Sometimes called rays and sometimes called streaks, crater rays are visible lines that radiate from the center or rims of some craters.
Rays are made up of material that was ejected from the crater when a meteorite hit the lunar surface.
The crater Tycho, located in the southeast quadrant of the Moon, illustrates the most spectacular example of crater rays.
The layering of rays across other surface features can be useful as an indicator of the relative age of the impact crater.
Lunar craters on the near side of the moon with pronounced ray systems are Aristarchus, Copernicus, Kepler, Proclus, and Tycho.