Souther Moon

The prominent crater is called Tycho, named for the sixteenth century Danish astronomer Tycho Brahe. His detailed observations of the movements of the planets, particularly Mars, allowed Kepler to work out his three laws of planetary motion.
The rays extending out from the crater are ejecta from the impact that created it. They show up particularly well at full moon and extend across the whole disc. The fact that they are so visible and overlay other craters and features indicate that they are relatively recent. Recent compared to the age of the Moon anyway! Only 100 million years ago or thereabouts.
Tycho is 86 kilometres in diameter and nearly 5 kilometres deep.