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Heh, not particularly accurate. The moon won't “eventually escape entirely”. It's orbit will keep increasing till the solar day = lunar month. At which point

by sliken 9y ago

Heh, not particularly accurate. The moon won't “eventually escape entirely”. It's orbit will keep increasing till the solar day = lunar month. At which points the tides stop and there's no more energy to increase the moon's orbit. The fun part is because vacuum is not perfect and the incredibly small effects of gravitational waves the orbit will start decreasing.... till it hits the Roche limit and becomes a ring! All that ignores the sun expanding and consuming the inner planets.

tvmalsv 9y ago
That'd be cool, but as it returned closer to Earth, wouldn't the tides resume and start the cycle all over again? (Assuming the oceans are still present and liquid, of course.)
- benchaney 9y ago
  No, the duration of a solar day would decrease with the duration of a lunar month.
mcstafford 9y ago
Which object's tidal forces would cause the moon's disintegration? I'm guessing either the Earth's, or the Sun's. I've only become aware of Roche limits from your comment, and glanced at the Wikipedia page, but don't really understand them.
- gizmo686 9y ago
  Tidal forces result from the difference in the strength of gravity at different sides of a body. Because we are so far away from the Sun, it does not exert any (significant) tidal force on us or the Moon. Moreover, the amount of tidal force exerting by the Sun is not affected by the distance the Moon orbits at [0]. In contrast, the moon is close enough to the Earth that those tidal forces are significant, and would drive the Roche disintegration. (They are also what drive the tides, the moons current orbital changes, and why many moons are tidally locked). [0] Technically, a smaller orbit will make the tidal force exerted by the Sun slightly more constant.
tzs 9y ago
Lunar tides would stop, but wouldn't Earth still have solar tides, causing bulges on the area of Earth closes to the Sun and on the opposite side? The Moon would still be passing over those bulges twice a lunar month. Wouldn't that continue to slowly modify its orbit?

by sliken 9y ago

tvmalsv 9y ago

That'd be cool, but as it returned closer to Earth, wouldn't the tides resume and start the cycle all over again? (Assuming the oceans are still present and liquid, of course.)

benchaney 9y ago
No, the duration of a solar day would decrease with the duration of a lunar month.

mcstafford 9y ago

Which object's tidal forces would cause the moon's disintegration? I'm guessing either the Earth's, or the Sun's. I've only become aware of Roche limits from your comment, and glanced at the Wikipedia page, but don't really understand them.

gizmo686 9y ago
Tidal forces result from the difference in the strength of gravity at different sides of a body. Because we are so far away from the Sun, it does not exert any (significant) tidal force on us or the Moon. Moreover, the amount of tidal force exerting by the Sun is not affected by the distance the Moon orbits at [0]. In contrast, the moon is close enough to the Earth that those tidal forces are significant, and would drive the Roche disintegration. (They are also what drive the tides, the moons current orbital changes, and why many moons are tidally locked). [0] Technically, a smaller orbit will make the tidal force exerted by the Sun slightly more constant.

tzs 9y ago

Lunar tides would stop, but wouldn't Earth still have solar tides, causing bulges on the area of Earth closes to the Sun and on the opposite side? The Moon would still be passing over those bulges twice a lunar month. Wouldn't that continue to slowly modify its orbit?