Comet C/1919 Q2 Metcalf catches the attention. The intriguing object was discovered in August of 1919 and remained visible until early 1920, but no subsequent observations have been made. In 1973, Allan Cook discovered that the Omicron Draconids meteor stream seemed to be following the orbit of the earlier comet. Suspicion is strong that the comet broke up and that the Omicron Draconids are simply the result of that event, a manifestation of cometary debris.
All of which makes the fireball that streaked through European skies last July a bit more interesting than your average bolide. A new paper will suggest that the boulder that caused it — probably a meter across and massing 1.8 tons — was a chunk of the original comet, a boulder that broke apart from the original ice and rock nucleus as C/1919 Q2 Metcalf disintegrated. That would mean we have comet fragments out there waiting to be discovered. Josep M. Trigo-Rodríguez (Institute of Space Sciences, CSIC-IEEC, Spain) explains:
“If we are right, then by monitoring future encounters with other clouds of cometary debris, we have the chance to recover meteorites from specific comets and analyse them in a lab. Handling pieces of comet would fulfill the long-held ambitions of scientists – it would effectively give us a look inside some of the most enigmatic objects in the Solar System.”
Image: A close-up image of the Bejar bolide, photographed from Torrelodones, Madrid, Spain. Credit: J. Perez Vallejo/SPMN.
A fascinating prospect indeed. The fireball was seen on July 11, 2008 at 2117 UTC, reaching an intensity 150 times brighter than the full Moon. Tracked by three stations of the Spanish Fireball Network, it disappeared at an altitude of 21.5 kilometers above the town of Bejar, near Salamanca in Spain. Studying large pieces of a comet in a laboratory would reward the search for fragments, but tracking them down won’t be easy. The paper is Trigo-Rodríguez et al., “Observation of a very bright fireball and its likely link with comet C 1919 Q2 Metcalf,” scheduled for publication in Monthly Notices of the Royal Astronomical Society (abstract). An RAS news release is also available.
Daylight fireball captured on video by chance over Texas:
http://www.news8austin.com/content/your_news/default.asp?ArID=232068
Space Weather News for Feb. 16, 2009
http://spaceweather.com
WEEKEND FIREBALLS: A daylight fireball over Texas on Sunday, Feb. 15th, triggered widespread reports that debris from a recent satellite collision was falling to Earth. Those reports were premature. Researchers have studied video of the event and concluded that the object was more likely a natural meteoroid about one meter wide traveling more than 20 km/s–much faster than orbital debris.
Meteoroids hit Earth every day, and the Texas fireball was apparently one of them. There’s more: On Friday, Feb. 13th, people in central Kentucky heard loud booms, felt their houses shake, and saw a fireball streaking through the sky. This occurred scant hours after another fireball at least 10 times brighter than a full Moon lit up the sky over Italy.
Although it is tempting to attribute these events to debris from the Feb. 10th collision of the Iridium 33 and Kosmos 2251 satellites, the Kentucky and Italy fireballs also seem to be meteoroids, not manmade objects. Italian scientists are studying the ground track of their fireball, which was recorded by multiple cameras, and they will soon begin to hunt for meteorites. Videos, eye-witness reports and more information about these events may be found at http://spaceweather.com.
Hi Folks;
Here in Northern Virginia, within the United States, at around the year 1995, it was reported within the local newspapers and media that an object emmiting a brilliant blue fiery tail associated with a very bright fireball made a sonic boom and a whistle like roar as it apparently traveled over northern Virginia at night to perhaps dump into the Atlantic Ocean off the coast of Virginia in the direction of the Virginia Tide Water region.
When I first read of the report in the morning newspaper, my thought was,
Damn! , I should have been out side to catch a glimpse!. This very news report stimulated my interest in astronomy, and by association, that of manned interstellar travel even more.
The point is the popularization of night sky meteor watching along with the pragmatic aspects of studying potential collisions with NEOs can lead to a resurgance of profound interest in astronomy, and by association manned space travel, within the U.S. and among the global community as well.
Thanks;
Jim
Release of meteoroids from asteroids by Earth’s tides
Authors: Leonard Kornoš, Juraj Tóth, Peter Vereš
(Submitted on 21 Feb 2009)
Abstract: The orbital evolution of particles released from the surface of a rubble-pile body by Earth’s tides during flyby within the Roche limit is studied. Test particles initially placed on the surface leave the surface and escape the parent body.
Released particles remain in a relative small cloud for about 500 years and spread evenly along the orbit of the parent asteroid during next several hundred years. Their orbital elements exhibit very small dispersion in the mentioned time frame.
Comments: 7 pages, 2 figures, 1 table
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:0902.3732v1 [astro-ph.EP]
Submission history
From: Peter Vereš [view email]
[v1] Sat, 21 Feb 2009 11:13:51 GMT (782kb)
http://arxiv.org/abs/0902.3732
Earthgrazer: The Great Daylight Fireball of 1972
Credit & Copyright: Antarctic Search for Meteorites program, Case Western Reserve University, James M. Baker
Explanation: What is that streaking across the sky? A bright earthgrazing meteor. In 1972, an unusually bright meteor from space was witnessed bouncing off Earth’s atmosphere, much like a skipping stone can bounce off of a calm lake. The impressive event lasted several seconds, was visible in daylight, and reportedly visible all the way from Utah, USA to Alberta, Canada.
Pictured above, the fireball was photographed streaking above Teton mountains behind Jackson Lake, Wyoming, USA. The Great Daylight Fireball of 1972 was possibly the size of a small truck, and would likely have created an impressive airburst were it to have struck Earth more directly.
Earthgrazing meteors are rare but are more commonly seen when the radiant of a meteor shower is just rising or setting. At that time, meteors closer to the Earth than earthgrazers would more usually strike the Earth near the horizon, while meteors further than earthgrazers would miss the Earth entirely.
http://antwrp.gsfc.nasa.gov/apod/ap090302.html