Beyond Wikipedia:
Harbingers in the Sky
Evelyn Smith
Revised November 8, 2013
Daily read up on meteors, asteroids, and comets in time for ISON by following "Comet Ison's Daily Progress" in "Comet Ison's Skywatch Journal" in the McGregor, Texas, McGinley Memorial Public Library Books and Friends' November issue. Since November 6, 2013, astronomers have disclosed more information on the Chelyabinsk February 15, 2013, meteor strike, revealed the discovery of an unusual "active asteroid", P/2013 P5, and have already observed evidence of the yearly Leonid meteor shower.
Vetted Websites:
Russian Meteorite Strike
& Asteroid Flyby
Cameras for Allsky Meteor Surveillance
(CAMS). (2013). Ames Research Center. NASA. Retrieved from http://cams.seti.org
Photography reveals recent meteor
fireballs as well as surviving meteorites.
Links to sky clocks reveal optimum viewing times for observatories while
a day-to-day tally gives the frequency of meteor showers. Related articles links connect readers to
news stories featuring recent meteorites.
Carr gives a simple explanation of this
scientific phenomenon.
Comets and meteors. (n. d.). Our Universe. ESA Kids. European Space Agency. Retrieved from
ESA furnishes a simplified take of
meteors accompanied by pictures. Links
direct readers to articles explaining asteroids, shooting stars, and comets.
The Russian Academy of Science has
examined 53 small fragments collected around the hole in the ice of a Siberian
lake.
Site contains a list of facts and
definitions that should intrigue a younger audience.
NASA gives a scientific explanation of
meteors as well as links to pertinent recent headlines and NASA resources,
furnishing photographs and videos of meteors and meteorites.
The New
York Times has compiled six videos from dash board video cams in Russia
that bear witness to the 15 February 2012 meteor strike.
Report estimates the size of the meteor
before its entering the earth’s atmosphere over Chelyabinsk, Russia, as well as
the time that elapsed after it first entered the atmosphere until its
disintegration was 32.5 seconds. The story also notes that the meteor’s
trajectory differed from that of the asteroid 2012DA14, which recently had a
close encounter with earth.
Web site features video and photography
of falling stars and gives instructions on how to observe a meteor shower.
Asteroid, Meteorite, &
Comet Websites
|
Asteroids that escape the Asteroid Belt between Mars and Jupiter become comets. |
November 2013
Review of the Chelyabinsk Meteor
Meteors the size of the Chelyabinsk meteor that
measured 62 feet across are probably between four to seven more times likely to
hit earth than astronomers previously estimated, according to three studies
published in the November issue of Nature.
Thus, 20 million space rocks the size of the Russian meteor may be orbiting
the solar system rather than an earlier estimate of three million since until Chelyabinsk,
NASA only looked for 100 feet wide meteors (Berenstein, 2013, November 7, p.
1). Until astronomers reexamined their
findings, they also estimated that large meteor strikes only struck earth every
150 years instead of their new estimate of every 30 years (Berenstein, 2013,
November 7, p. 1).
Taking
proactive steps, NASA this fall has reactivated WISE, a formerly dormant
orbiting telescope used to search the sky for meteors, and NASA and the Federal
Emergency Management Agency are looking into the need to evacuate population
should astronomers discover that a killer asteroid is headed to earth. Last spring
the two agencies also held an unpublicized disaster drill that imagined a
meteor strike outside of Washington, D.C. For now, however, asteroids are most
likely to cause “city-busting airbursts like the one that hit Chelyabinsk,
which surprised astronomers because it came from the direction of the sun. Fortunately for Chelyabinsk, the meteor’s
shallow entry spread out the explosion, limiting the worst damage (Berenstein,
2013, November 7, p. 1-2). Meanwhile,
this month NASA has discovered two 12-wide asteroids and a 1.2 mile asteroid
that it previously hasn’t noticed (Berenstein, 2013, November 7, p. 2).
Chang, Kenneth.
