Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Mike Finley on 26/11/2011 10:30:03

Title: Is the whole universe spinning?
Post by: Mike Finley on 26/11/2011 10:30:03

Mike Finley  asked the Naked Scientists:
   
Is the whole universe spinning and would that at least partially explain the accelerating expansion?  I am envisioning galaxies like barbells on a turn table, being flung away from the centre.

Spin around one axis would only explain expansion in a plane.  Would two orthogonal rotations result in a 3D expansion without the need for dark energy?

What do you think?

Title: Is the whole universe spinning?
Post by: syhprum on 26/11/2011 12:38:16

rotation can only be relative, the universe by definition is all that exists, relative to what could it be spinning ?

Title: Is the whole universe spinning?
Post by: Soul Surfer on 27/11/2011 23:42:32

It is quite possible for an extended body to possess angular momentum without any need for reference to an external point to detect the rotation.  this is because forces and directions of motion would be disturbed from those purely due to self gravity. 

To help with understanding this consider that our galaxy was the only thing in the universe and there was absolutely nothing to see beyond its immediate confines.  We can see quite a large part of the galaxy id it would be quite easy to tell it was rotating  it would also be possible to infer the existence of dark matter (in fact that was the way it was first discovered.  Now consider reducing our horizons to a few thousand light years and then shrinking the m steadily down to the local group of stars it would gradually get more difficult to detect the rotation and the curvature of stellar motions in their orbits. 

A great deal of work has been done to detect the sort of systematic distortions in velocities that would show that the universe as a whole was rotating but so far only lower limits can be set on the rotation.  i.e. it cannot be greater than some specific figure.  The CMB may have some indications of rotation and the so called "axis of evil" in it is considered by some to point towards this.

Title: Is the whole universe spinning?
Post by: MikeS on 28/11/2011 10:00:13

If the Universe is spinning and I'm inclined to think it is as virtually everything within it is spinning.  It must be spinning about an axis, so does this not imply that the Universe has a centre. ???

If the Universe is spinning could centripetal force account for (or at least be part of ) the supposedly observed expansion?

Title: Is the whole universe spinning?
Post by: yor_on on 28/11/2011 18:20:41

Yes Syhprum, it seems plausible, but I'm not sure. So, I would like to dissect what a 'spin' is defined as, again :)