Space photo

At this moment, the Rosetta spacecraft is about 250,000,000 miles away from Earth and quickly approaching the (not-so-poetically named) comet 67P/Churyumov-Gerasimenko. The European Space Agency launched Rosetta in 2004 with a plan to send it to 67P and drop a robotic lander onto a comet’s surface for the first time ever. But as Rosetta flies nearer and nearer to the comet, it has made an unexpected discovery.

When Hubble imaged 67P back in 2003, scientists concluded the comet was a giant three-by-two mile football-shaped rock. So, this is apparently what ESA expected to see once Rosetta got there:

Space photo

An artist’s impression of Rosetta orbiting Comet 67P/Churyumov-Gerasimenko, back when ESA thought the comet was normal-shaped.

Scientists began noticing something weird in the photos Rosetta sent back about a week ago. As the spacecraft approached within 23,000 miles of 67P, it started to look like the comet had three big bumps on its surface.

Now Rosetta is less than 8,000 miles from the comet, and it looks like 67P actually is composed of two distinct structures. “This is unlike any other comet we have ever seen before”, Carsten Güttler, who manages Rosetta’s imaging system, said in a press release. “The images faintly remind me of a rubber ducky with a body and a head.”

So far scientists aren’t sure where 67P got its irregular structure from, but an ESA blogger came up with four possibilities:

1) Two comets slowly collided together

2) A single comet was pulled into the weird shape by the gravity of the Sun or Jupiter. “Perhaps the two parts of comet 67P/C-G will one day separate completely,” the writer speculates.

3) A single comet deformed as the ice in its nucleus evaporated

4) A huge chunk of something slammed into the comet and ripped off big pieces of it.

Scientists hope to find out more about the mysterious rubber ducky’s composition when Rosetta’s lander touches down on the comet’s surface in November.