Although asteroid 2012 DA14 will fly past closer than some orbiting satellites, NASA says an analysis of its path shows no impact is possible.
Meanwhile, U.S. astronomers have played down a report by the Voice of Russia quoting two Russian astronomers predicting a possible impact by another asteroid in 2106.
The Russians suggested asteroid 2012 YQ1, 75 yards across, could hit the Earth.
Richard Binzel, an asteroid expert at the Massachusetts Institute of Technology, said there is no reason for fear.
"Looks like a rogue report," he told USA Today, citing NASA's risk table for asteroids, which doesn't include 2012 YQ1 as a concern.
The space agency's Jet Propulsion Laboratory in Pasadena, Calif., is tracking 2012 YQ1 and said its orbit doesn't intersect with Earth for the foreseeable future.
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