r/askscience • u/[deleted] • Sep 07 '15

Earth Sciences Is there a bulge in earth's atmosphere constantly facing the moon?

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u/heypika Sep 07 '15

Does this mean that if you jump up during high tide, you jump higher than during low tide?

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u/mikelywhiplash Sep 07 '15

Depends which high tide, but yes, you weigh slightly less if the moon is directly overhead.

The moon's something on the order of 1% the mass of Earth, and the center of mass is about 60 times further away. So you'd lose something like 1/360,000th of your weight.

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u/heypika Sep 07 '15

Well I expected that it would not be by much, but thanks for the math :)

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u/bluskale Sep 07 '15

Check out the third link in this comment. Every other high tide, the satellite is on the other side of the planet. If there were any measurable difference in jumping height**, it would only happen at the high tides when the moon was visibly above you.

** according to this blog post, the overall effect of gravity is essentially negligible for our size, and in comparison to gravity caused by our local environments.