A recently discovered asteroid, which passed close to the Earth in November, may strike Mars on 30 January 2008. Asteroid 2007 WD5 will pass very close to Mars at the end of the month. Astronomers had originally estimated a 1 in 75 chance that it would hit the planet. Recent observations have increased this to a 1 in 28 chance of an impact. As more observations are made, we may see that the most likely path of the asteroid will pass by Mars completely.

2007 WD5 was discovered on 20 November 2007 by the Catalina Sky Survey in Tucson, Arizona. It had passed within 7.5 million km of the Earth on 1 November 2007 and is moving away from the Earth towards Mars. Its orbit could bring it back to the Earth, years or decades from now, but there is no apparent risk of an impact with our planet.

If the asteroid were to strike Mars, it would produce an explosion equivalent to about 3 megatons of TNT. It would not be the first impact that we have seen in our solar system. In 1994, the fragments of Comet Shoemaker-Levy 9 struck Jupiter over several days, producing a series of explosions that were visible through small telescopes.