Asteroid 2008 BT18: 1 rock now seen as 2 asteroid buddies

by William Atkins

Monday, 14 July 2008

Page 1 of 2 ! Astronomers discovered asteroid 2008 BT18 earlier in 2008, thought it was a giant rock hurling through space near Earth, but now have found out that it is, actually, two asteroids--what astronomers call a binary asteroid. The closest approach to Earth by Asteroid 2008 BT18 is Monday, July 14, 2008, when it will be about 1.4 million miles (two million kilometers) from Earth—about six times the distance between Earth and the Moon. Asteroid 2008 BT18 was discovered on January 31, 2008, by the Lincoln Near-Earth Asteroid Research (LINEAR) Project at the Lincoln Laboratory, Lexington, Massachusetts, of the Massachusetts Institute of Technology (MIT), Cambridge, U.S.A. At that time, the asteroid was considered to be about 0.5 mile (0.8 kilometer) in diameter. LINEAR, funded by the U.S. Air Force and NASA, searches the skies above Earth to discover and catalog near-Earth asteroids and to provide warning to astronomers if any of them are headed toward Earth. Grant H. Stokes is the principal investigator of LINEAR. Stokes is the associate division head of Lincoln Laboratory at MIT. Since May 1998, LINEAR has found about 70% of all near-Earth asteroids discovered worldwide. It is considered by NASA as one of the major discoverers of asteroids as the space agency attempts to catalog at least 90% of all asteroids larger than 0.6 mile (one kilometer) in diameter by the end of 2008. However, on July 6-7, 2008 radar observations of the asteroid, using a "delay-Doppler" technique, by the Arecibo Observatory (Puerto Rico) found that the one object was really two objects, a binary asteroid. The larger of the two objects (the primary partner) is estimated to be about 1,970 feet (600 meters) in diameter (with a spherical shape), while the smaller one (the secondary object) is thought to be at least 650 feet (200 meters) in diameter (with a unknown shape at this time). The larger one is thought to rotate about its axis at a rate of about three hours or less. An image of the asteroid pair, taken on July 7, 2008, is found at the Space.com website “Asteroid 2008BT18, Arecibo Observatory.” The asteroid is considered by NASA to be "potentially hazardous." Please read on to find out why. << First page <   1 2 Next page > Last page - Post your comment >>

 

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