Comet 67P/Churyumov–Gerasimenko
Comet · The rubber duck
Comet 67P is the first comet a spacecraft has orbited and landed on. Up close, it turned out to be shaped like a giant rubber duck, with cliffs, boulders and jets of gas shooting out as the Sun warmed it.
- ~4 km longYou could line up 3186 of them across Earth.
- ~6.4 yearsOrbit
- Rosetta (2014–2016)Visited by
Take a closer look
Two comets stuck together
Why the duck shape? Scientists think 67P’s “head” and “body” were once two separate small comets that bumped together very gently, long ago, and stayed stuck. The narrow “neck” between them is where cliffs and cracks are found, and where many of its gas jets shoot out.
Light and fluffy
67P is more like a dusty snowball full of holes than a solid rock – about half as dense as water. Its gravity is so weak that a person would weigh about as much as a paperclip. One good jump could send you floating off into space, never to come back down.
A smelly comet
Rosetta carried an instrument that “sniffed” the gas around 67P. It found hydrogen sulphide, which smells of rotten eggs, plus ammonia and other strong-smelling chemicals. Luckily nobody was there to notice – but these smells tell scientists exactly what the comet’s ice is made of.
How we found out
- 1969
Klim Churyumov and Svetlana Gerasimenko discover the comet on photographs taken in Kazakhstan.
- 2004
The European Space Agency launches Rosetta on a 10-year chase.
- 2014
Rosetta arrives in August. On 12 November its lander Philae touches down – the first landing on a comet. It bounces twice before coming to rest in a shadowy spot.
- 2016
Rosetta ends its mission by gently crashing onto the comet.
Did comets bring water to Earth’s oceans?
Maybe some of it. But Rosetta found that 67P’s water is chemically different from Earth’s oceans, so scientists think comets like this one probably weren’t the main source. The debate continues!
See it yourself
Only with a telescope, when it comes closest to the Sun (next in 2028).
From the encyclopedia
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