result: a decrease of gravitational pull of the moon on you of 0.000000000000000146894299979968
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quantumclaustrophobe say: The moon is moving away from the Earth, at just about an inch and a third a year. So, it's about a yard and half further out today than it was when Apollo 11 touched down.
What happens is, the moon raises a 'tidal bulge' on the Earth; the Earth's rotation carries that bulge *ahead* of the moon, and the moon, in turn is attracted to that bulge through gravity. So, the moon gets slightly accelerated - boosting it's orbit by just a bit.
The energy going to boost the orbit isn't free, though - our day is getting a little longer because of it.
The Earth's gravity isn't changing - it's just the dynamics of tidal effects.
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Gray Bold say: True, but the change would not be noticeable. The gravitational effects of the Moon and the Sun (which are also the cause of the tides) have a very small effect on the apparent strength of Earth's gravity.
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poldi say: The moon is moving away from the Earth about 4 cm a year. This is due to tidal friction.
The moon does not change the gravity on Earth.
Your friend is misinformed.
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Clive say: 1 cm is hardly anything. Tidal drag does indeed slow the Moon down in its orbit, which means it moves further away so that angular momentum is conserved. If this goes on long enough, eventually the Earth and Moon will be tidally locked with each other - the same side of each will always face the other. Which you may know has already happened to the Moon - we only ever see the same side. It hasn't happened to the Earth yet because the Earth is bigger, and it's all happening so slowly that the Sun will have grown into a red giant and incinerated us before it happens. It HAS already happened to Pluto and Charon because they're more similar in size.