There’s a hole in the Moon!
I mean, seriously, there’s a hole in the Moon
Actually, it’s a pit, and there are several of these known in the lunar surface. I’ve even written about them before, but this shot from the Lunar Reconnaissance Orbiter is the best I’ve seen yet (and there are more at that link). You can clearly see the floor of the pit, with rubble strewn there, and the shadow gives it an excellent sense of relief (in fact, I have to laugh over how much the shadow looks like a little crescent Moon itself!).
These pits (or skylights as they’re sometimes called) form when lava flows over the surface of a world. The lava can carve a groove in the surface, and eventually the top of the lava flow solidifies even before the flow stops. When the lava flows away, you’re left with a tube under ...
