Doomsday in 2036 just got a lot less likely.

After recalculating the trajectory of the asteroid Apophis, scientists at the Jet Propulsion Laboratory in La Canada Flintridge, Calif., have determined that the odds of it hitting the Earth that year are only 4 in 1 million.

"We've all but ruled out" a collision in 2036, said Steve Chesley, an astronomer with the Near-Earth Objects office at JPL.

Previously, the odds had been calculated at one in 45,000, Chesley said.

While that doesn't sound like a very big danger, Apophis has been the greatest worry since 2004 for scientists who track threats from space. At that time, it appeared the asteroid had a 2.7 percent chance of hitting the Earth in 2029.

At nearly three football fields in diameter, Apophis would cause widespread damage if it hit the Earth.

, though not as much as the 6-mile-wide asteroid thought to have wiped out the dinosaurs.

The danger of a collision in 2029 was later downgraded, leaving 2036 as the encounter posing the greatest danger.

The latest calculations were based on observations with the University of Hawaii's 88-inch telescope, as well as the 90-inch Bok telescope on Kitt Peak in Arizona.

In 2029, Apophis will pass within 18,000 miles of Earth, closer than some satellites. Even though scientists are certain it won't hit the Earth, they are less sure about how that close approach will affect its future orbit.

"The deflection caused by the 2029 encounter will be significant," Chesley said. "We're not worried about 2029. We're worried about its future trajectory."

The latest calculations, according to Chesley, suggest that in 2068 there is a one-in-300,000 chance of Apophis hitting the Earth.