Last year, on March 7, the Mars rover Spirit took an image of a streak in the Martian sky. It looked like a meteor trail, but it might also have been an older probe like Viking still orbiting the Red Planet. Scientists weren't sure.
Now they are. The streak was the trail from a meteor burning up in the thin martian atmosphere. It was probably originally part of the comet Wiseman-Skiff, which takes about 6 years to orbit the Sun. Comets are big chunks of frozen gas and rock, and when they get near the Sun the frozen gas sublimates, or goes right from a solid to a gas. The little bits of rock frozen in the matrix then work their way free, and follow in roughly the same orbit. When a planet plows through the debris, you get a meteor shower. Evidently Mars had a shower of its own ...
