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Astronomy question
Posted: 30 December 2007 03:48 PM   [ Ignore ]   [ # 16 ]
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mckenzievmd - 30 December 2007 03:12 PM

Well, there is a “dark side of the moon,” it’s just not always the same portion of the surface. Some portion is always in darkness just as some portion of the earth is. But the “dark side” changes continuously while the side facing the earth is always the same.

Sure. But I do think that it is an “urban legend” of sorts that there is one side of the moon that never sees sunlight. And that’s not so. (Although there may be some deep craters near the poles that always remain in darkness).

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Posted: 30 December 2007 03:57 PM   [ Ignore ]   [ # 17 ]
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LOL  George you are so funny.  I can picture it in my head all spinning in my head, but I was picturing the moon spinning at the slower rate than the earth as my son described.  He, if I understood him right, said the moon spins on it’s axis slower than the earth spins on it’s own axis.

OK, let me see if I get this straight- they are spinning at the same rate, does this mean people on the opposite side of earth see something other than the mythical man in the moon? The U.S. sees the man and oh let’s see… Australia maybe even Russia sees something else? Now that I am having a hard time picturing.

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“Sometimes in order to see the light, you have to risk the dark.” ~ Iris Hineman (Lois Smith) The Minority Report

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Posted: 30 December 2007 04:03 PM   [ Ignore ]   [ # 18 ]
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dougsmith - 30 December 2007 03:48 PM
mckenzievmd - 30 December 2007 03:12 PM

Well, there is a “dark side of the moon,” it’s just not always the same portion of the surface. Some portion is always in darkness just as some portion of the earth is. But the “dark side” changes continuously while the side facing the earth is always the same.

Sure. But I do think that it is an “urban legend” of sorts that there is one side of the moon that never sees sunlight. And that’s not so. (Although there may be some deep craters near the poles that always remain in darkness).

Yes and that is what I tried to tell my son, but it would seem to me that the earth (not us per se, because we may be dead when it happens) will see the other side.  I don’t think the side with the U.S. flag is always facing the earth as my son insists.  At some point- maybe Russia’s night the U.S. flag is in the dark too.

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“Sometimes in order to see the light, you have to risk the dark.” ~ Iris Hineman (Lois Smith) The Minority Report

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Posted: 30 December 2007 04:14 PM   [ Ignore ]   [ # 19 ]
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Mriana - 30 December 2007 04:03 PM

... but it would seem to me that the earth (not us per se, because we may be dead when it happens) will see the other side.  I don’t think the side with the U.S. flag is always facing the earth as my son insists.  At some point- maybe Russia’s night the U.S. flag is in the dark too.

No, this will never happen. The moon’s rotation is fixed now.

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Posted: 30 December 2007 04:22 PM   [ Ignore ]   [ # 20 ]
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Again, careful definition of the words are needed.  The earth revolves around the sun and rotates on its axis.  The moon revolves around the earth and rotates on its axis.  It just so happens as has been pointed out here that the moon rotates and revolves at the same rate. 

I don’t want to muddy things because the moon also revolves around the sun, making a very strange combined motion.

Occam

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Posted: 30 December 2007 04:30 PM   [ Ignore ]   [ # 21 ]
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Mriana - 30 December 2007 04:03 PM

I don’t think the side with the U.S. flag is always facing the earth as my son insists.

Your son is right about that.

I’ll see if I can find a map pinpointing the spot.  It can be hard to find stuff with Google because there is so much JUNK!  #%$&*

The first moon landing was in the Mare Tranquillitatis (the Sea of Tranquility). Maria are concentrated on the side of the moon that faces the Earth; the far side has very few of these plains. Scientists don’t know why this is so.

http://www.enchantedlearning.com/subjects/astronomy/moon/


If they had landed on the far side they would have had problems communicating back to Earth.  Whenever the orbiter went behind the moon it was out of touch.  They would not have seriously considered landing on the far side back then.

psik

[ Edited: 30 December 2007 04:37 PM by psikeyhackr ]
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Posted: 30 December 2007 04:49 PM   [ Ignore ]   [ # 22 ]
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Mriana,

As Occam, cautioned, we have to watch our terminology. The Earth and moon rotate at different rates. The moons revolution around the earth and rotation around its axis are synchronized so that the same face always points towards the earth (1 full rotation for each full revolution). The rotation of the earth around its own axis is independant of this, which means that different parts of the earth see the moon at different times during the day/night cycle, but the face of the moon visible from the earth is always the same no matter what part of the earth you’re standing on.

