An asteroid which could theoretically one day wipe out humanity has been photographed in exquisite detail on a recent pass by Earth.
The massive asteroid 4179 Toutatis never posed a danger to Earth when it flew relatively close to our planet last week.
But the asteroid will return periodically. And while astronomers know it won't hit for at least 400 years, there is a chance it could one day - when it would almost certainly wipe out anyone living on Earth.
Nasa said the asteroid was about 4.3 million miles from Earth on 12 and 13 December, or about 18 times the distance of the Earth to the Moon.
It is about three miles wide and has an elongated, irregular shape with several bright ridges, which may be boulders. By comparison, the asteroid which doomed the dinosaurs to extinction was about 6 miles across.
The massive rock spins on its axis every 5.4 days and spins "like a wobbling, badly thrown football" Nasa said.
There is no chance 4179 Toutatis will hit the Earth in the next four hundred years, beyond which its orbit cannot be calculated accurately.
But the asteroid has still been listed as "potentially hazardous" because it could be a danger to the planet in the future.
However there is no reason to panic yet - the rock is just one of many being tracked by the Near-Earth Object Observations Program, commonly called "Spaceguard". Which we admit is a nerve-wracking name.
Toutatis is next scheduled to pass by the Earth in November 2069 when it will fly by at about 7.7 Earth-Moon distances.Suggest a correction