Why is Moon so round and spinless?

[Inquisitor]

Why is our moon so perfectly round and spinless?

 

I mean should it not be a bit irregural shaped, like most moons in our solar system? Especially if it was formed from a chunk of earth off Earth?

 

So why is it a near perfect sphere?

 

Also, why does the Moon not have spin at all??? The very same side faces eath all the time! Why is this??? How is this even possible???

 

I mean take a basketball and hang it from the ceiling. Then shoot at it with a bb gun, you know, the one that fires light plastic bullets. The basketball will start to spin, even though the projectiles are very light, and the ball very heavy.

 

Now why has this not happened with Moon? It has been hit with major amount of very large meteorites. Surely all these hits would have caused the Moon to start spinning even a little???

 

This is very mysterious to me. Can somebody explain all this, and make it a bit less mysterious???

 

And suspicious too. Especially the fact, that from human point of wiev, the moon is exactly the size of the sun, so that during the eclipse, it covers the sun perfectly... Hmmmm.

 

I bet the moon is artificial, full of monitoring equipment and powerfull relay thingummies. Put there by some higher authority to monitor us and to help us evolve. Kinda like in the space odyssey movies.

[swansont]

Also, why does the Moon not have spin at all??? The very same side faces eath all the time! Why is this??? How is this even possible???

 

If you think this through, you should find that the first and second statements are contradictory. If something was not spinning, it would face a fixed reference (e.g. a distant star) all the time. The moon is tidally locked to the earth.

 

http://en.wikipedia.org/wiki/Tidal_locking#Earth.27s_Moon

[J.C.MacSwell]

 

I bet the moon is artificial, full of monitoring equipment and powerfull relay thingummies. Put there by some higher authority to monitor us and to help us evolve. Kinda like in the space odyssey movies.

 

This is a Science Forum. It has long been proven that it is made of cheese.

 

Now given enough cheese in one place in space and it will tend toward round due to gravity. Not enough cheese and it stays in a nice tasty wedge shape.

Edited March 27, 2009 by J.C.MacSwell

[insane_alien]

This is a Science Forum. It has long been proven that it is made of cheese.

 

Now given enough cheese in one place in space and it will tend toward round due to gravity. Not enough cheese and it stays in a nice tasty wedge shape.

 

now the real question: cheddar or stilton?

[swansont]

Cheddar? We don't get much call for it around here.

[Kyrisch]

Not much call for..?! -- it's the single most popular cheese in the world!

[J.C.MacSwell]

Not much call for..?! -- it's the single most popular cheese in the world!

 

Not much of a cheese shop, here at SFN.

[Cap'n Refsmmat]

I always thought it was made of Venezuelan beaver cheese.

[Daecon]

I read the title of this thread three times and each time thought it said spineless.

[swansont]

I read the title of this thread three times and each time thought it said spineless.

 

I tend to do that, too. If you Google on spinless, it asks you if you meant spineless

 

http://blogs.scienceforums.net/swansont/archives/242

[doG]

I read the title of this thread three times and each time thought it said spineless.

 

Me too...

[Inquisitor]

Okay

 

I do not see any answers to my questions here...

 

So is the roundness of a moon still a mystery or something???

[swansont]

A sphere minimizes the energy of a system with a radial force that depends inversely on distance. The moon is spherical for the same reason that the other planets, and the sun, are round. Gravity.

[Daecon]

Any body with sufficiently high gravity will become spherical under it's own weight.

 

I believe it was considered to be one of the characteristics for determining the difference between an asteroid and a planet (by having enough gravity to become spherical) at one stage during the whole "Pluto" debacle.

[J.C.MacSwell]

A sphere minimizes the energy of a system with a radial force that depends inversely on distance. The moon is spherical for the same reason that the other planets, and the sun, are round. Gravity.

 

Add that the reason many smaller moons are not round is because due to their smaller size they are strong enough to resist the lesser forces that are involved that would otherwise force them into a round shape. So it depends on there mass and their make up and time.

 

The moon is also probably very (very, very) slightly egg shaped, with the pointy end pointing toward Earth, as the tidal forces would be strongest there, and the gradient of the tidal forces slightly higher than on the opposite side where the tidal forces are weakest.

[lenvanzanten]

Like two magnets Earth and moon by their gravity in their magnetic forces are held together

Earth holds the moon in same way as Earth holds space shuttle in orbit.

[Daecon]

Does the moon have a magnetic field?

[Sisyphus]

Like two magnets Earth and moon by their gravity in their magnetic forces are held together

Earth holds the moon in same way as Earth holds space shuttle in orbit.

 

Does the moon have a magnetic field?

 

No, it does not. An analogy with magnets is just going to be needlessly confusing, I think. It works quite differently.

 

EDIT: Just so there's no confusion, there are some weak magnetic fields on the Moon from various sources, but nothing analogous to the Earth's global magnetic field:

 

http://en.wikipedia.org/wiki/Magnetic_field_of_the_Moon

[J.C.MacSwell]

No, it does not.An analogy with magnets is just going to be needlessly confusing, I think. It works quite differently.

EDIT: Just so there's no confusion, there are some weak magnetic fields on the Moon from various sources, but nothing analogous to the Earth's global magnetic field:

 

http://en.wikipedia.org/wiki/Magnetic_field_of_the_Moon

 

I agree, a magnetic orbit would be unstable. The inverse squared gravitational field is what "makes the world go 'round".

[Sisyphus]

I agree, a magnetic orbit would be unstable. The inverse squared gravitational field is what "makes the world go 'round".

 

Groan...