Question about gravity?

Question

I was wondering....

Since the earth's gravity is so much stronger than the moon's gravity, why can't rocks on the moon be dropped from the moon to the earth?

Answer 1

Take a look at the law of universal gravitation. It states that the gravitational attraction between any two objects (the rock and the moon, the rock and the earth, or two rocks) is dependent on both of their masses, but decreases with the square of the distance between them.

If you had a rock on the moon, the moon's gravity would be a much stronger force than the earths, simply because you were so much closer to the moon!

In a similar way, we feel the influence of the moon's gravity every day, it is what creates the tides here on earth.

Answer 2

The strength of gravity is greatly affected by distance. In this case, Since the rocks are so much closer to the moon than the earth, they are affected by the moon's gravity more.

Here are two interesting side notes. First, the effect of gravity is proportional to distance by the inverse square law. In other words, if you double the distance between the objects, you quarter the strength of the force of gravity on that object. Second, if a rock where halfway between the earth and the moon, they would "fall" toward the earth. So, to drop rocks from the moon to the earth, if you throw them hard enough to get half way, the will come crashing down to earth.

Answer 3

Hi. The force of gravity on the moon holds the rock until it is traveling fast enough (the escape velocity). There are points between the Earth and Moon where the two gravities are in balance, and the rock would float. Any closer to the Earth and the rock would fall to Earth. Any closer to the Moon and it would fall to the Moon.

Answer 4

Gravity is a force that decreases with distance so a rock on the Moon is effected more by the moon's gravity than the Earth's. Rocks could be sent from the Moon to the Earth with the right force applied to them, otherwise they will stay on the Moon.

If you want more detail use Yahoo to search the web for effect of gravity.

Answer 5

Well, it's all about speed/acceleration, I believe. I don't think you can simply drop a rock from the moon to the earth, but one can surely toss it. It's gonna have to be one hell of a toss - to overcome the moon gravity field (trying to attract the rock), to overcome the sun's gravity (keeping all of the Solar System together, thus quite strong (has to do with the Sun's mass)) and I think there could be more. At the end, the rock would be close to the earth and it would be attracted predominantly by its gravity field, and eventually fall. Or stay as a moon (if the balance of gravitational attractions nulls). Gravity has to do mostly with mass, so it would also depend on the size on the boulder.
It is a fascinating topic....

Answer 6

Well, you can't really "drop" rocks from the Moon to the Earth, but you can throw them hard enough to escape the Moon's gravity. If you throw one of them just right, the Earth will run into it. Since the Earth is moving very, very fast, the impact would be both spectacular and locally catastrophic. Read "The Moon is a Harsh Mistress" by Robert A. Heinlein. Think about the American Revolution.

Answer 7

since there isn't gravity between the earth and moon, a rock would not drop down to earth, it would just float.

Answer 8

Because they cannott be pushed into the earth the gravity is pushing it!!!

Answer 9

because they would need something to propel them to earth there's nothing in space to do that that is why the space shuttles thrusters propel it through the earths atmosphere or it would never be able to return to earth just continue to float in space indefinitely

Answer 10

it would, but it's not close enough, an object would have to enter the earths atmosphere, (which is generally the end of earths gavitational pull effect)