Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

If the expansion of the universe is accelerating, doesn't that mean that the entire universe is a non-inertial frame of reference? And if so, what implications does this have (if any)?

share|cite|improve this question
Frame of reference should be defined at single point, or you palling to shrink whole universe to a point?, even so being our earth is not inertial frame of reference, Astronomers includes that in there measures, and it's not enough to describe the expansion. – TMS Dec 2 '12 at 21:40
Note: In GR, generally there cannot be any global inertial frame of references, only local ones. – namehere Dec 3 '12 at 11:13
up vote 1 down vote accepted

No. The expansion of the universe and the accelerated expansion is simply a scale factor change, not any kind of motion at all. For there to be a real acceleration there would have to be a preferred direction to the acceleration. The universe is isotropic so there is no direction for the acceleration, the scale factor change simply increases the distance between any pair of points.

share|cite|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.