(2013, November 6). More asteroid
strikes likely. Space & Cosmos. New York Times. Retrieved from http://www.nytimes.com/2013/11/07/science/space/more-large-asteroid-strikes-are-likely-scientists-find.html?ref=science
An article published in Nature estimates that Chelyabinsk-sized meteor strikes could occur
as often as a decade or two, and these findings have pushed forward the topic
of planetary defense, so that in December the United Nations General Assembly
may establish an International Asteroid Warning Network as well as call of
space agencies to set up an advisory group (Chang, 2013, November 6, para.
4-5). Surveys have spotted 95 percent of
near-earth asteroids that are at least one kilometer or 0.6 miles wide (Chang,
2013, November 6, para. 6). A proposed telescope, to be called Sentinel will
find asteroids about 450 feet wide—a size that won’t destroy humanity, but
could kill 50 million people and collapse the world economy (Chang, 2013,
November 6, para. 10-11). Even with
Sentinel, however, many Chelyabinsk-sized asteroids, however would still escape
detection. Accordingly, the University of Hawaii is
setting up telescopes with a 5 million dollar grant from NASA “to scan the sky
for quick-moving spots of light” starting in 2015 that might be asteroids
(Chang, 2013, November 6, para. 17-18).
The asteroid impact near Chelyabinsk, Russia, on
February 15, 2013, was the largest airburst to hit earth since the 1908
Tunguska event; however, modern cameras as well as laboratory methods have
allowed for an un-preceded contemporaneous measurement of the comet’s
impact.
Sample, Ian. (2013, November 6). Scientists reveal the full power of the
Chelyabinsk meteor explosion. The Guardian. Retrieved from http://www.theguardian.com/science/2013/nov/06/chelyabinsk-meteor-russia
Scientists have evaluated the explosion of the
Chelyabinsk meteor, and have determined that the 20 meter-wide rock began to
come apart at an altitude of 28 miles, traveled at a speed of 12 miles per
second, and exploded with the energy of 500 kilotons of TNT (Sample, 2013,
November 6, para. 1-2). The meteor at
its brightest glowed 30 times brighter than the sun, leaving observers with
retina and skin burns, even as the intense heat evaporated 3/4ths of the meteor
(Sample, 2013, November 6, para. 5). As noted in Science, the meteor left a shock wave of damage 55 miles on either
side of its trajectory, sending 1,200 patients to hospitals while it also left
a 650 kilograms that fell into 70 centimeter thick ice on Lake Chelyabinsk
(Sample, 2013, November 6, para. 6-8). The November issue of Nature also reported
that the orbit of the meteor traces back to asteroid 86039, and the scientific
models for estimating meteor airbursts are very “off the mark” (Sample, 2013,
November 6, para. 10-11).
After assessing videos of the Chelyabinsk meteor
strike in February 2013, astronomers now theorize that the risk of asteroids
entering earth’s atmosphere may be ten times greater than they previously
thought (Schiermeier, 2013, November 6, para. 1). Although no known asteroid is on a collision
course with earth for the next two centuries, astronomers know very little
about smaller bodies that might impact the earth (Schiermeier, 2013, November
6, para. 11-12). Thus, “residual impact
risk” is shifting to smaller sized objects since astronomers have only
catalogued about 500 of the millions of estimated near-earth asteroids 10 to 20
meters in diameter (Schiermeier, 2013, November 6, para. 13-14).
Comet P/2013 P5
Jewitt, David, et al. (2013, November 7). The Extraordinary Multi-tailed Main-belt
Comet P/2013 P5. Abstract. The
Astrophysical Journal Letters, 778: 1. doi:10.1088/2041-8205/778/1/L21.
A system
of six-dust tails set apart a main-belt comet, P/2013 P5, discovered August 27,
2013, from all other comets previously found. Observations made 13-days apart by
the PAN-STARRS surveying telescope, located on Mount Haleakalā, Maui, Hawaii, also
reveal a spectacular change in the tails as well as indicate that the comet isn’t
fading. Using a computer model,
astronomers have determined that “each tail corresponds to a unique ejection
date, revealing continued, episodic mass loss from the radius nucleus” since
April 15. As an inner-belt asteroid, P/2013 P5 is unlikely to contain ice, and
its drawn-out period of dust release isn’t inconsistent with an impact
origin. However, this may indicate that
it is losing mass through rotational instability.
