How much is visible from the surface of the Moon, in percentage, from the Earth surface ?

Question

...and why ?

Answer 1

I think you mean "How much is visible OF the surface of the Moon, in percentage, from the Earth surface?" 59% of the Moon's surface is visible from the Earth. This is due to libration: slight tilting of the Moon caused by irregularities in its orbit, which allows us to peek over the edge of the Moon and get partial views of the far side.

Answer 2

The same side of the moon always faces the earth so you'd think the answer is: 50%, but it is actually closer to 59%.

The reason is 2-fold.

1. The moon is in an elliptical orbit, so it gets closer and further away (the "average" distance is about 250,000 miles). When it is closer, we see less of the facing surface. When it is further away we can see a little bit more of the surface (at the 'edges'). If this were the only way to see more than 50% of the surface, then it would amount to an increase of only a few % -- not 9%.

2. The moon "wobbles" slightly due to gravitational forces of the sun, when it is further away and closer in it's orbit around the earth. Think of the moon as in orbit around the sun, but zig-zagging around the earth. This "wobble" causes the moon to show just a little more of the "back" side both left and right at different times of the year.

Between 1. and 2. it adds up to about 9% more than just the plain old 50% front 'face' of the moon.

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Answer 3

59% of the Moon's surface can be seen from Earth. The Moon is tidally locked to the Earth, meaning the period of its orbit around the planet is equal to the period of its rotation on its own axis. The result is that the same side always faces towards the Earth. So the apparent answer is 50%. But the Moon moves at slightly different speeds at different points in its elliptical orbit (faster when it is closer to Earth, slower when it is further), causing it to swing just a little bit forwards and back as seen from the Earth. The orbit of the Moon is inclined from the plane of Earth's equator, so we can also see a little bit "above" and "below" the poles as it reaches its extremes. This sytem of wobbles is known as "libration."

Answer 4

The moon rotates once as it revolves around the earth. The earth rotates once in that same period, a day. Therefore we will never see the "darkside," actually the backside of the moon, ever. We will always see the same face of the moon, only 50 percent of it.

Answer 5

I guess this depends on what phase the moon or earth is in when looking at it. You can see 0% (new moon/earth) to 50-60% (full moon/earth) and everything in between.
PS: when on the moon looking at earth, the earth also has phases just like the moon.