Why is it that we only see one face of the moon? I used to know a long time ago, but forgot.?

Answer 1

The first two people are WRONG.
The moon is spin orbit coupled (or called spin orbit resonance). What it means is that for every one time around the earth, it spins around one time.

So for every revolution (that is orbit around the earth), it has one rotation (that would be a Moon DAY).

To see this effect, have a friend be the moon. and have them walk around you.

now if they did not have any rotation (ie stopped spinnign) they would have to face the exact same direction when going around you. as the earth (you) would spin. When they go around you, you would be able to see their sides and theri backs if they had NO rotation.

Now have your friend keep facing you (like the moon does on towars the earth) and have them walk in a circle around you. You will notice that they will have gone in one circle (revolution) around you , and have turned in a circle themselves (rotation)

here is what the straight dope staff report
Dear Straight Dope:

As every fourth grader (at least of my generation) is or was taught, the moon revolves once on its axis for every orbit around the earth. Thus, the same side of the moon is seen from earth at all times. OK, fine. But it recently struck me that it's gotta be EXACTLY one r.p.o.; if it's off by even half a footprint, before long we'll be able to see the dark side of the moon for ourselves, rather that depending on Pink Floyd's description. My question: Is this a cosmic coincidence? Or is there something regulating Luna's spin? My first reaction is that maybe the moon's mass is off center, and the earth's gravity is holding the heavy side down. But then wouldn't the moon revolve around its center of mass (rather than its center of volume) and thus appear to wobble?--Tim Snyder

SDSTAFF Chronos replies:

After I got done writing this up I discovered Cecil had already answered the question. But my feeling is that celestial mechanics is a topic of enduring interest. It's not like because Shakespeare wrote sonnets on the subject we don't get to write any more about love.

Anyway, Tim, your intuition is on the money. Yes, the moon's rotation is perfectly synchronized with its orbit; no, it's not coincidence; yes, it has to do with the moon's mass distribution, and yes, the moon does wobble.

From NASA
The Moon's Orbit
The Moon orbits around the Earth, taking about a month to go all the way around our planet. Its orbit is very nearly circular; it stays about 380,000 kilometers away from us as it moves counterclockwise (as viewed from a northern hemisphere perspective). It also stays fairly close to the Earth's equatorial plane (an imaginary extension of Earth's equator out into space); the point on the Earth directly under the Moon is never more than 29° north or south of the equator.
Demonstrating the Moon's Motion
Over the millenia, the Moon has become "locked" into a special kind of motion around the Earth. It rotates on its axis at the same pace as it revolves around the Earth. As a result, the Moon keeps the same face toward us throughout its orbit.

Younger students can enjoy demonstrating this motion by "orbiting" around another student seated in the center of the classroom. Have the "Moon" student begin by facing the "Earth" student (the one seated in the center). Then have the "Moon" student "orbit" — circle around the student in the center. The "orbiting" student will find that if he carefully swivels his body 1/4 turn for each 1/4 "orbit" around the room, then he will always be facing inward as he completes a full circle. (His back will never be visible to the seated "Earth" student in the center.) This is why astronomers speak of the "nearside" and "farside" of the Moon.
Phases of the Moon

Since the Moon shines by reflecting sunlight, what it looks like to us at any particular time depends on the angle at which the Sun's light is hitting the Moon. For example, if sunlight is coming from the right, the right half of the Moon's globe will be bright and the left will be dark. If sunlight is coming from behind the Moon as we look at our satellite, then its farside will be illuminated, and we will see a dark globe or "new moon."
Moon phases

FIGURE 1: The pictures are shown from a northern hemisphere perspective. Those of us who live in the northern hemisphere (outside the tropics) have to look generally south to see the Moon when it's highest in the sky, and we wee the right-hand side illuminated at first quarter phase, for example. People who live in temperate or high latitudes south of the equator must look toward the north; to them the first quarter moon has its left side illuminated.

The diagram is not to scale. In reality, the Moon is 1/4 the diameter of the Earth and its orbit's width is about 60 times the Earth's diameter.

Figure 1 shows the Moon during one orbit around the Earth from a vantage point far above Earth's North Pole. It also shows what the Moon would look like when it is highest in the sky at eight times during the month.

Answer 2

relatively there have been 5 manned missions to the Moon after the 1st -- get your data right now! Why no Moon landings for the reason that 1972? particularly undemanding: loss of money. Congress decrease NASA's investment after the 6th lunar touchdown in 1972 by using fact the conventional public looked as though it would have lost interest interior the Moon and the "area race" with the Soviet Union have been won. It grow to be tragically undesirable timing, by using fact Apollo 17 in 1972 grow to be the _first_ Apollo voyage to have a knowledgeable scientist, Harrison Schmitt, on board, and grow to be meant to be the 1st of three scientific expeditions. extra grow to be discovered suitable to the Moon and its historic past in that voyage than interior the previous 5 prepare, and lots extra might have been discovered if the two next voyages have been funded. relatively the US area software grow to be redirected into the boondoggle of the return and forth and area station classes, neither of which has made lots contribution to technology. each and every time this question is asked, some human beings respond that we now be attentive to each little thing there is to be attentive to suitable to the Moon. What a daft theory! How can everyone say that we discovered each and everything some place with almost as lots dry land by using fact the Earth in six visits of a few hours or days?

Answer 3

The time it takes the Moon to rotate once on its axis is the same time it takes to orbit the Earth once, so the same side is always facing the Earth (though there's a 1 or 2 degree wobble around the edges). The Moon used to spin faster, but tidal forces from Earth's gravity slowed it down so it's now "spin-orbit locked".

Answer 4

It takes the moon 29.5 days to turn once on its axis. It also take the moon 29.5 days to go once round the earth. So therefore only one side of the moon faces the earth all the time. Try it at home and face something like a table and walk around it facing it all the time. Once you have walked around it once, you will also have rotated once. It will give you a better visualisation of the explanation.

Answer 5

The moon DOES rotate unlike what the first two answerers said. It's rotational period is the same as it's orbital period (27.3 days) so the same side always faces the Earth.

If it didn't rotate, we would see differen't sides during the course of the orbit.

Answer 6

Hi. The Moon slowed down due to tidal forces until the rotation stopped.

Answer 7

Because the moon does not rotate on it's axis like the earth. It is basically a static lump of rock orbiting the earth

Answer 8

hold your hand up i front of your face how many sides do you see, the moon is not made from clear glass

Answer 9

It's also called tidal locking.