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Why or why not?

2007-11-27 12:12:38 · 10 answers · asked by Anonymous in Science & Mathematics Astronomy & Space

10 answers

Yes. If you were on the Moon (let's say on its equator) and lied down on your back looking straight up, you'd see the stars (very slowly) go around. It would take 27.321662 Earth days for the same star to return right above you.

So the Moon turns on its axis once in 27.321662 Earth days
(27 d 7 h 43 m 12 s) relative to the stars.

It just so happens (it is not a coincidence) that the Moon's average orbital period, around Earth, is also 27.321662 Earth days. It is kept like that by the effect of Earth's tidal force on the Moon.

So, as you look at the stars slowly going around, you would notice (lying in your space suit) that Earth does not appear to move compared to you (but it would when compared to the background of stars).

For someone on Earth, whatever direction the Moon is compared to the stars (or to the sun), we always see the same face because the rotation period is the same as the orbital period.

2007-11-27 12:21:19 · answer #1 · answered by Raymond 7 · 2 0

Suppose the dust that formed the planets were to simply fall down towards the center of gravity, without ever getting any rotational velocity, then the planet (and everything else created this way) wouldn't rotate. If the dust-cloud that formed the planet were to be given a slight rotational velocity, even the smallest, then - when falling towards the center of gravity - the preservation of angular momentum would induce a faster and faster rotational velocity, as the the dust got closer and closer to the center of gravity. This small starting rotational velocity could be caused by a number of things, but the most probable is simply that the gas originally wasn't spread out homogeneously around the center of gravity of a planet. In that case, the gravitational pull on the heavier part of the dust cloud, compared with that on the lighter one, would be sufficient to start a rotation - not a very large rotational velocity, but as stated before, it just needs to get it started, then the preservation of angular momentum does the rest.

2016-05-26 04:09:56 · answer #2 · answered by ? 3 · 0 0

Yes, the Moon rotates in exactly the same amount of time that it takes to orbit the Earth once. This explains why the Moon always keeps the same face toward the Earth. Think of it this way: if the Moon did NOT rotate as it orbited the Earth, we would see different sides of it as it moved around us. You can verify it with a friend. You be the Earth and watch as your friend (the Moon) moves in a circle around you. If your friend faces the same direction the entire time, you'll see different sides of your friend as he or she moves around you. In order to remain facing you, your friend will have to turn while he or she orbits you.

Good luck!

2007-11-27 12:21:04 · answer #3 · answered by Lucas C 7 · 5 0

Yes. It rotates once a month, or 13 times per year. It's the reason we only see one face of the moon. This is because it is 'gravitationally locked' to the earth. Apparently, the moon's center of mass is not its center of gravity.

2007-11-27 12:33:01 · answer #4 · answered by Anonymous · 0 0

Yes. The moon rotation period (about 30 days) same with its revolution period to earth (about 30 days) and has same direction. So, the same surface of moon will "face-to-face" with earth anytime.

Every you see moon at night, you will see the same moon surface. I think you get the point.

2007-11-27 12:27:03 · answer #5 · answered by Erick K 3 · 1 0

even moon rotates. it takes 23 days to complete one rotation around the earth. i can't answer why....sorry.
just in case you wanted to know, the planet uranus rotates in the direction of 90 degrees.

2007-11-27 15:39:36 · answer #6 · answered by SIMONE 5 · 0 0

Yes, it does and it takes approximately 29 days. That is why the same side of the moon always faces earth.

2007-11-27 14:02:10 · answer #7 · answered by Scott S 3 · 0 0

Yes, once every 28 days.

2007-11-27 12:57:29 · answer #8 · answered by ecinoderm 1 · 0 0

yes.
everything in universe rotates and goes in orbit.
dont believe me.
trust me i know this one for sure.

2007-11-27 12:20:12 · answer #9 · answered by ARocks 2 · 0 0

no it does not......for info look it up on google

2007-11-27 12:19:50 · answer #10 · answered by DeerSlayer 2 · 0 9

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