Washington - Scientists have drastically reduced the chances of a 50-metre-wide asteroid striking Mars later this month, saying Thursday the rock will likely keep a distance of about 26,000 kilometres. US space agency NASA said it was "effectively ruling out" a collision, reducing the probability to 1 in 10,000. Ten days ago the odds stood at 1 in 25 - nearly 4 per cent.
The 2007 WD5 asteroid, discovered late November, resembles in its dimensions one that exploded over Siberia in 1908, destroying 80 million trees over an area of nearly 2,200 square kilometres. It is expected to pass Mars on January 30.
Scientists said it was natural for the probability of an impact to increase dramatically before all uncertainty is eliminated, but 1 in 25 was still an unusually large chance. Steve Chesley, a scientist at NASA's Jet Propulsion Laboratory in Pasadena, California, said astronomers rarely had to deal with odds greater than 1 in a million.
