Behemoth asteroid plays footsy with Earth

A mount-sized asteroid that crosses paths with the Earth every three years has been discovered by a Russian scientist.

Vladimir Lipunov, a professor at Moscow State University, said the space rock, named 2014 UR116, poses no immediate threat.

But he warned that it could hit Earth with an explosion 1000 times greater than that caused by the surprise 2013 impact of a bus-sized meteor in Russia.

That object entered Earth's atmosphere over the city of Chelyabinsk, resulting in a series of blasts that blew out windows and damaged buildings for kilometres around.

Lipunov said it was difficult to calculate the orbit of big rocks like 2014 UR116 because their trajectories are constantly being changed by the pull of other planets.

He warned that we know dangerously little about asteroids that could harm the planet.

"We need to track this asteroid permanently because even a small mistake in our calculations could have serious consequences," he said.

Of 100000 objects that can cross our planet's orbit and are large enough to be dangerous, only about 11000 have so far been tracked and cataloged.

Scientists from across the world came together last week to warn that asteroids could wipe out humanity unless more effort were made to track and destroy them.

Lord Martin Rees, the UK's Astronomer Royal, academic and television presenter Brian Cox, and biologist Richard Dawkins are among more than 100 experts calling for the creation of an asteroid detection system.

"The ancients were correct that the motion of astronomical bodies affects life on Earth.

"Sometimes those heavenly bodies run into Earth. This is why we must make it our mission to find asteroids before they find us," said Lord Rees.