Trippy

This is a rock the size of a house rolling down a slope on the moon. It seems so unlikely; we grow up assuming the moon is a cold, dead rock.

Clearly, something is going on. Moonquakes, perhaps?

Maybe it's the same thing that causes this. Rocks rolling around in Death Valley. No one knows why. Trippy.

I've read (but am to lazy to bother Googling it for a source) that water molecules dance about on the surface of the moon when sunlight hits the surface. They fall to the ground when it's dark, take up the dance once again the next time the sun clears the horizon.

The photo is from the Lunar Reconnaissance Orbiter. I grabbed it from Bad Astronomy.