Why doesn't the moon spiral into the earth?

Question

If there is a constant G force on the moon, then it falls about 5m/s for the FIRST second, which it overcomes with it's tangential motion. But in the second second (heh) it should fall TWENTY m, thereby losing 15m from it's motion. The next second should be even more, and so on.

If the moon, or any satellite(doesn't have to be the moon, it's just an example) is moving tangent to the earth, then it has no centripetal force. It only has the downward pull of the earth which should cause it to spiral. It would need boosters or something to gain centripetal force.

Answer 1

First, the gravitational pull of the Earth on the Moon at the distance of the moon doesn't pull it 5 m. It's much weaker and actually only moves it about 1/20 of an inch off an otherwise straight path.

Because of the moon's forward motion, the 1/20 of an inch is just enough so that the Moon remains (roughly) the same distance from the Earth.

As far as the Moon getting faster the next second, you have to realize the pull of the Earth is perpendicular to the Moon's motion. As such, it doesn't speed up or slow down the moon, merely change its course.

Answer 2

As is falls 'down', the meaning of 'down' is constantly changing (since the Moon is changing position with respect to the Earth). Basically, the curvature of the Earth makes it 'fall away' from the moon as fast as the Moon is falling towards it.

HTH ☺


Doug

Answer 3

The moon is actually moving slowly away from the earth.

Answer 4

The centrifugal force is equal to the centripetal force which produces a stable orbit.

Answer 5

The earth and the moon just happy where they is. Moon got lots of gravity earth got lots of gravity. Everybody happy. Just leave them alone.

Answer 6

maby all the astriods or mars has a pull on it to