A question regarding our moon

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Glo

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Heh, well .. kind of an astronomy question I was wondering about
Hope someone might know this.

I've heard a couple of times the fact that only one side of the moon is facing us all the time. How is this possible?

The reason I ask this here is because I didn't find an answer anywhere else.

Thanks anyway : o
 
Yep, that's true... just take your hand and spin it around your head always having your palm facing you... it's like that...

As for the physics behind it... uhhhh...
 
yes it's true. hence the phrase 'the dark side of the moon'. although i don't know why the moon has no rotation. google it.
 
What I mean is, I understand it is a fact.
I am curious about what causes only one side of the moon to face Earth.
The moon and Earth are two seperate objects. Wouldn't they have to spin differently, without any connection?
 
The moon is in a synchronous rotation with the Earth, so the features you see on the moon will be similar on a nightly basis, with some slight changes due to librations in the latitude and longitude of the moon. The librations allow us to see 59% of the moon's surface (but no more than 50% at one time)
 
Glo said:
What I mean is, I understand it is a fact.
I am curious about what causes only one side of the moon to face Earth.
The moon and Earth are two seperate objects. Wouldn't they have to spin differently, without any connection?
Click to expand...
They do spin differently... the moon just happens to spin in such a way with its orbit so that it's always facing Earth... it has nothing to do with Earth's rotation...
 
That was kind of what I thought.
The moon's spinning is synchronized to always face earth is that it?
If so, there has to be reason why it is. I mean, were earth and moon the same object once? and then got detached?
 
The reason is, the moon isn't exactly sperical, thus one side is slightly heaver. This side is always facing us due to the strong pull of the Earth's gravity.
 
Matthias said:
The reason is, the moon isn't exactly sperical, thus one side is slightly heaver. This side is always facing us due to the strong pull of the Earth's gravity.
Click to expand...

Oh, sounds logic : o
This was what I wanted to know actually.
Thanks guys
 
Matthias said:
The reason is, the moon isn't exactly sperical, thus one side is slightly heaver. This side is always facing us due to the strong pull of the Earth's gravity.
Click to expand...

Bingo...

Also.. You shouldn't think of the moon as not turning around (on its axis).

Even though it always faces earth it is still turning. Its just hard to think of it that way because we usually just think of the moons position with how it is around the earth.

If you were to say have a little moddle of the moons rotation ( like on a program) and had the view fixed above the moon wile it orbits the earth, you will see it spin too.
 
I see.
I was searching for the physics behind that fact.
Saying something is always facing earth on the same side holds a reason behind it. Now I understand it, thanks
As for the spinning of the moon, I guess the spinning poll is aligned to meet earth, is that right?

edit:
something like the attached image
 
So basicly, when the moon is surrounding earth, its axis changes direction to always meet earth?
Or is this whole thing a mistake?
 
The reason why you only see one side of the moon is because the moon rotatates at the same speed as it revolves around the earth. It's simple as that.
 
Babka said:
The reason why you only see one side of the moon is because the moon rotatates at the same speed as it revolves around the earth. It's simple as that.
Click to expand...

I have some difficulties with explaining things I guess : o
What I was wondering about at the first place was what causes the moon to do that. I thought the moon should spin at one direction and speed which are not connected to earth.
Now I see I completely ignored the fact that earth's gravity affects the moon.
Thanks anyway
 
The moon always faces the Earth because of gravitational pull.

Basically, the moon was formed from debris resulting from a collision between the Earth (while very young), and another planetary body (estimated to be around the size of Mars). We know this because scientists brought back moon rocks in one of the later moon missions, and the rock was dated at exactly the same age as the Earth. I can't remember the science, but the rock was also proved to have been formed in a way which indicated it had been molten from the collision.

The Moon's orbit around the Earth is actually taking it further away each year (by about an inch if memory serves). Its reckoned that in a few thousand years the 'diamond ring' effect seen towards the end of a lunar eclipse (caused by the sun appearing from behind a mountain on the moon) will no longer be visible because of this gradual change in orbit.

Its only in the last 100 years or so that people have actually accepted that the craters on the Moon are the result of meteor impacts. Most people used to believe them to be volcanos. Nobody would believe that meteors had struck the Earth throughout history, even with the evidence staring them in the face.
 
one point: "dark side of the moon" is a misnomer, obviously, because it isn't actually dark. it's light there whenever it's a new moon.

on lunar orbits, synchonous, how and why: good explanation page here.

FYI, mercury also has a inward facing face. the temperature on that side is over 600 degrees, hot enough to melt lead. not as hot as venus, or course, but for different reasons. though it doesn't spin, it does actually 'rock' back and forth a little.
 
Cool thanks
Nice read, this answered my questions
 
This is so reminding me of Magic School Bus, that one episode where they visited all the planets, and that one guy totally took his helmet off on Pluto and his head froze into a solid block of ice so they flew back to Earth in time to sit him in front of a heater and it melted and he was okay.

It was kinda unrealistic though, cause that little iguana dude had to wear a suit too but aren't reptiles cold blooded?
 
Bad^Hat said:
This is so reminding me of Magic School Bus, that one episode where they visited all the planets, and that one guy totally took his helmet off on Pluto and his head froze into a solid block of ice so they flew back to Earth in time to sit him in front of a heater and it melted and he was okay.

It was kinda unrealistic though, cause that little iguana dude had to wear a suit too but aren't reptiles cold blooded?
Click to expand...
His head froze into a block, but was warmed up against a heater unscathed and your problem with realism revolves around the iguana!?
 
Parrot of doom said:
Its reckoned that in a few thousand years the 'diamond ring' effect seen towards the end of a lunar eclipse (caused by the sun appearing from behind a mountain on the moon) will no longer be visible because of this gradual change in orbit.
Click to expand...

The 'diamond ring' effect is demonstrated very nicely by Phisionary's avater.


Oh and the blood of reptiles and other cold blooded animals is still composed primarily of water, and will freeze at the same temperature as the blood of warm-blooded animals. I don't think the magic school bus is meant to be entirely realistic anyhow...
 
I thought cold blooded animals prefer being in a hot climate, as they don't have a way of regulating their body temperature internally.
 
good point. but if their body temperature is reduced, they don't die from it.

bottom line, I don't think Iguanas want to be in space without suits.
 
I think the moon does spin it just orbits around us at the same speed or something so we only ever see one side :rolleyes:
 
Damnit, I read the topic title as "A question about your mom" and was all like WTFuxors? :O
 
Alec_85 said:
Hmm if the moon doesn't rotate, then how come moons in for example American movies looks differently from the one I see outside my house here in Sweden? The surface formations are practially always different. Maybe I need new eyes or something.

http://images.google.se/images?q=Moon&hl=sv&lr=&ie=UTF-8&sa=N&tab=wi
Maybe it has to do with angles (not angels...) and stuff like that :)
Click to expand...

The Moon does rotate, it just rotates on its axis at the same speed it takes it to circle the Earth. Hence we only see one side.

Regarding the different faces, well, get a telescope and have a proper look at the moon, and it won't be so different. Even if you have binoculars, have a look on a full moon, it looks amazing.
 
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