LOS ANGELES, California (AP) -- Mars could be in for an asteroid hit.
If the asteroid strikes Mars, it will probably hit near the equator close to where the rover Opportunity is exploring.
A newly discovered hunk of space rock has a 1 in 75 chance of slamming into the red planet on January 30, scientists said Thursday.
"These odds are extremely unusual. We frequently work with really long odds when we track ... threatening asteroids," said Steve Chesley, an astronomer with the Near Earth Object Program at NASA's Jet Propulsion Laboratory.
The asteroid, known as 2007 WD5, was discovered in late November and is similar in size to an object that hit remote central Siberia in 1908, unleashing energy equivalent to a 15-megaton nuclear bomb and wiping out 60 million trees. See where Earth was hit and what happened »
Scientists tracking the asteroid, currently halfway between Earth and Mars, initially put the odds of impact at 1 in 350 but increased the chances this week. Scientists expect the odds to diminish again early next month after getting new observations of the asteroid's orbit, Chesley said.
"We know that it's going to fly by Mars and most likely going to miss, but there's a possibility of an impact," he said.
If the asteroid does smash into Mars, it will probably hit near the equator close to where the rover Opportunity has been exploring the Martian plains since 2004. The robot is not in danger because it lies outside the impact zone. Speeding at 8 miles a second, a collision would carve a hole the size of the famed Meteor Crater in Arizona.
"Unlike an Earth impact, we're not afraid, but we're excited," Chesley said.