A mountain-sized asteroid is heading towards Earth, sort of, but we need not worry. Picture: NASA/JPL-Caltech Source: Supplied

But don’t worry, because both the scientist who discovered it, as well as NASA, reckon the 400 metre wide rock is nothing to worry about.

Moscow State University Professor Vladimir Lipunov who discovered the asteroid said the space rock 2014 UR116 posed no immediate threat, because its orbit isn’t close enough to the Earth’s orbit to cause a collision.

The asteroid was discovered in October at the MASTER-II observatory in Kislovodsk, Russia.

But while Prof Lipunov doesn’t think it’s about to hit our planet any time soon, he did warn it has the potential to hit the Earth with an explosion 1000 times greater than the 2013 meteor which exploded over Russia, The Telegraph reported.

That 11,000 tonne rock was the size of a house, and speared through the atmosphere at 64,000km/h before it detonated above a remote Russian ice lake near the city of Chelyabinsk, injuring more than 1000 people.

This asteroid was regarded as a ‘surprise’ as it had avoided detection due to the sun’s glare.

Some astronomers warned there could be more “killer” rocks following a similar path.

Prof Lipunov told the Telegraph it was difficult to calculate the orbit large rocks such as 2014 UR116 because their trajectories are constantly being changed by the gravitational pull of other planets.

He also warned one small mistake in calculations could have serious consequences for the planet.

But don’t go looking for your apocalyptic bunker just yet because the team at NASA assure us it’s not that bad and the asteroid poses no danger to us.

In a statement released this week NASA said while the giant rock does indeed have a three year orbital period around the sun and returns to the Earth’s neighbourhood periodically, “it does not represent a threat because its orbital path does not pass sufficiently close to the Earth’s orbit”.

Tim Spahr, Director of the Minor Planet Center in Cambridge Massachusetts, recalculated the object’s orbit and ruled out it being any direct threat to Earth (or any other planet) for at least the next 150 years.

That didn’t stop space nuts expressing their opinion over the giant asteroid.