Why is the surface of the moon covered in dust?

If YOU floated around for 4 billion years without dusting off, don't you think you would be covered in dust too? There is no air on the Moon because it's to small to hold an atmosphere.

It's covered in dust because the side of the Moon receiving sunlight is very hot and the side of the Moon that is dark gets very cold so over time rocks are thermally expanding and contracting rapidly causing them to shatter. Also meteor impacts shatter the rocks into dust. The dust on the Moon (lunar regolith) is not like dust on Earth, it's not dead skin cells it's powdered rock. You know how much dust on Earth can be abrasive so imagine how much more abrasive dust on the Moon is.

Why is there no air on the moon to blow the dust around? Because the Moon doesn't have enough surface gravity to hold onto an atmosphere.

How cold would the Moon be? I notice you're American so I'll give the answer in Fahrenheit. It ranges from around 225 degrees F in daytime to -243 degrees F at night time.

The surface of the Moon (and probably all other moons in the Solar System) is covered with dust called regolith. It has formed over the 4billion year history of the Moon from the impacts of vast numbers of micrometeorites. Interplanetary space is filled with fine dust, and the Moon has swept this up over its history. It doesn't get blown around; it just accumulates. It would be hot when the Sun is shining, and very cold when the Sun is below the horizon.

It's essentially pulverized rock, from the many meteor impacts.

The moon isn't massive enough to retain an atmosphere; and, even if it had one, it doesn't have a magnetic field to protect it if it did.... As a result - the dust isn't worn and smooth like how you expect Earth dust to be; it's almost like little pieces of sharp glass - the Apollo astronauts noticed just *how* irritating it was if it got on you.

And cold? In the shadows, the temperature can fall to 240 degrees below zero. It can also be 250 - 300 degrees in the direct sunlight.

Moon dust can be explained by impacts.

It is now generally accepted that the moon does have a small amount of atmosphere surrounding it, though it is practically a vacuum in comparison to the Earth's atmosphere. Why doesn't the moon have a more substantial atmosphere? Lack of a strong magnetosphere and not enough mass means not enough gravity to hold an atmosphere against the solar winds that constantly bombard it.

Please look into this link

http://answers.yahoo.com/question/index?qid=201103...

Hope it helps.