sun, but probably a very small nucleus or ‘rubble pile,’ and I fear that it may have dissolved” (Boyle, 2013, November 30, para. 3).

Scientists first thought that Comet ISON had disintegrated completely November 28^th, when the Solar Dynamics Observatory failed to pick up any signs of the comet as it was to pass within 730,000 miles, or 1.2 kilometers, of the sun (Boyle, 2013, November 30, para. 4).   But several hours later, the Solar and Heliospheric Observatory picked up a bright spot with a fan-shaped tail that was following the comet’s expected trajectory.  Furthermore, this spot showed up in coronagraphic images from NASA’s STEREO satellites A and B (Boyle, 2013, November 30, para. 5).

These images gave astronomers hope that Comet ISON might be visible by next week, but they now believed that the comet is now only “a dissipating cloud of cosmic dust in the solar wind.”  Friday Battams estimated that the then magnitude +5 comet was fading fast (Boyle, 2013, November 30, para. 5).  Even so, he thought that skilled astrophotographers might possibly photograph ISON’s “Thanksgiving leftovers, or there might be an odds-defying chance that the comet might yet begin to brighten again (Boyle, 2013, November 30, para. 6).

While Comet ISON’s growing dimness might disappoint the public, its journey helped astronomers compile the largest data set about a single comet ever to watch a pristine comet from the Oort Cloud make its first circle around the sun (Boyle, 2013, November 30, para. 7-8). 

Comet ISON current status.  (2013, November 30).  NASA Comet ISON Observing Campaign.  Retrived from http://www.isoncampaign.org/Present

Comet ISON begin to die away in the hours just before it reached its perihelion, so the coronagraph images from the LASCO C2 did not pick up any obvious nucleus, although the comet’s tail remained rather broad and full (Comet ISON, 2013, November 30, para. 1).

Moreover, when Comet ISON actually skirted the sun’s corona neither the ESA Proba-2 SWAP nor the NASA SDO satellite detected any evidence of the comet’s passing (Comet ISON, 2013, November 30, para. 3).  However, after ISON traveled around the sun and for 24 hours afterwards, the LASCO C2 satellite captured a “very diffuse and dusty fan-shaped tail” as well as what could have been a remnant of its nucleus or else a “rubble pile” (Comet ISON, 2013, November 30, para. 4). 

What's up in space.  (2013, November 30).  Space Weather.  Retrieved from http://www.spaceweather.com/

Dodging CMEs:  On the far side of the sun, a bright Coronal Mass Ejection hit Comet ISON with a “glancing blow”.  If it had landed a knock-out punch, this could have revealed the nature of the comet’s “mysterious undead core”(What’s up, 2013, November 30, para.2).

Comet ISON Lives: Comet ISON is now traveling away from the sun after it “revived, sprouted two tails and rapidly brightened”, so it has a chance of becoming a “photographic object in the morning sky on December 2nd or 3rd as a new coronagraph movie from SOHO shows (What’s up, 2013, November 30, para. 2).

Karl Battams, of NASA’s Comet ISON’s Observing Campaign, offers an  hypothesis as to what took place: As ISON “plunged toward the sun, it began to fragment into chunks as shown in SOHO’s coronagraph images.  While actually going through the sun’s outer atmosphere, it continued to vaporize, losing its coma and tail, emerging from behind the sun with a smaller nucleus that has restarted emitting dust and gas. As for now, it’s too soon to know how big ISON’s nucleus now is, or how bright the “resurgent comet” will be (What’s up, 2013, November 30, para. 3 & 5-6). 

However, an HD video comparing the views from both of SOHO’s coronagraphs indicates that a crippled Comet ISON with a “scattered tail” might be visible to the naked eye December 2^nd or December 3rd (Comet ISON, 2013, November 30, para. 8).

November 29, 2013

Byrd, Deborah. (2013, November 29).  Comet ISON down … but not out? EarthSky. Retrieved from http://earthsky.org/space/big-sun-diving-comet-ison-might-be-spectacular-in-2013

After Comet ISON reached its perihelion on Thursday, it supposedly disintegrated, but last night it appeared to be reviving.  Most probably Comet ISON won’t return as the bright comet astronomers predicted, but a faint comet might re-materialize in December skies.  Indeed, Comet ISON’s more-or-less official voice Karl Battams of NASA’s Goddard Space Flight Center, posted the following message Friday evening: “We’re calling it … you heard it here first … we believe some small part of ISON’s nucleus has survived (Byrd, 2013, November 29, para.1-3).

Later, Battam blogged further details, explaining that when Comet ISON didn’t show up in Solar Dynamics Observatory images, astronomers concluded that it “died a fiery death.  Except it didn’t. Well maybe” (Byrd, 2013, November 29, para. 5-6).  Then, a faint “smudge” appeared in Large Angle Spectometric Coronagraph (LASCO) C3* images, and Battam noted, “We are seeing something beginning to gradually brighten up again.  One could almost be forgiven for thinking there’s a comet in the images” (Byrd, 2013, November 29, para. 7-8).  

Accordingly, the astronomer’s working hypothesis is that when Comet ISON “plunged” through the sun’s corona, it lost its coma and tail completely as Comet Lovejoy did in 2011.  But later, it emerged with a small “coherent nucleus” and a tail that is growing back in a repeat of Lovejoy’s performance (Byrd, 2013, November 29, para. 9-11).

Thus, for now:  At least a small part of Comet ISON has survived and “is actively releasing material” (Byrd, 2013, November 29, para. 12).  Battam doesn’t know if a nucleus exists, or if there is, analysis of the coronagraph images can’t tell if and how long that core will last, or the comet's visibility or brightness (Byrd, 2013, November 29, para. 13-15).

Byrd also includes evidence of Comet ISON’s survival in a 35-second, condensed video that blogger Sireen Gonzaga put together from SOHO LASCO C3 images.  Comet ISON appears fainter just after it comes back into sight from around the sun and then brightens as it escapes the sun’s gravity (Byrd, 2013, November 29, para. 4).

*Byrd identifies the camera taking pictures of the sun’s corona as “LASCO C2”, but since several other articles designate the camera as LASCO C3, this is likely a typographical error.  However, the Large Angle Spectometric Coronagraph uses two cameras to take images of the sun’s corona--C2 and C3:  http://www.spaceweather.sflorg.com/current/lasco_c3.html

Faint smudges may indicate Comet ISON survived sun encounter. (2013, November). (AP).  Fox News.  Retrieved from http://www.foxnews.com/science/2013/11/29/faint-smudges-may-indicate-comet-ison-survived-sun-encounter/

After Comet ISON “was initially declared dead” on Thursday after it came within one million miles (1.6 kilometers) of the sun, it may have survived since additional images  analyzed late Friday showed “a streak of light moving away from the sun” (Faint smudges, 2013, November 29, para. 1-2  & 4).

The European Space Agency was backtracking early Friday on its premature pronouncement of Comet ISON’s death on Thursday by noting that it “continues to survive” (Faint smudges, 2013, November 29, para. 6).

When  Comet ISON failed to show up in images from the Solar Dynamics Observatory spacecraft at around noon eastern time (1700 GMT), and then almost four hours later, observations showed “no sign of it whatsoever", astronomers concluded that ISON had broken apart and evaporated (Faint smudges, 2013, November 29, para. 9). Images from other spacecraft observatories, however, showed a “a light streak continuing past the sun” but a NASA physicist originally dismissed this as “a trail of dust continuing in the comet’s trajectory” (2013, November 29, para. 10).

This trail, nevertheless, brightened on Friday suggesting that at least a small portion of ISON survived, although if a solid nucleus still exists, it may not last for long (2013, November 29, para. 11).  In 2011, Lovejoy, a smaller comet, similarly “grazed the sun and survived” only to disintegrate several days later (2013, November 29, para. 12).

Malik, Tariq. (2013, November 29).  Comet ISON gets roasted by sun and vanishes, but did it survive?  Space.com. Retrieved from http://news.yahoo.com/comet-ison-gets-roasted-sun-vanishes-did-survive-145840058.html

“Something” of Comet ISON “it seems—may have survived” after the sun appeared to have vaporized the sun grazing comet on Thursday when it vanished from the view of NASA’s Solar Dynamics Observatory (Malik, 2013, November 29, para. 1-2).  However, late Thursday night, the Solar and Heliospheric Observatory’s LASCO C3.4 camera picked up a “blip” coming around the sun.  The latest LASCO C3 images now see “something” slowly brightening (Malik, 2013, November 29, para. 4-5).

As scientists analyze images of this debris from SOHO and NASA’s twin STEREO, they are reassessing their earlier observations, even though they always knew that the sun’s gravity and solar wind might destroy the comet’s less than a mile nucleus when it came within 684,000 miles, or 1.1 million kilometers, of the sun’s surface on Thursday (Malik, 2013, November 29, para. 6-7). As for now, astronomers have no way to estimate the nucleus size based on the images from SOHO or STEREO, for it’s simply too early to consider ISON’s resurrection (Malik, 2013, November 29, para. 8). 

Although Comet ISON didn’t live up to its original billing as “the comet of the century” it did brighten enough to be faintly visible to the naked eye as it neared the sun (Malik, 2013, November 29, para. 13). But it will take several days of monitoring to determine if any of the comet survived as well as to forecast what earthbound astronomers will be able to see (Malik, 2013, November 29, para. 15-16).


Perihelion 

November 28, 2013--A Post Game  Perihelion Wrap Up

Barrett, Amanda. (2013, November 28).  Comet ISON: Emerging 'dust tail' catches scientists' eyes. CNN Retrieved from http://www.cnn.com/2013/11/27/us/ison-comet/index.html

Updated 7:27 PM EST, Thu November 28, 2013

Analyzing the images from NASA satellites, astronomers note that “something has emerged from the sun after Comet ISON made it closest approach”, but they don’t know if it is Comet ISON since they haven’t discerned any definite nucleus yet, although members of the Comet ISON Observing Campaign’s Facebook page have spotted what may be remnants of the comet's tail (Barrett, 2013, November 28, para. 1-4). However, observers aren’t sure whether the comet’s nucleus is intact (Barrett, 2013, November 28, para. 7). 

Barnett, Amanda.  (2013, November 28, 2:09 CST).  Comet ISON likely destroyed by sun:  If ISON survived, comet will make its closest approach to Earth Dec. 26.  KCCI (CNN).  Retrieved from http://www.kcci.com/news/national/Comet-ISON-likely-destroyed-by-sun/-/9357144/23195012/-/e7vqh0/-/index.html

Never mind all the build up, Comet ISON disappeared completely from the view of space telescopes during its brush with the sun and most probably “has not survived the journey”, fragmenting into pieces, whereupon the sun evaporated it, according to the professional astronomers taking part in a NASA Google Hangout (Barrett, 2013, November 28, para. 1-4).

Along with the observers on a Google Hangout Web site watching Google fizzle instead of emerging from its plunge into the sun's corona, an international fleet of spacecraft, including NASA’s STEREO, the Solar Dynamics Observatory, and the European Space Agency/NASA SOHO, were near the scene when Comet ISON faded into oblivion (Barrett, 2013, November 28, para. 5-6).

Scientists are interested in observing comets reach their perihelion since when the sun acts upon these conglomerations of frozen gases and rocks, this violent encounter might impart clues about the composition of the solar system (Barrett, 2013, November 28, para. 7-8).  Russian astronomers Vitali Nevski and Artyom Novichonki  first spotted ISON while using a telescope near Kislovodsk, Russia, that is part of the International Scientific Optical Network, thus bequeathing C/2012S1 the name of ISON From then on, when ISON was still 584 million miles away, telescopes have been trained on the comet (Barrett, 2013, November 28, para.7-8).

Howell, Elizabeth. (2013, November 28). Is Comet ISON Dead? Astronomers Say It’s Likely After Icarus Sun-Grazing Stunt.  Universe Today.  Retrieved from http://www.universetoday.com/106813/is-comet-ison-dead-astronomers-say-its-likely-after-icarus-sun-grazing-stunt/

Update, 6:30 p.m. EST: Phil Plait'S blog on Slate summarizeD the comet’s fate--debris will most likely continue to show up in images.

Update, 4:40 p.m. EST: The European Space Agency, quoting SOHO scientist Bernhard Fleck, Twittered that the comet is gone. Separately, the Naval Research Laboratory’s Karl Battams posted that recent observations show debris, but not a nucleus.

Update, 3:56 p.m. EST: Experts are divided as to whether the left overs of ISON’s tail have shown up, or the comet’s nucleus itself.

More than an hour after Comet ISON made its closest approach to the sun around 1:44 p.m. EST, no observations had spotted the comet, but it will take several hours before NASA can give its opinion as to what Comet ISON’s fate is, but astronomers theorized that the comet broke up when it trespassed into the sun’s outer-most atmosphere (Howell, 2013, November 28, para. 1-2).

Even as the comet approached its perihelion, astronomers voiced skepticism that it had survived, Phil Plait pointing out that the ISON’s nucleus already appeared dimmer than its tail in the images from NASA’S Solar and Heliospheric Observatory (SOHO) space craft, which most likely signified that is was disintegrating. Both Plait and Battams agreed that ISON is an “ex-comet” (Howell, 2013, November 28, para. 4-5).  However, since the Solar Dynamic Observatory and SOHO ordinarily survey the sun instead of looking for comets, they at first said it would take more image processing to determine what happened, but eventually both astronomers admitted that the comet hadn’t survived (Howell, 2013, November 28, para. 6).

Scientists, all the same can still learn a lot from the remaining debris since ISON came from the Oort  Cloud. Therefore, it might be able to tell them about the solar system’s origins (Howell, 2013, November 28, para. 7).   Additionally, Battams comment upon ISON’s continual unpredictability (Howell, 2013, November 28, para. 8). 

Jansen, Bart. (2013, November 28, 3:51 EST).  Comet ISON doesn't appear to survive trip around sun. USA Today.  Retrieved  from http://www.usatoday.com/story/news/nation/2013/11/28/comet-ison-nasa/3776419/

NASA’s telescopes captured Comet ISON skirting the sun’s corona, but they didn’t pick up any evidence that it has emerged on the other side.  However, researchers will continue to look for debris, reviewing images from the eleven telescopes from around the world that tracked the comet.  Experts nevertheless are reluctant to sign Comet ISON’s death certificate if a comment from Karl Battams of the Naval Research Laboratory, is any indication:  “Let's at least give it a couple of more hours before we start writing the obituary.” (2013, Jansen, 2013, November 28, para. 1-3 & 23).

Not that  Comet ISON’s initial encounter with the sun lacked witnesses: When looking at an image  that the Solar and Heliospheric Observatory had taken at 12:24 p.m.,  astronomer Phil Plait said, “That to me looks like the nucleus broke up"  A little later, when ISON approached its perihelion at 1:48 p.m. ET, the comet’s coma had faded, and its tail had became fuzzier.  But even though the Solar Dynamic Observatory satellite shifted to watch the comet reappear on the other side, Comet ISON never emerged, This created a mystery since even if the comet broke up, its debris should have been visible in the sun’s magnetic field for 45 minutes  (Jansen, 2013, November 28, para. 13 &16-18).

However, even if Comet ISON has met its fate, it has given scientists “a very rare opportunity to see how the oldest objects in the solar system” like Comet ISON straight from the Oort Cloud, interact with the sun’s magnetic field (Jansen, 2013, November 28, para. 4-6).   

November 28, 2013--Before Comet ISON's Perihelion

Byrd, Deborah. (2013, November 28).  Experience Comet ISON’s encounter with the sun online. EarthSky.  Retrieved from http://earthsky.org/space/how-to-experience-comet-ison-closest-to-sun-perihelion-november-28

Byrd rates the Web sites where amateur astronomers can witness the star-grazing Comet ISON the moment it reaches its perihelion at 18:44 UTC, or 1:44 p.m. EST, (1:44 CST):  Although the comet is temporarily lost from view for earth-bound because of the glare of the sun, they can link into NASA’s SDO page at that time (Byrd, November 28, para. 1-3). SDO’s real time images will let viewers see Comet ISON from its closest approach as it will appear to travel above the sun (Byrd, November 28, para. 5 & 7).

Computer users can also participate it a Google hangout from 1:00 to 3:30 p.m. EST or 18:00 to 20:30 UTC in the company of professional astronomers Phil Plait, C. Alex Young, W. Dean Pesnell, and Karl Battams as everyone views a live feed from NASA’s SOHO satellite and from the Kitt Peak Observatory Telescope (Byrd, November 28, para. 4).  

