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With the masses of the comet and the spacecraft being relatively close, it's hard to tell whether Rosetta is co-orbiting the sun or orbiting the comet itself.

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> With the masses of the comet and the spacecraft being relatively close

No, they're not close at all. The comet is three by five kilometers across, and the mass is around 3.14 * 10^12 kg. The orbiter at launch weighs in at 2900 kg and the lander is 100 kg.

http://en.wikipedia.org/wiki/Rosetta_(spacecraft) http://en.wikipedia.org/wiki/67P/Churyumov%E2%80%93Gerasimen...

I think jeroen94704 is saying "With the masses of the comet, and the spacecraft being relatively close"

[comma added]

I disagree. At the very least it would need to be "mass" not "masses". The closest statement should be more like "With the mass of the comet, and the spacecraft being relatively distant."

It's orbiting the sun, however its orbit is such that it will take it around the comet in a roughly triangular shape - but this isn't the same thing as orbiting.

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