Here's a picture of the moon. That splat on the bottom is Tycho crater, a relatively young impact.

The crater is about 82 km (51 miles) across. (Bristol to London is about 100 miles. The M25 around London would fit neatly inside the crater.)

The radial lines are exactly what they look like: debris from the impact.

Here's a closeup of the crater:

Impact craters often have a central peak like this, caused by material falling back after being flung out.

Here's a closeup of the peak, which is about 2000m high:

Here's a closeup of the tiny white dot on top, which is a boulder about 100m across.

Here's a closeup of the boulder, taken from above:


This post was originally on LiveJournal.