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News briefs: March 15
Posted: Sat, Mar 16, 2002, 11:52 AM ET (1652 GMT)
- A near-Earth asteroid passed within 450,000 kilometers from the Earth but was not discovered until after its close approach, New Scientist reported Friday. The asteroid, 2002 EM7, was discovered on March 12, four days after zipping past the Earth. The asteroid eluded earlier discovery because it flew in from a "blind spot", close enough to the Sun in the sky that it could not be seen from the Earth. 2002 EM7 is estimated to be 50-100 meters across.
- Scientists have new evidence that magnetite crystals found in Martian meteorite ALH84001 do not have a biological origin, Sky & Telescope reported. Two presentations at the Lunar and Planetary Science Conference in Houston showed that the crystals, similar to those created by terrestrial bacteria, could also be formed at high temperatures by nonbiogenic processes. The magnetite crystals had been one of the leading lines of evidence in support of claims that the meteorite was proof that primitive life once existed on Mars.
- NASA has selected a "disturbance reduction system" as the next technology to be tested by NASA's New Millennium program, the agency announced Friday. The system features sensors and ion thrusters designed to control a spacecraft's flight path so it only responds to gravitational forces, a system that would be useful for future spacecraft studying gravitational waves. The system will fly on the Space Technology 7 spacecraft in 2006.
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