Bright spots on Ceres...

Bright spots on Ceres...  The Dawn robotic explorer is approaching the asteroid Ceres, and as it draws closer the images it's returning get better and better.  One recent image (at right) shows two bright spots at the bottom of a basin (or crater).

NASA scientists don't know what the bright spots are.  Two speculative explanations: some kind of volcanic activity (possibly involving water), or some sort of shiny surface that reflects more sunlight.  The UFO crazies are of course all over this, with some claiming this is clearly an alien spaceship. 

Personally, I think it's most likely some litter left behind by some alien tourist who took one look at Earth and ran away screaming after seeing a political TV ad...