Odds plummet that asteroid will hit Earth in 2032

The chance that an asteroid capable of wiping out a city will hit Earth in eight years has been cut in half to around 1.5 per cent, according to new calculations from NASA.

The drop in odds had been widely anticipated by the global astronomical community, which now broadly expects the probability the asteroid will hit Earth on 22 December, 2032 to fall down to zero.

For more than 24 hours, the asteroid did have the highest probability of hitting Earth -- 3.1 per cent -- of such a big space rock in modern forecasting.

Updated calculations posted by NASA late Wednesday said the odds of a direct hit had fallen to 1.5 per cent. The European Space Agency's separate calculations plunged to 1.38 per cent.

Richard Moissl, head of the ESA's planetary defence office, told AFP this had been expected as the "uncertainty region" where the asteroid could strike starts to "slip off" Earth.

The percentage chance will likely still "wiggle slightly up and down a bit" but is now expected to soon fall below one percent, he added.

It is not clear whether that will happen before the James Webb Space Telescope turns its powerful gaze to the asteroid next month.

There is still an 0.8 per cent chance that the asteroid will hit the Moon, according to NASA. The asteroid, which is known as 2024 YR4, was first detected in December.

It is estimated to be around 40-90 metres (130-300 feet) wide, which would not cause a global catastrophe, but would still be capable of causing significant destruction to a city.

The last time an asteroid of greater than 30 metres in size posed such a significant risk was Apophis in 2004, when it briefly had a 2.7 per cent chance of striking Earth in 2029 -- a possibility later ruled out by additional observations.