Even though NASA launched twin Solar Terrestrial Relations Observatory (or STEREO) spacecraft in 2006, only STEREO B will be observing ISON travel across the face of the sun.  To view STEREO B’s transmissions, watch for images from SECCHI (Byrd, November 28, para. 6 & 8). STEREO B's full resolution data will be delayed, but its lower-resolution should be available in full time (Byrd, November 28, para. 9). SOHO’s coronagraphs should also document Comet ISON when it passes through its view field (Byrd, November 28, para. 10). The x-ray telescope of the JAXA/NASA Hinode mission spacecraft will also be aimed at Comet ISON for about 55 minutes during its perihelion, although its Web page doesn't mention any way for Internet viewers to see its transmissions in real time (Byrd, November 28, para. 14).

Several things may happen to ISON when it’s closest to the sun: 1) The sun’s gravity may disintegrate the comet; 2) the sun’s heat may boil off so much of the comet’s icy nucleus that it “falls to pieces”; or 3) the comet’s nucleus will survive, thus enabling Comet ISON to brighten the sky before dawn in early December and in the evening in the second half of December (Byrd, November 28, para. 17-19).  Beginning the last half of December,however, Comet ISON will dim as it heads out of the inner solar system (Byrd, November 28, para. 15-16).

Bottom line: Byrd favors the SDO Web site for viewing Comet ISON reach perihelion, followed by SECCHI’s Web page (Byrd, November 28, para. 21). 

Rao, Joe. (2013, November 28). An observer's guide to Comet ISON's Thanksgiving sun encounter.  Space.com.  Retrieved from http://www.foxnews.com/science/2013/11/28/comet-ison-thanksgiving-sun-encounter-observer-guide/

Rao gives some last minute advice before amateur astronomers go “comet hunting” since Comet ISON will fly within 730,000 miles of the sun today and then reach its “greatest brilliance” in December (Rao, 2013, November 28, para. 1-3).

Admittedly, however, ISON’s recently growing brightness has left astronomers puzzled particularly when they compare comet’s sudden flare up on November 13^th with its previous “sluggish pace”. Then, between November 13 to 21, the comet brightened by 3.5 magnitudes while its nucleus released elevated rates of dust and gas (Rao, 2013, November 28, para. 4-5).

Thus, recent, world-wide observations give veteran “comet watchers” the hope that Comet ISON might end up being ranked one of the brightest comet of the last half century, so much so that at its brightest, Comet ISON might be visible during the day.  However, exactly how bright Comet ISON will appear will depend upon whether sky gazers are looking at it in the city or the country (Rao, 2013, November 28, para. 6-9).

As for when Comet ISON reaches its perihelion on November 28, at 1:38 p.m. EST, its brightness will intensify dramatically, although science cannot predict how bright it will become.  However, if the sun’s gravitational forces fracture the comet, this would heighten ISON’s brightness as well as the luminosity of its tail (Rao, 2013, November 28, para. 10).

As Comet ISON circles around the sun at 234.62 miles per second or 844,632 miles per hour, it will appear closest to the sun just before 2 p.m. EST, even though looking directly at the sun will burn the eye’s retina.  This makes the computer the safest place to view Comet ISON’s progress from the Large Angle and Spectrometric Coronagraph Experiment (LASCO) on the SOHO spacecraft. ISON should be within LASCO’s field of view from 7 a.m. EST (1200 GMT) on Nov. 27 to 7 p.m. EST on Nov. 29 by logging on to NASA’s SOHO Web site: http://sohowww.nascom.nasa.gov/data/realtime/c3/512/ (Rao, 2013, November 28, para. 11-13).

Rao finishes up by furnishing Comet ISON’s expected itinerary until January 10, 2014 (Rao, 2013, November 28, para. 15-24). 

Building up to an Anti-Climax


November 27, 2013

Clark, Stuart (2013, November 27).   Comet Ison to light up morning skies in the run-up to Christmas. The Guardian. Retrieved from http://www.theguardian.com/science/2013/nov/25/comet-ison-astronomy-uk-sun-stargazing-christmas-december

Comet ISON will light up the pre-dawn skies until mid-December if it outlasts its coming within 720,000 miles, or 1158727.6800000002 kilometers, of the sun’s surface tomorrow when the sun will heat the comet to about 4892° Fahrenheit (2,700° Celsius). But by Christmas Day, it will likely be too faint to see with the naked eye (Clark, 2013, November 27, para. 1-3).

Comet ISON unexpectedly increased in brightness this past weekend, making it visible to the naked eye over the weekend.  While this delighted astronomers, it also increased their fear that the comet is disintegrating (para. 4-5).

Even so, although astronomers class ISON as a “star-grazing” comet, it won’t pass as near the sun when it reaches its perihelion as Comet Lovejoy did in December 16, 2011, when that comet came within 85,000 miles, or 1.3679e+5 kilometers, of the solar surface, coming away with very little of its 0.3 mile wide (0.4828032 kilometer wide) nucleus left.  Comet ISON, by comparison, is approximately two miles, or 3.218688 kilometers, wide (Clark, 2013, November 27, para. 7-9).  

Thus, John Brown, Regius Professor of Astronomy at the University of Glasgow, says, “I’m not a gambling man but if I had to bet a fiver, I’d say ISON will survive” (Clark, 2013, November 27, para. 10).  Nevertheless, the sun’s gravitational pull and its solar winds could still drastically erode fragments from Comet ISON’s nucleus, which would only make the tail more “spectacular” (Clark, 2013, November 27, para. 11).

Space-based observatories will continuously monitor Comet ISON while it will be lost from sight on earth for the next several days, but if the comet survives, it will reappear the first and second weeks in December with a “well-developed tail . . . pointing straight up” in the eastern sky before dawn (Clark, 2013, November 27, para. 12-14).  As Christmas Day nears, a possibly fading Comet Ison will then rise earlier and earlier in the morning sky (Clark, 2013, November 27, para. 15).  At the same time, a difficult to spot Comet ISON will be visible in the western sky at twilight (Clark, 2013, November 27, para. 16).

Alan Fitzsimmons, from the Astrophysics Research Center at Queen’s University, Belfast, believes that a close observation of such an acclaimed comet will help determine its chemical and physical make up, by he also would like to see the comet since “it’s been 16 years since the last one, Comet Hale-Bopp and it’s about time for another” (Clark, 2013, November 27, para. 17).

Gannon, Meagan. (2013, November 27).  What Happens When a Comet Loses Its Tail? Mashable.com.  Retrieved from http://mashable.com/2013/11/27/comet-ison-thanksgiving/

Science can’t forecast if any Coronal Mass Ejections (CME) will erupt when Comet ISON comes closest to the sun on Thursday, but since the comet will graze the sun’s outer atmosphere, this ejected, electro-magnetically-charged plasma might damage the comet (Gannon, 2013, November 27, para. 1-2).

In 2007, as Comet Encke similarly reached its perihelion, a CME struck the comet, tearing off its tail as an animated video shows: http://www.space.com/23723-can-comet-ison-s-tail-survive-solar-storm-video.html (Gannon, 2013, November 27, para. 3-4). 

Comet ISON, whose orbit takes it 30 times closer to the sun than Comet Encke’s did, could also have its tail clipped particularly since the sun is now at the peak of its 11-year solar weather cycle.  During this time, sunspots increase, and this upsurge, in turn, increases the chance of CME’s (Gannon, 2013, November 27, para. 5-7).

Additionally, Comet ISON trajectory will take it over the sun’s equator where there is “a recently active cluster of sunspots” (Gannon, 2013, November 27, para. 8).  However, the gas inside this magnetized bubble of plasma isn’t that dense.  Therefore, it probably wouldn’t be strong enough to tear apart the comet’s nucleus, but it could pull off the comet’s tail (para.10).  Any CME’s that might potentially slam into ISON would have much stronger magnetic fields than the CME that clipped Comet Encke’s tail, however, so astronomers can’t predict what will happen (Gannon, 2013, November 27, para.11-12).

STEREO-A's Heliospheric Imager currently has both Comet ISON and Comet Encke in its field of view, ‘their tails waving back and forth with the solar wind”, so if a CME hits both comets, researchers can contrast the reactions of the two comets (para. 13).  NASA’s solar observatories, including STEREO-A and STEREO –B, the Solar Dynamic Observatory (SDO), and the Solar and Heliophysics (SOHO) will be watching the comet when it reaches perihelion (Gannon, 2013, November 27, para. 13).

Malik, Tariq.  (2013, November 27). Comet ISON Nears Sun for Thanksgiving Encounter in NASA Video.  SPACE.com. Retrieved from http://news.yahoo.com/comet-ison-nears-sun-thanksgiving-encounter-nasa-video-115928783.html

NASA’s STEREO-A spacecraft has taken the latest video of Comet ISON.  Taken from the spacecraft’s Heliospheric imager, it shows ISON, Mercury, Comet Encke, and Earth from November 20 to November 25, 2013 (Malik, 2013, November 27, para. 1-3).

Scientists have labeled Comet ISON a “sungrazer” because its orbit brings it extremely close to the sun.  In the video, Comet ISON is the brighter dot with a tail while Comet Encke is a somewhat fainter speckle:  http://www.space.com/23752-best-yet-comet-ison-footage-from-stereo-released-video.html (Malik, 2013, November 27, para. 4-5).

On Thursday, a large contingent of international spacecraft will be tracking Comet ISON as it reaches perihelion.  Not only are scientists interested in the comet because of its potential brightness, but also because Comet ISON comes the Oort Cloud, making it “a pristine sample of the raw ingredients” that make up the solar system. That means both earth-bound and space-based observatories, including the Hubble Space Telescope and NASA spacecraft orbiting Mars and Mercury, have been following Comet ISON’s journey since two amateur Russian astronomers first spotted it in September 2012 (Malik, 2013, November 27, para. 6-8).

Computer users can join this group of comet watchers on Space.com when NASA holds a Google Hangout from 1 p.m. to 3:30 p.m. EST (1800 to 2030 GMT) to steam live views of the comet as it comes closest to the sun (Malik, 2013, November 27, para. 9). 

Sesana, Laura. (2013, November 27). 10 ways to increase your chances of seeing Comet ISON.  Washington Times. A World in Our Backyard. Retrieved from http://communities.washingtontimes.com/neighborhood/world-our-backyard/2013/nov/27/10-ways-increase-your-chances-seeing-comet-ison/

Sesana offers readers ten ways readers can enhance their changes of viewing the “Comet of the Century” (Sesana, 2013, November 27, para. 1-2), including some that other columnists haven’t mentioned in detail:

Backyard astronomers can keep up with time by calculating sunrise through the following link http://www.timeanddate.com/worldclock/sunrise.html (Sesana, 2013, November 27, No. 1, para. 3)

They can also determine if their sky will be clear here: http://cleardarksky.com/csk/ (Sesana, 2013, November 27, No. 2, para. 4).

Comet Watch is also a free app that tells comet watchers where to look: https://itunes.apple.com/us/app/comet-watch-powered-by-distant/id710273903?mt=8 (Sesana, 2013, November 27, No. 4, para. 6).

While the exact moment at which Comet ISON will reach perihelion is on November 28, 2013, at 18:37:45 (1:37 EST, 12:37 CST). Several Websites will broadcast this moment live (Sesana, 2013, November 27, No. 5, para. 7-8).

Meanwhile, CIOC regularly posts updated news on ISON: http://isoncampaign.org/Present  (Sesana, 2013, November 27, No. 8, para. 10).

Comet ISON 2013 shows a live feed, giving up to the second information on Comet ISON’s speed, distance from the sun, distance from the Earth, and estimated magnitude: http://www.cometison2013.co.uk/perihelion-and-distance/ (Sesana, 2013, November 27, No. 8, para. 10).

Sesana's post  certainly proves the cliché "there's an app for that" when it comes to Comet ISON coverage.

November 26, 2013

Chang, Kenneth. (2013, November 26).  Comet Nears Sun, Offering Planetary Clues.  New York Times.  Retrieved from http://www.nytimes.com/2013/11/27/us/comet-nears-sun-offering-planetary-clues.html

When Comet ISON grazes the outer atmosphere of the sun on Thursday,  it will give scientists a look at the components that make up planets.  Carey M. Lisse, a senior researcher at the Applied Physics Laboratory at Johns Hopkins University, thus calls ISON “a dinosaur bone of solar system formation" (Chang, 2013, November 26, para. 1-3).

If ISON comes away from this close encounter with the sun intact, and many experts like Lisse believe it won’t, it might make “a bright and striking addition” to the early December sky before sunrise or after sunset\, but even if it doesn’t survive, it will provide scientists with invaluable information both because of ISON’s age and the distance it has come (Chang, 2013, November 26, para. 4).

Comet ISON is different from most of the “sun grazing” comets that have appeared in recent years because astronomers hypothesize that it came from the Oort Cloud on the edge of the solar system, most probably dislodged by the gravitational “nudge” of a passing star that sent the comet on a path that ultimately took it into the inner solar system (Chang, 2013, November 26, para. 5-6).

From that time onward, the Hubble Space Telescope and the Mars Reconnaissance Orbiter have been monitoring the comet.  ISON’S original brilliance when astronomers  first spotted it led some scientists to suggest that Comet ISON would “rival the brightness of a full moon”, but when  ISON passed Mars’ orbit, photographs showed that it was only about a mile wide.  However, because ISON came from so far away, astronomers have been able to organize  a welcoming party of orbiting observatories (Chang, 2013, November 26, para. 7-10).

Infrared photos taken by NASA’s Spitzer Space Telescope show a large envelope surround ISON’s nucleus; consequently, Lisse theorizes that carbon dioxide rather than carbon monoxide may have been a very fundamental molecule in the early solar system.  Close observation of ISON’s tail is also revealing the usually invisible movements of the solar wind (Chang, 2013, November 26, para. 11-12).

During the last week, ISON has alternated between brightening and dimming, leading some astronomers to posit that it has already disintegrated.  But even if this has happened, or is happening, ISON’s fragmentation could help scientists learn how fine dust particles merge to form even larger particles that eventually come together to create comets.  By witnessing how ISON comes apart, researchers can reverse engineer how it came together (Chang, 2013, November 26, para. 13-15). 

Fazekas, Andrew. (2013, November 26).  Comet ISON Cliffhanger.  Star Struck.  National Geographic. Retrieved from http://newswatch.nationalgeographic.com/2013/11/26/comet-ison-cliffhanger/

Astronomers are debating just what is happening to Comet ISON as it races toward the sun since latest observations show a “dramatic drop” in the comet’s release of hydrogen cyanide gas from within the comet's nucleus.  These emissions, however, have substantially waned in the past week, perhaps hinting that the comet’s nucleus has started to disintegrate (Fazekas, 2013, November 26, para.1-4). 

Even so, astronomers haven’t written Comet ISON’s obituary quite yet since comets often behave unpredictably (Fazekas, 2013, November 26, para. 5-6).  Today, NASA gave ISON an up to a 40 percent chance of surviving and also speculated that even if its nucleus does disintegrate, it still could display a visibly long tail in early December (Fazekas, 2013, November 26, para. 5-7). 


At exactly the time ISON is scheduled to slingshot around the sun on November 28th, NASA will host a live Google+ Hangout with comet experts from 1 p.m. to 3:30 p.m. EST (18:30–20:00 UT).  “Fire vs. ISON – the Epic Battle Live” will allow users to ask scientists questions and track the comet live through streaming images beamed back from NASA’s Solar Dynamics Observatory (SDO) spacecraft (Fazekas, 2013, November 26, para. 10). 

Howell, Elizabeth. (2013, November 26). Where to catch the best views of Comet ISON.

Mother Nature Network (MNN).  Retrieved from http://www.mnn.com/earth-matters/space/stories/where-to-catch-the-best-views-of-comet-ison

The best places to view Comet ISON are those away from city lights, with clear skies, low humidity, and a low eastern horizon with no trees, building or mountains blocking the view—in the United States, that means come December observers are heading for higher elevations in the American southwest or other out-of-the-way locations (Howell, 2013, November 26, para. 1-3).

Great Basin National Park in Nevada and Bryce Canyon National Park in Utah are ideal spots for observing ISON.  Moreover, Bryce Canyon hosts regular astronomy nights during the winter in the company of an expert guide (Howell, 2013, November 26, para. 5).  In the East, Appalachian State University Dark Sky Observatory might catch some unobstructed views of ISON if the sky is clear.  The Harvard-Smithsonian Center for Astrophysics Observatory in Cambridge, Massachusetts, and the Griffith Observatory in Los Angeles, although near city lights might offer visitors the opportunity to look at Comet ISON (Howell, 2013, November 26, para. 6-7).

