earth and moon

[sciman]

As we all know that the earth has more attraction power than the moon.Then why don't the earth attracts the moon and moon collides with the earth?

[insane_alien]

it does attract the moon. the moon is just moving sideways enough so it always misses by a few hundred thousand kilometers. nature has lousy aim.

[swansont]

The earth and the moon attract each other equally. Newton's third law.

 

And i_a will be hit on the head by a meteorite for taunting mother nature.

[sciman]

Swansnot , the moon has a gravity of only 1 by 6th in comparison to the earth.So the earth should pull the moon.

[Janus]

Swansnot , the moon has a gravity of only 1 by 6th in comparison to the earth.So the earth should pull the moon.

 

First off, the Moon has 1/81 the mass of the Earth, not 1/6. The 1/6 is the surface gravity of the Moon.

 

Secondly, the force acting between the Earth and the Moon is equal to

 

[math]F = \frac{GM_1M_2}{d^2}[/math]

 

M1 and M2 are the masses of the Earth and Moon respectively. But you get the same answer for force if M1 is the mass of the Moon and M2 is the mass of the Earth.

 

They exert equal force on each other, the Moon just has a greater response to this force because of its smaller mass.

[Sisyphus]

Indeed, gravity is always a symmetrical force. You always exert exactly as much force on a body as that body exerts on you. Just another example of Newton's Third Law of Motion.

[iNow]

To the OPs point, since they do attract each other, how come they don't just smash into one another? Is it something to do with their velocity in another direction, or around the Sun?

[Klaynos]

To the OPs point, since they do attract each other, how come they don't just smash into one another? Is it something to do with their velocity in another direction, or around the Sun?

 

The moon is in orbit, so it is accelerating constantly, and keeps missing the earth as it falls...

 

http://en.wikipedia.org/wiki/Orbit#Understanding_orbits

[iNow]

The moon is in orbit, so it is accelerating constantly, and keeps missing the earth as it falls...

 

http://en.wikipedia.org/wiki/Orbit#Understanding_orbits

 

Well, thanks. I sort of was hoping to help the OP since only post #2 touched on this part of their question. I see I was just being lazy, and have found another source also:

 

 

http://www.cs.dartmouth.edu/farid/sciencekids/gravity.html

Gravity is also the reason why the moon (and satellites) orbit the earth and why we orbit the sun. But then why doesn't the moon crash into the earth? The moon is, in fact, constantly falling towards earth, it is just that it keeps missing. With an initial motion along the path of the orbit, the moon can continually fall towards earth without ever reaching it. This is illustrated on the right in the above diagram, where a cannon is shown firing a cannonball. If the speed of the cannonball is too slow it will crash into the earth. If the speed is too fast, the cannonball will escape the gravitational attraction of the earth. But, if the speed is just right, then the cannon ball will continually fall towards the earth, but never reach it -- it will orbit the earth.

 

 

Fact 1.

Mass is a measure of how much matter is in an object. On earth, mass and weight are effectively the same thing.

Fact 2.

The earth's mass is approximately 6,000,000,000,000,000,000,000,000 kg (13,000,000,000,000,000,000,000,000 lb).

 

Fact 3.

Gravity is an attractive force between any two objects in the universe. The force attracting any two bodies is proportional to the product of their masses and is inversely proportional to the squared distance between them. Below, the gravitational attraction is stronger for the right-most pair of objects because they are more massive and closer together.

 

 

 

Sciman, hopefully this has answered your question. If not, feel free to ask more. Enjoy mate.

[Innit]

Just to expand on this - The type of orbit that the moon has around the Earth is known as a non-interrupted or a circumnavigating orbit, as it also states in the Wikipedia page.

 

What I don't understand, however, is - Why doesn't the moon just "ditch" the earth, and go in orbit around the sun, like a planet? I suppose that it is already "stuck" in orbit around the Earth, but would it be possible, somehow?

[iNow]

What I don't understand, however, is - Why doesn't the moon just "ditch" the earth, and go in orbit around the sun, like a planet?

It's not moving fast enough to break away from the pull of Earth's gravity.

[Sisyphus]

Also, it is orbiting the sun. It's just also orbiting the Earth.

[Innit]

Also, it is orbiting the sun. It's just also orbiting the Earth.

 

I was more under the impression that the moon was orbiting around the Earth, which was orbiting around the sun. So in theory, the moon was just going around the sun because it was attracted to the Earth.

 

But would it be possible, if the moon were to break loose of this circumnavigating orbit around the Earth (which wouldn't happen), that it would orbit around the sun (or could it crash into the sun?).

[losfomot]

I was more under the impression that the moon was orbiting around the Earth, which was orbiting around the sun. So in theory, the moon was just going around the sun because it was attracted to the Earth.

 

But would it be possible, if the moon were to break loose of this circumnavigating orbit around the Earth (which wouldn't happen), that it would orbit around the sun (or could it crash into the sun?).

 

 

I think the most correct response would be to say that the Earth-Moon system is orbiting the Sun. If the Earth suddenly vaporized, the moon would continue it's orbit around the Sun.

[D H]

Any satellite orbiting the Earth would simply continue to orbit the Sun if the Earth suddenly ceased to exist. The Earth's orbital velocity around the Sun is about 29.8 km/sec. In comparison, the Moon's orbital velocity around the Earth is a paltry 0.9 km/sec. A low Earth orbit satellite moves faster at 7.9 km/sec, which is still small compared to 29.8 km/sec.

 

It takes an immense amount of energy to make something orbiting the Earth crash into the Sun. In fact, it takes more energy than is needed to make the object escape the solar system.