MIT Study Aims to Understand "Killer" Asteroids

We all know what a large asteroid could do to us on Earth. In order to gauge the magnitude of a possible threat from one of these killers, we need to know its physical properties. Short of sending a spacecraft to study the hazardous object, the best way to come to grips with it will be to analyze its spectral signature. That's the idea behind the recent work of a researcher at the Massachusetts Institute of Technology.

Richard P. Binzel, a professor of planetary sciences at MIT, has been studying the composition of a large asteroid called Apophis that has been making some pretty close passes at our planet and could get even closer in the future. Using spectroscopic analysis, Binzel's team has been able to compare the wavelengths of light coming from Apophis to those of meteorites in the laboratory. His research leads him to believe he has found a match to the threatening asteroid's make up, according to the MIT News Office.

"Basic characterization is the first line of defense," Binzel told attendees at a meeting of the Division for Planetary Sciences of the American Astronomical Society last week. "We've got to know the enemy."

On 13 April 2029, Apophis (about 270 meters in diameter) will come relatively close to Earth, missing us by about 22000 miles. But when it comes by again in 2036, there is a small possibility that it could be on a collision course, Binzel noted. So his team has been hard at work determining its composition as a test case to serve as a method for studying all future close-calling asteroids, because "you never know when the real one will come along," he said.

"We don't know when the real test will come, but we're ready," Binzel stated.

He could make such a claim because his work seems to have solved the riddle of Apophis. "The composition, I think, is really nailed," he said. Binzel's team found that Apophis is composed of a mineral called type LL chondrite, which is quite rare even among meteorites.

"The beauty of having found a meteorite match for Apophis is that, because we have laboratory measurements for the density and strength of these meteorites, we can infer many of the same properties for the asteroid Apophis itself," Binzel commented.

A catastrophic asteroid strike in the future may be the stuff of scary sci-fi movies, but we know that the threat is all too real. Now, we're developing the scientific tools to come to grips with how we should respond to such a worst-case scenario.


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