Sci-News.com
thoughtfully provides a link to the submission article that appears in the November issue of Astrophysical Journal Letters
while also offers a summary of the scientific paper.
About 240 meters in diameter, P/2013 P5 sports six
comet-like tails of dust radiating from it like wheel spokes. Although astronomers first discovered it
using the Pan-STARRS Survey telescope in Hawaii, they didn’t see the tails
until September 10, when Hubble first focused on them. Then on September 23,
when Hubble focused on them again, P/2013 P5’s appearance had drastically
changed (P/2013 P5, 2013, November 8, para. 1-3).
One theory explaining P/2013’s behavior
postulates that it’s rotation span has increase so that its surface has started
coming apart, gathering dust in episodic eruptions for the last five months
(P/2013 P5, 2013, November, 8, Para. 5-6).
Modeling shows that a series of “impulsive dust-ejection events” could
have formed the comet’s tails as radiation from te sun has smeared its dust
into streamers. Thus, astronomers have
inferred that P/2013 P5 might be losing surface debris as it rotates at a high
rate of speed just as radiation from the sun could have similarly spun it into
a high rate of speed (P/2013 P5, November 8, para 7-9). If future observations discover that dust
leaves the asteroid from its equatorial regions, this would show that it is
experiencing a rotational break up (P/2013 P5, November 8, para. 8-11). If the comet is a part of the Flora asteroid
family, it may have been born as a result of a collision that happened 200
million years ago (P/2013 P5, November 8, para. 12).
Leonoid Meteor Shower
Leonid meteor shower peak scheduled for November 16
to November 18. (2013, November 6). Examiner. Retrieved from http://www.examiner.com/article/leonid-meteor-shower-peak-scheduled-for-november-16-to-november-18
Every November the Leonid meteor shower yearly bursts
forth from Leo the Lion’s constellation.
While this “king of all meteor storms” is active from November 5th
through the 30th, its peak window for observation runs from November
16th to 18th (Leonid, 2013, November 6, para. 1). On
November 17, 1966, the Leonid meteor shower rained thousands of meteors per
minute during a quarter-hour span; however, the most memorable Leonid meteor
shower in recent history occurred in 1833.
The Alabama state slogan, “stars fell upon Alabama”, for example, is a
reference to this event, although the Chinese and Arabs observed Leonid meteor
showers as far back as the 9th century CE (Leonid, 2013, November 5,
para. 3-4). Associated with the comet Tempel-Tuttle, the Leonid meteor shower
is best seen this hear between midnight and dawn, but since the shower will
occur during a full moon, light-wash interference might obscure viewing
(Leonid, 2013, November 5, para. 5-7).k
Prestor, Jennifer. (2013, November 7). Possible meteor over California has social
media. Ablaze. New York Times. Retrieved
from http://thelede.blogs.nytimes.com/2013/11/07/possible-meteor-over-california-has-social-media-abuzz/?ref=science
Video from a security camera sent to KCAL -9 in Los
Angeles, showing “a bright streak flashing across the sky”. Observers from as far away as Utah and
Arizona have also spotted a “fireball” (Prestor, 2013, November 7, para.
1). Prestor links these observations to
an article in Nature that suggests the earth is more vulnerable than
astronomers previously thought (2013, November 7, para. 5).
April--February 2013
Asteroids. (2012, April 26). National
Space Society. Retrieved from http://www.nss.org/settlement/asteroids/
The National Space Society provides an
excellent sources for links giving information about asteroids.
Asteroids & Comets. (2013). National Geographic. Retrieved from
Scary stuff—article peeks readers’ interest when it mentions the
destruction of the dinosaurs whereupon it goes on to define asteroids, the
asteroid belt, and comets.
Web-based magazine gives links to
asteroid articles.
Asteroids, comets, meteorites. (n. d.).
Asteroid Watch. Jet Propulsion Laboratory. California Institute of Technology.
