What is the "dark side of the moon" and why is there a dark side of the moon?

Answer 1

When we refer to the 'dark side' of the Moon, we are talking about the side that we never see from Earth, because the Moon is tidally locked and rotates only once as it goes all the way around the Earth, so the same side is always facing us.

But that side isn't always dark. At any given time, half the Moon will be illuminated by the Sun. Sometimes it's the part facing us (full Moon - going in order, Sun - Earth - Moon) and sometimes it's the part facing away (new Moon, in order Sun - Moon - Earth.

Try drawing yourself a picture if that still doesn't make sense.

Answer 2

The moon circles around the earth like a pingpong ball attached to the axle of a spinning top with a string! The point of the ball, where the string is attached, always faces the spinning top. Thus, from the spinning top you can never see the opposite side of the ball, even if the top is spinning faster or slower than the ball is circling the top! In the moon's case-- the string is the pull of earths gravity on the moon and it does circle our earth at a different rate than our earth spins. We earthlings call the far side of the moon as the 'dark side' only because we cannot see it! When we have the beginning of a 'new' moon, the unseen side is actually lit up by the sun. When we have a 'full' moon, the unseen side is actually dark!

Answer 3

Because the sun can only shine on one side of the moon at a time. Each point on the moon is dark for half the Lunar day (@28 Earth days) as the moon rotates on its axis. Since the moon revolves around the Earth, we are exposed to the dark (fully shadowed) side of the moon during the night of the 'new moon'. Of course, it's difficult to 'see' the new moon, since it's only illuminated by 'earthshine', sunlight reflected from the Earth.

Another sense of 'dark side of the moon' is related to the expression 'darkest Africa' meaning least explored, or unknown. Since the moon revolves around the Earth at the same rate that it rotates on its axis, the same face of the moon is always pointed at us. Hence the far side of the moon was, until spacecraft orbited the moon and sent/brought back picture of it, known as the 'dark side of the moon'.

Answer 4

The literal dark side of Moon is the side that faces away from Sun (that is, the side that is in Moon's own shadow). Because Moon rotates on its axis, the side that is dark always changes. During a New Moon, the dark side of Moon faces Earth; during a Full Moon, the dark side of Moon faces completely away from Earth.

Note that most of the same points of Moon's surface always face Earth, because time required for Moon's rotation on its axis is the same as the time required for Moon's orbit around Earth. This also means that one side of Moon always faces away from Earth. Some people have the mistaken notion that the side of Moon that faces away from Earth is always literally dark.

Answer 5

The length of a lunar day, and a lunar year are the same. So the same side of the Moon always faces the Sun. The side that never sees the Sun is called the dark side.

Answer 6

Of the answers received so far, no one has mentioned one big fact. The duration (roughly 28 days) for Moon 's one rotation on its own axis is exactly the same the time (~28 days) the moon takes to make one complete revolution around the earth. That is, the moon completes one rotation on its axis while completing its revolution around the earth.

This results in moon always presenting the same face to the earth all the time and we never get to see "the far side of the moon."

Answer 7

Actually, there is no dark side on the moon. What you probably were referring to is "The far side" , which can never be seen from Earth, because the moon is in a captive orbit and keeps the same face to Earth.

Answer 8

The dark side of the moon is the side of the moon that is opposite from what's visible to Earth.

The moon is geosynchronous, and it rotates itself and orbits Earth while Earth rotates itself at the same time in such a way that only one side is visible to the Earth's inhabitants at any given time.

This leads into the theory that the moon originated from a body of matter in space that hit the Earth, took a chunk out of the Earth and consolidated into the moon we know today, and caused the Earth to spin, the moon to spin, and the moon to orbit Earth so that the moon created geosynchronicity between the Earth and the moon.

Since the moon does orbit the Earth, there are times when the moon comes between the sun and the Earth. In that case, the "dark side of the moon" to us is actually lit-up by the sun on the moon's "back side." Solar eclipses also demonstrate that the "dark side of the moon" to us becomes the "light side of the moon" as the sun shines on it, the moon blocks the sun from Earth, and the moon side facing us becomes the dark side while part of Earth becomes dark, too.

Answer 9

The "dark side" of the moon is the side of the moon we never get to see. While it's revolving around us, it's spinning. That is the part of the moon the sun doesn't hit.

Answer 10

The moon orbits the earth in a way that always keeps the same "face" toward us. Since we never see the opposite side it is refered to as the unknown "dark side" of the moon.

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