Is the moon really spinning?

[crisitunity]

I hadn't really thought about it much before, but then I read in another thread someone talking about the fact that the moon is obviously spinning and it made me curious as I don't really see it that way.

Then I looked around on google and didn't find much debate on the issue, it completes one revolution each orbit which is why its always facing us, but I still don't see it that way. I can see what is being said, I think the idea of spin comes from viewing the situation as though earth is not the center of the moons orbit.

Am I just getting hung up on semantics somehow? I don't know that it really means anything in the end anyway... but I did make a gif of what it looks like in my head. How can you say the moon isn't stationary if the bar never breaks?

http://i860.photobucket.com/albums/ab162/TheGamefather/StillMoon.gif?t=1272686869

[armoured_amazon]

That's what it looks like in my head, too. :)

[kappy0405]

The idea that it rotates exactly one time per exactly one revolution seems farfetched to me, but supposedly, it's pretty common throughout the universe.

The moon became so locked to the Earths gravitational pull that it ended up like that.. Then why isn't the Earth locked into the Suns pull at an equal force causing the Earth to rotate only once per Earth year?

Somethings not adding up imho..

[batou]

dude.. if you want to see the moon spinning:
change your gif to the pov of the moon, and imagine looking from earth at it?
does that make sense..? since you are looking from the earth to the moon in yours, and cannot see how the moon spins, reverse your view point.

the bar not breaking has nothing to do with rotating or not, does it? it simply is following the orbit. maybe im wrong...

anyway... edit : 1 rotation per orbit is what is called geosynchronous orbit = im wrong and its late moon isn't in geosynchronous orbit :(

which is why my suggestion to switch your gif might show you how the moon is rotating. :confused:

[shed7628]

Somethings not adding up imho..

I will second that

The death star in star wars would have to do the same thing to keep its main weapon pointed at the planet.

[crisitunity]

dude.. if you want to see the moon spinning:
change your gif to the pov of the moon, and imagine looking from earth at it?
does that make sense..? since you are looking from the earth to the moon in yours, and cannot see how the moon spins, reverse your view point.

the bar not breaking has nothing to do with rotating or not, does it? it simply is following the orbit. maybe im wrong...

anyway... 1 rotation per orbit is what is called geosynchronous orbit, and ends up with one side always facing the earth.
which is why my suggestion to switch your gif might show you how the moon is rotating. :confused:

So if that red bar was a real bar pivoting on the center of the earth, and it was spiked straight through the moon like the gif shows, and the moon traveled the exact same path it travels now...

You still figure the moon is spinning?

And I am indeed not quite sure what you suggested as first you said the pov of the moon but then you said looking from earth. I think the correct point of view in this situation is the center of the earth though.

[shed7628]

Am I just getting hung up on semantics somehow? I don't know that it really means anything in the end anyway... but I did make a gif of what it looks like in my head. How can you say the moon isn't stationary if the bar never breaks?

http://i860.photobucket.com/albums/ab162/TheGamefather/StillMoon.gif?t=1272686869

The bar is not breaking on your diagram because if your look at your gif of the moon you will see that it is rotating. The features on your moon gif rotate 360 degrees in one orbit of the earth just like the real moon.

You have created a gif illustrating very well the rotation of the moon as it obits the earth,

The poster below this post has got it in one

When you see it you will think doh, had me thinking for a few mins

[theperceivingeye]

Relativity is a bitch... :)

[batou]

So if that red bar was a real bar pivoting on the center of the earth, and it was spiked straight through the moon like the gif shows, and the moon traveled the exact same path it travels now...

You still figure the moon is spinning?

And I am indeed not quite sure what you suggested as first you said the pov of the moon but then you said looking from earth. I think the correct point of view in this situation is the center of the earth though.

Hmm.. well i cant whip up a gif right now

ok on your red bar there is pivot on the earth and pivot on the moon correct?

well if you have an line always going vertically for example through the pivot of the moon... as the moon orbits the earth, you'll see sections of the moon pass through that line, which means the moon is rotating about it's axis = spinning

[crisitunity]

The bar is not breaking on your diagram because if your look at your gif of the moon you will see that it is rotating. The features on your moon gif rotate 360 degrees in one orbit of the earth just like the real moon.


When you see it you will think doh, had me thinking for a few mins

Your back the the original point yeah, if viewed as though the earth is not the center of the moons orbit there is rotation. Of course I had to rotate the image, I don't quite have the skills to render a 3d perspective from the center of the earth. :o

The point is, if you stuck a tennis ball on the end of a broomstick and swung the broomstick around, would you say the tennis ball was spinning?

[crisitunity]

Hmm.. well i cant whip up a gif right now

ok on your red bar there is pivot on the earth and pivot on the moon correct?

well if you have an line always going vertically for example through the pivot of the moon... as the moon orbits the earth, you'll see sections of the moon pass through that line, which means the moon is rotating about it's axis = spinning

now you've got me confused :)

I hadn't imagined a pivot on the moon, spike goes straight through the moon solid. The pivot is the center of the earth.

[shed7628]

Your back the the original point yeah, if viewed as though the earth is not the center of the moons orbit there is rotation. Of course I had to rotate the image, I don't quite have the skills to render a 3d perspective from the center of the earth. :o

The point is, if you stuck a tennis ball on the end of a broomstick and swung the broomstick around, would you say the tennis ball was spinning?

Yes the ball would be spinning in space, to me it would appear not to be spinning.

When you get it you will chuckle

[crisitunity]

Yes the ball would be spinning in space, to me it would apear not to be spinning.

