What is the dark side of the moon? Is it visible?

The "dark" side is generally referred to as the "far" side in the poetic sense that "unseen" is usually dark.
But; the far side is lit up as much as the near side (ignoring some effect of Earth's reflection) and is thus as easily visible as the near side. The problem is, you have to go quite far into space to see it.

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Numbers are not case sensitive. (me)

I think each point on the moon has 2 weeks of daylight and 2 weeks of nighttime, so no part of moon is dark.

But each point on moon, earth maintains a fixed position, so on one lunar hemisphere the earth is permanently above horizon, and on other hemisphere, it would be permanently below horizon.

The Bad Astronomer himself talks about the difference between the Far Side and the Dark Side of the moon here.

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At night the stars put on a show for free (Carole King)

One Earth, One Sky - IYA 2009
All moderation in purple

:frbee. It's his hangout...see:http://goatmilk.files.wordpress.com/...ader-face1.jpg

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A third rate theory forbids.
A second rate theory explains after the fact.
A first rate theory predicts.
A. Lomonosov

With respect, for asking this question; Without knowing your age or education.
How can you not know this ?
The Moon is a sphearicle saterlight of Earth. Its about 385,000km away and takes a lazy 28 days to compleat one orbit. As such sunlight falls on the side of the Moon facing the sun. Just as Earth has days and nights, so to does the Moon. At about 14 days long.
When you ask... do you mean the side of the moon we never see. I suspect so.
This is because one side of the moon is always facing Earth. We call it tidal locking.
The Far side of the Moon is well mapped as any orbiting craft has and must go around there...There is no mistery. Half the Moon is in its shadow just as on Earth. We call it night time.

A lot of people don't know the moon is tidally locked to the earth. It's the kind of thing that you might conclude independently if you look at the moon a lot, but it's also easy to find justifications, like maybe people in different places around the world see different parts of the moon or something.

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As above, so below

Quote, " like maybe people in different places around the world see different parts of the moon or something." end quote.

Jens., but as you said... just observing the phases soon reveals the fact. We all see the same moon. No, or something about it...are you winding me up ?I am loosing grip and my sanity is already in some questionable state

The OP asked "What is the Dark side of the Moon ?" and " Is it visible."
I will answer that a fresh with, Its an album by 'Pink Floyd'. and if you have one, Yes...
If its not visible then that would be invisible and thus unseen... NONE of this actually helps here, does it ?

If we call the period of time that the moon takes to do one revolution of the Earth a month (28 days ) The 28 is the number of times the Earth rotates on its axis while the Moon Orbits it once. From our view point. ( On Earth ) We see the same face of the Moon. The amount of it in sunlight changes. We call that phasing.... is that better ?

No, I'm not winding you up, and unfortunately I can't say anything about your sanity. I just meant to say that I think there are many people who do not know that the moon is tidally locked. A lot of people don't really look at the moon that carefully.

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As above, so below

Of this I also know... A work friend noticed the moon in the morning sky. " must be something wrong. Its not night time yet." You are right... some people just do not care.
We have arrived at the local observatory for a planning meeting on a wet and cloudy night. Only to find a queue of people waiting to see the Moon.... while asking what they expected to see. The underside of cumulus clouds...

Mine and Astromark's view of the moon is right way up. You others in the northern hemisphere see the Moon upside down!

Tidal locking has caused the moon to always have the same side facing the earth. Take a tennis ball and mark a black spot. Get a basket ball and make the tennis ball 'orbit' or go around the basket ball in your hand. Easy, now make the black spot on the tennis ball face the basket ball. Get the tennis ball to go around again while the spot continues to face the basket ball. You will notice that the tennis ball does spin as you will have to turn your hand in order for the spot to face the basket ball. In fact the tennis ball will spin once for each time around the basket ball. This is very close to what happens with the moon. It turns round once for each orbit of the earth so we always see the same side. The side we don't see is referred to popularly as the dark side. But in fact sunlight often falls on the other side, we just don't see it.

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Yes, but only when viewed through your astronomical telescope.

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γνῶθι σεαυτόν

Absolutely not. I'm always very careful to do a headstand when viewing the moon, so that I can see it the correct way.

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As above, so below

The question is, who actually looks up at the Moon on any given night? Essentially nobody. And why's that? No apparent reason whatsoever. It's just the skewed nature of today's people.

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"Science is physics and astronomy." -Me
"There is absolutely no law in physics that prevents time travel." -Dr. Michio Kaku

We can fix this... well, we can try...
In this year of astronomy I took it upon myself to bring my interest in things astronomicle to the public.
I loaded the 10 inch ( 250mm ) Dobsonian into the car and down to the local McDonald's I went. With the permission of the management in the darkest corner of that car park I set up ... the first interested viewer was the police. They thought it looked like a rocket launcher, or some idiot rang them... that evening the Moon was at first quarter and Saturn was overhead. The second policeman has joined our society and has a celestron of his own now. over thirty people looked through this old dobi that night. Yes we can fight the complacency and win some... Just getting people to look is all it takes to spark the quest for knowledge.
"Yes the Moon does orbit Earth." and, " We only see one side of her." and the questions just keep coming.

Very nice story, Mark. I would love to do something like that one day. All it takes is a dark sky to begin a lifelong interest in astronomy.

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"Science is physics and astronomy." -Me
"There is absolutely no law in physics that prevents time travel." -Dr. Michio Kaku

Most people don't have a clue about the geometry of the universe.
See the Moslem flag.
How can there be a star or planet between the Earth and the moon?.

Maybe they launched Michael Jackson's body into orbit.

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As above, so below