Greetings! I'm afraid I'm not nearly as educated as many who come to this forum, but I did have a nagging question. Google sent me here in my quest for the answer.

What is it called, where the "shadowed" side of the moon and the illuminated side meet? Does this place/event have a name?

Thanks!

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Phainein Terra

Yes, it is called Moon's terminator.

Apollo 12 picture:

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Yeah earth has one too I think.

It's also the best place to look when observing the moon because of the long, morning, shadows give high relif making the suface features realy stand out.

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If this writing is blue you're going too fast!

Yup. Every planet--heck, every object orbiting a star would have one, since it's the line between the "day" and "night" sides of an object.

Thanks for the replies! What a weird name for it. X^D Was expecting something a little more obscure. Now I know!

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Phainein Terra

Yeah (deep voice) The Terminater (/evil deep voice) any way just a qustion about your location... your pants 8-[

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If this writing is blue you're going too fast!

Wherever you are, that's where you be. And I'm always in my pants.

X^D

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Phainein Terra

ok then thats a good thing as long as its not my pants 8-[

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If this writing is blue you're going too fast!

[nitpick]
Nope. If a star orbits another star, the orbiting star has no terminator.
[/nitpick]

:P

Harald

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"Flying in space is risky business, but just staying on this planet is risky business too." - John Young, astronaut

I bet other stars have very deep craters at there poles (like the moon and mercury) that never see daylight... so would that be called a terminater.

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If this writing is blue you're going too fast!

I doubt. Such a crater has to be close to the terminator. The terminator demarks the night/day line, not just any light/shadow line.

Hasta la vista, baby!

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"Flying in space is risky business, but just staying on this planet is risky business too." - John Young, astronaut

That and the fact that stars don't have craters :wink:

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If this writing is blue you're going too fast!

So now would be the worst time to mention that I'm working on interacting binaries, wouldn't it. #-o 8-[ I meant, of course, non-stellar (or not highly luminous) bodies--yeah, that's it, that's what I meant to say.

Phainein,
Did you mean something different to the 'terminator'?

I thought that the terminator was the line on a planet, or satellite (use 'planet') where a surface observer would see sunrise or sunset. That line rotates with the planet. So it does with the Moon, but unlike every other planet where at some time, in theory, we can see every part of the surface, we can't see the back side of the Moon. However, libration, the Moon's orbital wobble, reveals a little of each limb of the Moon so that parts of the back side can be seen at an extreme angle.

So there is a terminator on every planet, nothing exclusively Lunar about it. The unique area the Moon does have is between the fully visible and the always invisible, that can only be seen from time to time. Is there a name for this mysterious, difficult to see area?

John

The "Far Side"? Not to be confused with the Dark Side.

Edit: Maybe you did mean the dark side? It would to fit the "difficult to see" description.

Permit me to contend once again that dark is fine, for one meaning of dark is hidden or concealed. It is a traditional name. It is unfortunately confusing because some people (ahem, BA?) appear to think dark must always mean lacking brightness, and therefore "far side" is probably a more meaningful moniker -- at least until people start hanging out in the vicinity of that side.

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I agree with your point, in a popular sense (like it is ok to say that the sun sets). Although when it comes to modern science, we need defined terms, and in that case I think the BA's definition of Dark and Far side is appropriate.

All,
Clearly I didn't make myself clear, though I did differentiate between "difficult to see" and "impossible to see".

The back of the Moon is impossible to see. At the edge of the Moon's disk, as we look at it from Earth, there is an area which is seen at an oblique angle. So it is difficult to see the landscape, in contrast to the almost vertical view of the rest of the disk.
Moreover, the Moon librates, 'wobbles' in its orbit, so more and less of this area comes into view from time to time.

This is the area that I had in mind. Not the Far side, dark side, backside. The Edge of the Moon. Nowadays, no doubt we have a full pic ture of the Moon's whole lunography, but still, the Edge of the Moon has a mysterious ring. And if anyone says that the Moon has no ring, I shall have to accuse them of having no sense of humour, let alone of mystery.

JohnD

All,
Clearly I didn't make myself clear, though I did differentiate between "difficult to see" and "impossible to see".

The back of the Moon is impossible to see. At the edge of the Moon's disk, as we look at it from Earth, there is an area which is seen at an oblique angle. So it is difficult to see the landscape, in contrast to the almost vertical view of the rest of the disk.
Moreover, the Moon librates, 'wobbles' in its orbit, so more and less of this area comes into view from time to time.

This is the area that I had in mind. Not the Far side, dark side, backside. The Edge of the Moon. Nowadays, no doubt we have a full pic ture of the Moon's whole lunography, but still, the Edge of the Moon has a mysterious ring. And if anyone says that the Moon has no ring, I shall have to accuse them of having no sense of humour, let alone of mystery.

JohnD