When you get it you will chuckle

yeah the tennis ball stopped making sense right away heh

would have edited but you were on me :)

theres no center perspective to the tennis ball.

wont likely chuckle regardless

[batou]

ok i kinda give up.. i meant to go to bed an hour ago

im not sure how to make it any simpler

the moon goes around the earth and 1 side always faces. you understand that its clear.

a tennis ball on a stick going around your head isnt rotating TO YOU
its just on a stick and always facing you


BUT to an outside observer, they see all sides of the ball as it goes around you
so yes the ball is rotating

As another poster said: relativity is a bitch

the moon rotates as it orbits.

If it didn't rotate & orbit at such a speed, it would not always be facing us with 1 side.

Hmm. :(

Stop thinking from the Earth so much, and think of being an observer unattached to a planet?

Like i said, draw a line through the center of the moon, vertically.
All parts of the moon pass through that line at some point during it's orbit.
This means it's spinning.

I dont know man.
Good luck figuring it out.
The moon rotates, that's pretty much the bottom line. It's what makes us see only 1 side of it.

[crisitunity]

ok i kinda give up.. i meant to go to bed an hour ago

im not sure how to make it any simpler

the moon goes around the earth and 1 side always faces. you understand that its clear.

a tennis ball on a stick going around your head isnt rotating TO YOU
its just on a stick and always facing you


BUT to an outside observer, they see all sides of the ball as it goes around you
so yes the ball is rotating

As another poster said: relativity is a bitch

the moon rotates as it orbits.

If it didn't rotate & orbit at such a speed, it would not always be facing us with 1 side.

Hmm. :(

Stop thinking from the Earth so much, and think of being an observer unattached to a planet?

Like i said, draw a line through the center of the moon, vertically.
All parts of the moon pass through that line at some point during it's orbit.
This means it's spinning.

I dont know man.
Good luck figuring it out.
The moon rotates, that's pretty much the bottom line. It's what makes us see only 1 side of it.

You're not sure how to make it any simpler?? really?



yeah, you guys are telling me its semantics after all. It is indeed the perspective you chose. Where should physics be viewed from?

I know it can be viewed from an arbitrary third perspective, obviously, I covered it in the OP...

but to say the moon is rotating when in fact it is actually orbiting in a stationary position is misleading.

Edit: and just forget the tennis ball was a thoughtless example...

[shed7628]

http://img195.imageshack.us/img195/7885/orbitwithotrotation.jpg


http://img693.imageshack.us/img693/3463/54954546.jpg

[crisitunity]

heh, well aware of that perspective shed.

[shed7628]

heh, well aware of that perspective lol

So i dont understand what you are getting at then ?

[crisitunity]

So i dont understand what you are getting at then ?

honestly?

I don't think orbit should be considered rotation when the orbiting object is completely stationary due to the gravitational center for the object in question being the object its orbiting.


Edit: or, the point of perspective for the rotation of any orbiting object should be the center point of the object its orbiting.

[shed7628]

honestly?

I don't think orbit should be considered rotation .

Well it does not mater what you think, if the moon did not rotate we would see all sides of it.

[crisitunity]

Well it does not mater what you think, if the moon did not rotate we would see all sides of it.

hahaha, thanks shed, what would I do without you :D

[shed7628]

For anyone not getting this, here is something to try and this should physically illustrate the rotation to you.

Place an object on the table say a CD to represent the earth.

Grab a coffee cup in one hand with the handle pointing at the CD, now try orbiting the CD keeping the handle pointing at the CD. See how you have to rotate your hand.

[crisitunity]

Its just the point of view you chose, relativity indeed, seems misleading to call it rotation to me cause intrinsically I think the most relevant point of observation for an orbiting object is the center of the object its orbiting...

Of course from any other perspective its rotating as it goes through its orbit, but its not physically spinning.

[shed7628]

Its just the point of view you chose, relativity indeed, seems misleading to call it rotation to me cause intrinsically I think the most relevant point of observation for an orbiting object is the center of the object its orbiting...

Of course from any other perspective its rotating as it goes through its orbit, but its not physically spinning.

eh from our point of observation it has to be rotating, if it was not we would see all sides,

Try the coffee mug thing

[crisitunity]

eh from our point of observation it has to be rotating, if it was not we would see all sides,

Try the coffee mug thing

or how about you grow the fk up?


fkn loser.

why are you disgusting folk everywhere I go

[shed7628]

or how about you grow the fk up?


fkn loser.

why are you disgusting folk everywhere I go

What people who point out your stupidity

[practicaltheorist]

Is it usual to start lashing out at people who does not agree with oneself here?

[crisitunity]

was just thinking and felt like talking about it, didn't expect to start getting ridiculed

I know I should expect it but I never do, I'm just not like you people.

anyways this was all a mistake of course

night

[dreamweaver]

Does this video make things any clearer?

Synchronous Rotation of the Moon - YouTube

[21_12_2012]

What isn't being pointed out on this thread is the word AXIS.

Forget about the earth for a minute, concentrate on the moon, and think about just the moon as it slowly orbits around earth.

Now think of it's AXIS (the central vertical line through the moon) and picture what the moon is doing.

It's spinning around it's own AXIS once every time it orbits the earth.

edit:-
Yes, the video above mentions the axis, and is a good representation of how it spins.

[ambler1980]

Does this video make things any clearer?

http://www.youtube.com/watch?v=OZIB_leg75Q

makes perfect sense...the moon is fake:)

[elcribbo]

Is it usual to start lashing out at people who does not agree with oneself here?

Yes.

[mr stoppitall]

Tis awfully spherical for a static moon ;)