Why the moon does not escape or attract to earth?

Answer 1

It can be shown that the moon, in its present orbit around the Earth, is actually "falling" around the Earth. This is a somewhat difficult concept to get one's brain around, but it can be explained this way: The moon is falling around the Earth, which is why it won't crash into us.

Answer 2

It does but the inertia of the moon (it is travelling in an orbit around the Earth) keeps it in it's orbit. If gravity would stop all of a sudden it would fly off on a tangent.

If the moon just flew in from some other part of space, and happened upon the earth, it might very well crash into us. Fortunately, the moon is spinning around the earth in a very stable orbit. Its orbital velocity keeps it doing what it is doing.

The moon's orbit around the Earth is (mostly) stable because the force of gravity is balanced by the reaction force (centripetal, in this case) of the moon due to it not travelling in a straight line. (Newton's Third Law: For every force, there is an equal and opposite reaction force)

Answer 3

In any orbit, the force of gravity is balanced by the inertia of the object. The object is moving so quickly sideways that by the time the object has fallen, it has already missed.

That's why it is called "free fall"; a moon or satellite is freely falling - AROUND the planet!

Answer 4

The sun has a greater pulling force because of its greater mass, but, gravity's strength drops expontentially, the further you move away from the centre of mass. That is why the moon's gravity has more effect on our tides than the sun, and why the earth's gravity holds the moon in earth orbit, rather than the sun pulling it away.

Answer 5

he moon does not fall to Earth because it is in an orbit.

One of the most difficult things to learn about physics is the concept of force. Just because there is a force on something does not mean it will be moving in the direction of the force. Instead, the force influences the motion to be a bit more in the direction of the force than it was before.

For example, if you roll a Bowling ball straight down a lane, then run up beside it and kick it towards the gutter, you apply a force towards the gutter, but the ball doesn't go straight into the gutter. Instead it keeps going down the lane, but picks up a little bit of diagonal motion as well.

Imagine you're standing at the edge of a cliff 100m tall. If you drop a rock off, it will fall straight down because it had no velocity to begin with, so the only velocity it picks up is downward from the downward force.

If you throw the rock out horizontally, it will still fall, but it will keep moving out horizontally as it does so, and falls at an angle. (The angle isn't constant - the shape is a curve called a parabola, but that's relatively unimportant here.) The the force is straight down, but that force doesn't stop the rock from moving horizontally.

If you throw the rock harder, it goes further, and falls at a shallower angle. The force on it from gravity is the same, but the original velocity was much bigger and so the deflection is less.

Now imagine throwing the rock so hard it travels one kilometer horizontally before it hits the ground. If you do that, something slightly new happens. The rock still falls, but it has to fall more than just 100m before it hits the ground. The reason is that the Earth is curved, and so as the rock traveled out that kilometer, the Earth was actually curving away underneath of it. In one kilometer, it turns out the Earth curves away by about 10 centimeters - a small difference, but a real one.

As you throw the rock even harder than that, the curving away of the Earth underneath becomes more significant. If you could throw the rock 10 kilometers, the Earth would now curve away by 10 meters, and for a 100 km throw the Earth curves away by an entire kilometer. Now the stone has to fall a very long way down compared to the 100m cliff it was dropped from.

Check out the following drawing. It was made by Isaac newton, the first person to understand orbits. IMHO it is one of the greatest diagrams ever made.

What it shows is that if you could throw the rock hard enough, the Earth would curve away from underneath the rock so much that the rock actually never gets any closer to the ground. It goes all the way around in the circle and might hit you in the back of the head!

This is an orbit. It's what satellites and the moon are doing. We can't actually do it here close to the surface of the Earth due to wind resistance, but on the surface of the moon, where there's no atmosphere, you could indeed have a very low orbit.

This is the mechanism by which things "stay up" in space.

Gravity gets weaker as you go further out. The Earth's gravity is much weaker at the moon than at a low-earth orbit satellite. Because gravity is so much weaker at the moon, the moon orbits much more slowly than the International Space Station, for example. The moon takes one month to go around. The ISS takes a few hours. An interesting consequence is that if you go out just the right amount in between, about six Earth radii, you reach a point where gravity is weakened enough that an orbit around the Earth takes 24 hours. There, you could have a "geosynchronous orbit", a satellite that orbits so that it stays above the same spot on Earth's equator as Earth spins.