Wall, Mike. (2013, November 26). Last glimpse of Comet ISON before Thursday encounter with sun.  Space.com. Fox News.   Retrieved from http://www.foxnews.com/science/2013/11/26/comet-ison-spotted-by-mercury-probe/

Wall’s article features photos taken recently by an unnamed NASA probe as well as NASA’s STEREO –A probe on November 21st, and the Messenger spacecraft orbiting Mercury on November 19th, making these images the last ones available for inspection before Comet ISON brushes by the sun on Thursday (2013, November 26, para. 1-3).

For the last month, Messenger’s scientific instruments have examined both Comet ISON and Comet Encke to determine the comet’s structure and makeup, even though engineers didn’t design the spacecraft with comets in mind (Wall, November 26, para. 4-5). Although Messenger will continue to watch Encke in early December, after Tuesday, ISON will be too close to the sun for Messenger to monitor it (Wall, November 26, para. 6). 

At that time, the international scientific community will concentrate its energies on obtaining different views of Comet ISON as it comes closest to the sun: STEREO-B will watch the comet from Tuesday through Friday while the NASA/European Space Agency (ESA) spacecraft SOHO will witness ISON’s movement from Wednesday through Saturday. Additionally, NASA’s Solar Dynamics Observatory (SDO) and Japan’s Hinode probe will follow ISON as it reaches perihelion on Thursday (Wall, November 26, para. 7-8).

All these space-based observatories will have slightly different views, but only STEREO-B will actually document Comet ISON transit across the face of the sun.  From SDO’s viewpoint, ISON will appear to travel above the sun since SDO’s instruments will paradoxically point away from the sun’s center for three hours on November 28th, to find a better view (Wall, 2013, November 26, para. 9-10).  Because Comet ISON is a “relatively pristine comet”, fresh from the Oort cloud, it “could put on a great show” if it survives its encounter (Wall, 2013, November 26, para. 11). 

November 25, 2013

Comet ISON's Current Status. (2013, November 25).  Comet ISON Observing Campaign (CIOC).  NASA.  Retrieved from http://isoncampaign.org/Present

CIOC reports that “We are seeing reports online that molecular emission from the comet has fallen dramatically, meanwhile dust production seems to be enormous. What this could indicate is that the nucleus has completely disrupted, releasing an enormous volume of dust while significantly reducing emission rates. Fragmentation or disruption of the nucleus has always been the highest risk factor for this comet so if this has indeed happened then while unfortunate, it would not be a surprise” (2013, November 25, para. 1). 

CIOC, however, cautions, that astronomers need to continue to observe ISON to verify these observations because they have never studied before studied a “dynamically new sungrazing comet, fresh from the Oort Cloud” this near perihelion (2013, November 25, para. 2).  Meanwhile NASA’s STEREO-A spacecraft is “returning some amazing views of both comets ISON and Enecke (CIOC, 2013, November 25, para. 3). 

Plait Phil.  (2013, November 25).  Slate.  UPDATE: Is Comet ISON Heading for Interstellar Space? Retrieved from http://www.slate.com/blogs/bad_astronomy/2013/11/25/comet_ison_pictures_and_info.html

Some terrific photographs and charts along with a rethinking of Comet ISON’s predicted orbut grace Plait’s blog today.  First of all, Plait details the observations of NASA’s STEREO spacecraft that for now are doing the viewing for astronomers: On the far side of the sun, NASA’S STEREO A spacecraft is currently observing ISON, a view from which both Comet ISON and Comet Encke are visible, while STERO B is on earth’s side of the sun (Plait, 2013, November 25, para. 1-3). 

Encke has a 3.3 year orbit and just happens to be near the sun at this point in time.  Encke is also a much larger comet than ISON, measuring five kilometers versus ISON’s 2 kilometers, but it’s much more indistinct.  It’s faintness and its short orbit indicates that it has traveling around the sun many times (Plait, 2013, November 25, para. 4-5).  ISON is now only 15 degrees from the sun, well within Mercury’s orbit.  This proximity makes Comet ISON almost impossible to see from earth (Plait, 2013, November 25, para. 6). All of which, points to some rethinking about Comet ISON’s orbit.

Although last Friday Plait wrote about how Comet ISON’s escape velocity will ensure that this is the only time it will pass by the sun, two competing calculations  made by different groups of astronomers have made him reassess his thoughts (2013, November 25, para. 7).  Most comets travel in elliptical orbits around the sun because they don’t have enough energy, or velocity, to escape the sun’s gravity.  However, it they have enough velocity to get away, their orbit is hyperbolic, or open-ended:  They orbit once around the sun before heading out into deep space (2013, November 25, para. 8). 

Researchers determine a comet’s orbit by making multiple observations of its position into time that they enter into a series of complex equation that solve for the shape of the orbit.  At some point, however, individual astronomers have to decide exactly how to calculate the orbit, and different groups of observers can calculate different shapes (Plait, 2013, November 25, para. 12-13). 

That is what happened this weekend when the International Astronomical Union’s Minor Planet Center (MPC) and NASA’s Jet Propulsion Laboratory came up with different conclusions:  The MPC has calculated that Comet ISON is a hyperbolic comet that will escape the sun forever, but JPL has determined that ISON’s orbit is elliptical, and it will return in 400,000 years (Plait, 2013, November 25, para. 14). 

For now, Comet ISON is moving so close to escape velocity that it may—or may not—escape.  In the meanwhile, the comet is expelling gas that also changes its velocity, and the exact distance at which it passes the sun, makes a difference as well, so astronomers will need to continue to observe ISON to determine its orbit or else humanity will need to wait and see a long, long time (Plait, 2014, November 25, para. 15-16).

Rao, Joe. (2013, November 25).  How to watch Comet ISON's Thanksgiving sun encounter. SPACE.com.  Mother Nature Newtwork (MNN).  Retrieved from http://www.mnn.com/earth-matters/space/stories/how-to-watch-comet-isons-thanksgiving-sun-encounter

Rao recommends viewing Comet  ISON online as it enters the home stretch of its trip around the sun since on Thursday,  it will come within 730,000 miles or 1.2 million kilometers of the sun’s surface (2013, November 25, para. 1-3).  Come December, forecasts predict that ISON will achieve its greatest magnitude, but for now, Rao stresses that viewing a comet during its perihelion phrase is always “hazardous” (Rao, 2013, November 25, para. 4-5).

Until November 14, ISON’s brightening proceeded at a very slow rate, but from November 13 to November 21, it brightened by 3.5 magnitude—a 25-fold increase in brightness that signaled that ISON’s nucleus was releasing much more dust and gas (Rao, 2013, November 25, para. 5-6). All of this has increased the chances that ISON might yet be ranked as one of the brightest comets of the last half century—so much so that it might be visible during the day time (Rao, 2013, November 25, para. 8-9).  However, as previously noted in numerous articles, catching this stellar show depends on viewing it from an open horizon away from urban areas (Rao, 2013, November 25, para. 10).

Astronomers, however, know exactly when Comet ISON will come closest to the sun—November 28^th at 1:38 P.M. EST, or 1838 GMT.  What they don’t know is how bright it will be when it passes the sun, or if the sun’s gravitational forces will splinter the comet into pieces, creating a brilliant tail (Rao, 2013, November 25, para. 11-12). 

Rao thus consuls, “As the comet loops around the sun, and begins its return journey out of the inner solar system, it ‘may’ be dimly visible in daylight by merely blocking out the sun with your hand” (Rao, 2013, November 25, para. 13).  However,  he also issues this warning against viewing the comet this week as it approaches perihelion, “Viewing the comet itself poses no danger, but potential danger lies in staring directly at the sun whose infrared rays can burn the retina of the eye without causing any pain” (Rao, 2013, November 25, para. 14). 

As an alternative, viewers can watch this event on their computer since the Large Angle and Spectrometric Coronagraph Experiment (LASCO) on the SOHO spacecraft should have ISON within its sights from 7 a.m. EST (1200 GMT) on Nov. 27 to 7 p.m. EST on Nov. 29 (0000 Nov. 28 GMT) (Rao, 2013, November 25, para. 15).  Rao then furnishes a schedule of Comet ISON “expected behavior” at ten day intervals for the month of December  through January 10, 2014 (2013, November 25, para. 16-25).

Spotts, Pete. (2013, November 25).   Comet with two tails? Comet ISON could provide fascinating spectacle. Christian Scientist Monitor.  Retrieved from http://www.csmonitor.com/Science/2013/1125/Comet-with-two-tails-Comet-ISON-could-provide-fascinating-spectacle

Comet ISON is headed “deep into the sun’s fiercely hot outer atmosphere, or corona”, where scientists expect that the sun’s magnetic fields and solar wind will produce a change in the comet’s gaseous halo, or coma, and its tail.  By closely observing ISON’s  gaseous tail, scientists hope to discover why the temperature of the sun’s corona at 10,000 °F (5537.7° C), is so much hotter than its surface, or photosphere,  that is only 7,000° F  (3871.1° C) (Spotts, 2013, November 25, para. 1-2).

The heat from the corona makes up the sun’s solar wind, “a persistent flow of charged particles and their associated magnetic fields that travel to the very edge of the solar system” (Spotts, 2013, November 25, para. 3-4).  Ordinarily, solar storms only influence earth by creating auroras. But corona mass ejections can also damage satellites and trigger surges that knock out electrical power grids (Spotts, 2013, November 25, para. 5).  Moreover, scientists theorize that the sun’s solar wind has stripped Mars of  the atmosphere it once had (Spotts, 2013, November 25, para. 6).  

Because solar observatories cannot see beyond the corona as a whole during solar eclipses, astrophysicists ordinarily cannot investigate the interaction between the corona and the magnetic fields on the sun’s surface.  However, by analyzing ISON’s emission of frozen gases after they escape from the comet’s nucleus, they hope to understand more about the corona’s magnetic fields, and they also might be able to track the solar wind carrying off ISON’s ions into interplanetary space (Spotts, November 25, para. 13-14).

As a comet nears the sun, the frozen gases within its nucleus erupt, creating two tails.  Dust particles ejected by these eruptions make up one tail while a second tail forms from the electrically charged, ionized gases discharged from the nucleus and bombarded by the solar wind and the sun's outer atmosphere's magnetic fields (Spotts, 2013, November 25, para, 9).  If researchers can study how these fields change thee ionized gases in ISON’s tail, this will turn the comet into a useful probe of the corona (Spotts, 2013, November 25, para. 10). 

The oxygen ions in the comet’s tail should lay a trail that shows the path the solar wind takes from the sun because these ions aren’t as highly ionized as the oxygen in the corona.  If the solar wind grabs these ions and carries them into the path of sensors currently orbiting the sun, then instruments can evaluate models of how the corona generates solar wind (Spotts, 2013, November 25, para. 15-16). However, the use of comets as probes of the sun’s corona is only two years old since scientists first  tried this in 2011 when C/2011N3 and C/2011W3 (Lovejoy) broached the sun’s corona.  C/2011 N3 vanishing while Lovejoy broke apart as it started to head back into space (Spotts, 2013, November 25, para. 11).

Because C/2011N3 and Lovejoy came too close to the sun, its radiation ionized their oxygen levels to match the corona’s surrounding oxygen, so space-based observatories couldn’t detect a difference in the ions.  This time around, however, scientists hope that ISON will “hang on” to enough of its ionized particles to detect them in the solar wind (Spotts, November 25, para 17-18).  

Parts of the sun (NASA)

November 24, 2013

Kim, Meeri. (2013, November 24).   Comet ISON, if it survives trip around the sun, could bring spectacular sky show. Health and Science.  Washington Post.  Retrieved from http://www.washingtonpost.com/national/health-science/comet-ison-if-it-survives-trip-around-the-sun-could-bring-spectacular-sky-show/2013/11/24/f544103a-53b6-11e3-a7f0-b790929232e1_story.html

As Comet ISON comes closest to the sun on Thanksgiving, November 28^th, solar particles may rip off its tail, or solar radiation and gravitational pressure may tear it apart, or it may survive to put on a “spectacular show”, living up to its early publicity as the “comet of the century” (Kim, 2013, November 24, para. 1-2 & 4). What makes Comet ISON so special is that it comes from the Oort cloud at the very edge of the solar system: Earth is one astronomical unit, or AU, away from the sun, and Pluto is as far away as 40 AU from the sun.  But Comet ISON began its journey 100,000 AU from the earth in this nebulous sphere (Kim, 2013, November 24, para. 6--9).  

Thus, for at least a million years, ISON has been heading for this rendezvous.  On Thursday, it will reach its perihelion when it will come within the atmosphere of the sun’s corona, and then slingshot back out into space.  However, whether it will emerge intact is the question science can’t answer—yet (Kim, 2013, November 24, para. 10-11).Solar radiation might vaporize the comet, either disintegrating it totally, or else Comet ISON might survive initially only to break apart, or the sun could send out a coronal mass ejection that would pull off ISON’s tail.  Whatever happens, space-based and earth bound telescope will be closing observing the comet, documenting any changes in its shape and make up in real time (Kim, 2013, November 24, para. 12-13).

If Comet ISON swings away from the sun in one piece, it probably will be at its brightest the first two weeks of December, the sun reflecting in the wake of ISON’S nucleus a spray of dust, water, and carbon dioxide (Kim, 2013, November 24, para. 14-15).  Additionally, the comet might leave behind some souvenirs; for example, the Leonid meteor shower that peaked last week began as “leftovers of an old comet” (Kim, 2013, November 24, para. 16). 

When astronomers working for the International Scientific Optical Network discovered ISON in September 2012 beyond the orbit of Jupiter, it was shining so brightly, many researchers thought it would be massive.  But observation now verifies that the comet’s mass is only about two kilometers--about the distance from the Capitol to the Washington Monument (Kim, 2013, November 24, para. 17-19).

As Comet ISON closes in on the sun, however, it is becoming increasingly difficult to see. Amateur astronomers should thus wait until the first or second week of December when it should be faintly visible to the naked eye.  Then they can take photos of ISON by using a simple digital camera mounted on a tripod, setting an exposure time of 10 to 30 seconds (Kim, 2013, November 24, para. 21-22).

Will icy comet ISON survive a close encounter with the sun? (2013, November 24).  Fox News.  Retrieved from http://www.foxnews.com/science/2013/11/24/will-icy-comet-ison-survive-close-encounter-with-sun/

For Comet ISON, “the moment of truth comes Thursday—Thanksgiving Day,” for at that time the comet “will either fry and shatter . . . or endure and quite possibly put on a fabulous celestial show.”  However, as of now, astronomers don’t know which will happen (Icy comet, 2013, November 24, para. 1-5).

Should Comet ISON survive this close scrape with the sun’s outermost atmosphere, observers in the Northern Hemisphere will be able to see it with the naked eye; and given its potential, its best is possibly yet to be because this is the first trip through the inner solar system for this comet fresh from the Oort cloud (Icy comet, 2013, November 24, para. 6-8).

As the sun’s gravitational pull draws Comet ISON onward, it travels even faster:  In January, for example, it was traveling at 40,000 miles per hour; and on Thursday, November 21^st, ISON was speeding along at 150,000 miles per an hour, November 28^th, when it will travel within 730,000 miles of the sun’s surface, it will have accelerated to 828,000 miles per hour (Icy comet, 2013, November 24, para. 9-14).

As to fears as to whether Comet ISON endanger earth, its predicted trajectory won’t take it any closer to earth than 40 million miles, or less than half the distance between the earth and the sun (Icy comet, 2013, November 24, para. 15-16).

When Russian astronomers named the comet for the International Scientific Optical Network, in September 2012, Comet ISON officially became C/2012 S1--the 2012 S1, noting the year and month that observers first spotted, and the “C” signifying that it will not come this way again (Icy comet, 2013, November 24, para. 17-18).

NASA’s Deep Impact spacecraft first observed Comet ISON in January from 500 million miles away, and since then a whole fleet of NASA telescopic spacecraft, including Swift, Hubble, Spitzer, Mars Reconnaissance Orbiter, SOHO, Chandra, Messenger, and Stereo, have all witnessed ISON’s journey, documenting its progress, while long after Comet ISON reaches its perihelion, the Maven spacecraft, launched November 20th en route to Mars, will take ultraviolet photos of the comet during the second week of December, (Icy comet, 2013, November 24, 19-23).  

Additionally, last Wednesday NASA launched an ultraviolet telescope that rose 172 miles into the atmosphere before coming down via parachute to get a closer look at ISON than earth-based telescopes can see (Icy comet, 2013, November 24, para. 30-31). 

NASA is also observing Comet Siding Spring, another Oort cloud comet discovered in January by the Siding Spring Observatory in Australian observatory of the same name. Astronomers believe that Siding Spring will pass so close to Mars next October, that its coma will envelop the planet (Icy comet, 2013, November 24, para. 26).

