Maybe because it's a COMET?

The headline to the Daily Article asked this:


Why is Rosetta's comet spewing jets of water? Mysterious plumes of vapour are spotted on 67P

To which I replied with the title of this post.  Of course it's spewing jets of water -- that's what comets do when they get closer to the Sun.  Which is what this comet is doing.

That factor, of course, it what is going to make choosing a landing site for Rosetta's lander a challenge, because given the fact that this little snowball has hardly any gravity, if the lander happens to land where a jet erupts under it, it could go spinning off into the abyss of space, never to return.

Which is poetic wordage for saying it's gone, gone, gone.

But that's why this mission to a comet is so much fun.