Why is one side of the moon called?

Answer 1

the moon both rotates on its axis and revolves around earth every 28 days.

Answer 2

The "dark side" usually refers not to the illuminated half of the Moon (of which we see varying amounts depending on the phase) but to the face of the Moon that is always pointed away from the Earth, also known as the "far side of the Moon."

The Moon slowly completes one spin during the same time it takes to orbit the Earth, so we always see the same side, or face. This equal period of spin and orbit was caused by tidal effects of the Earth's gravity on the Moon.

The Orbit of the Moon

The first thing to realize is that the Moon both spins on it's axis and orbits the Earth. Crucially the amount of time it takes to rotate around its axis is the same amount of time it takes to orbit around Earth. This means that the same side is always pointing toward the Earth. (This is not a coincidence.) The entire Moon experiences day and night, just as Earth does (because different parts face the Sun). However, a full lunar 'day' takes the same time as an orbit. It takes about a month for the Moon to go all the way around the Earth, so on the Moon the Sun rises (in the west) and sets 2 weeks later.

The hidden half gets the same amount of sunlight as the visible face, so it is completely dark only when there is a Full Moon (the entire illuminated half is the side visible from Earth). The first pictures of the far side of the Moon were taken in 1959 by the Luna 3 probe sent by the Soviet Union.

Confusing Terminology

The side of the moon that we can never see from Earth is often called the "dark side" (a) because it sounds cool, and (b) because darkness is a powerful metaphor for the unknown. In fact, the so-called dark side of the moon is not really dark. Luna has day and night on every part of its surface (just like Earth, only Lunar days are 28 Earth days long). During a new moon, for instance, the "dark side" is flooded with light.

Tidal Forces

How is it that there's a part of the moon we never see? Like many moons of planets in our solar system, our moon, Luna, keeps one side to its primary continually (there's a little wobble, so we can really see about 55% of the lunar surface). This condition of the Moon is being "tidally locked." This situation develops with all moons and planets over a long time. This means that the Earth's rotation is slowing, too, and it will eventually become tidally locked to the Moon. At that point, only about half of the Earth would be able to see the Moon. This will not occur for a very, very long time, but scientists can measure the tiny lengthening of the day.

Quibble

To be fair, the far side of the Moon does receive less light than the rest of the Moon, because it doesn't see any of the sunlight reflected from the Earth. So technically, it is a bit darker overall. But almost no one who uses the phrase "dark side of the Moon" is thinking of it in this way.

Answer 3

Half of the Moon is always illuminated and half of it is in darkness. But, we see only one side of the Moon, so there is a close side and a far side.

Over the course of 27 days the illuminated part changes and goes over the entire Moon, so there is not one side that is always dark.

Answer 4

The "dark" terminology for the "far" side of the Moon refers to the inability to view it from Earth. Due to orbital variations (libration), about 18% of the "far side" will be visible from Earth at varied times of the year.

Answer 5

There is only one Sun in our solar system, and all the planets (and most of the moons) are round. So with only one light source, half of every ball is going to be dark.

When the ball is spinning, as most of them do, then there is a light period and a dark period.

Photographers often use large flash reflectors to soften the harsh shadows caused by the primary light source. We here on Earth are blessed with a large reflector in the sky, which reflects the Sun's light back onto the dark side of the Earth. It's the Moon.

Some scientists have proposed building enormous mirrors in orbit to reflect the Sun's light back down onto the Earth, to give us a more uniform illumination. Sort of the ultimate solar-powered street lighting.

Answer 6

Not any more. It was at one time, though even then it was somewhat misleading. The word "dark" in the phrase "dark side of the moon" is from an older sense of the word meaning "unexplored, unmapped" (the same sense is meant in another phrase you may have heard: calling Africa "the dark continent".)

On average it's no darker (in terms of illumination) than the side facing us, and we've sent probes there so now it is in fact mapped and can no longer properly be called "dark" even in the "unknown" sense.

When there's a full moon the far side is the dark side, but when it's new moon the far side is actually the light side.

Actually, all the lunar maria are on the near side, and they're rather darker in color than the average lunar surface, so it would be more correct in one sense to call the near side "the dark side".

Answer 7

-- Take a soccer ball and a flashlight into a dark room.

-- Turn on the flashlight, and point it at the soccer ball.

-- Half of the ball is lit up, and the other half is dark.

-- No matter how you turn the ball, no matter how quickly you move

or which way you bend, no matter how you manipulate the flashlight,

no matter how much you wiggle and dance ... 50% of the surface of

the ball is lit up, and the remaining 50% of its surface is dark.

-- 50% of the Earth is lit up, and the remaining 50% of it is dark.

The light and dark places keep changing, but the Earth is always

half light and half dark.

-- 50% of the Moon is lit up, and the remaining 50% of it is dark.

The light and dark places keep changing, but the Moon is always

half light and half dark.

Answer 8

Well, technically the phrase "dark side" of the Moon is only half-correct. The Moon's hemispheres are divided into the near side and the far side, and both of these sides receive the same amount of sunlight. We, however, from the point of view of the Earth, only ever see one side of the moon. This is due to the influence of the Earth's gravitational forces on the Moon's irregular shape; this tug gradually reduced the rotational period of the moon until it was the same as its orbit. Because the Moon's gravitational influence is not enough to change the Earth's rotational frequency (only cause the tides), it does not have the same effect. Thus, we only see one side of the Moon, leaving the other side a mysterious "dark side."

Answer 9

'Dark side' is really a misnomer. The entire moon experiences daylight and night time, just as earth does. However, a full day (analogous to earth's 24 hour day) is an entire lunar cycle long on the moon. The side of the moon that faces away from earth might be more properly called the 'far side'.

Many believe that the moon does not turn on its axis, but this is a completely geocentric (and inaccurate) assumption. It is not unlike the belief of centuries past that the sun, moon, planets and stars must orbit around earth; after all, that is how it appears.

In order for the same face of the moon to orient toward earth all of the time, while the moon orbits around the earth, then the moon must turn on its axis exactly once for every orbit that the moon makes around earth.




It was named the 'Dark side' because until the Luna 3 probe in 1959 nothing was known about it. (Dark being used as meaning 'unseeable' or 'mysterious') Now days it is more commonly known as the Far Side.

Answer 10

I hope you're joking

Every planet has a dark side because the sun isn't directing its light toward it thus having darkness. Which is why Earth has a little something called "Night" and when the Sun is directing its light we have the "Day"