Expert: James Gort - 12/19/2006

Question
How would a photon behave in a universe where all dimensions are collapsing at the speed of light?

Answer
Hi Luis,

I'll give you my best guess on this one.  It's certainly an interesting question!

According to Einstein, the speed of light is a constant.  It doesn't matter that's it's a moving frame of reference.  An observer within the frame or outside the frame both measure the speed as c.

So if all dimensions are collapsing at c (we'll assume at least the four dimensions of space-time are collapsing), then an observer within that universe would not notice the collapse just by measuring c.  However, light would be extremely blue-shifted (to the point where it would be invisible).  If further objects would be approaching at c, but closer objects approaching at less than c, then the observer would observe some stars, but the furthest ones would become invisible as their light gets shifted to the blue, ultraviolet, x-ray, etc.

So if the universe was collapsing uniformly at c, one might think that photons (which still have constant velocity c) would be so blue shifted that no light is possible.  This would amount to time "standing still" for such an observer.  This would be true for an observer "stationary" with respect to the moving frame (or an observer "outside" the universe).  But in our case, I would think that "frame dragging" would cause our observer (within the collapsing universe) to move along at c, so that photons wouldn't be blue shifted at all!  In fact, I would contend that such an observer would not be aware of the collapsing universe, and the photons would behave the same as photons in our universe.

All of the above, of course, is argumentative and subject to change at no notice!

Prof. James Gort