27 March 2009

2008 TC3 Asteroid monitored from outer space to ground 26MAR09

Public Affairs

Sandia National Laboratories

Media contact: Neal Singer, (505) 845-7078


We saw it coming:
Asteroid monitored from outer space to ground impact
Sandians Mark Boslough and Dick Spalding watch it in real time

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 difficultto get more than very basic facts.Now an international research team has been able to identify an asteroid inspace before it entered Earth's atmosphere, enabling computers to determineits area of origin in the solar system as well as predict the arrival timeand location on Earth of its shattered surviving parts."I would say that this work demonstrates, for the first time, the ability ofastronomers to discover and predict the impact of a space object," saysSandia National Laboratories researcher Mark Boslough, a member of theresearch 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 litup 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 issueof 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."Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin company, for the U.S. Department of Energy's National Nuclear Security Administration. With main facilities in Albuquerque, N.M.,and Livermore, Calif., Sandia has major R&D responsibilities in national security, energy and environmental technologies, and economic competitiveness.

Don't look back -- it may be gaining on you: Sandia's Mark Boslough discusses aspects of asteroids (Photo by Randy Montoya)

[Image 2:
Dick Spalding examines the night sky (Photo by Randy Montoya)

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