How many year, approximately before the moon leaves earth's orbit?
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answers:
Raymond say: Never.
The recession of the Moon is caused by the tidal bulges it causes in Earth's ocean. Because of Earth's rotation, the bulges are displaced to the East of the line joining the centres of Earth and Moon.
The bulge closest to the Moon has an ever-so-slightly greater gravitational attraction (on the Moon) pulling it to the East (in the Moon's direction of orbit - thus adding to orbital energy).
1) As the Moon moves away (4 cm per year), the tides will get smaller, thus the bulge will have less and less of an effect.
2) The bulge does rub against the bottom of seas (at least, in the shallow parts) and that slows down Earth's rotation: the displacement of the bulge towards the East will be less and less.
3) Earth is slowly losing its oceans (a million years or so?) which will reduce the tides.
Taking all the effects together: the recession of the Moon cannot last more than 6 billion years (6,000 million). At that time, the Earth will be in spin-lock with the Moon (the same way that the Moon is already in spin-lock with Earth: always showing us the same face). When that happens, further recession will be impossible. By that time, the Moon will still be in orbit around Earth (it will not have reached escape speed).
Mind you, by that time, the Sun will have bloated out into its red giant phase, frying away all water and life from the Earth's surface, then the Sun's outer layers will have been (gently?) blown away into space, leaving only its core as a white dwarf. Therefore, most of us will not care by then.
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tham153 say: never--it will recede to a distance here its orbital period is 43 days, and then gradually move closer. The Sun's red giant phase will destroy Earth and Moon before anything else happens
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Faesson say: That's never going to happen.
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poldi2 say: It won't leave orbit.
The reason the moon is receding is due to tidal friction. That will end in a billion years when the expanding sun boils the oceans dry.
https://www.britannica.com/science/tidal...
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Scott say: It wont. It is drifting roughly 3cm away per year. If you take the gravitational equation of "-G=(m1m2)/r2 it becomes weaker but will still have a force.
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Atheist Dude say: Never
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quantumclaustrophobe say: It never will. Even if the sun had an unlimited lifetime, the moon wouldn't leave orbit. It'll move further out, but the further out it goes, the slower the rate of it's moving away becomes. Earth would first become tidally locked with the moon (and, that would be the end of the moon moving further away).
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Seeker say: never
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billrussell42 say: never, or until the sun blows up. The orbit will lengthen slowly over time, but still remain an orbit until something else intervenes, such as mars or venus.
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Miłosław say: ~1,399,381 years
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Raymond say: Never.
The recession of the Moon is caused by the tidal bulges it causes in Earth's ocean. Because of Earth's rotation, the bulges are displaced to the East of the line joining the centres of Earth and Moon.
The bulge closest to the Moon has an ever-so-slightly greater gravitational attraction (on the Moon) pulling it to the East (in the Moon's direction of orbit - thus adding to orbital energy).
1) As the Moon moves away (4 cm per year), the tides will get smaller, thus the bulge will have less and less of an effect.
2) The bulge does rub against the bottom of seas (at least, in the shallow parts) and that slows down Earth's rotation: the displacement of the bulge towards the East will be less and less.
3) Earth is slowly losing its oceans (a million years or so?) which will reduce the tides.
Taking all the effects together: the recession of the Moon cannot last more than 6 billion years (6,000 million). At that time, the Earth will be in spin-lock with the Moon (the same way that the Moon is already in spin-lock with Earth: always showing us the same face). When that happens, further recession will be impossible. By that time, the Moon will still be in orbit around Earth (it will not have reached escape speed).
Mind you, by that time, the Sun will have bloated out into its red giant phase, frying away all water and life from the Earth's surface, then the Sun's outer layers will have been (gently?) blown away into space, leaving only its core as a white dwarf. Therefore, most of us will not care by then.
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CarolOklaNola say: Never.
The Moon will never will leave Earth's orbit because of conservation of energy and momentum . The Moon's orbit is getting longer and the speed is increasing , but the Moon's speed probably will never reach escape velocity. Earth's rotation rate is slowing down. Earth eventually will be tidally licked with the Moon, like Pluto and Charon are tidally locked with each other, but the Sun may become large enough during the red giant stage to consume both the Earth and the Moon before that happens.
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