NASA. Retrieved from http://www.jpl.nasa.gov/asteroidwatch/asteroids-comets.cfm
The Jet Propulsion Laboratory site
explains the difference between asteroids, comets, near-earth objects,
potentially dangerous objects, meteors, and meteorites.
Clark discusses the European Union’s
plan to build a NEO shield as well as the ESA and NASA’s efforts to detect
“killer” asteroids in time for populations to evacuate
predicted impact areas.
Comet Watching Websites
Visual
Comets in the Future:
|
Meteor, Comet, & Asteroid Videos
|
The Chelyabinsk Meteor streaked over Russia on February 15, 2013. |
Video explores the theory that not only
a meteor wiped out the dinosaurs, but that an earlier meteor also about their
rise.
Above ground and in underground caves,
National Geographic explores the geological evidence of the impact of the
massive meteor off the Yucatan Peninsula dooming the dinosaurs and bringing about
the rise of the dinosaurs.
This video that gives the definition of
what meteor are and an overview of what students need to know about them could
serve as either an introductory activity or a review before a unit test for
middle school physical science students.
Comets
This collection of short videos explores
in details what the middle school student needs to know about comets,
meteorites, and asteroids under the general heading of comets.
- Exploring Comets with Dr. Alan Stern. (9:20
minutes).
- Unlocking Comet secrets—A Comet’s Tale.
(2:25 minutes).
- Comets—Remnants of the Beginning. (4:50
minutes).
- Asteroid vs. Comet. (8:05 minutes).
- Jupiter Explosion—A Comet’s Tale. (1:10
minutes).
- Mission: To Catch a Comet. (2:15
minutes).
- NASA Spacecraft Meets Comet Tempel.
(2:20 minutes).
- Meteorites. (3:30 minutes).
- Meteors from Halley’s Comet. (2:30
minutes).
- Comets and Meteor Showers. (Perseid
Meteor Shower) (2:20 minutes).
- Doomsday Asteroid. (3:05 minutes).
Collection of short videos summarizes and
dramatizes what middle school students most of what middle school students might
need to know about commas.
- Earth Impact. (Length: 01:50). “See what happens when a
comet hits the Earth!”
- Planet Formation. (Length: 02:05). “Find out
the comet's role in the creation of Earth's oceans.”
- Isaac Newton.
(Length: 02:06). “Newton actually
discovered gravity by studying comets, not apples falling from a tree.”
- Everything You Thought You Knew about a
Comet - Might Kill Us! (Length: 03:31). “What exactly are comets and what did
they have to do with life on Earth?”
- Origin of Comets. (Length: 02:30). “On TLC's Solar Empire
‘Impact,’ learn about the Oort Cloud where comets come from.”
- Halley History. (Length: 02:56). “On TLC's Solar Empire ‘Impact,’ learn the
history of Halley's comet.”
- Hale Bopp. (Length: 03:00). “On TLC's Solar Empire ‘Impact,’ learn how
comets get there name.”
- Comet Tail. (Length: 01:5). “On TLC's Solar Empire ‘Impact,’ learn what a
comets tail is made of."
- Comet Aftermath. (Length: 02:34). “On TLC's Solar Empire
‘Impact,’ learn what would happen if a big meteor hit the earth.”
- Spotting a Comet. (Length: 01:52). “Was the Star of Bethlehem
that led the Magi to the birth site of Jesus Christ a comet or something else?”
- Comet Impacts Jupiter. (Length: 02:02). “Astronomers spot a massive comet impact on
Jupiter. How would a similar hit affect Earth?”
- Comets.
(Length: 02:51). “On The Learning
Channel's series, ‘Ultra Science,’ learn what comets are and where they come
from.
- Comet.
(Length: 02:07). “On TLC's
‘Understanding Asteroids,’ learn how comets were perceived in the days of
yesterday.
Visual learners will appreciate this
short video that briefly explains everything middle school might need to know
about comets.
Asteroids
Bill Nye, “the Science Guy”, gives his
take on whether scientific knowledge could help stop a Domesday comet—possibly, but don’t
count on it.
A NASA space probe takes a flyby of the
surface of a large asteroid called Vesta.
NASA predicted this asteroid’s encounter
with earth will be uneventful.
