Question about gravity and the moon

How can the moon's gravity effect the tides of the waters on earth but yet the earths gravity does not pull the moon from the sky and make it crash to earth?

The moon seems to be in a fixed orbit but how can it be so with the laws of gravity?

a reply to: Belcastro

I would also like to know this and it is interesting that the moon is slowly drifting away from the earth.

I know that Billions of years ago the moon was alot closer to earth. The tidal waves where huge covering vast amounts of the earths land day after day under hundreds of feet of water.

Your question is very valid, if years ago when the moon was much close why wasnt it sucked in then. Who knows?

Found abit of info here
physics.stackexchange.com...

Actually, that is a good question. One that I cannot answer.

I could give you an answer that really doesn't apply and hope you believe me and go away.

a reply to: Belcastro

Gravity pulls down straight at the earth. The moon is moving sideways.. Picture this.. So you have a sideways movement and a downward movement. As the moon falls, it is moving forward.. This is how satellites work.. This is what all orbits are.

It can never hit the earth because it's not falling as fast as it is moving forward.

I don't quite agree with the words below, but the picture is good enough.

a reply to: KnightLight

but how can the moons gravity affect the tides on earth at the same time as Moving forward, and yet the earth's gravity seems to not affect the moon.

a reply to: Belcastro

Gravitational Interactions of the Earth and Moon

originally posted by: Belcastro
a reply to: KnightLight

but how can the moons gravity affect the tides on earth at the same time as Moving forward, and yet the earth's gravity seems to not affect the moon.

they both affect each other equally for the same mass. You are pulling the earth up as we speak. If the earths gravity was not affecting the moon it would fly away.. You would never see it again.

whell thanks knightlight and zarniwoop for your info,

The topic was just something that ive been curious about.

a reply to: Belcastro

they say a catastrophic collision created the moon, but how could it have escaped the gravity of the newly formed earth and results in an orbit?

a reply to: Belcastro

Again that's from the starting speed of the object that collided.. Objects in motion remain in motion. So there is still a motion at some angle away from the gravity. Some pieces would make the earth larger. Some pieces would keep on going maybe hitting the sun.. maybe escaping the solar system.. And some would attract to each other.

A couple things to help with your imagination.
1) gravity seems really strong to us, but we are very close to the earth. Gravity gets weaker by an inverse square. So it's an exponential weakening by distance.
2) momentum. Our momentum sitting on earth is to stay not moving (relative to earth). A big massive object moving through space, has a LOT of momentum Moving.. To get it to stop or change direction takes a LOT of gravity. Momentum is mass x speed.

Here's a short video.

originally posted by: Belcastro
a reply to: KnightLight

but how can the moons gravity affect the tides on earth at the same time as Moving forward, and yet the earth's gravity seems to not affect the moon.

The earths gravity is holding the moon in orbit, if there was liquid water on the moon it would also have tides like the earth does.

The water can move very easily, so you see the gravity of the moon effecting more than say the ground.

The ground on earth also deforms just like the water, but to a much lesser extent, that we dont see it.

The moon is moving away from us because it is going a little bit faster than the speed it would take to be in a perfect orbit.....one day it will be gone forever.

The moon isn't at a "fixed" distance. It's moving away from the Earth at the rate of about 1.5 inches per year.

The moon also deforms slightly due to it orbit around the Earth (solid-body tide) - that's around 4 meters, compared to the 20 cm deformation on the Earth caused by the Moon.

www.astronomycafe.net...

Gravity alone would pull the Moon towards the Earth, but Newton's laws of motion would cause the Moon to fly off in a straight line if there were no gravity and just velocity/momentum. Combined together, the force of gravity and current velocity, are enough to nudge the Moon to a new position where the velocity has rotated slightly as the Moon has moved, but the distance to the Earth is still the same. Though this distance is increasing as the Moon and Earth gain extra mass from asteroid impacts and cosmic dust.

originally posted by: Belcastro
a reply to: KnightLight

but how can the moons gravity affect the tides on earth at the same time as Moving forward, and yet the earth's gravity seems to not affect the moon.

If the Earth's gravity didn't affect the moon, the moon would continue on in a straight line, never to be seen again.

That's why it goes *around* the Earth.

The Earth also raises tides on the Moon, you just can't see it because there's no water. It shows up as small plastic deformations of the surface.