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One advantage of getting older is I get less self conscious of sounding stupid. With that said, here is my stupid question. For approximately half the day we rotate away from the sun. This isn't true for the moon is it? Why not?

Rudy1962 9 Jan 6

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The moon is gravitationally locked with one side always facing the Earth. It is actually orbiting the sun, and has been captured by the Earth's gravity. The planet and the moon do a whacky orbital waltz, with the moon dragging behind. 12 hour half day for the moon.

Now that is an explanation I can totally understand. Thanks


Thanks for the answers. For some reason I cannot "like" some of the comments that were helpful. Particularly, Astrochuck's. Based on your name and bio, this is your cup of tea.


The moon is closer much much smaller and rotates around the earth.


Our Moon (Lunar) is in a locked orbit around our home Earth (Gaia) which causes it to show only one side of its total surface area to us. Strictly speaking though it is a bit more than 50% as it also 'wobbles' (called libration) slightly enabling us to see about a total of 60% over the duration of a month of 28 days or thereabouts. So it does spin on it's own axis but this takes about 28 days because of the 'locked' orbit. Difficult to visualize. When it's full moon the sunlit side is facing us. When it's 'new' moon the sunlit side is the unseen side of the lunar surface.


OK, I admit this is weird, just as they say a stopped clock shows the correct time twice a day, if the moon did not rotate we would eventually see the other side from Earth. I don't know the physics behind this, but the moon does rotate, but in the direction and at the speed necessary for the one side to always face us. Go figure. Maybe it is an alien base and they want keep their activities hidden from us?


The moon does spin but it's tidally locked to the Earth. It's a common situation when one of a close gravitational pair is much larger than the other. Mercury is tidally locked to the Sun for instance.

BTW.. I wouldn't call not knowing that dumb. It's a pretty esoteric detail of astronomy.

The moon is locked so that one of its rotations takes exactly the same time as one of its orbits.

Thank you. I couldn't remember if the tidal lock for the Sun/Mercury system was the same in detail as the Earth/moon and I was in too much of a hurry to look it up.


We aren't orbiting the moon, like we are the sun. The moon is orbiting the earth.


the moon is does not spin, the same side faces us all the time

erm no it does not, you just said we see the same side, that tells you the same part of the moon is always facing earth, it is not spinning.

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