Layperson here. In a theoretical big crunch with space contracting faster than the speed of light, would information be travelling faster than speed of light? Because the points A and B themselves would be moving towards each other FTL.

Maybe this is obvious or I have made a wrong assumption. Either way, please answer. Also, forgive if this has already been asked. I did search and couldn't find such a question.

  • $\begingroup$ What do you mean by "faster than light"? Nothing moves faster than c in a local inertial frame (see this article on the equivalence principle for a basic explanation of local inertial frames), but in some non-local coordinate system defined on the entire spacetime, various things (including light itself) may move faster than c--is that all you mean? Or are you asking if I send two signals to my friend simultaneously, one using light and the other gravitational, if the second could reach him before the first? (if so, no) $\endgroup$ – Hypnosifl Aug 17 '15 at 22:43
  • $\begingroup$ Ah yes, I ignored the global/local frames.Thanks. $\endgroup$ – Juhi Aug 18 '15 at 17:39

You are not travelling faster than light in the sense that if you send some light to your destination it gets there before you do.

It can be faster than light in the sense that if space is isotropically and homogeneously distributed with energy and such then there is an obvious global frame and distance in the global frame between two points can decrease faster than light.

It's like you and your friend sitting at home in your galaxies as the universe collapses to a point. Light is getting between the two of you faster than you two are getting close to each other. But there might be a while where your distance gets small quite fast.


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