Cartoon explains the solar system’s
asteroid belt.
Near earth objects that the asteroid
that had a close encounter with Russia in February 2013 could possibly threaten
earth.
Books on Comets, Asteroids, &
Meteors
|
After reading about meteors, Americans may want to visit Meteor Crater, Arizona. |
Eicher, David J. (2013). Comets! Visitors from Outer Space. New York: Cambridge University Press.
Eicher has compiled a very current book
on comets that the average reader can understand. An instructive, very easily understood
glossary, plenty of photograph plates, and a large bibliography provide lots of
additional helpful information.
---. (September 2013). Comets! Visitors from Deep Space. New York: Cambridge University Press.
Eicher, who writes frequently for the popular press (as shown above), has updated his study of comets to include the latest details about comet ISON.
Guruge, Anura. (2013). Comet Ison,
C/2012 S1 (ISON): The Great Comet of 2013. Seattle: Createspace Independent
Publishing Platform (Amazon).
Serious stargazers will
want to have this guide to help them follow ISON.
Levy, David H. (1998). Comets: Creators
and Destroyers. 1st edition; New York: Touchstone/Simon & Schuster.
Levy, one of the astronomers who first
tracked the Levy Shoemaker comet that collided with Jupiter in 1994, combines
astronomy, history, and literature into a very readable book on comets.
Norton, O. Richard & Chitwood,
Lawrence. (2008). Field Guide to Meteors and Meteorites. The Patrick Moore Practical Astronomy Series. London: Springer-Verlag.
This
field guide winner of the 2009 Mary Ansari Best Reference Work Award should enlighten astronomers and geologists.
Comet, Asteroid, &
Meteor Books for Elementary & Middle
School Students
Chrismer, Melanie. (2008). Comets. Scholastic News for Nonfiction Readers: Space
Science. Danbury, Connecticut: Children’s
Press (Scholastic).
Beginning readers (age 6 and up) who are
fascinated with outer space should enjoy this book.
Henderson, Douglas. (2000). Asteroid
Impact. New York: Dial Books/ Penguin Putnam.
Readers in grades 5 to 8 will be
enthralled by the drawings and the text as Henderson presents the hypothesis
that the impact of a massive asteroid at the end of the Cretaceous Period
exterminated the dinosaurs.
Kerrod, Robin. (2000). Asteroids,
comets, and Meteors. Planet Library.
Minneapolis, Minnesota: Lerner Publishing Group.
Kerrod breaks the text into short
paragraphs that don’t overwhelm the reader while lots of intriguing
photographs, diagrams, and pictures accompany the text.
Simon, Seymour. (1998). Comets, Meteors,
and Asteroids. New York: Harper-Collins.
Seymour, the “Dean of children’s science
writers”, according to the New York Times, furnishes colored photographs of
comets, meteors, and asteroids, accompanied by blocks of text. Seymour explains scientific concepts in a way
elementary school age children (grades 3 to 5) can understand the material, yet
he doesn’t talk down to his audience.
_____________________
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Khan Academy promises a free first-class education to everyone. |
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Free Virtual University Lectures
To find the
university-level Online university-level lectures in astronomy, scroll down to
the sciences. Penn State, Yale, the
University of California, Berkeley, Ohio State, and the University of
Missouri offer Online lectures
free-of-charge. The late Carl Sagan also
presents a lecture on "The Planets” as a Christmas lecture for children. Use this Web site to preview university-level courses or to become a lifelong learner of Science, Technology, Engineering, & Math, humanity, and language courses.
Scientific
Research Subscription-based Databases
Since most high school teachers and almost all
college and university instructors will not accept Wikipedia references because
they are not vetted, students may need to turn to subscription databases with
some editorial control to complete their research. Accordingly, McGregor residents who are also
card-carrying Waco-McLennan County Library patrons can turn to a large array of
databases for help with scientific research and homework. These databases include, but are
not limited to Academic Search Complete, a Science and Technology Collection,
Access Science, Green FILE, and Internet and Personal Computing Abstracts.
Texans who are patrons of TexServe-member libraries can also access similar
subscription databases Online.