,why does the moon always rotate in a one to one ratio with earth?
597835
It isn't "chance" although that is why it is the right/size to produce solar eclipses.\n\nThe moon is not perfectly symmetrical. The crust is thinner on our side, and the core (heavy part of the moon) is displaced towards our side. That acts almost like a handle for the earth's gravity. It has slowed to the point where the earth's gravity now keeps this side pointed towards the earth.\n\nHowever it is not perfect. As seen from the earth, the moon wobbles slightly --- both side to side and up and down. The motion is called libration and allows us to see more than half of the moon. We had a discussion on the yahoo lunar group recently with a link to an animated gif that showed the moon's libration.\n\nIf you are interested in the moon, try\nhttp://groups.yahoo.com/group/lunar-observing/\n\nChuck
463189
The earth orbits the sun; the moon orbits the earth. The cycles of rotation are different meaning that the moon will orbit the earth many times every year. This means that it will very often be in a position to be seen during the day. The moon itself has no axial rotation so on earth we always see the same side of the moon.
73091
Yes, the Moon does rotate around it's own axis.\n\nHowever, the reason we always see the same side of it is the fact that the Moon rotates about as fast as it makes one full lap around the Earth.  It takes about 27 days.  So, the Moon doesn't rotate as fast as Earth does(27 days compared to one day).
762918
The moon's orbit is in a balance between centrifugal force (outward motion) and gravitation (inward force toward the earth).
218551
It rotates on its axis once per month. If you could stand on the sun, you would see all sides of the moon in the course of a month. Also, if you could stand on Mars you would see all sides of the moon in the course of a month. The "single face" issue arises because we on earth are right in the middle of it--as the moon rotates on its axis once per month, it also revolves about the earth at the same speed, always showing the same face to the earth.\n\nSince the moon does not always show the same face to the sun, there is no "dark" side of the moon. All parts of the moon get equal amounts of sunlight, just as all parts of the earth do. There is a "far" side to the moon, the side that is always facing away from earth.\n\nAnother way to think of it is to think of the flagpole planted by astronauts. It of course is pointed toward the earth at all times. At the time of new moon (when the moon is between the earth and the sun), the flagpole is pointed toward the earth and the outer solar system, toward the realm of Mars, Jupiter, and Saturn. At the time of full moon (when the earth is between the sun and the moon), the flagpole is pointed toward the earth and the sun. Obviously the moon rotated so as to bring the flagpole from pointing to the outer reaches around to pointing toward the sun.\n\n\nFor Dirty Idea (below): ask your question as a Yahoo! question and maybe I'll look it up for you. I think it has to do with tidal locking. It's not a coincidence at all.
59556
It's due to the formation of the planets themselves.  the gases and the dust spun around the sun as the star formed itself, and congealed into the planets we know.  And since they spun as they formed, they started the spinning on their axis as well.  \n\nBesides, we'd be either cooked or frozen if the Earth didn't revolve!\n\nHarley's wrong.  The moon DOES spin on an axis.  However, its spinning is on par with the Earth's spinning, thus you only see the one side of the moon.
330241
Well the moons rotation is not a problem because it is tidally locked with the earth. It always has the same face pointing towards to earth.\n\nThere are a few reasons why it isn't practical to use it as a satellite. As has been mentioned above it is expensive to get there, and it is far enough away to have a significant delay in transmission.\n\nApart from that, there is another reason. When we deploy satellites we generally want to have extremely precise orbits. We may want a geostationary orbit, so the satellite is always in the same position relative to the earth, or we may want a satellite that covers the whole earth at one time or another. With the moon we have absolutely no control over its orbit, so unless you're lucky enough to have it in exactly the right orbit for you (highly unlikely), it's pretty useless.