Although gravity gets weaker as you go further out, there is no cut-off distance. In theory, gravity extends forever. However, if you went towards the sun, eventually the sun's gravity would be stronger than the Earth's, and then you wouldn't fall back to Earth any more, even lacking the speed to orbit. That would happen if you went about .1% of the distance to the sun, or about 250,000 km, or 40 Earth radii. (This is actually less than the distance to the moon, but the moon doesn't fall into the Sun because it's orbiting the sun, just like the Earth itself is.)

So the moon "falls" toward Earth due to gravity, but doesn't get any closer to Earth because its motion is an orbit, and the dynamics of the orbit are determined by the strength of gravity at that distance and by Newton's laws of motion.

Answer 6

Actually, the moon is drifting away from the earth every year by about 1.5 inches. Its orbit is very gradually spiraling outward. There will come a time when it more or less has a planetary orbit within out solar system. It will not be a real planet, as evidenced by the recent demotion of Pluto, but it will no longer be a satellite of our planet.

Thus, the answer to your question is that the moon is undoubtedly escaping earth's gravitational attraction.

Answer 7

Who said it is falling? In fact, the moon is moving very slowly farther away from earth. You are thinking of what you have been told about how the moon stays in orbit, and probably what you have been told is basically correct. Imagine a chunk of rock (not too big!) flying through space, making contact with our atmosphere, partially burning and then falling to earth's surface. The difference between this object and the moon is that the moon has enough orbital velocity to keep it in a stable orbit instead of crashing down. If the moon were moving a lot faster, it might fly off into space and leave earth's orbit altogether. So in a sense the moon is 'falling' toward earth, and this is just another way of saying that the moon is in the thrall of earth's gravity. This pull is perfectly offset by the velocity of the moon in its orbit. The story of it moving away very slowly is another question altogether and is a little complicated.

Answer 8

The other part of an orbit is that the Moon is flying away from earth at the same time they pull together. This is what keeps the moon in orbit, as opposed to the crashing or the complete loss of the moon.

Or , a balance between the pull of the earth's gravity , and centrifugal force , in which spinning objects send other objects out from the center.

Answer 9

The moon is not attracted by the gravity of earth as it rotates around the earth. When it rotates, a force is exerted, due to it's motion, that is directed outwards, and the gravity acts inwards, so it stays on it's own path, rotating.

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Another contributor bristled:

We want to be charitable and diplomatic, so all we can say is that the first answer,

up there above the dotted line, is not only wrong, it's also mean and unkind, because

if you swallow it, it plugs up your brain with so many false concepts that your brain

is closed to any accurate understanding of the real deal, just as sure as a tight cork

keeps the bugs out of a wine bottle.

The moon is attracted to the earth, and the earth is also attracted to the moon.

Because of that mutual force of attraction, the earth and moon both orbit the point

between them called their mutual "center of mass" ... the point where the balance

would have to be if the earth and moon were both on a see-saw. Since the earth

is about 80 times 'heavier' than the moon, the pivot point has to be about 80 times

farther from the moon than from the earth, and actually winds up inside the earth.

That's why, even though they're both orbiting the same point, it looks like the moon

is doing all the orbiting.

If there was no force of gravity between the earth and moon, then the moon would

stop moving in a curved closed orbit around the earth, and it would just take off in a

straight line and never be seen around here again.

If that happened, the earth would continue swinging around in its orbit around the sun,

because after all, the earth would still be attracted to the sun.

And furthermore, please forget that nonsense about a force due to the moon's motion

that's directed outwards. There is no such force. The only force present is the force

of gravity, and it's always directed towards the center of the earth.

Answer 10

Because of the sun's gravitational pull and the earth's "swinging" of the moon. First of all, the moon is orbiting the earth because of the earth's gravitational pull and it's rotation. The moon is also being pulled back from the sun, and although the sun is thousands times larger than the earth, it has an almost equal gravitational pull on the moon. The moon can strike the earth if earth's rotation was slower or faster. Now, the moon isn't being pulled closer to the earth; rather, it's being pulled away at a constant speed of 1-1.5 inches per year.