The Moon's Sunburns

Solar wind being emitted by the sun damages the moon’s surface as well much like humans who spend too much exposure to the sun’s rays. Since the Earth’s magnetic field acts as a protective barrier that deflects the sun’s rays so that we don’t get direct exposure from its heat, the moon has a weaker magnetic field and thus sustains more damage.

(Image credit: NASA LRO WAC)

Source: neatorama