This is a first: a very small asteroid (or rock) has been discovered
that is on course for an impact tonight in Sudan. This information is
from various reports to posted to MPML (the Minor Planet Mailing List
at groups.yahoo.com/group/mpml/). The impactor is only about 2 m
across and will break up in the atmosphere, with no risk to those on
the ground. (If something this size hit in the daytime, it would
probably not be noticed, but at night it should put on quite show).
Alan Harris writes that this object, with the survey-assigned
designation 8TA9D69, was discovered by the University of Arizona Mt.
Lemmon survey and will almost certainly, tonight, become the first
impacting bolide discovered before entry into the Earth’s atmosphere.
Steve Chesley (JPL) reports that atmospheric entry will occur on 2008
Oct 07 0246 UTC over northern Sudan.
Andrea Milani of the University of Pisa wrote the following: Today
the object with the provisional designation 8TA9D69 was submitted to
impact monitoring by using the normal software of the NEODyS system,
by using the observations as reported by the MPC on the NEO
Confirmation Page. Based on 26 optical observations from
2008/10/06.278 to 2008/10/06, the probability of impact is between
99.8% and 100%; in practice the impact can be considered sure and is
for tonight. Our computation has already been confirmed independently
by others, including the JPL NEO Program Office (with which we
consult in all relevant cases of possible impact). The effect of this
atmospheric impact will be the release, in either a single shot or
maybe a sequence of explosions, of about 1 kiloton of energy. This
means that the damage on the ground is expected to be zero. The
location of these explosions is not easy to predict due to the
atmospheric braking effects. The only concern is that they might be
interpreted as something else, that is man-made explosions. Thus in
this case, the earlier the public worldwide is aware that this is a
natural phenomenon, which involves no risk, the better.
This is the first time an asteroid impact has been predicted, and it
reflects the increasing capability of the Spaceguard Survey. There
was one previous false alarm when, for a few hours around Christmas
2004, it appeared that an impact by a 30-m asteroid was possible, but
this was ruled out by additional observations. The current case,
however, seems much more solid.
David Morrison —
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But events like this happen several times a year somewhere on this planet. The unique thing about this case, is that this is the first time we see it coming before impact.
Yeah. Like you got that from a reliable news source.
Seriously, though, it should be a neat show. I’m sure we’ll have video almost as soon as it’s over, but video hardly ever does something like this justice. But it will be neat to see, just the same.
Small Asteroid Predicted to Cause Brilliant Fireball over Northern Sudan
Don Yeomans
NASA/JPL Near-Earth Object Program Office
October 6, 2008
A very small, few-meter sized asteroid, designated 2008 TC3, was found Monday morning by the Catalina Sky Survey from their observatory near Tucson Arizona. Preliminary orbital computations by the Minor Planet Center suggested an atmospheric entry of this object within a day of discovery. JPL confirmed that an atmospheric impact will very likely occur during early morning twilight over northern Sudan, north-eastern Africa, at 2:46 UT Tuesday morning. The fireball, which could be brilliant, will travel west to east (from azimuth = 281 degrees) at a relative atmospheric impact velocity of 12.8 km/s and arrive at a very low angle (19 degrees) to the local horizon. It is very unlikely that any sizable fragments will survive passage through the Earth’s atmosphere.
Objects of this size would be expected to enter the Earth’s atmosphere every few months on average but this is the first time such an event has been predicted ahead of time.
I have seen a post on the MPML that places the predicted impact point near 33 E, 21 N, on the Sudan/Egypt border. I have no idea what the uncertainty is in those predictions.
I think you mean “Asteroid/Meteoroid Impact Coming Tonight”.
A meteorite is the e.t. rock that’s sometimes left on the ground afterwards. In other words, a meteoroid that hits the atmosphere is a meteor. If the meteor survives impact, what remains is called a meteorite.
I think you mean “Asteroid/Meteoroid Impact Coming Tonight”.
A meteorite is the e.t. rock that’s sometimes left on the ground afterwards. In other words, a meteoroid that hits the atmosphere is a meteor. If the meteor survives impact, what remains is called a meteorite.
Strictly speaking you are right in that. I was merely looking forward already to meteorites reaching ground surface, because an object of this size and impact velocity (12.8 km/s) will likely (depending a bit on the exact composition) result in fragments of meteorite raining down over the area.
Release No.: 2008-19 For Release: Monday, October 06, 2008
Boulder-sized Asteroid Will Burn Up in Earth’s Atmosphere Tonight
Cambridge, MA - A tiny asteroid discovered just hours ago at an Arizona observatory will enter Earth’s atmosphere harmlessly at approximately 10:46 p.m. Eastern time tonight (2:46 a.m. Greenwich Mean Time). There is no danger to people or property since the asteroid will not reach the ground. It is between 3 and 15 feet (1-5 m) in diameter and will burn up in the upper atmosphere, well above aircraft heights. A brilliant fireball will be visible as a result.
“We want to stress that this object is not a threat,“ said Dr. Timothy Spahr, director of the International Astronomical Union’s Minor Planet Center.
“We’re excited since this is the first time we have issued a prediction that an object will enter Earth’s atmosphere,“ Spahr added. Odds are between 99.8 and 100 percent that the object will encounter Earth, according to calculations provided by Andrea Milani of the University of Pisa.
When a meteoroid (small asteroid) enters the atmosphere, it compresses the air in front of it. That compression heats the air, which in turn heats the object, causing it to glow and vaporize. Once it starts to glow, the object is called a meteor.
“A typical meteor comes from an object the size of a grain of sand,“ explained Gareth Williams of the Minor Planet Center. “This meteor will be a real humdinger in comparison!“
The meteor is expected to be visible from eastern Africa as an extremely bright fireball traveling rapidly across the sky from northeast to southwest. The object is expected to enter the atmosphere over northern Sudan at a shallow angle.
“We’re eager for observations from astronomers near the asteroid’s approach path. We really hope that someone will manage to photograph it,“ said Williams.
The Minor Planet Center, which is located at the Harvard-Smithsonian Center for Astrophysics, serves as the worldwide clearinghouse for asteroid and comet observations. It collects, checks and disseminates observations and calculates orbits.
Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.