But as to whether Comet ISON’s magnitude will brighten enough for it to live up to its billing as the “Comet of the Century”, researchers should soon know since three spacecraft will be focusing in on ISON as it comes closest to the sun (Icy comet, 2013, November 24, para. 33-34).   

November 23, 2013

Atkinson, Nancy. (2013, November 23).  Say goodbye to Comet ISON (for now):  Timelapse & image gallery.  Universe Today.  Retrieved from http://www.universetoday.com/106674/say-goodbye-to-comet-ison-for-now-timelapse-and-image-gallery/

Earthbound viewers will need to rely on spacecraft to send back images of Comet ISON because it has now entered the sun’s blinding glare. The STEREO spacecraft has already started sending back images while the Solar and Heliospheric Observatory (SOHO) will start doing so  November 27^th.  Then on November 28, the Solar Dynamic Observatory and the x-ray telescope on the Hinode spacecraft will observe Comet ISON as it comes closest to the sun (Atkinson, 2013, November 23, para. 1).   Additionally, readers can keep track of ISON through NASA’S Comet ISON’s Website and the Comet ISON’s Observing Campaign (CIOC) Web site.  On November 28^th, amateur astronomers can also go to a Hangout on Google+ (Atkinson, 2013, November 23).  Interspersed with this information, Atkinson’s article furnishes a galley of ISON’s latest photos.

Links for the viewing sites mentioned in Atkinson’s article are as follows:

• STEREO: http://stereo.gsfc.nasa.gov/

• SOHO: http://sohowww.nascom.nasa.gov/

• Hinode Mission: http://www.nasa.gov/mission_pages/hinode/index.html#.UpE1AeLCprM

• Comet ISON.  NASA: http://www.nasa.gov/ison/#.UpE2L8SkqP9

• CIOC: http://www.isoncampaign.org/

November 22, 2013

Colville, Charles.  (2013, November 22). Ison: The comet of the century.  Science & Environment.  BBC News.  Retrieved from http://www.bbc.co.uk/news/science-environment-25052236

If Comet ISON emerges on the horizon from its encounter with the sun’s corona on December 2, for the rest of the month, viewers in the northern hemisphere might be able to see a tail several millions of kilometers long stretching across the very early morning sky (Colville,  2013, November 22, para. 1-3).

ISON hails from the Oort Cloud on the edge of the Solar System, but what makes it special is that is that it will pass through the corona of the sun when it reaches its perihelion on November 28th (Colville, 2013, November 22, para. 4-6).  When this happens, astronomers are not sure just what the sun’s heat and gravity will do to the comet.  Matthew Knight of the Lowell Observatory in Arizona, nevertheless, suggests three possible scenarios (Colville, 2013, November 22, para. 7):

• ISON could explode when it emerges again if the sun’s gravity pulls one side of the nucleus more strongly than the other side, stretching in apart.  Since comets of two kilometers or under are at most risk of doing this, ISON is in danger (Colville, 2013, November 22, para. 8-10).

• Comet ISON could also just fizzle out after using up all its ice and gases (Colville, 2013, November 22, para. 11-13).

• After ISON passes through the sun’s corona, the sun’s heat could ignite its gases, so ISON could emerge with a truly spectacular tail (Colville, 2013, November 22, para. 14-15).

If ISON survives past November 28th, this will give scientists the change to test several scientific theories:  Astrochemists plan to use spectrometry to analyze the make-up of the frozen gases within ISON’s nucleus and thus discover how the solar system formed 4.6 billion years ago.  They also might be able to analyze the comet’s water signature.  This study could possible back up one of two hypotheses about where earth’s water originated.  Some researchers theorize that water came to earth on comets while others speculate that it collected and came up from below the earth’s surface (Colville, 2013, November 22, para. 16-17).

Biochemists might even be able to observe the chemical precursors of amino acids, or the molecules that form the “building blocks of life” since experiments at NASA’s Ames, California, laboratory have confirmed that these chemical could be created in a hostile environment like a comet’s nucleus (Colville, 2013, November 22, para. 18-19).  Comet of the Century: A Horizon Special airs on BBC Two on Saturday at 2115 GMT (Colville, 2013, November 22, para. 20).

  

How bright will Comet ISON get? New predictions are in! (2013, November 22).  Examiner.com. Retrieved from http://www.examiner.com/article/how-bright-will-comet-ison-get-new-predictions-are-in

A year ago NASA’S  Jet Propulsion Laboratory speculated that Comet ISON might reach magnitude -11.6, making it as bright as a full moon and thus easily seen during the day.  Now less than a week before ISON comes closest to the sun, researchers are making some new predictions, although different experts disagree (How bright, 2013, November 22, para. 1-3).

At the start of November, Comet ISON had reached a magnitude of around +8, but then without warning, it jumped in magnitude by a factor of five, and by November 16^th, ISON had leaped to a magnitude of approximately +5, about the amount of illumination that the naked eye can see.  At this time, observers place ISON’s magnitude at about +4 (How bright, 2013, November 22, para. 4).

After Comet ISON reaches its perihelion on November 28^th, optimistic estimates “push” it to a -11 magnitude. Then again, the sun heat and gravity could disintegrate the comet (How bright, 2013, November 22, para. 4-5). 

 

In the meanwhile,  sky watchers should pencil these dates on the calendar:

• November 23: ISON will pass near the planetary pair of Mercury and Saturn;

• November 28: If Ison survives entering the sun’s corona, it will display a breathtaking tail:

• Early December:  ISON will be visible in the evening and morning skies for observers in the mid-northern hemisphere as well as in the circumpolar region;

• December 26: ISON will be at its closest to earth at 39.6 million miles.

(How bright, 2013, November 22, para. 7-8)

An after-thought: John Bortle on the September 25, 2012 issue of Spaceweather.com, speculated that Comet ISON’s projected path paralleled the journey of the Great Comet of 1680 that was brilliant enough to be seen during the day (How bright, 2013, November 22, para. 9).  

See:  http://www.spaceweather.com/archive.php?view=1&day=25&month=09&year=2012

http://streetsofsalem.com/tag/natural-history/

Gannon, Megan. (November 22). Tails of Comet ISON and Comet Lovejoy Caught in Stunning Time-Lapse Video.  Space.com.  Retrieved from http://news.yahoo.com/tails-comet-ison-comet-lovejoy-caught-stunning-time-123155108.html

Space.com editor Megan Gannon shares a time-lapse video of both Comet ISON and Comet Lovejoy shooting across the sky just before daybreak on November 11th. The two comets look as if they are traveling quickly through the stars since Singapore photographer Justin Ng used a small field of view and long exposures in this 1:35 minute video that covers 50 minutes of imaging time for ISON and 90 minutes of imaging time for Lovejoy, showing both images are slower and faster speeds: http://vimeo.com/79188919 (Gannon, 2013, November 22, para. 1-4). Ng's photos can be found on his website: http://www.justinngphoto.com/  (Gannon, 2013, November 22, para. 9).

Both ISON and Lovejoy are streaking towards the sun, and Comet ISON has “brightened rapidly" recently. So much so that if a viewer has an unobstructed view away from city lights, it’s possible to see it in the southeastern sky before sunrise, although binoculars and telescopes make the image more distinct (Gannon, 2013, November 22, para. 5-6).

Russian amateur astronomers Vitali Nevski and Artyom Novichonok first spotted Comet ISON (a.k.a. C/2012S1) in September 2012.  But Terry Lovejoy, an Australian astronomer, only discovered Comet Lovejoy (C/2013 RI) in  September.  While Comet ISON will be closest to the sun on November 28^th, Comet Lovejoy won’t reach its perihelion until December 22^nd at a distance of 75.4 million miles or 121.4 million kilometers (Gannon, 2013, November 22, para. 7-8).  Ng photographed Comet ISON as it appeared in the constellation  of Virgo while he photographed Comet Lovejoy as it passed the constellation  of  Leo (Gannon, 2013, November 22, para. 7-8).

Joson, Imelda and Aguirre, Edwin. (2012, November 22). Skywatching photo guide: Here's how to capture Comet ISON.  Space.com. Retrieved from http://news.yahoo.com/photograph-comet-ison-skywatching-photo-guide-225424363.html

If Comet ISON outlives grazing the sun on November 28th, it could resurface in the dawn sky in early December as a “spectacular naked-eye subject for photography” (Jonson, 2012, November 22, para. 1). Accordingly,  Imelda Joson and Edwin Aguirre offer some tips for photographing the comet (Jonson, 2012, November 22, para. 2).  First of all, they advise photographers to find an unobstructed view away from city lights, and they also warn them to not to look at the comet directly or through binoculars or a telescope when it is close to its perihelion since looking at the sun without a filter can blind the observer (Jonson, 2013, para. 3-4). 

Jonson and Aguirre also recommend using a digital single-lens reflex camera because it gives more control over exposure settings and allows for the change of lens from wide-angle to medium telephoto--a lens that is necessary to match the length of ISON's tail (2013, November 22, para. 5).  The successful photographer needs to use a tripod or to mount the camera because the exposures will take a least a few seconds (Jonson, 2013, November 22, para. 6). 

To ensure for more control over the camera's focus, switch from auto to manual; this helps to mange not only the focus, but also the camera's aperture, shutter speed, and white-balance settings (Jonson, 2013, November 22, para. 7). Additionally, the camera needs to be set at its highest resolution to capture fine details (Jonson, 2013, November 22, para. 7). 

Instead of focusing on the comet, the photographer should pre-focus the camera on Mars, Mercury, or Saturn, or Spica and then use the camera's Live View feature (Jonson, 2013, November 22, para. 8).  To minimize vibration,  Jonson and Aguirre also suggest  using the camera's lock-up feature before taking each photo as well as operate the shutter with an electronic cable so as not to shake the camera (2013, November 22, para. 9). 

Keeping the exposures short (to at least ISO 800) will stop the comet and its background stars from "trailing" with the earth's rotation, and it will keep the growing brightness of the early morning sky from washing out the photo (Jonson, 2013, November 22, para. 1).  Moreover, if the photographer takes a series of shots at different shutter speeds and/or apertures, this increases the odds of getting a correct exposure (Jonson 2013, November 22, para. 11).

Because cold weather can make a camera battery lose its charge, a prepared photographer double checks to see that the battery is fully charged, and he or she keeps a spare in his or her warm coat pocket (Jonson, 2013, November 22, para. 12). To give the  final photos a sense of scale, he or she also fits some visual elements in the foreground of the camera's frame (Jonson, 2013, November 22, para. 13). 

Binoculars or Telescope Pictures

Since shots that include the comet's tail require a more sophisticated tracking apparatus than just a camera on a tripod, Joson and Aguirre advise the photographer to acquire a more sophisticated tracking apparatus: He or she should use a zoom or telephoto lens with a focal length of 400 millimeters or more and mount the camera or telescope on either a "Polar-aligned, motor-driven equatorial mount or put it on a ball-head mount or a bracket to "piggy back" the camera lens set up to a large telescope to keep everything stable (2013, November 22, para. 14-15). 

Of course, creative photographers do have some options: They can use  the camera's bulb (B) setting to take exposures that are more than 30 seconds or else they can take a series of short exposure that can be "stacked" together digitally, using an image-editing program (Jonson, 2003, November 22, para. 16-17). 

Shooting through a long-focus telescope mounted on an equatorial drive will also help capture close-ups of the comet's coma and tail.  To do so, Jonson and Aguirre advocate attaching the camera with a T-threaded adapter and a T-ring (2013, November 22, para. 18).  An autoguider, or an electronic guiding system, can also  "lock on"  ISON's coma or to a guide star and automatically adjust the telescope's drive system (Jonson, 2013, November 22, para. 19).

November 21, 2012

Dance, Scott. (2013, November 21). Science magazines hosting Comet ISON online Q&A. Baltimore Sun. Retrieved from http://www.baltimoresun.com/news/weather/weather-blog/bal-wx-science-magazines-hosting-comet-ison-online-qa-20131121,0,3316969.story

The editors from Astronomy and Discover magazines will answer them online Thursday. November 21, IN a Google Hangout chat from 3 p.m. to 4 p.m., with editors and experts answering visitors’questions.  RSVP for the event or simply tune in at 3 p.m. (Dance, 2013, November 21, para. 1-3) .  For more information on how to access this seminar, go to http://www.google.com/hangouts/

The magazines, along with the National Science Foundation, are holding a Comet ISON photo contest with three top $2,500 prizes: photos taken with cameras and tripods, through piggyback cameras on telescopes, or through-the-scope photos where a telescope acts as the camera's lens (Dance, 2013, November 21, para. 4).

Plait, Phil. (2013, November 21). 12 Cool Facts about Comet ISON. Slate. Retrieved fro http://www.slate.com/blogs/bad_astronomy/2013/11/21/comet_ison_12_cool_facts.html?wpisrc=burger_bar

Plait gives readers a dozen facts about Comet ISON as well as some ‘gorgeous” photos (2013, November 21, para. 1-2).

1. ISON is a n00b, that’s urban slang for something new: Most comets are regular visitors to the inner solar system, taking an elliptical comet around the sun whenever they pass by; but, Comet ISON, once kicked out of the Oort Cloud, launched into an orbit that’s an open-ended hyperbola.  Thus, ISON has never come this way before, and as a hyperbolic comet, it isn’t coming back again (Plait, November 21, para. 4-6).
2. ISON is a sun-diver: It passes very near the sun, within 1.1 million kilometers or around 700,000 miles (Plait, November 21, para. 7-8).
3. When it passes the Sun, it will be moving at more than 600 kilometers per second: Since Comet ISON comes from far away, as the gravity of the sun draws it nearer, it will be moving at the sun’s escape velocity, 620 kilometers, or 380 miles per second. That’s 0.2 percent of the speed of light (Plait, November 21, para. 9-12).
4. The solid part of ISON is only about two kilometers across: Using estimates taken from the Hubble Space Telescope, astronomers have estimated that Comet ISON’s nucleus, or its solid core, is two kilometers or 1.2 miles across.  That’s small compared to Hale-Bopp, which is 30 kilometers or 20 miles across (Plait, November 21, para.  13-15).
5. The coma is well over 100,000 km in size:  In contrast to a comet’s nucleus, the coma, or the gas that surrounds the nucleus that once was once frozen below the comet’s surface is much, much larger.  ISON’s coma is about ten times the earth’s diameter (Plait, November 21, para. 14-15).
6. The tail of the comet is (at least) 8 million kilometers long: Affected by the solar wind and the pressure of sun light, a comet’s gases and dust once emitted into space form a long tail.  ISON’s tail is an estimated 8 million kilometers or 5 million miles long; that’s 20 times the distance of the moon from earth (Plait, November 21, para. 16).
7. The tail is essentially a vacuum: Comet ISON’s tail is only bright because it covers so much territory, and since it reflects sunlight.  Compared to the troposphere, or the air that supports life on earth, the “tail is a hard vacuum” (Plait, November 21, para. 17).
8. The total mass of the comet is about 2 -- 3 billion tons:  As a mixture of ice and rock, that’s far less dense than a solid mountain would be (Plait, November 21, para. 18)
9. ISON is shrinking, losing about 1029 molecules of water every second.  Given Comet ISON’s total mass, it would take it 25 years to completely disappear (Plait, November 21, para. 19).
10. ISON may disintegrate: As the heat from the sun warms the comet’s mixture of frozen gases, rocks, and water vapor, chunks of ice break off, in a process called “calving”.  Sometimes comets dramatically disintegrate, but sometimes they evaporate.  Astronomers still don’t know what ISON will do (Plait, November 21, para. 20-21).
11. ISON won’t hit the Earth:  The closest ISON will be to earth at its closest on December 26th is 60 million kilometers or 40 million miles away—150 times farther away than the moon (Plait, November 21, para. 22).
12. You can see it for yourself, and it may become visible in broad daylight: ISON is bright enough to see without any magnification, and is more clearly seen with binoculars since “it’s jumped in brightness twice just in the past week or so!” (Plait, November 22, para. 23).  

As Comet ISON approaches perihelion, it’s important not to look directly at the sun because this can blind the observer.  Nevertheless, it might be possible to see ISON during the day for the short time that it’s near the sun (Plait, November 22, para. 24-25).  But it will be safer to find ISON in the western sky shortly after sunset after it rounds the sun.  After December 20th, ISON should be out of the glare of the sun and easily visible with binoculars (Plait, November 22, para. 27).  

