The Moon

[jcb33]

I was just wondering, The moon always faces us, so how come it has so many crators, does it suck them away from earth.... because I would have thought Earth would pull them in rather than them floating into earths gravity then being thrown towards the moons face.....

[Pax Unum]

LINK-> Moon

[War-Junkie]

its because theres no wind on the moon to cover up the craters and the earth has an atmosphere so it burns most of em up

[Picturesque Orion]

As war- junkie said, the moon has no wind because of the lack of atmosphere and it is not geogacally active. Those crater are really old you know. So the smallest thing that hits the surface make a crater.

P.S Spellcheck that.

[The Silver Thong]

The moon it very far away ! So an asteroid or meteor does not have to hit the earth facing side straight on. They can come in at many angles, and the earths gravity I'm sure has thrown many asteroids into the moon's face by changing there direction. You have to think the moon and earth I do believe have been here for around 4 billion years. Thats alot of time to aquire many creators

Edited October 18, 2006 by The Silver Thong

[MID]

I was just wondering, The moon always faces us, so how come it has so many crators, does it suck them away from earth.... because I would have thought Earth would pull them in rather than them floating into earths gravity then being thrown towards the moons face.....

An interesting question!

Indeed you are correct in that the same hemisphere of the Moon always faces the Earth. However, that fact is fairly irrelevant when discussing the fact that the Moon presents many visble craters, while the Earth does not.

Craters are of course caused by impacts; meteors, comets or pieces thereof (in the case of the Moon...on the Earth, it is thought that cometary or cometary fragment "impacts" don't actually strike the surface, since their composition is mostly ice, which is evaporated by atmospheric friction upon entry), metorites, or even micrometeorites..

These things occur from all angles in space. Thus, we see that the entire face of the Moon, both sides, is populated by craters, some relatively young, and many billions of years old.

The reason the Moon has so many craters is twofold. First, the Moon has no defense against surface scarring, in the form of an atmosphere. An atmosphere produces high energy friction against an entering space object. The vast majority of objects entering the Earth's atmosphere are burned up during entry and never actually strike the surface. On the Moon, any object approaching at an adequate angle will strike the surface.

Now, the crater forming epoch has long since past, but there was a time wheh many objects in the early solar system impacted planets, the Earth, and the Moon. The frequency of such impacts or encounters is much, much less than it was, but only the largest of the objects impacting the Earth actually impacted its surface.

The second part of the reason also involves the atmosphere of the Earth, and the weather systems produced by its interaction with solar energy. On Earth, we have wind and rain and snow and hurricanes and floods, and all sorts of atmospheric erosion effects, which, over time, alter the surface of the Earth.

In a nutshell, these effects wipe away evidence of any cratering that may have once been present from extremely large objects on Earth. Only the very youngest craters are visible on the Earth (Meteor Crater in Arizona, as a classic example...perhaps 50,000 years old)...

See? Pretty cool stuff. That crater is about 35 miles east of Flagstaff, Arizona...it's about a mile accross and over 500 feet deep!

So, the Moon, having no atmosphere to either burn up approaching objects, or weather systems to erode them, is populated by thousands of ancient, and not so ancient impact craters which will remains for billions of years. The Earth minimizes the number of impacts, and erodes the craters of those few objects that actually impact its surface over time.

Therefore, we have very few craters, while the Moon has bunches of them.