What Is This?

Is this a particularly early batch of Christmas of cookies? No, that's not it. Maybe a microscopic view of bacteria or—no, not that either. Oh, it's probably a snowy group of polar islands. But where?

The south pole of Mars, if you must know. And they're actually pits, not islands. Every Martian summer, parts of its carbon dioxide ice caps evaporate directly to gas, and you're looking at the pits that are left behind. As Mars gets colder, it'll fill the pits back in by freezing more carbon dioxide solid.

Scientists actually aren't quite sure what the brown lining of the pits is made of, but looking at it just makes me want to sprinkle some holiday candy on the Martian landscape and eat it. [APOD]