The forum discussion centers on the implications of the "Big Rip" scenario in cosmology, specifically regarding time dilation and the concept of time stopping. It is established that time dilation does not apply to the universe as a whole and that the expansion velocity of the universe does not equate to speed in the context of special relativity. Furthermore, if the Big Rip were to occur, it is highly unlikely that time would stop; instead, new physics would likely emerge to regularize the singularity before reaching infinite energy density, particularly around the Planck density.
PREREQUISITESAstronomers, physicists, and students of cosmology interested in the implications of cosmic expansion and the nature of time in extreme conditions.
Lionel Doolan said:Would an accelerating expansion create any time dilation effects?
Lionel Doolan said:And once the expansion velocity between any two adjacent points reached c would time stop altogether?
If the "Big Rip" scenario were accurate (which is highly unlikely), the most unlikely outcome is that new physics would take over once the energy density of our universe got high enough (certainly by the time the density reached the Planck density, possibly before then). The new physics would almost certainly "regularize" the singularity in some way, making the universe change its behavior to prevent the Big Rip from resulting in infinite energy density. Without knowing what physics is at very high energies, we can't know precisely how the singularity would be avoided.Lionel Doolan said:Would an accelerating expansion create any time dilation effects? And once the expansion velocity between any two adjacent points reached c would time stop altogether?