

The European Space Agency's Rosetta probe has been whizzing through space since 2004 on a mission to intercept a comet. But new pictures have shown that it's actually chasing two comets in one.

It turns out that 67P/Churyumov-Gerasimenko is what astronomers call a "contact binary" -- when two astronomical bodies gravitate towards each other until they touch. They often appear as just one object until you get close.

It's not known exactly how the comet came to take this form -- it may have fractured apart at some point in its four-billion-year history, or it may comprise two parts that have completely different origins. Some think it might even be a giant rubber duck.

Whatever it is, it makes the planned landing on the comet rather more complex. Rosetta is scheduled to drop a landing unit, named Philae, onto the comet's surface -- which will then anchor itself in place with a harpoon and remain there as the comet passes around the Sun. Working out exactly how that's going to be done with two bodies spinning around each other is rather more difficult.

The historic landing is scheduled for 11 November, but we'll know more when Rosetta enters orbit around the comet on 6 August, by which time it'll be just 70km from its surface. Until then, all we can do is sit and wait.


Latest on