Smoothed SOFIA images of Comet ISON.  (2013, November 21). NASA. Retrieved from http://www.nasa.gov/mission_pages/SOFIA/sofia_targets_comet_ison.html#.Uo9uneLCprM

Comet ISON doesn’t have that much debris to spare, according to infrared photos taken by NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA).  On October 24, 2013, it took off aboard a modified 747SP carrying a German-built 2.5 meter infrared telescope to capture images of Comet ISON—its mssion: To take Comet ISON’s temperature and determine exactly what gases and mineral make up the comet, characteristics earthbound telescopes can’t analyze.  The approximately 10-hour, non-stop flight from Palmdale, California, flew over Colorado, and then headed northeast to Ontario, Canada, and then west to Alberta, before flying south over Idaho and Montana flying at 43,000 feet altitude (SOFIA, 2013, November 21, para. 1-2).

Principal investigator Diane Wooden’s observations aboard SOFIA measured the thermal emission from small and large dust grains in the coma of Comet ISON by determining the mid-infrared wavelengths with the FORCAST or Faint Object InfraRed CAmera for the SOFIA Telescope. FORCAST collects infrared photons at wavelengths between five- and 40-microns.

Wooden took three infrared wavelengths, two of which cannot be seen from Earth-based telescopes because the atmosphere blocks infrared energy from reaching the ground, measuring the thermal emission from small and large dust grains in the coma of Comet ISON. The third micron wavelength tied SOFIA observations to ground-based measurements (SOFIA, 2013, November 21, para. 4-6).

“We learned that the comet is dust-poor not only for small grains, as already known by the weak scattered light at visible wavelengths, but also for larger grains detectable at these mid-IR wavelengths from SOFIA,” Wooden explained (SOFIA, 2013, November 13, para. 13). 

November 20, 2013

Rao, Joe.  (2013, November 20). Promising Comet ISON Gets Brighter, But Will It Really Sizzle? SPACE.com. Retrieved from http://news.yahoo.com/promising-comet-ison-gets-brighter-really-sizzle-231350373.html

Experienced astronomers are greeting Comet ISON’s recent brightening with guarded optimism. As late as November 12, it appeared to be brightening “at a disappointingly slow pace.” That day ISON shone at a 7.9 magnitude--3.5 times dimmer than the faintest star visible to the naked eye (Rao, 2013, November 20, para. 1-2).  Then suddenly on November 14^th, Comet ISON’s magnitude quickly jumped in intensity to 5.9 while on November 15^th the comet increased in scale to 5.1--a greater than 13-fold increase in magnitude in less than three-days (Rao, 2013, November 20, para. 3).

Now, however, astronomers fear that Comet ISON’S surge in brightness might portend its end, possibly prematurely breaking up or disintegrating before it reaches its perihelion, November 28^th, 730,000 miles, or 1,175,000 kilometers from the sun. Thus, if Comet ISON suddenly disintegrates into dust at the time it comes closest to the sun, it will likely “unfurl a long and spectacular tail” similar to Comet Lovejoy's in December 2011.  But if ISON fragments several days before perihelion, after an initial outburst in brightness, it will slowly fade as Comet de Toit did in December 1945 (Rao, 2013, November 20, para. 4-6). 

Thus, on November 16^th, David Seargent, an eminent Australian comet observer, noted that Comet ISON was about the same distance from the sun as Comet du Toit was when it disintegrated;  moreover, Comet du Toit had grown “intrinsically brighter” than Lovejoy when it faded out before perihelion (Rao, 2013, November 20, para. 7).  Similarly, Zdenek Sekanina of NASA’s Jet Propulsion Laboratory, warned, "It is unclear whether this event's nature is benign or cataclysmic" (Rao, 2013, November 20, para. 8).

Looking on the bright side (pun intended), however, ISON’s growing illumination might mean that the comet’s nucleus has opened a new fissure that is expelling a reservoir of gas and dust. But since the experts can’t guarantee what will happen, everyone will have to wait (Rao, 2013, November 20, para. 9-10).

At about magnitude 5, Comet ISON is indistinct, but visible under a full moon, even without the aid of binoculars or a telescope, some observers even spotting a faint tail (Rao, 2013, November 20, para. 11).  The morning of November 20^th, ISON was “roughly between Spica in the constellation Virgo and Mercury. After Friday, the comet’s low altitude and the dawn’s twilight will complete hide Comet ISON, and then observers will need to wait and see if it resurfaces after it makes it way around the sun (Rao, 2013, November 20, para. 12-13).

Editor’s Note: Joe Rao will be giving a special presentation on Comet ISON at the Hayden Planetarium of the American Museum of Natural History on Tuesday, November 26th at 6:30 p.m. EST (2230 GMT) In New York City. For more details: http://www.amnh.org/calendar/rendezvous-with-ison-comet-of-the-century-with-joe-rao

Riley-Smith, Ben (2013, 20 November).  Comet Ison: daylight sighting of 'once in a lifetime' event possible.  Science.  The Telegraph.  Retrieved from http://www.telegraph.co.uk/science/space/10462290/Comet-Ison-daylight-sighting-of-once-in-a-lifetime-event-possible.html

Observers who don’t catch a glimpse at Comet ISON* as it approaches the sun, can possibly see it during the day time in early December, thus, “achieving a feat which hasn't happened since 1680” (Riley-Smith, 2013, November 20, para. 1-4). Tom Feilden, Speaking on BBC’s Today program, explains, "The good news is Ison is going to get brighter and higher in the night sky as it approaches the sun, so we are going to get a much better view as the days go by . . . If it survives that encounter with the sun it could even be bright enough to be seen during the day in early December” (Riley-Smith, 2013, November 20, para. 5-7).

Named for the International Scientific Optical Network telescope from which Russian astronomers Vitali Nevski and Artyom Novichonok first spotted ISON in September, 2012, ISON supposedly originated from the Oort cloud, 93 trillion miles from earth (Riley-Smith, 2013, November 20, para. 9-10).

Although scientists also believe that Comet Hale-Bopp had its beginnings in the Oort Cloud, Comet ISON is the first comet to graze the sun that has come from the edge of the solar system in 200 years. Researchers expect it to pass 720,000 miles from the solar surface and heat up to 2,760 C (5,000 F) ON November 28^th (Riley-Smith, 2013, November 20, para. 11-12). If their predictions prove correct, ISON “will rival the Great Comet of 1680” (Riley-Smith, 2013, November 20, para. 13).  

*Reporters in the United Kingdom don't always capitalize the abbreviation for the International Scientific Optical Network that is ISON's namesake.  However, this synopsis after giving the title as it appears in The Telegraph, follows American usage.

November 19, 2013

Byrd, Deborah. (2013, November 19).  Everything you need to know: Comet ISON in 2013. EarthSky.  Retrieved from http://earthsky.org/space/big-sun-diving-comet-ison-might-be-spectacular-in-2013

For now, experts are saying that Comet ISON hasn’t fragmented, and amateur astronomers can catch a faint glimpse of the comet in the predawn sky.  However, at perihelion, November 28^th, it will be lost in the sun’s glare, so the best upcoming chance to see ISON is in early December (Byrd, 2013, November 19).  Accordingly, EarthSky furnishes the links for ISON’s viewing schedule as well as other pertinent background information.

Currently, ISON is “heading downwards, toward the sunrise.  It'll pass near Mercury around November 22.  Look in a dark sky if you can!  Use binoculars to sweep for the comet, then try to see it with the eye alone” (Byrd, 2013, November 19, para. 2).  In the meanwhile, serious star gazers shouldn’t miss Byrd’s month to month, copiously illustrated and much photographed viewing guide of Comet ISON!

Kingery, Aaron.  Comet ISON to fly by sun on Thanksgiving Day.  Reuters. Washington Post.  Retrieved from http://www.washingtonpost.com/lifestyle/kidspost/comet-ison-to-fly-by-sun-on-thanksgiving-day/2013/11/19/fe893e72-4c86-11e3-9890-a1e0997fb0c0_story.html

When Comet ISON travels around the sun at 234 miles per second, the sun will heat it to around 5,000 degrees—“hot enough to vaporize not just ice in the comet’s body but also rock and metal” while the sun’s gravity might also break it apart (Kingery, 2013, November 19, 1-2).  Then again, recent calculations forecast that ISON will survive (Kingery, 2013, November 19, para. 2).

When two amateur astronomers from the International Scientific Optic Network first detected ISON beyond Jupiter’s orbit in September 2012 after the Oort Cloud booted it into the inner solar system, this “first-time visitor” to the inner solar system was bright enough to predict that it might put in a truly impressive appearance since the sun’s intense heat usually causes ice in a comet’s body to vaporize, forming distinctive tails and “fuzzy-glowing” comas (Kingery, 2013, November 19, para. 3-4 & 8). 

If ISON behaves as predicted, it should remain visible to the naked eye in the early-morning sky in early December and throughout the night in January.  During the last ten days, amateur astronomers have begun posting on the Web faint images of ISON moving through the constellation Virgo low in the eastern sky before dawn taken with just binoculars or small telescopes (Kingery, 2013, November 19, para. 5, 9 & 10). 

A six-minute journey to study ISON.  (2013, November 19).  Solar System Exploration.  NASA.  Retrieved from http://solarsystem.nasa.gov/news/display.cfm?News_ID=45533

A technical glitch with the Fortis satellite payload has rescheduled NASA’s launch to observe Comet ISON for the morning of November 20, 2013.

Netburn, Deborah.  (2013, November 19).  Comet ISON appears to have sprouted wings.  Science.  Los Angeles Times.  Retrieved from http://www.latimes.com/science/sciencenow/la-sci-sn-comet-ison-sprouts-wings-20131119,0,3149194.story#axzz2l8sDiXt3

Astronomers from the Max Planck Institute for Solar System Research (MPS) in Katlenburg-Lindau, Germany, spotted two wing-shaped extensions around the head of Comet ISON after they eliminated the bright background of the comet's atmosphere in the image. While the “wings” were only slightly noticeable on November 14th, they dominate the November 16th photographs (Netburn, 2013, November 19, para. 1-4).

The Germans theorize that individual fragments breaking off the nucleus might have created these appendages, which might also explain why Comet ISON unexpectedly brightened last week, as debris and gas fragments possibly reflected the sunlight.  If this is true, then Comet ISON doesn’t stand much of a chance of surviving its close sweep by with the sun November 28^th if the behavior of previous comets is any indication (Netburn, 2013, November 19, para. 5-7).  

However, Karl Battams of NASA's Comet ISON Observing Campaign blog, points out that “the wings look a bit too symmetrical to have been caused by nucleus fragmentation” (Netburn, 2013, November 19, para. 10).  Battams speculates that jets in the comet's nucleus are shooting dust off the comet, or a chance in the solar wind might have created these wings (Netburn, 2013, November 19, para. 10). 

Sen, Nina.  (2013, November 19). Stunning comet ISON photographed by amateur astronomer.  Fox News.  Retrieved from http://www.foxnews.com/science/2013/11/19/stunning-comet-ison-photographed-by-amateur-astronomer/

Fox News has just published “a spectacular set of photos” that amateur astrophotographer, Mike Hankey has taken over the last few months using a 14.5 inch RCOS telescope at the Sierra Remote Observatory in Auberry, California, which he accessed from his home in Maryland (Sen, 2013, November 19, para. 1-3). 

Spectacular Comet ISON shines bright in new photo from Chile telescope. (2013, November 19). Space.com. CBS News.  Retrieved from http://www.cbsnews.com/8301-205_162-57613007/spectacular-comet-ison-shines-bright-in-new-photo-from-chile-telescope/

http://www.n-tv.de/wissen/Ison-jetzt-mit-blossem-Auge-sichtbar-article11751791.html

“A dazzling new image”, taken by the European Southern Observatory's La Silla Observatory’s TRAPPIST national telescope at in Chile, captures an image of Comet ISON in the early morning of November 15,  complete with “a brilliant blue cloud of material surrounding its core” (Spectacular Comet ISON, 2013, November 19, para. 1-2).   TRAPPIST, incidentally stands for TRAnsiting Planets and PlanetesImals Small Telescope.  The photo is “a composite of four different 30-second exposures through blue, green, red, and near-infrared filters . . . As the comet moved in front of the background stars, these appear as multiple colored dots" (Spectacular Comet ISON, 2013, November 19, para. 3).

First discovered by two Russian amateur astronomers in September 2012, ISON has reached “the home stretch of its first-ever trip through the inner solar system, which will bring it within just 730,000 miles (1.2 million kilometers) of the sun's surface on November, 28” (Spectacular Comet ISON, 2013,  November 19, para. 4).  If Comet ISON survives this by pass, it should put on “a great show”; however, viewers can now see ISON unaided before dawn  in the east-southeastern sky after two recent outbursts [although using a telescope or binoculars certainly enhances the comet’s features] (Spectacular Comet ISON, 2013, November 19, para. 5).  Of course, professional astronomers have focused on the comet, trying to learn of its composition by documenting the gases ISON emits as it zips closer to the sun (Spectacular Comet ISON, 2013, November 19, para. 6).

Spotts, Pete. (2013, November 19). Comet ISON puts on a show. Will it survive its solar flyby? Reuters. Christian Science Monitor.  Retrieved from http://www.csmonitor.com/Science/2013/1119/Comet-ISON-puts-on-a-show.-Will-it-survive-its-solar-flyby

Comet ISON’s growing brightness is making scientists wonder if it will survive its November. 28th solar flyby since some astronomers believe that ISON is already starting to lose chunks of its nucleus as indicated by the “dust and ionized gas erupting from its nucleus and flowing alongside its tail” (Spotts, 2013, November 19,  para. 1 & 4).  Features like these “wings”, which aren’t visible without the use of high tech image processing procedures, often occur when individual fragments break off from the comet’s core (Spotts, 2013, November 19, para. 5-7).

Then again, Comet ISON’s responses to the sun might fluctuate a bit since it’s encountering high temperatures (Spotts, 2013, November 19, para. 8). Odds are, however, that ISON might not survive the sun’s heat and gravity based on a range of values: ISON is rotating once every 10 hours, which heightens its chances of disintegrating.  Furthermore, the comet’s nucleus is only 1.2 miles across (Spotts, 2013, November 19, para. 17-19).

By observing other long-period comets that pass through the solar system and noting ISON’s slow pace of brightening, astronomers infer that ISON originated in the Oort Cloud, “a collection of debris left over from when the solar system formed 4.6 billion years ago, (Spotts, 2013, November 19, para. 10-11). Since ISON is the first recorded comet to come from so far afield and to pass so near the sun on its first trip through the solar system, researchers hope that they will be able to analyze some “pristine” evidence, testing the hypothesis that the rocks and ice in the  Oort-Cloud originated much nearer the sun, but collisions with the giant planets kicked them out to the edge of the solar system. Thus, researchers hope to perceive a difference in the comet they see before and after ISON reaches perihelion (Spotts, 2013, November 19, para. 12-16).   the solar system (9-10).rs ago According from its nucleus and flowing

Zolfagharifard, Ellie. (2013, November 19. Comet ISON puts on its greatest display yet -- but catch it while you can as it could be about to EXPLODE in our skies.  Science. Daily Mail. Retrieved from http://www.dailymail.co.uk/sciencetech/article-2509826/Comet-ISON-puts-greatest-display--catch-EXPLODE-skies.html

Even though Comet ISON is now visible to the naked eye, a sighting of “wings” sprouting from the comet may indicate that its center has already broken apart.  Karl Battams, of NASA’s Comet ISON Observing campaign, however, thinks that solar winds may be buffeting the comet, or dust emissions may be responsible for these discharges (Zolfagharifard, 2013, November 19, para. 1-4).  But if the comet has disintegrated, then ISON’s recent, impressive increase in brightness should come just before a dramatic dimming. On Saturday, the comet was in “full outburst mode” after having increased in intensity by a magnitude of two in a single day (Zolfagharifard, 2013, November 19, para. 5 & 7-9).

Many amateur astronomers throughout the United Kingdom have taken images of Comet ISON only with the aid of only binoculars or small telescopes, and since scientists are forecasting that it will continue to grow in brightness, they are encouraging observers to see ISON themselves. Even though observers can see the comet without any magnification on a clear dark sky with an unobstructed horizon, binoculars will definitely enlarge its tail and streamers as well as the “bumps” on the comet’s surface (Zolfagharifard, 2013, November 19, para. 10-12).

Wednesday morning, it will be almost sunrise before sky gazers can see ISON on the horizon (Zolfagharifard, 2013, November 19, para. 13). By the time ISON reaches its perihelion, it will be 100 times closer to the sun than Comet Hale-Bopp was in 1997 (Zolfagharifard, 2013, November 19, para. 15).

