Throwing Snowballs at Xanadu by Bartholomew Thockmorton
Approx. 11,570 words.
Published on November 18, 2011.
Betty and Sam are the luckiest System Searchers in the universe! After months of cataloguing solar systems, they discover the very first Earth-normal planet! But as they ponder oddities in the native species and the planet, they find not one, but two comets are about to hit their paradise! And it'll be an Extinction Level Event! What can they do? What will they do? And can they do it in time?