An asteroid the size of a house is on course to shave the Earth’s orbit this week, but experts said the near-miss poses no risk for the planet.
Called 2012 TC4, the asteroid will pass by Earth at an altitude of less than 44,000 km, just above the 36,000 km level where hundreds of satellites orbit the Earth.
Mike Kelley, who works to spot and track the space rock at Nasa, said there was “no danger. Not even for satellites”.
“We’ve now been observing TC4 for two months, so we have very accurate position information on it, which in turn allows very precise calculations of its orbit,” which will not cross that of Earth nor its satellites, he said.
The asteroid was spotted five years ago as it passed by Earth at about double the distance it is expected to approach us on Thursday. It wil likely return in 2050 and 2079 as it continually loops around the sun.
“We know today that it will also not hit the Earth in the year 2050, but the close flyby in 2050 might deflect the asteroid such that it could hit the Earth in the year 2079,” said Rüdiger Jehn of the European Space Agency’s Near-Earth Object programme in the Netherlands.
It measures between 15 to 30 metres wide, the same size as the meteoroid that exploded over Chelyabinsk in 2013, and whose shockwaves blew out the windows of thousands of buildings and injured more than 1,000 people. TC4 is expected to approach the planet at a point south of Australia.
Millions of similar asteroids’ locations are not known, while TC4 is one of just thousands that can be tracked.
TC4 is one of about three similar-sized objects that pass the Earth at the equivalent projected distance every year.
But TC4 has been picked by experts to test the global asteroid pre-warning system, which involves observatories, science labs and universities around the world.
Experts will find out how accurate their projections of size and distance were on Thursday, as well as study what the asteroid is made of. It has been described as a dress-rehearsal in case a similar asteroid hits the Earth.
Many scientists believe that the dinosaurs were wiped out by an asteroid.
There is little to be done in terms of planetary defence at the moment, except carry out evacuations of anyone in harm’s way.