Why do we see just one side of moon (almost half exactly 59%)?

Answer 1

the time taken by moon to rotate itself about its axis once is equal to the time taken by it to revolve around the earth once..
just imagine that moon doesn't rotate and it only revolves around the earth.. then we could see both sides of the moon for its every revolution...
since its rotation and revolution time are the same, it always has its one face towards the earth...
just imagine the moon revolving around the earth with its same side facing the earth.. then you could fine that it makes one rotation for its every revolution..

Answer 2

Umm ... I've looked at other answers, and none seem to explain the "why" part of the question.

The key concept needed to understand this phenomenon is "center of gravity". Imagine the moon as a spherical shell filled with a viscuous fluid such as molasses or gelatin, but also containing a lead ball -- the center of gravity of the moon.

Eons ago, shortly after the moon formed, this lead ball, attracted by the earth's gravity, slowly moved from the center of the moon toward the earth -- that is, toward the side of the moon facing the earth. With the lead ball being off-center in the moon, gravity forces the lead ball, hence one side of the moon, to always be in the same position, facing the earth. Right now, the lead ball is fairly close to the edge of the moon, away from its center.

If the earth and moon were just points in space, the above would explain why we'd see 50% of the moon. What about the other 9%?

That's explained by something called "libation", or wobbling, which comes in three flavors. First, "diurnal libation". Suppose there's a full moon at midnight over the Pacific. An observer in New York would see a bit more of the left side of the moon at moonset, while an observer in Beijing would see a bit more of the right side of the moon at moonrise.

The moon orbits the sun as well as the earth. In the course of a month, from full moon to full moon, the moon speeds up, slows down, gets ahead of the earth, and falls behind the earth, all in relation to the sun. Furthermore, the distance between the earth and moon changes slightly. As seen from earth, this amounts to a slight "wobble" that enables us to see a bit more of the moon.

Finally, the plane of the moon's orbit around the earth is slightly different (about 5%, I think) than the plane of the earth's orbit around the sun (the ecliptic plane). If the two planes were identical, we'd have full lunar and solar eclipses every month. This difference in the two planes also enables us to see a bit more of the moon.

These last two features of the moon's orbit are called latitudinal and longitudinal libation, though I can't remember which is which. Taken together, the three varieties of libation allow us to see 59% of the moon rather that just 50%.

But the main answer to your question -- why do we just see one side -- is fundamentally related to the moon's asymmetric center of gravity -- the position of the lead ball in the moon's interior. That lead ball is away from the moon's center, forcing the same side to face the earth, always. And it's always due to gravity.

I think this answers the "why" part of your question.

Answer 3

The moon rotates on its axis at 10.3 mph while Earth rotates at 1035 mph. These two rotational velocities are such that the Earth and moon rotate in synchronization which keeps only one side of the moon always turned towards. Earth.

Answer 4

It is a spherical shape. Just look at a basketball, you can't see around the entire thing, only 1 side.

Answer 5

The moon does not rotate.

Answer 6

Because its orbital period is about the same as it's period of revolution.