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Posted: 30 December 2007 05:08 PM   [ Ignore ]   [ # 23 ]
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Brennen, I’m trying to understand, but it still doesn’t make sense, esp if the moon is revolving around it’s own axis too.  Does anyone know where there is an online similation of this?

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“Sometimes in order to see the light, you have to risk the dark.” ~ Iris Hineman (Lois Smith) The Minority Report

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Posted: 30 December 2007 05:22 PM   [ Ignore ]   [ # 24 ]
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Mriana,

HERE is a site that has diagrams and a protocol for an experiment like George’s you can do at home.

Here is a VIDEO SIMULATION that might help.


Another VIDEO SIMULATION The “view from the sun” is the best way to look at this one for our purpose.

[ Edited: 30 December 2007 05:29 PM by mckenzievmd ]
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Posted: 30 December 2007 06:21 PM   [ Ignore ]   [ # 25 ]
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In both similations the dark side faced the earth, as well as the light side.  I don’t think I understand any better than I did before.

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“Sometimes in order to see the light, you have to risk the dark.” ~ Iris Hineman (Lois Smith) The Minority Report

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Posted: 30 December 2007 06:25 PM   [ Ignore ]   [ # 26 ]
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Mriana - 30 December 2007 12:32 PM

This is one of the things my son want to post after he joined, but couldn’t.

We are in a debate about the moon.  He insists that the dark side of the moon (not the far side, but the dark side- so he says are different) will never be seen by the earth. 

.

This thread is already overkill so what is one more response.
The moon keeps one side to the earth so we only see one side. (it wobbles a little but we basically can’t see the far side).
When the moon is ‘full’ the side facing the earth is fully lit by light from the sun.
When the moon is ‘new’ the side away from the earth is facing the sun so the side we see looks really dark (it is lit slightly by sunlight reflected from the earth back to the moon).
In the course of a month, as the moon goes around the earth, always keeping one face to the earth, different parts of the moon become exposed to the light from the sun, and then go into the dark.  A “day” on the moon lasts ~14 days (half a month). There are no parts of the moon which are always in the dark in the way that you folks are discussing it.

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Posted: 30 December 2007 08:35 PM   [ Ignore ]   [ # 27 ]
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Mriana - 30 December 2007 06:21 PM

In both similations the dark side faced the earth, as well as the light side.

Right, that’s what I said before. When there is a “new moon”, the dark side of the moon faces earth. When there is a “full moon” the light side is facing us. But it is the same PART of the moon that faces us all the time.

Ergo, the same part of the moon is sometimes in light, and sometimes in darkness.

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Posted: 30 December 2007 09:22 PM   [ Ignore ]   [ # 28 ]
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dougsmith - 30 December 2007 08:35 PM
Mriana - 30 December 2007 06:21 PM

In both similations the dark side faced the earth, as well as the light side.

Right, that’s what I said before. When there is a “new moon”, the dark side of the moon faces earth. When there is a “full moon” the light side is facing us. But it is the same PART of the moon that faces us all the time.

Ergo, the same part of the moon is sometimes in light, and sometimes in darkness.

Huh?  question  gulp  My brain just blew a cell.

[ Edited: 30 December 2007 09:25 PM by Mriana ]
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Posted: 30 December 2007 10:04 PM   [ Ignore ]   [ # 29 ]
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Mriana - 30 December 2007 06:21 PM

In both similations the dark side faced the earth, as well as the light side.  I don’t think I understand any better than I did before.

Actually I think it is best to not regard any part of the moon as “light side” and “dark side”.

There is “near side” and “far side”.  Those remain fixed.  But what part of the moon is facing the sun is constantly changing.

Does the Earth have a “light side” and “dark side”?

People don’t usually appl those terms to the Earth they just say day and night.  The days and nights on the moon just happen to be 14 Earth days long.

psik

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Posted: 31 December 2007 04:05 AM   [ Ignore ]   [ # 30 ]
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dougsmith - 30 December 2007 08:35 PM
Mriana - 30 December 2007 06:21 PM

In both similations the dark side faced the earth, as well as the light side.

Right, that’s what I said before. When there is a “new moon”, the dark side of the moon faces earth. When there is a “full moon” the light side is facing us. But it is the same PART of the moon that faces us all the time.

Ergo, the same part of the moon is sometimes in light, and sometimes in darkness.

Thanks!

When there is a new moon the side which is enjoying ‘night’ faces the earth and the point most directly facing earth is enjoying ‘midnight’—it has been 7 days since the sun set and 7 days before the sun rises.
              when there is a full moon the side which is now enjoying ‘day’ , and the point most directly facing earch is at ‘high noon’—for 7 days it has seen direct sun light and this will continue for another 7 days.

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