why does`nt the earths gravity, pull the moon down on to it?
2007-09-10 08:36:09 · 16 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
If you disregard the fact that the Moon's orbit around the Earth is an elipse, and for purposes of giving a simple answer to your question, then:
The Earth has a diameter of 7,926 Miles. So, its radius is 3,963 miles.
And, the Moon (on average) is 238,900 miles from the Earth.
So the Moon is orbiting a fixed point in the center of the Earth at a total distance of 3,963 + 238,900 = 242,863 Miles.
The circumference of a circle, (orbit of the Moon) is
2 x Pi x R = 2 x 3.14 x 242,863 Miles = 1,525,179 miles.
The Moon travels all the way around that 1 Million five hundred thousand some odd miles in 27.3 Days (Each Day has 24 Hours).
So the speed of the Moon around the Earth is:
242,863 divided by (24 Hrs x 27.3 Days) = 2,327.8 MPH.
Now I know it looks like it is just sitting out there all fat, dumb and happy...But, it is really circling around the Earth at
Two Thousand Three Hundred and Twenty Eight Miles Per Hour. It wants to travel that fast in a straight line, but the Earth's gravity tugs at it and pulls it into a circle around the Earth. If it were not traveling so fast, the Earth might have pulled it right down onto the surface of the Earth a long time ago. So, the velocity of the Moon and Earth's gravity have reached a happy balance wherein the Moon orbits the Earth at roughly 240,000 Miles for ever and ever...
The Moon is actually moving away from the Earth by about one Inch per year. In 1000 years it will only have moved away from us by 83 feet. That is nothing to be alarmed about.
2007-09-10 09:07:24 · answer #1 · answered by zahbudar 6 · 2⤊ 0⤋
The Earth's gravity does pull on the moon, but not enough to bring it toward the Earth.
The Moon has a speed that it is traveling. The Earth's gravity causes the Moon to circle around it, rather than fly off into space.
The Moon's speed is too much for the Earth to completely capture, and the Moon is moving away from the Earth at about an inch per year. In many many millions of years, it will finally break away from the Earth and orbit the Sun on it's own.
2007-09-10 15:46:09 · answer #2 · answered by Mr. Scientist 4 · 1⤊ 0⤋
Because the moon is orbiting the earth, the speed of the orbit in space is such that the gravitational pull is felt and applied to the moon, but not strong enough or close enough to apply a continual encounter with the earth.
The best illustration I have found is with magnets. Turned one way, they attract, but the other way, they repulse. The earth and moon and a steady balance of attract and repulse that keeps the moon orbiting and the earth recieving the life giving tides that the moon provides.
Without the moon's tidal affects, there would be very little sealife in the oceans, making it very difficult for humans to get food.
God designed such a perfect planet, yes?
2007-09-10 15:43:56 · answer #3 · answered by Anonymous · 1⤊ 1⤋
Because the velocity of the moon and the Earth's mass are in perfect harmony to keep it where it is. If the moon ever slowed down significantly or the Earth suddenly got much much bigger then the moon would be pulled in; but this is doubtful. All orbits work this way.
2007-09-10 15:39:44 · answer #4 · answered by toblerone.king 2 · 3⤊ 0⤋
Just like the artificial satellites which orbit the Earth at various altitudes, the Moon is in orbit about the Earth. This means that it is moving fast enough for its own momentum to keep it from falling to the Earth; this has been dealt with in great detail in the answers to several other questions of the same form. I suggest you check some of them out.
2007-09-11 12:27:05 · answer #5 · answered by general_ego 3 · 1⤊ 0⤋
Because the moon is moving so fast. Plus the Moon is actually moving away from Earth by about one and a half inches per year.
2007-09-10 15:41:10 · answer #6 · answered by the_sheik_of_sheet_lightning 3 · 1⤊ 0⤋
For the same reason(in part at least) that planes don't, it's to do with the relationship of gravity and momentum and technically it is perpetually falling to earth...it's just lucky that the trajectory of the moon and the curvature of the earth is such that it just keeps missing us!
2007-09-11 14:02:44 · answer #7 · answered by airhead 2 · 1⤊ 0⤋
it is pulling the moon down to us. thats what an orbit is.
there is a force down towards the earth, and a tangential force which is the momentum of the moon. the net result is an orbit.
2007-09-10 15:40:14 · answer #8 · answered by Faesson 7 · 2⤊ 0⤋
It does - that's why it doesn't spin off... Its centrifugal force that keeps it where it is, in balance with gravity... a bit like spinning a weight in the end oof a bit of string... but the string in this case is earth's gravity.
2007-09-10 15:41:33 · answer #9 · answered by Robert W 5 · 1⤊ 0⤋
isnt it because the the earths gravity locks the moon into its own orbit ...... or something like that..
2007-09-10 15:41:35 · answer #10 · answered by corrinab2705 3 · 1⤊ 0⤋