The six red dots in this composite image indicate the position of 2013 YP139. Credit: NASA/JPL-Caltech


NASA's recently recommissioned Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) has detected its first new asteroid since coming out of hibernation in December 2013.

The asteroid, 2013 YP139, was discovered by NEOWISE on 29 December 2013 when it was seen moving against a background of stationary stars.

Currently 43 million kilometres from Earth and estimated to be 650m in diameter, until now 2013 YP139 has evaded detection by optical telescopes due to its coal-black colouring.

But NEOWISE, hunting for these illusive space rocks in the infrared, detected the asteroid's heat instead of any visible light reflected from the Sun.

2013 YP139 is in orbit around the Sun at nearly the same plane as the Earth and has been classed as a potentially hazardous asteroid – but there’s no need to panic yet, as the asteroid is unlikely to approach close to Earth for at least another century.

In future, the asteroid's motion could bring it within 490,000km of the Earth, so scientists will continue to monitor its trajectory.

If an asteroid of this size were to impact the Earth it would flatten a radius of at least 150 km and cause damage to a much larger area.

NEOWISE started life as an infrared survey of the entire sky called WISE, a mission that ended in 2011.

The space scope was reinstated two years later with a new mission to detect near-Earth asteroids that could be a threat to the planet, but were missed in previous searches.

It is hoped the mission will help to ensure that any asteroids that could disrupt life on Earth are known about well in advance.

Currently, many of the space rocks that impact the planet are undetected until they strike.

On 1 January this year an asteroid entered the Earth's atmosphere only 21 hours after it was discovered.


The meteor, 2013 YP139, was only a few metres in size so burned up harmlessly in the atmosphere, but had it been larger it could have caused a lot of damage with no warning and no chance to deflect it.