Asteroid monitored from outer space to ground impact

March 25, 2009

ALBUQUERQUE, N.M. -- Reports by scientists of meteorites striking Earth in the past have resembled police reports of so many muggings -- the offenders came out of nowhere and then disappeared into the crowd, making it difficult to get more than very basic facts.

Now an international research team has been able to identify an asteroid in space before it entered Earth's atmosphere, enabling computers to determine its area of origin in the solar system as well as predict the arrival time and location on Earth of its shattered surviving parts.

"I would say that this work demonstrates, for the first time, the ability of astronomers to discover and predict the impact of a space object," says Sandia National Laboratories researcher Mark Boslough, a member of the research team.

Perhaps more importantly, the event tested the ability of society to respond very quickly to a predicted impact, says Boslough. "In this case, it was never a threat, so the response was scientific. Had it been deemed a threat -- a larger asteroid that would explode over a populated area -- an alert could have been issued in time that could potentially save lives by evacuating the danger zone or instructing people to take cover."

The profusion of information in this case also helps meteoriticists learn the orbits of parent bodies that yield various types of meteorites.

Such knowledge could help future space missions explore or even mine the asteroids in Earth-crossing orbits, Boslough says.

The four-meter-diameter asteroid, called 2008 TC3, was initially sighted by the automated Catalina Sky Survey telescope at Mount Lemmon, Ariz., on Oct. 6. Numerous observatories, alerted to the invader, then imaged the object. Computations correctly predicted impact would occur 19 hours after discovery in the Nubian Desert of northern Sudan.

According to NASA's Near Earth Object program, "A spectacular fireball lit up the predawn sky above Northern Sudan on October 7, 2008."

A wide variety of analyses were performed while the asteroid was en route and after its surviving pieces were located by meteorite hunters in an intense search.

Researchers, listed in the paper describing this work in the March 26 issue of the journal Nature, range from the SETI Institute, the University of Khartoum, Juba University (Sudan), Sandia, Caltech, NASA Johnson Space Center and NASA Ames, to other universities in the U.S., Canada, Ireland, England, Czech Republic and the Netherlands.

Sandia researcher Dick Spalding interpreted recorded data about the atmospheric fireball, and Boslough estimated the aerodynamic pressure and strength of the asteroid based on the estimated burst altitude of 36 kilometers.

Searchers have recovered 47 meteorites so far -- offshoots from the disintegrating asteroid, mostly immolated by its encounter with atmospheric friction -- with a total mass of 3.95 kilograms.

The analyzed material showed carbon-rich materials not yet represented in meteorite collections, indicating that fragile materials still unknown may account for some asteroid classes. Such meteorites are less likely to survive due to destruction upon entry and weathering once they land on Earth's surface.

"Chunks of iron and hard rock last longer and are easier to find than clumps of soft carbonaceous materials," says Boslough.

"We knew that locating an incoming object while still in space could be done, but it had never actually been demonstrated until now," says Boslough. "In this post-rational age where scientific explanations and computer models are often derided as 'only theories,' it is nice to have a demonstration like this."
-end-


DOE/Sandia National Laboratories

Related Solar System Articles from Brightsurf:

Ultraviolet shines light on origins of the solar system
In the search to discover the origins of our solar system, an international team of researchers, including planetary scientist and cosmochemist James Lyons of Arizona State University, has compared the composition of the sun to the composition of the most ancient materials that formed in our solar system: refractory inclusions in unmetamorphosed meteorites.

Second alignment plane of solar system discovered
A study of comet motions indicates that the Solar System has a second alignment plane.

Pressure runs high at edge of solar system
Out at the boundary of our solar system, pressure runs high.

What a dying star's ashes tell us about the birth of our solar system
A UA-led team of researchers discovered a dust grain forged in a stellar explosion before our solar system was born.

What scientists found after sifting through dust in the solar system
Two recent studies report discoveries of dust rings in the inner solar system: a dust ring at Mercury's orbit, and a group of never-before-detected asteroids co-orbiting with Venus, supplying the dust in Venus' orbit.

Discovered: The most-distant solar system object ever observed
A team of astronomers has discovered the most-distant body ever observed in our solar system.

Discovery of the first body in the Solar System with an extrasolar origin
Asteroid 2015 BZ509 is the very first object in the Solar System shown to have an extrasolar origin.

First interstellar immigrant discovered in the solar system
A new study has discovered the first known permanent immigrant to our solar system.

A star disturbed the comets of the solar system in prehistory
About 70,000 years ago, when the human species was already on Earth, a small reddish star approached our solar system and gravitationally disturbed comets and asteroids.

Scientists detect comets outside our solar system
Scientists from MIT and other institutions, working closely with amateur astronomers, have spotted the dusty tails of six exocomets -- comets outside our solar system -- orbiting a faint star 800 light years from Earth.

Read More: Solar System News and Solar System Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.