why does not the earths gravitation cause the moon to crash on it?

Answer 1

Zahbudar got the answer ALMOST right. The moon stays in orbit around the earth for the same reason that the earth stays in orbit around the sun: its centrifugal acceleration (the pull of the brick on the rope) matches its gravitational acceleration, so it is in a constant state of free fall.

What Zahbudar got wrong was the speed of the moon. The moon orbits the earth once every MONTH (actually closer to every 27.3 days), not once a day. Still, this is obviously fast enough to keep the moon in orbit (since, in fact, the moon DOES stay in orbit!).

Answer 2

Because the Moon is flying around the Earth at a great rate of speed. Tie a rope around a brick, and twirl the brick around you as fast as you possibly can without loosing the brick or the rope. As long as you can hold on to the rope while the brick is flying around you - that is the relationship between the Earth and the Moon. The rope is the pull of the Earth's gravity.

Remember that the Moon (about 250,000 miles from Earth) circles completely around the Earth once per day. That is a distance of roughly 1,595,120 miles per day. In simpler terms, if you divide the orbital path of 1,595,120 miles by 24 hours in a day, the result is 66,463 Miles Per Hour. So, while it looks kind of slow and all that...in fact, it is really hauling butt out there. The fairly large distance from Earth makes it appear to move very slowly.

Answer 3

Imagine this. Go outside and pick up some rocks. (Taking care not to hit anything but the ground of course) Throw one with just a little force and it hits the earth right in front of you. Now throw one with a bit more force and it will land a little farther away than the first one did. Now throw one really hard. It lands really far away. If you could throw a stone fast enough, it would go all the way around the earth and hit you in the back of your head. That's what the moon is doing.

Answer 4

If you swing a heavy object about you on the end of a rubber band the band will stretch and the object will rotate rather than fly away. The rubber band (like gravity) holds the object in orbit about you. If you slow down the rubber band will pull the object closer to you. The moon orbits about the earth at nearly constant speed and there is nothing (like wind resistance) to slow it down. If the moon stopped orbiting, the earth would pull it down from the sky.

Answer 5

http://curious.astro.cornell.edu/question.php?number=699

Check this out it should answer your question ( This theroy is based on the theroy the earth was struck by a mars sized object which ejected a large amount of crust from the earth which formed the moon. Which is why the moon is mostly made of the same material the crust of the earth is.)

The Fellow above is using the capture theory to answer your question.

Answer 6

Inertia

The same reason the shuttle and thousands of satellites orbit around the earth without crashing into it.

In fact, the moon is moving further away by a few inches every year.

Answer 7

the moon is travelling along a path thru the curvature of space-time imposed by the gravitational field of the Earth.

Answer 8

the moon is in motion and was hurdling through space in a straight line until it passed through the earths gravitational field at that point earths gravity pulled on the moon bending its trajectory and drawing it closer. Because it still has forward momentum it remains in a constant state of falling

Answer 9

the moon will crash to earth if the earth's gravitational pull is too great.
(I think)