November 18, 2013

Boyle, Alan.  (2013, November 18).   Comet ISON looks fantastic in latest pictures — maybe too fantastic?  Science.  NBC News.  Retrieved from http://www.nbcnews.com/science/comet-ison-looks-fantastic-latest-pictures-maybe-too-fantastic-2D11619011

Although Comet ISON’s brightening last week has elated astro-photographers, some scientists fear that this perhaps signals that its nucleus is splitting apart, according to Karl Battens, of the Naval Research Laboratory (Boyle, 2103, November 18, para. 1 & 3).  Then again, Battens suggests, “It could equally likely be the result of the expected increase in activity as it continues to approach the sun" (Boyle, 2013, November 18, para. 4-5). 

Observers should know in a couple of days what is happening since if ISON is fragmenting, a dramatic decrease in magnitude should follow this increase in brightness. However, if ISON is not breaking apart, it should become even brighter. Battens speculates that earth-bound observers will not know for sure which scenario is unfolding until ISON comes into the field of view of the NASA STEREO spacecraft on Thursday, November 21, 2013 (Boyle, 2013, November 18, para. 6-).

The photographs taken by experienced astro-photographers  of Comet ISON are certainly stellar, but Battens and other professional astronomers warn that the professionals taking these images use special equipment as well as high-powered telescopes.  Thus, observers viewing ISON unaided or only with the help of field binoculars should only make out “a ‘green fuzzball’ with maybe a very faint tail visible” (Boyle, 2013, November 18, para. 7-8).  Even so, “It's worth trying to see ISON if you're up before the sun with clear skies to the east. Get out the binoculars and look for the fuzzball near the bright star Spica. The Comet Watch app for iPhone and iPad can help you get your bearings, or you can turn to the Heavens Above website for guidance” (Boyle, 2013, November 18, para. 9).

Friedlander, Elaine. (2013, November 18).  Hard-to-find comet ISON loiters low on the eastern horizon.  Capital Weather Gang. The Washington Post.  Retrieved from http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2013/11/18/hard-to-find-comet-ison-loiters-low-on-the-eastern-horizon/

This week Comet ISON is visible low on the horizon before sunrise with binoculars, but next week it will be too close to the sun to see. After ISON reaches its perihelion on November 28^th, it may be visible again in early December (Friedlander, 2013, November 19, para. 1-3). 

On November 14, ISON noticeably brightened, and on November 15^th, observers at the University of Maryland’s Observatory in College Park, Maryland, saw a fifth-magnitude comet, reporting that it exhibited  “a noticeably green tail” while a member of the Northern Virginia Astronomy Club described “a fuzzy green ball with a wisp of a tail” caused by “a combination of sunlight reflected from dust grains and molecules struck by ultra-violet moonlight”, according to NASA’s CIOC Website (Friedlander, 2013, November 19, para. 4-6).

Through Thursday, sky gazers have their best chance to see ISON between 5 and 6 A.M> in the east-south-eastern sky where ISON is below Spica in the constellation Virgo, but on Friday and through the following Monday, November 22^nd through the 25^th, backyard astronomers should shift their search to the right of Mercury and Saturn (Friedlander, 2013, November 19, para. 7-9).

However, around the time of ISON’s perihelion, November 27^th and November 28^th,  it would be foolhardy to look for ISON at all either with the naked eye or through binoculars or a telescope since looking directly into the sun’s glare could cause permanent blindness (Friedlander, 2013, November 19, para. 11-12).  But the first week in December, they may be able to spot it again in the east southeast morning sky if it escapes its encounter with the sun. Later in December, it also might be visible in the evening sky. (Friedlander, 2013, November 19, para. 13-14).

Links to the University of Maryland’s Observatory and the Northern Virginia Astronomy Club are as follows:

• University of Maryland Observatory: http://www.astro.umd.edu/openhouse/

• Northern Virginia Astronomy Club: http://www.novac.com/wp/

Howell, Elizabeth. (2013, November 18).  NASA probe to watch comets Encke, ISON zip past Mercury.  Science.  Christian Science Monitor.  Retrieved from http://www.csmonitor.com/layout/set/r14/Science/2013/1118/NASA-probe-to-watch-comets-Encke-ISON-zip-past-Mercury

NASA’s Messenger Space probe on November 18^th and 19^th is determining exactly what the comets Encke and ISON are made of as they fly by Mercury by detecting x-ray emissions from silicon, magnesium, and aluminum (Howell, 2013, November 18, para. 1-4).  Messenger’s assessment of ISON as it zips past should also help astronomers decide whether solar radiation is dissolving the comet, or if Comet ISON is merely brightening further (Howell, 2013, November 18, para. 5-7).

Comet Encke, the origin of the Taurid meteor shower, comes by Mercury’s orbit around the sun every 3.3 years, has flown by Messenger in 2007.  At that time, the twin STEREO spacecraft recorded a solar storm tearing apart Encke’s tail, and then documented it as it grew again (Howell, 2013, November 18, para. 8-9). 

McFarland, Sheena. (2013, November 18).  Comet ISON starts to brighten, astronomers begin to hpe for a show.  Cosmos >> sun grazer at risk of being torn apart by tidal forces.  Salt Lake City Tribune.  Retrieved from http://www.sltrib.com/sltrib/news/57135479-78/comet-ison-jarvis-astronomers.html.csp

Both earth-bound astronomers and nine spacecraft orbiting earth are closely observing ISON as it speeds towards its encounter with the sun whereupon the “three to four mile diameter chunk of ice and rock” will reach 5,000 degrees”, and tidal forces could very well tear it apart. The Chandra x-ray Observatory has also confirmed the hypothesis that comets emit x-rays as ionized gases respond to solar winds (McFarland, 2013, November 18, para. 3 & 14).

ISON started to brighten noticeably late last week, and if this increasing magnitude continues, viewers may possibly be able to see the comet unaided through mid-January if ISON doesn’t disintegrate since ISON’s trajectory will take it perilously closer to the sun than other well-known comets like Hale-Bopp and Halley (McFarland, 2013, November 18, para. 4 & 11).  Solar radiation is the root cause of this brightening, for as it begin to warm ISON’s nucleus, the comet’s once frozen gases start to vaporize, creating a coma while solar radiation as well as solar winds push the gases backward into a tail (McFarland, 2013, November 18, para. 12). 

November 17, 2013

Plait, Phil. (2013, November 17). Comet ISON is  (so far) living up to the hype.  Slate.  Retrieved from http://www.slate.com/blogs/bad_astronomy/2013/11/17/ison_spectacular_pictures_of_a_gorgeous_comet.html

ISON  has been brightening over the last several weeks, but a few days ago, “an outburst”  increased its magnitude more than a few times.   Meanwhile, Ison grew a tail that sported “several separate streamers” (Plait, 2013, November 17, para. 2).  Thus, ISON is starting to put on a show, even if it may break apart before it reaches its perihelion (Plait, 2013, November 17, para. 3).  As ISON approaches the sun, the sun penetrates the surface whereupon a process called sublimation takes place wherein the frozen liquids that the comet stores turn into gases that further fuel the comet’s journey (Plait, 2013, November 17, para. 5). Dust mixed with the gas forms the fuzzy coma surrounding the comet; and as it nears the sun, solar winds “excite” the gases, so they emit either a green or bluish light.  These ionized particles, blown away from the sun, grow the comet’s tail (Plait, 2013, November 17, para. 6).

ISON is at this point closer to the sun than Venus, so while it will continue to brighten, it will also become harder to see as it nears the sun.  This week, it’s possible to see ISON unaided closer to the eastern horizon just before dawn, but binoculars certainly make the image clearer (Plait, 2013, November 17, para. 8).  After November 28^th, ISON will be traveling back out to the outer reaches of the solar system in the evening sky—if it survives grazing the sun (Plait, 2013, November 17, para. 9).

November 16, 2013

Sesana, Laura. (2013, November 16).  Comet ISON visible to the naked eye: If you want to see it, do it now. Washington Times. Retrieved from http://communities.washingtontimes.com/neighborhood/world-our-backyard/2013/nov/16/comet-ison-visible-naked-eye-if-you-want-see-it-do/

Researchers associated with NASA’s Comet ISON Observation Campaign (CIOC) report that ISON after brightening suddenly Wednesday is now visible to the naked eye (Sesana, 2013, November 16, para. 1).  Astronomers, who have had a difficult time predicting just hwo bright ISON would be, are taken aback at the comet’s 16-fold increase in magnitude in just 72 hours (Sesana, 2013, November 16, para. 2).  Moreover, they don’t know whether this brightness will be “short-lived” or else the start of a more “active” phrase, according to Carl Hergenrother, acting co-coordinator of the comet section of the Association of Lunar and Planetary Observers (Sesana, 2013, November 16, para. 4).  As ISON heads towards its rendezvous with the sun, its speed is also expected to increase in speed from 95,000 miles per hour at the beginning of November to 845,000 miles per hour (Sesana, 2013, November 16, para. 5).  If, however, ISON behaves as it has in the last two months, a rapid reduction in brightness will follow this outburst in magnitude (Sesana, 2013, November 16, para. 6).

For months, astronomers have warned that ISON will not live up to its initial forecasts, although it will be one of the brighter comets of more recent years (Sesana, 2013, November 16, para. 7-8).  They estimate ISON’s core to be between 0.12 to 1.2 miles across, which is much smaller than the mass of other well-known comets: Hale Bopp is 19 miles across while Halley is 9 miles in width (Sesana, 2013, November 16, para. 9). Unlike Halley, however, Comet ISON appears to be a “dynamically new comet, fresh from the Oort Cloud”, so the sun’s radiation has yet to melt it (Sesana, 2013, November 16, para. 10).  Thus, astronomers don’t know whether ISON will either 1) “fizzle out unceremoniously”, becoming structurally unstable and vaporizing, 2) lose its central nucleus and creating a cloud of dust upon reaching its perihelion, or 3) living up to its up to now somewhat dubious title--“Comet of the Century”, making it visible in daylight (Sesana, 2013, November 16, para. 11-14).

As for this weekend, amateur astronomers can possibly see ISON unaided or more probably enhanced by binoculars or a telescope the hour before the sun rises if the sky is clear and dark, and if they look east toward the rising sun.  Carey Lisse, CIOC co-coordinator, suggests that sky watchers “look for Mars and then draw a line to the east –where you think the sun is going to rise” (Sesana, 2013, November 16, para. 12-19).  The CIOC’s Web site also suggests, “If you want to see ISON with your own eyes, do it now” (Sesana, 2013, November 16, para. 20).

November 15, 2013

Atkinson, Nancy. (2013, November 15).  Whoa, take a look at Comet ISON now.  Universe Today.  Retrieved from http://www.universetoday.com/106465/whoa-take-a-look-at-comet-ison-now/

“Let the show begin”, for ISON’s tail is suddenly full of streamers (Atkinson, 2013, November 15, para. 1-2). The photographs and video that Universe Today provides are through “good quality telescopes since viewing ISON unaided, it looks like a “faint smudge” in the predawn sky (Atkinson, 2013, November 15, para. 3).

Chung, Emily. (2013, November 15).  Comet ISON viewing may be at its best: Comet may soon be lost in sun’s glare and might not survive November 28 solar encounter.  Technology & Science.  CBC News. Retrieved from http://www.cbc.ca/news/technology/comet-ison-viewing-may-be-at-its-best-1.2428280

A sudden brightening this week might be observers’ best chance to see Comet ISON since as a NASA blog notes, “We cannot guarantee that is will survive the next few weeks and become naked-eye visible in our night’s skies” (Chung, 2013, November 15, para. 1-2). Amateur astronomers, however, may be able to see ISON unaided in some isolated localities this week, for its magnitude has jumped in brightness (Chung, 2013, November 15, para. 3-4).  Away from city lights, these observers, as well as those with binoculars, may find the comet just above the star Spica in the constellation Virgo in the predawn southeastern sky (Chung, 2013, November, 15, para. 5-6).  ISON is currently closer to the sun than the earth is, but the comet should come closest to the sun on November 28^th (Chung, 2013, November 15, para. 7).

When astronomers first spied ISON near the orbit of Jupiter in 2012, they predicted that it might become “the brightest comet ever seen” (Chung, 2013, November 15, para. 8), but so far, it hasn’t achieved the awaited magnitude.  Even so, astronomers anticipate that ISON will continue to brighten as it simultaneously moves closer to the sun and appears lower in the sky—so low and so near the sun that it’s no longer safe to look at directly (Chung, 2013, November 15, para. 9 & 11).   Accordingly, experts are giving amateur astronomers only “a handful more days” before its reaches its perihelion whereupon it might be “spectacular” (Chung, 2013, November 15, para. 12-13).

But ISON’s brightening this week may also mean that its “solid core is fragmenting” (Chung, 2013, November 15, para. 14).  If this is happening, and astronomers won’t immediately to be able to tell if it has, it’s unlikely that ISON will survive its brush past the sun (Chung, 2013, November 15, para. 17).

Comet ISON: What’s next. (2013, November 15).  EarthSky.  Retrieved from http://earthsky.org/science-wire/comet-ison-whats-next

Now Comet ISON is inside the orbit of earth as it heads towards its close encounter with the sun on November 28^th, both telescopes aboard NASA spacecraft and earth-bound amateur astronomers are furnishing “crisp pictures of the comet’s gossamer green atmosphere and filamentary double tail” (EarthSky, 2013, November 15, para. 1).  Since this is the first time [in recorded history] that ISON has passed through the inner social system, experts don’t know what will next happen to the comet (EarthSky, 2013, November 15, para. 2).

Several possibilities exist: 

1)    ISON might without warning fall apart since it is reaching that region of space where less than one percent of all comets traveling around the sun have fragmented.  If this occurs, its disintegration will be the most documented ever observed (EarthSky, 2013, November 15, para. 4-6). 

2)    ISON will most probably lose mass as it comes in contact with the heat of the sun, and even if it survives the vaporization of its interior, the sun’s gravity might pull it apart (EarthSky, 2013, November 15, para. 7-9).

3)    ISON may also survive coming near the sun, emerging with enough nuclear material to still remain an active comet whereupon it most likely will also display a “nice tail” like Comet McNaught did in 2007 (EarthSky, 2013, November 15, para.10).

The best scenario, according to Lowell Observatory astronomer Matthew Knight, would be if it “threw out enough extra material to make the comet really bright from the ground, while giving astronomers pieces of a comet to study for months to come”(EarthSky, 2013, November 15, para. 11).   Whatever the outcome, Knight says, “Hang on . . . because this ride is just getting started”(EarthSky, 2013, November 15, para. 13).

Netburn, Deborah. (2013, November 15).  Comet ISON is now visible to the naked eye, but fro how long.  Science Now.  Los Angeles Times.  Retrieved from http://www.latimes.com/science/sciencenow/la-sci-sn-comet-ison-visible-to-naked-eye-20131115,0,7360433.story

As of Friday morning, ISON has achieved a magnitude of around 4.8, and since most observers can see stellar objects displaying a fifth magnitude of brightness, Carey Lisse, coordinator of NASA’S Comet ISON’s Observation Campaign, announced, “We now have a naked-eye object (Netburn, 2013, November 15, para. 1-3). Even better, the comet appears to be becoming increasingly brighter, even as the moon itself becomes more full and bright (Netburn, 2013, November 15, para. 4-5).

To find ISON in the predawn, darkened sky, early risers will need to look east towards where the sun rises around 5 to 5:30 A.M., and look for a “green lollipop with a fuzzy emerald head, trailed by a pale white trail” (Netburn, 2013, November 15, para. 5-6; 9).  Lisse can’t explain why ISON has suddenly brightened, but he theorizes that an explosion might have occurred that might lead to the comet’s dissolving before it reaches its perihelion (Netburn, 2013, November 15, para. 7).  Then again, the sun’s heat may have just begun to penetrate ISON’s crust, so it’s releasing a previously trapped reservoir of frozen gases (Netburn, 2013, November 15, para. 8). 

Rao, Joe. (2013, November 15). Comet ISON visible to naked eye after outburst of activity, observers say.  Science.  Huffington Post.  Retrieved from http://www.huffingtonpost.com/2013/11/15/comet-ison-visible-naked-eye_n_4280731.html

After experiencing “a sudden and radical upsurge in brightness,” ISON is faintly visible without the aid of a telescope or binoculars, according to observers (Rao, 2013, November 15, para. 1-3).  This past week from Monday through Thursday, ISON increased nearly 16 times in brightness: On Thursday morning, ISON’s magnitude was 5.4, two full magnitudes brighter than Wednesday’s 7.3, and three magnitudes brighter than Monday’s 8.5 (Rao, 2013, November 15, para. 5-8). At last glance, observers judged ISON’s magnitude to be between 5.7 and 6.1 (Rao, 2013, November 15, para.  10).

