Is the moon moving away?

Question

I heard it moves a inch a year

Answer 1

Yes it is. And how fast is it doing that? I have seen numbers that range from 1 inch to almost 2 inches a year. As someone else pointed out this is caused by tidal forces that cause the side of the earth nearest the moon to bulge towards the moon. And since the earth rotates in 24 hours and it takes the moon over 27 days to orbit the earth, the bulge tends to pull on the moon to speed it up in it's orbit. Likewise the moon pulls on the tidal bulge and tends to slow the earth down. The net result is that energy of the earth's rotation is transferred to the moon causing it to move further away.

It is estimated that in about about 15 billion years the Moon's orbit will stop increasing in size. If left alone the Moon would continue moving away until it would take about 47 days to orbit the Earth. Both Earth and Moon would then keep the same faces permanently turned toward one another as Earth's spin would also have slowed to one rotation every 47 days. But this will most likely never happen since the sun will evolve into a red giant before this time is reached. It is possible that the earth and moon will survive this stage of the sun's evolution but not real probable.

As the sun expands, the drag caused by the Sun's atmosphere will cause the Moon's orbit to decay. The Moon will swing ever closer to Earth until it reaches a point 11,470 miles above the Earth called the Roche limit. Reaching the Roche limit means that the gravity holding the Moon together is weaker than the tidal forces acting to pull it apart and the Moon will be torn to pieces to form a spectacular 23,000-mile-diameter Saturn-like ring of debris above the equator. The new rings will be short-lived as current theory says they'll eventually fall down onto the Earth's surface. The Earth of course will then be swallowed by the sun. As I mentioned there are possibilities that this will not happen depending on how much mass the sun loses before it reaches our neighborhood and things like that.

Equally interesting is how the moon was formed. The Moon is thought to have formed when an object about the size of Mars hit the Earth. The impact was so great that it threw large amounts of the Earth's mantle into orbit. This material evenually gravitated together and formed the Moon.

Answer 2

Yes it is. The moon causes a tidal bulge on Earth, and, due to Earth's rapid rotation, this bulge is always a little *ahead* of the moon. The extra gravitational pull speeds the moon up, which gradually moves it further away.

The energy delivered to the moon is being robbed from the Earth, in that as the moon moves away, Earth is slowing down in it's rotation. Every year, our day gets just a little bit longer.

If it went on long enough (I remember doing the calculation about 20 years ago), in something like 16 billion years, the Earth's rotation will exactly match the period of the moon's orbit, and one side of the Earth will always face one side of the moon - but, Earth and the moon will be destroyed by the sun long before that happens.

Answer 3

Nope. 4.5 billion years ago the moon was formed by the collision of some other object with the Earth. Part of the Earth and part of the object makes up the Moon. It of course was much closer to the Earth but since gravity falls off with distance there was a much stronger pull on the Moon a couple of billion years ago so it was not receding at the same speed as today. Gravitational pull and tidal forces were much stronger the closer the Earth and Moon were.

Answer 4

Yes, the moon is gradually migrating away from us due to its gravitational interactions with the tidal bulge of the Earth. The same process causes the Earth's rotation to slow down gradually.

The Earth's gravitational interactions with the Moon's tidal bulge has already slowed the Moon's rotation so that it always faces the Earth.

Answer 5

Yes by approx 2 inches a year.

Answer 6

Most definitely, and millions of years in the future it will have receded so far the Earth will topple over and Surbiton will be on the Equator which, as far as I am concerned, is the best place for it.

Answer 7

yes the moon is gradually moving further away,as the distance from us to moon is simple to measure

Answer 8

Yes, but not very quickly - about an inch a year, or so.

Answer 9

i have not about but i know its kept in an orbit due to the earth's gravitational force... but if your source is true... then yes, we may be experiencing loss in mass

Answer 10

No it is kept in the orbit of the earth by gravity. If the mass changes then maybe since gravity is related to the deformation of space.