An asteroid that has a one in 20 chance of striking Mars on January 30, might just fly past, which would probably make it target Earth at some point in future.
Designated 2007 WD5, the 160-foot wide asteroid was originally identified as a possible risk to Earth, though later analysis showed that it actually might be on a collision course with Mars.
According to a report in Discovery News, Donald Yeomans, a planetary scientist at NASA's Jet Propulsion Laboratory in Pasadena, California, has said that the odds are that the asteroid is going to fly right past Mars.
In the long run, that may not be good news for Earth, which could find itself in the asteroid's path at some point in the future. "Something of this size could take out a fairly large metropolitan area," said Yeomans.
But unlike the 1908 Tunguska event, when a large asteroid exploded over central Siberia with the force of a large nuclear bomb, now there would be advance warning of a possible strike, as well as the tools and knowledge to divert the threat.