Thus, ISON is finally beginning to impress astronomers; for example, Long Island amateur astronomer, Dennis Wilde, who say the comet through binoculars, reported, “ISON while not as large as the full moon was an impressive sight in the eyepiece . . . The coma was very compact with a very bright apparent nucleus, very green in color.  The tail was very thin and bright near the comet and widened slightly as it extended out to almost 3.5 degrees” (Rao, 2013, November 15, para. 12).  Nevertheless, astronomers don’t know whether ISON’s outburst will last until it reaches perihelion (Rao, 2013, November 15, para. 13-16).  As the comet approaches the sun it will become increasingly difficult to observe, but observers with an unobstructed horizon should still be able to see ISON for another week.  Come Monday morning, November 18^th, they can find ISON by first finding the handle of the Big Dipper and from there first locating Arctarus and then Spica (Rao,  2013, November 15,  para. 21). 

Samenow, Jason.  (2013, November 15). Weekend “Beaver” moon to dull Leonid meteor shower; comet ISON emerging. Washington Post.  Retrieved from http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2013/11/15/weekend-beaver-moon-to-dull-leonid-meteor-shower-comet-ison-emerging/

A full moon, known in November as either a “beaver moon” or a “frosty moon”, occurs on Sunday, making viewing of the Leonid meteor shower more difficult when it peaks between Saturday evening and Monday morning (Samenow, 2013, November 15, para. 1-4; 6-7).  NASA suggests, however, that the best time to observe the Leonid meteor shower is after midnight (Sanenow, 2013, November 15, para. 8).

Comet ISON, which underwent an abrupt brightening” on Thursday, November 14^th, is now visible to the naked eye,  given the best viewing environment, even though viewing ISON through binoculars or a telescope will give amateur astronomers a sharper view (Samenow, 2013, November 15, para. 11 & 13). Such a sudden  brightening in magnitude could foretell ISON’s end, or it might indicate that ISON will shine even more brightly. Observers in the United States may nevertheless find that cloud cover may block their view of these stellar events this weekend (Samenow, 2013, November 15, para. 14 & 17).

Wall, Mike. (2013, November 15).  Comet ISON headed for close sun encounter on Thanksgiving.  The Weather Channel. Retrieved from http://www.weather.com/news/science/space/comet-ison-headed-close-sun-encounter-thanksgiving-20131115

Astronomers associated with NASA’s Comet ISON Observatory Campaign hope to understand more about ISON’s composition by documenting what gases boil off it at various distances from the sun (Wall, 2013, November 15, para. 4). Because they speculate that “ISON appears to be a dynamically new fresh comet fresh from the Oort cloud” that has never endured the “melting effects of soar radiation” (Wall, 2013, November 15, 2013, para. 5), they admit that. no one knows what will happen as ISON nears perihelion. Some astronomers, however, anticipate that it won’t disintegrate if has the mass and make up of a “typical” comet (Wall, 2013, November, 15, para. 6-7).  As for now, ISON is visible if amateur astronomers view it through binoculars or a telescope as it shoots past the constellation Virgo in the predawn sky (Wall, 2013, November 15, para. 8).

November 14, 2013

Boyle, Alan. (2013, November 14).  Looking for the ‘comet of the century’? Watch ISON online. Science. NBC News.  Retrieved from http://www.nbcnews.com/science/looking-comet-century-watch-ison-online-2D11599302

If viewers are looking for a “cosmic spectacle”, the best place to start is online.   Admittedly, astronomers first recognized ISON’s potential to put on a show over a year ago, and if it survives its close encounter of within a million miles or 1.6 kilometers of the sun, after November 28^th, it might live up to its billing.  As for now, the comet is “potentially visible” an hour or two before sunrise in eastern skies just above Spica, a star in the constellation of Virgo (Boyle, November 14, 2013, para. 1-3).

However, each day ISON stands a greater chance of “getting lost in “the glare of the dawning sun and the setting of full moon” (Boyle, November 14, 2013, para. 4). Moreover, it might fizzle out.  Accordingly, those averse to rising before dawn and trekking out beyond city lights can instead turn to the following links:

• Spaceweather.com: http://www.spaceweather.com/

• Space Telescope Institute ISON blog (Hubble telescope): http://hubblesite.org/hubble_discoveries/comet_ison

• Comet ISON’s Observing Campaign: http://www.isoncampaign.org/

• NASA’s Messenger Probe has photos of ISON and Comet Encke: http://messenger.jhuapl.edu/gallery/sciencePhotos/image.php?gallery_id=2&image_id=1296

• The Sloah Virtual Observatory provides a double billing of both Comet ISON and the Leonid Meteor Shower: http://events.slooh.com/

Vimeo time-lapsed videos are available from the following photographers:

• Halverson, Randy:  http://vimeo.com/78882931

• Ng, Justin:  http://vimeo.com/79188919

• Spencer, Roy: http://vimeo.com/79396921

On Twitter, go to

• @ISON updates:  https://twitter.com/isonupdates

• @Comet ISON News: https://twitter.com/cometisonnews

• @Comet ISON 2013: https://twitter.com/cometison2013

• @Sungrazer Comets: https://twitter.com/SungrazerComets

(Boyle, 14 November 2013, para. 7-12)

Bruce, Gary. (2013, November 14).  Photos of comet ISON: A potentially great comet.  Space.com.  Retrieved from http://www.space.com/19372-comet-ison-photos-2013-great-comet.html

Link takes viewers to 50 photos of Comet ISON taken by amateur astronomer Bruce Gary as seen from Hereford, Arizona. 

Rao, Joe. (2013, November 14).  Outburst lights up Comet ISON; it’s now visible to naked eye. Science. NBC News.  Retrieved from http://www.nbcnews.com/science/outburst-lights-comet-ison-its-now-visible-naked-eye-2D11591258

Comet ISON is suddenly brightening enough so that it’s now visible to the naked eye, although earlier this week, its brightening seemed stalled (Rao, 2013, November 14, para. 1-3).  In the predawn hours of Wednesday morning, ISON had brightened to a magnitude of 7.3 from a 8.5 magnitude Monday morning, and on Thursday morning, morning the comet had jumped in magnitude to 5.4, increasing nearly 16 times in brightness in only 72 hours.  Observers with 10 x 50 and 30 x 125 binoculars thus can clearly make out a “nice lollipop comet with a very condensed blue-green head and a long narrow tail (Rao, 2013, November 14, para. 4-8).  Although ISON is not as bright as a full moon, very early Thursday morning, ISON’s compact coma sported “a very bright nucleus, very bright green in color” while “the tail was very thin and bright near the coma and widened slightly as it extended out almost 3.5 degrees” (Rao, 2013, November 14, para. 9).  Paradoxically, however, while ISON is rapidly brightening, it’s also becoming harder to see in the southeastern dawn sky (Rao, 2013, November 14, para. 16). 

November 13, 2013

Poladian, Charles, (2013, November 13).  Comet ISON approaches: ‘Comet of the Century’ visible through binoculars as it heads toward the sun.  International Business News.  Retrieved from http://www.ibtimes.com/comet-ison-approaches-comet-century-visible-through-binoculars-it-heads-towards-sun-1469324

Disparaging Comet ISON as a “weird space object” and a “cosmic stranger”, Poladian admits that ISON has thus far been a disappointment; however, he also acknowledges that this “non-periodic comet” encloses “uncontaminated information” from the beginning of the solar system” (2013, November 13, para. 2-3). ISON has not achieved the “bump in its magnitude astronomers had predicted it would reach in November, so they are suggesting that “ISON’s axis of rotation is reserving its resources until it reaches its perihelion and starts to make a return trip back into space (2013. November 13, para. 3-4).

November 12, 2013

Ng, Justin. (2013, November 12).  Time lapse of Comet ISON and Comet Lovejoy.  Vmeco.  (1:35 minutes).  Retrieved from http://vimeo.com/79188919

Ng collapses 50 minutes of imaging time for Comet ISON AND 60 minutes of imaging time for Comet Lovejoy into less than two minutes.  ISON gives off a greenish glow, suggesting that its cyanogen and diatomic carbon gases are reacting to the ultraviolet light of the sun.  

Walsh, Michael. (2013, November 12).  Comet ISON, now visible with binoculars, races toward sun for first time.  New York Daily News.  Retrieved from  http://www.nydailynews.com/news/world/comet-ison-view-reveal-deep-secrets-article-1.1514621

Comet ISON is now visible with binoculars and perhaps by the weekend it might be seen unaided (Walsh, 2013, November 12, para. 1). NASA scientists in the meanwhile are looking forward to seeing how ISON reacts to ultraviolet light and solar wind since the last comet to behave predictably was Comet Ikeya-Seki in 1965.  As for now, heat has yet to scorch ISON’s top layers (Walsh, 2013, November 12, para. 2-4). Scientists, however, don’t know exactly what will happen when ISON comes close to the sun on Thanksgiving Day, Thursday, November 28^th, for it may disintegrate (Walsh, 2013, November 12, para. 7-8).  The comet is currently about as bright as Venus, so sky watchers should find Comet Lovejoy, also visible in the predawn sky, more “visually spectacular” (Walsh, 2013, November 12, para. 13-14). 

November 11, 2013

Eicher, David J. (2013, November 11).  How to see Comet ISON this week—Nov. 11-17.  Science. Huff Post.  Retrieved from http://www.huffingtonpost.com/david-j-eicher/how-to-see-comet-ison-thi_2_b_4254744.html

During the first part of this week, amateur astronomers might catch a glimpse of ISON, now traveling through the constellation Virgo, around 4 A.M. through binoculars and telescopes or possibly without any help at all while the sky is still dark (Eicher, 2013, November 11, para. 2).  By the weekend,  they should easily spot the comet near Spica, the brightest star in Virgo, although the moon might interfere with viewing since moonlight makes spying indistinct objects like this “faintly glowing fuzz ball” more difficult (Eicher, 2013, November 11, para. 3).  Comet Lovejoy (C/2013.R1) is also visible in the northern part of the constellation this week (Eicher, 2013, November 13, para. 6).

Klotz, Irene. (2013, November 11).  Incoming comet ISON heading for close encounter with sun.  Reuters.  Retrieved from http://www.reuters.com/article/2013/11/11/us-space-comet-idUSBRE9AA11620131111

This past weekend amateur astronomers began posting on the Web the first photographs taken of Comet ISON with only the aid of binoculars or small telescopes (Klotz, 2013, November 11, para. 7).

Kluger, Jeffrey & Wilson, Chris.  (2013, November 11).  Interactive ‘Comet of the Century’ tracker: Where’s ISON now.  Time.  Retrieved from http://science.time.com/2013/11/11/interactive-comet-of-the-century-tracker-wheres-ison-now/

Playing upon ISON’s earliest billing, Carvey Lisse, senior scientist for NASA’s Comet ISION Observing Campaign, quips, “It’s not going to be the comet of the century, . . . , but “going  straight from the frozen Oort Cloud to next to the surface of the sun, it’s going to be the comet of the half century—something closer to Kahoutek, still, that makes it special” (Kluger, 2012, November 11, para. 5). Accordingly, Time furnishes an Interactive Comet tracker, so reader can keep track of its progress.

It’s not as if anyone was around to watch when ISON made its last flyby around the sun abound a million years ago, so astronomers don’’t know whether it will break up, crash into the sun, or survive to return around the sun again and go back by earth on its way back to the edge of the solar system (Kluger, 2012, November 11, para. 8).  Recent observation, however, yields some new facts about the comet:  Ison has begun fluorescing green as solar radiation begins to affect it, which means that ISON’s gases are predominantly composed of a combination of carbon and nitrogen (Kluger, 2012, November 11, para 9).   To observe ISON better, Lisse and his associate astronomers have gather together “more than a dozen ground-based observatories” from around the world as well as 18 different spacecraft (Kluger, 2012, November 11, para. 10).

Wall, Mike. (2013, November 11).  Got a good pair of binoculars? Incoming Comet ISON’s visible now.  Space.com. Science. NBC  News.  Retrieved from http://www.nbcnews.com/science/got-good-pair-binoculars-incoming-comet-isons-visible-now-2D11577710

ISON is now visible through 15 x 70 optic binoculars as of last Saturday.  The comet is currently an 8^th magnitude star—two dim to see without help, but visible through binoculars or a small telescope low in the predawn eastern sky (Wall, 2013, November 11, para. 1-4).

November 8, 2013

Comet Ison is within earth’s orbit. (2013, November 8).  Examiner.com. Retrieved from 
http://www.examiner.com/article/comet-ison-is-within-earth-s-orbit

Comet ISON  crossed to within earth’s orbit November 7^th as it traveled at 103,000 miles per hour or 28 miles per second (Comet ISON, 2013, November 8, para. 2).  On November 28^th, ISON will pass within 732, 000 miles to the sun; at which time, optimistic predictions estimate that it should be about as bright as a full moon (Comet ISON, 2013, November 8, para. 4).  With any luck, ISON will be visible in both the early evening and very early morning skies in the Northern Hemisphere, and on December 26, it will pass nearest to earth (Comet ISON, 2013, November 8, para. 4).

Rao, Joe. (2013, November 8).  Promising Comet ISON now brightening for stargazers on earth.  Retrieved from http://www.space.com/23515-comet-ison-brightness-stargazing-update.html

Space.com serves up sky watchers three separate vidoes about Comet ISON while summarizing the comet’s ever-brightening appearance as it makes it way towards the sun.  Spanish and British astronomers concur that during the last week Comet ISON’s coma has brightened, and it has lengthened its tail (Rao, 2013, November 8, para. 1-4). While ISON remained stable during October, its gas production has started to rapidly increase, and its coma doesn’t seem to be breaking up or showing any particularly distinctive features in its coma or shell or in its dust production (Rao, 2013, November 8, para. 6).  

Worldwide, astronomers agree that by November 1^st ISON had brightened to a magnitude of 9.0—a good sign since the lower the number of magnitude, the brighter the comet's coma (Rao, 2013, November 8, para. 9).  However, ISON needs to brighten considerably before viewers can see it unaided because the faintest magnitude the eye can see is 6.5.  On November 4, a noted American comet watcher viewed ISON through his 15 x70 binoculars, estimating that it had a magnitude of 8.8 and commenting upon its unusual “even-surface” brightness (Rao, 2013, November 8, para. 10). 

Some astronomers predict that ISON might possibly disintegrate about the time it reaches its perihelion as Comet Lovejoy did in 2011.  If,  however, ISON breaks apart before its comes nearest the sun, it will exit largely unseen (Rao, 2013, November 8, para 13-17).  

November 7, 2013

King, Bob. (2013, November 7).  Comet ISON heats up, grows new tail.  Universe Today.  Retrieved from http://www.universetoday.com/106205/comet-ison-heats-up-grows-new-tail/

ISON’s most recent photographs show a new gas tail that stretches half a degree of a full moon’s diameter emerging from the comet (King, 2013, November 7, para. 1). Solar wind blows gases like carbon monoxide and carbon dioxide into a tail as the sun’s ultra violet light electrifies them into a fluorescent streak whereupon their ions interact with the sun’s own charged particles (King, 2013, November 7, para. 2).  ISON’S inner coma is also becoming more compact as it is brightening to a magnitude of 8.0 (King, 2013, November 7, para. 3).  ISON’s gas production has also increased by a factor of 2 since November 3rd while its dust production has remained the same (King, 2013, November 7, para. 4). 

November 5, 2013

Bleier, Eran. (2013, November 4).  Comet ISON will make its closest pass of the sun on Thanksgiving Day.  UPI Beta.  Retrieved from http://www.upi.com/blog/2013/11/04/Comet-Ison-will-make-its-closest-pass-of-the-sun-on-Thanksgiving-Day/9981383587650/

ISON should be closest to the sun on November 28, 2013 (Bleier, 2013, November 4, para. 1); however, its value may lie in its journey, for astronomers view ISON’s trip as an “exceptional chance to learn about the history of the solar system” (Bleier, November 4, para. 4), for they have never before seen a comet that comes from the Oort Cloud come “all the way to within three solar radii of the solar surface” (Bleier, 2013, November 4, para. 5). Observations indicate that ISON’s core is still intact, and it is still brightening (Bleier, 2013, November 4, para. 8-9).  Thus, even if ISON is not as bright as hoped, ISON’s passage should prove illuminating (Bleier, 2013, November 5, para. 10).

