# system rotation?

• June 23rd, 2006, 08:38 PM
icewendigo
system rotation?
I was wondering why did the initial gas cloud that is thought to have formed the solar system rotate?
Is there a relationship between most of our solar system's rotation and our system's movement and location in the galaxy?

(like the toilets funnel on the north emisphere rotate one way while whirlpools on the southern emisphere turn the otherway)
• June 24th, 2006, 01:32 AM
grav
It is said that if all of the matter in the universe is spread evenly within an infinite amount of space, it will not collapse because there is no center of gravity to fall to. It is also said that this cannot be true because if we take first a finite amount of matter, then it will have a center point, and it will all collapse to that point under the influence of gravity. If we then add more matter, it will also collapse to that point, and this will continue regardless of how much matter we add, even to infinity.

The problem with the second scenario, however, is that infinity cannot be built up to. Nevertheless, both of these statements are true to some degree. The reason is that matter is not evenly distributed throughout the universe because of random motions of particles which create random fluctuations in density. Any region of space that is slightly more concentrated than another will begin to fall in on itself, as is evident in the existence of the planets and stars. Each individual atom that makes them up must have once been a free atom or particle in space that was caught by gravitational fields. This is obviously an extremely large number of bits which have fallen into a single body.

At some point, however, the very motions which caused the random fluctuations in the first place will prevent matter from congregating any further. Kinetic energies will combine until large bodies will rotate and orbit each other instead of falling together. Equilibrium will therefore always be achieved and maintained at some point.

I think it is also interesting that rotation appears to be absolute. With relativity, if we were in a box, we would not know if we were moving and the speed of light would remain the same in all frames of reference. Any objects moving toward or away from us would be the same as if we were moving toward or away from them. Also, we would not know the difference for gravity and normal acceleration. These are what relativity is founded upon and implies that there is no absolute time or space to use as a frame of reference. However, I have realized that if the Earth was in such a box ( or any rotating mass ), we could determine its rotation from the difference in the acceleration of gravity at the equator and the poles for the distance from the center for each, whereby the difference would be equal to its centrifugal force. This implies in some strange way that gravity is absolute in reference to the angular momentum of a body.
• June 24th, 2006, 06:39 AM
icewendigo
1- Your comment is very interesting, but why do most planets in the solar system rotate in the same direction(lets say clockwise) instead of an alternate possibility of most of them rotating counter-clockwise? Does the rotation of the galaxy make one direction more likely?