1165448
One earlier answer is close but does not go all the way.  \n\nThe material it formed out of was slowly rotating already, and angular momentum is conserved;  the more compact that material became the faster it had to rotate to conserve angular momentum.\n\nWhy did the material have some rotation in the first place?  Because it is statistically VERY improbable to have a large extended ANYTHING with net zero rotation.  Contract such an anything enough and its rotation becomes appreciable.\n\nIt is worth noting that it is the combined angular momentum of the Earth-Moon system that is relevant here. The moon once orbited much closer and the Earth rotated much faster.  The transfer between the two (terrestrial rotation and the moon's orbital motion) continues, but the total of the combined has changed little since the hypothesised collision that formed the moon.
711962
probably because it takes the same time for the Moon to rotate around its axis (a day) and orbit the Earth (a year) \nit is always facing the same side because it rotates in conjunction with its orbit (bit hard to explain)\nbecause it is also rotating at the same time, we always see the same side of the Moon
135072
I would expand this to say that a lunar eclipse occurs when the earth is positioned directly between the sun and the moon, and their plane of orbits align.\n\nThe last point is critical because you could easily wonder why we don't have lunar eclipses every month when the moon's orbit is such that the earth is in the middle... because the order of the planets is not only important, but that they line up just exact so that the earth's shadow does not fall just above or below the moon, but directly on it.
1132192
Yes, as long as definitions are consistent.\n\nThe Moon rotates from west to east, the same direction that it revolves around the earth. At its equator, the Moon rotates at a speed of about 10 miles (16 kilometers) per hour. \n\nThe Earth rotates on its axis from West to East with its axis in the North/South direction.\n\nIt is sometimes thought that the Moon does not rotate, because it always presents the same face (roughly) to a point on Earth. However this is because the time it takes to complete one rotation is almost the same as the time it takes to complete one revolution around the earth; not because it does not rotate.
596684
The correct option is 'rotation of the earth'. When earth revolves, some part of it is directly facing the sun, and the other part is not. That explains the presence of day in one part of the world, and night in the other.
60264
Our moon is locked in what is known as a geo-synchronous orbit. For millions of years the angular momentum has stablized the moon to provide very little loss of energy between earth and moon. This does not account for the influences that the moon has upon our oceans though. (Tides) Our solar system has "moved about" for many millions of years to allow for efficient energy transfers between baryonic masses.  This is not unlike a person who sit's in a chair and move's about to become more comfortable.  Peace
77245
"The Moon also turns around, but its "day" is a whole month long.  Because it takes as long for the Moon to orbit the Earth as it does for the Moon to rotate once, the same face of the Moon is always pointed at the Earth.  Humans had not seen the "far side of the Moon" until we were able to send spacecraft behind it.  Remember, though, that the FAR side of the Moon is not always the DARK side of the Moon"
788193
Yup, Earth's rotation rate is slowing down.  You've always wished for more hours in the day, right?  Well, it's happening!  Of course, we won't notice a difference in our lifetimes.  It should be noted, that our speed around the Sun isn't changing, just our spin rate - as our day becomes longer, there will be fewer days in one year.\n\nThis is actually tied in to your previous question - the same thing that slows down Earth's rotation also causes the Moon to get farther and farther away from us.  The tidal force from the Moon on Earth creates tidal bulges on Earth.  Earth essentially rotates underneath the tidal bulges.  There's friction there, so there's a loss in energy.  This is manifested by a slower rotation rate for Earth (the same thing happened to the Moon long ago, which is why it always keeps one side facing Earth).\n\nThe Sun fuses hydrogen into helium in its core to produce energy via E = mc^2, so the Sun is converting some of its mass into energy.  Also the Sun loses some of its mass to the solar wind.  So technically the Sun is becoming less massive as time goes on, so its gravitational force must weaken.  However, the fraction of mass the Sun loses is so small that we can ignore it.  When the Sun dies and sheds its outer layers, then there will be a significant mass loss, but not until then.
272130
When the moon is full, it is on the side of the Earth opposite the sun. It takes the moon about a month to go around the Earth once. So in the course of a single day, it remains in almost the same position.
308171
this is an answer to a slightly different question (how long does the moon take to make one rotation?): 27 days, 7 hours, and 43.2 minutes.  someone must remember that the moon revolves around the earth (earth-moon center of mass) at the same time that it rotates.