When we see comets up in the sky they're really spectacular. But unless you get close to a comet, you can't really figure out what's going on.

The damn thing is layered like a frozen onion.

For example, some boulders seem to have just disintegrated on the surface. We've also seen that some of the fine surface material moves downhill, filling low areas and creating flat surfaces in craters, even with Eros' low gravity. These are big puzzles and we need to get a better look.