Eicher, David J. (2013, November 4).  How to see comet ISON this week—Nov. 4-10.  Science. Huff Post.  Retrieved from http://www.huffingtonpost.com/david-j-eicher/how-to-see-comet-ison-thi_1_b_4214152.html

To catch a glimpse of ISON this week, viewers will need to head outside at 4 A.M. whereupon they should look east to see Leo rising with the aid of binoculars or a telescope—provided they are away from city lights.  The constellation of Leo looks like a question mark or sickle, along with a “bright triangle of stars closer to the horizon” (Eicher, 2013, November 4, para. 2-3).  Sky watchers can find ISON near Denebola [β Leo], the brightest star in the triangle if the moon isn’t shining too brightly.  ISON currently has a magnitude of 8.5, making it still too dim to see unaided, although it may reach “naked-eye visibility in the next few weeks (Eicher, 2013, November 4, para. 4-6).

Rao, Joe. (2013, November 4).  On way to the sun, Comet ISON continues to confuse observers.  Mother Nature Network.  Retrieved from http://www.mnn.com/earth-matters/space/stories/on-way-to-the-sun-comet-ison-continues-to-confuse-observers

With less than a month before ISON reaches its perihelion, its progress continues to confuse astronomers (Rao, 2013, November 1, para. 1).  They still don’t know whether it will disappoint or dazzle since CCD-V observations indicate a comet brightening at a normal rate while CCD-R observations suggest a comet that is barely brightening.  Thus, while ISON’s gas production rate has increased as predicted, its dust production rate hasn’t (Rao, 2013, November 4, para. 3).  On October 19th, ISON appeared to suddenly brighten, but on October 23rd, it showed a sign of fading, implying that ISON is reacting to the sun’s radiation more as a solid body would than a typical “fluffy” comet does (Rao, 2013, November 4, para. 7-9).   

November 4, 2013  

Huestis, Dave.  (2013, November 2).  Comet ISON Part II: What to expect. Go Local. Worcester.com. Retrieved from http://www.golocalworcester.com/lifestyle/comet-ison-part-ii-what-to-expect/

Huestis traces the history of Comet ISON from when Russian astronomers first observed it using a 16-inch reflector telescope as part of an asteroid search conducted by the International Scientific Optic Network on September 21, 2012, predicting its future magnitudes of brightness based on previous observation until it passes from view (2013, November 2, para. 1). When astronomers first observed ISON beyond Jupiter's orbit, they noted that it was six miles across and forecast that it would be visible without the aid of binoculars or a telescope during the day (Huestis, 2013, November 2, para. 3).  They also hypothesized that at this stage ISON was particularly bright because this is probably its first trip toward and sun, and solar radiation was carrying away loose debris on its surface.  After a while, however, when ISON’s brightness didn’t increase in magnitude, they theorized that this was probably since this same solar radiation had already blown away the surface rubble.  Consequently, by the time ISON had reached the point where its water and other volatiles would react to the sun’s heat, it was already 6.3 times fainter than first forecast (Huestis, 2013, November 2, para. 7-8).

At the end of May, ISON was lost from view, but when it became visible again August 12, it was still fainter than the astronomers had first forecast (Huestis, 2013, November 2, para. 9).   Nevertheless, even by late October astronomers like Huestis have found it very difficult to predict whether observers will be able to see the comet without the aid of binoculars or telescopes.  Huestis, however forecasts that currently star gazers with “modest” telescope should be able to see ISON at about 22 degrees above the eastern horizon at 4 A.M., but by November 17, it will be about 17 degrees above the horizon (Huestis, 2013, November 2, para. 10-12). They may also lose sight of it a day or two before its perihelion, after which ISON will be visible in the evening sky after sunset during the first weeks of December through binoculars with an unobstructed view.   By December 25, ISON will still be visible through the lens of a telescope, and on January 7, 2014, it will pass within two degrees of Polaris and will have a magnitude of +7 degrees (Huestis, 2013, November 2, para. 14-15).

Less than a month to perihelion for Comet Ison.  (2013, November 2).  Examiner.com. Retrieved from http://www.examiner.com/article/less-than-a-month-to-perihelion-for-comet-ison

Last year, NASA’s Jet Propulsion Laboratory predicted ISON could reach a magnitude of -11.6, or about as bright as a full moon.  This would make it bright enough to spot during daylight with binoculars or a telescope] (Less than a month, 2013, November 2, para. 1).  On November 28, the comet will pass close enough to the sun to push it possibly to a magnitude -11, although the comet has proved unpredictable thus far (Less than a month, 2013, November 2, para. 3).

In the meanwhile, sky watchers should note the following dates:

• November 18:  ISON will be within a degree of Spica; 

• November 23rd:  ISON will pass very near Mercury and Saturn;

• November 28:  ISON will exhibit a spectacular tail if it survives its close encounter with the sun;

• Early December: ISON will be visible without a telescope in both the evening and the morning skies in the mid-Northern latitudes and in the far North; 

• December 26: ISON will be closest to earth.

 (Less than a month, 2013, November 2, para. 4).

ISON also very closely parallels the Great Comet of 1680, according to the Spaceweather.com’s entry for September 25, 2012 (Less than a month, 2013, November 2, para. 4).  To view this link, go to http://www.spaceweather.com/archive.php?view=1&day=25&month=09&year=2012

On November 2, 2013, ISON was already displaying a greenish glow.

  (Bruce Gary photo.  Retrieved from http://www.transients.info/)

November 1, 2013

Musgrave, Ian. (2013, November 1).  Catch Comet ISON: Sky guide.  ABC Science.  Retrieved from

http://www.abc.net.au/science/articles/2013/11/01/3880970.htm?topic=space

Optimum comet watching depends upon whether the comet comes “reasonably close to both the sun and to the earth, if it has a good dust to gas ratio, and if it is “reasonably large” (Musgrave, 2013, November 1, para. 11).  Since comets are clumps of dust and frozen, water, carbon dioxide, and carbon dioxide as well as other gases, they ordinarily aren’t particularly dense.  Hence they ordinarily are at their brightest upon reaching their penhelion, when they are nearest the sun, which then vaporizes the ice (Musgrave, 2013, November 1, para. 12).

ISON's path will certainly take it close to both the sun and the earth, but astronomers still can’t tell whether it will be bright enough to see after it reaches its penhelion.  So far, ISON has both of lot or gas and a dusty tail (Musgrave, 2013, November 1, para. 15), but it's turning out to be unpredictable:   ISON is a “fresh” comet that hasn’t traveled the inner solar system before, but it doesn’t follow all the characteristics that newly observed comets often show, for its steadily becoming brighter, but more slowly than optimistically predicted.  All of which means that the best views of ISON might be in the southern hemisphere before the comet goes around the sun (Musgrave, 2013, November 1, para. 19 & 21).

Rao, Joe. (2013, November 1).  Comet ISON photo shows ‘downright weird’ space rock en route to sun.  Science.  Huff Post.  Retrieved from http://www.huffingtonpost.com/2013/11/01/comet-ison-photo-space-rock-sun_n_4192057.html

According to compiled observations, ISON around October 24th was running 3.3 times fainter than the “official” brightness forecast that the Minor Planet Center in Cambridge, Massachusetts predicted since over the past month the comet has increased its gas production but not its dust output (Rao, 2013, November 1, para. 2-3), which creates “a bright, miniature long-tailed comet situated within a much larger, but very much fainted and diffuse halo of a coma” (Rao, 2013, November 1, para. 4).  Observers thus note that ISON “is responding to the sun more like a solid body would respond rather than as a typical ‘fluffy’ comet” would (Rao, 2013, November 1, para. 10). 

October 29, 2013

Byrd, Deborah.  (2013, October 29).  See Comet ISON move in front of the stars.  Earthsky.org. Retrieved from http://earthsky.org/space/see-comet-ison-move-in-front-of-the-stars

Photographer Justin Ng used a 20-inch telescope and a specialized mon0chrome OCD camera to capture a time lapse photo of Comet ISON taken over 69 minutes on October 27.  Each exposure was only 90 seconds, but as an end result, this breath-taking image makes ISON appear to streak in front of the stars.

October 27, 2013

Comet ISON to be brightest on November 28.  (2013, October 28).  Times of India.  Retrieved from http://timesofindia.indiatimes.com/home/science/Comet-ISON-to-be-brightest-on-Nov-28/articleshow/24789942.cms

In the Northern Hemisphere, ISON will be its brightest on November 28th, when it is nearest the sun (Comet ISON, 2013, October 27, para. 1 & 2).  While Indian students are on vacation at this time (Comet ISON, 2013, October 27, para. 3), conspiracy theorist should note that the comet reaches its perihelion around 6 P.M. on Thanksgiving Day in the United States as well as the first day of the Jewish holiday of deliverance, Hanukkah.  For Comet ISON’s schedule from now until then, check out the following link:

Dickinson, David. (2013, September 23).  Comet ISON: a viewing guide from now to perihelion.  Universe Today.  Retrieved from http://www.universetoday.com/104818/comet-ison-a-viewing-guide-from-now-to-perihelion/

October 24, 2013

Powell, Corey S.  (2013, October 24). All eyes on Comet ISON.  Discover.  Retrieved from http://discovermagazine.com/2013/nov/21-urban-skygazer#.Umm_qRDCr9k

Amateur astronomers might find ISON hard to spot if they live in polluted area, or it could be visible to the eye for a few hours around 1:40 P.M. EST on November 28th, although viewers will need to look tor this “fuzzy dot or dagger” from a location that blocks the sun since the comet will be so near it (Powell, 2013, October 24, para. 2-3).  At night, if sky gazers can search for ISON in a dark sky with an unobstructed horizon, they can find it around five in the evening on November 17th or 18th.  If they can observe ISON, it should have an obvious tail by December 10th that “should stretch a quarter of the way across the sky” (Powell, 2013, October 24, para. 4-5).

Villamarin, Jenalyn. (2013, October 24).  2013 Comet ISON: Hubble Space Telescope captured intact: ‘comet of the century’.  International Business Journal.  Retrieved from http://au.ibtimes.com/articles/516463/20131024/2013-comet-ison-hubble-space-telescope-captured.htm#.Umm8CBDCr9l

 

Villamarin believes that the Hubble Space Telescope has captured the “comet of the century” as evidenced by NASA’s analysis:  The absence of small fragments of debris breaking off from the comet’s reverse shows that its nucleus is in far better health than some experts have conjectured” (2013, October 24, para. 1-2). Nevertheless, according to Zdenek Sekanina, the principal scientist with NASA’s Earth and Space Sciences Division, “In recent weeks, ISON’s brightness has hit a plateau” (Villamarin, 2013, October 24, para.4 & 6).  At this point the comet is brightening very slowly (Villamarin, 2013, October 24, para. 7). 

October 22, 2013

Fuller-Wright, Liz. (2013, October 22).  Will Comet ISON make it to Christmas” Past comets offer clues. Science. Christian Science Monitor. Retrieved from http://www.csmonitor.com/Science/2013/1022/Will-Comet-ISON-make-it-to-Christmas-Past-comets-offer-clues

ISON's coma probably won’t be as bright by the time it makes it journey pass the sun as it was a few months ago based on a comparison to two historical comets (Fuller-Wright, 2013, October 22, para. 3-4). This loss of intensity occurs because a comet consistently loses material from its nucleus as frozen gases and dust particles disperse.  Thus, while ISON is still actively discharging debris, it is only barely replacing the gases and dust it has lost (Fuller-Wright, 2013, October 22, para. 11-12).   Even so, since astronomers can't see a part of ISON until it swings around the sun, it might be far more brilliant than its currently is come December (Fuller-Wright, 2013, October 22, para. 15).

Myslenski, Rik. (2013, October 22).  Comet ISON perhaps NOT GARBAGE after all—glows GREEN in latest snaps: Derided mere weeks ago as a washout, looking good again.  The Register.  Retrieved from http://www.theregister.co.uk/2013/10/22/new_image_of_comet_ison_shows_marked_improvements/

A recent photograph taken October 8th at the University of Arizona’s 32-inch Schulman telescope is still glowing, although not as brightly as when Russian astronomers Artyom-Kislovodsk and Vitaly Nevsky discovered ISON entering the solar system through the Oort cloud this past spring when it was burning brightly (Mysenski, 2013, October 22, para. 2-3).  ISON will make its pass around the sun on November 28th, and if it survives this encounter, it should be easily observable in December without a telescope (Mysenski, 2013, October 22, para. 4-5).  

 October 21, 2013

Sen, Nina.  (2013, October 21).  Comet ISON’s blazing green tail captured in stunning photo.  Space.com. Retrieved from http://www.foxnews.com/science/2013/10/21/comet-ison-green-blaze-captured-in-stunning-photo/

The accompanying photo was taken through the 32-inch Schulman Telescope atop Mount Lemmon from the University of Arizona’s Sky Center on the morning of October 8, 2013 (Sen, 2013, October 21, para. 1).

Sokol, Josh. (2013, October 17).  New Hubble image of comet ISON: Behind the release.  ISON Links Roundup.  Retrieved from http://hubblesite.org/hubble_discoveries/comet_ison

The symmetry of ISON’s coma suggests that the comet’s entire surface area is feeding it; thus, it isn’t rotating a great deal (Sokol, 2013, October 17, para. 1 & 4).   Astronomers theorize that ISON peaked early since it was extraordinarily bright when first discovered when it was out past Jupiter since perhaps an outburst of carbon monoxide fueled its brightness (Sokol, 2013, October 17, para. 5). 

Wall, Mike.  (2013, October 21).  Is Comet ISON breaking apart?  Science. The Christian Science Monitor.  Retrieved from http://www.csmonitor.com/Science/2013/1021/Is-Comet-ISON-breaking-apart

A recent Hubble telescope image of ISON taken October 9th when the comet ISON was within the orbit of Mars discloses that the comet’s nucleus remains intact.  If it had broken up, telescopes otherwise would most probably have revealed several fragments (Wall, October 21, para. 1-2 & 4).   The polar jet evident in April, however, is no longer visible (Wall, October 21, para. 3).

 ____________

Reviewed Videos on ISON: 

Weeded from Conspiracy Hype

Web pages and web pages exist anticipating Comet ISON, but very few of them even attempt to describe this phenomenon in scientific terms.   Other Online sources may wish to deal with catastrophic scenarios or end time prophecies, but this Web page  only gives links to Web pages that seek to describe the passing by of ISON as an event observed by astronomers.

November 14, 2013

SuspiciousObservers. (2013, November 14). 5 Min.  News.  ISON Outbrust.  Spaceweather. (6:30 minutes).  Retrieved from http://www.youtube.com/watch?v=iJUpp4I27jY

Don’t believe the hype many Youtube videos are presenting about ISON.  In truth, it’s one of the most observed comets in history.

November 7, 2013

SyspiciousObservers. (2013, November 7).  5 Min. News. ISON brightening! Solar flares/Ge. . . Retrieved from http://www.youtube.com/watch?v=VbpknyDRpaI

Video reports NASA’s “underwhelming” description of ISON’s brightening.

November 4, 2013

5 MIN (2013, November 4).  Weather, Spaceweather (5:03).  Youtube.  Retrieved from http://www.youtube.com/watch?v=NoWeymCmxAQ

Observations indicate that ISON has no forwarding jets.

Nemesis Maturity.  (2013, November 4).  Comet ISON enters the danger zone and it’s turning into the . . . (6:10 minutes).  Retrieved from http://www.youtube.com/watch?v=SZascyM-N1E

Video hypothesizes that Comet ISON is running out of fuel.

October 31, 2013

Nemesis Maturity. (2013, October 31).  Comet ISON—3 comets threaten earth with unprecedented meteor shower.  Retrieved from http://www.youtube.com/watch?v=5eYNBrkou-g

Three comets will be visible from earth in early December: Enicke, ISON, and Lovejoy.  Encke will reach its perihelion November 21^st, ISON will be closest to the sun on November 28^th, and Lovejoy will reach this marker on December 25^th. 

October 15, 2013

SuspicousObservers.  (2013, October 15).  Comet ISON. NewNASA trajectory—JPL orbital diagram. (1:59 minutes).  Retrieved from http://www.youtube.com/watch?v=qjNvv4de9x8

Thankfully, Suspicious Observers sticks to the facts and doesn’t offer any apocalyptic speculations

.

October 3, 2013

5 Min. News.  (2013, October 3).  Sky spray admitted, ISON, quakes 2.  (4:38 minutes).  Retrieved from http://www.youtube.com/watch?v=QpzTgzNWI9w

ISON is sticking together, so the focus on ISON shifts to its trajectory around the sun.

September 27, 2013

ISON—the Electric Comet—Full Documentary. (2013, September 27).   Youtube. (1:29.02).  Retrieved  from http://www.youtube.com/watch?v=LN1dI_7macw

The Electronic Comet video challenges standard comet theory that comets aren’t balls of frozen water and gases and instead hypothesizes that their surfaces might emit electronic plasma arcs.  Current theory based on recent data thus suggests that comets respond electrically as they move into the electrical field of the sun.