- #1
Gerinski
- 323
- 15
It is often said that although the expansion of the universe may create the illusion of objects in very far regions of the universe to recede from each other at superluminal speed, that does not violate c because locally they never move faster than c. This I can understand.
How would things look like during the inflationary period is more confusing to me though. The rate at which space expanded was huge even in a local context. Without caring to do any math, the space separation which at a certain moment was, say 1,000 km, after a few seconds would have become hundreds of thousands or billions of kilometers, as 'new kilometers got pumped in between'. Even locally, if you tried to measure the speed at which objects receded from each other (ok there were no 'objects' yet but go along with me), you would get apparent superluminal speeds, wouldn't you? (or more precisely, you would not be able to measure it because all the neighbour 'objects' would just disappear from sight with the space between you both stretching faster than the distance the emitted photon traveling at c towards you could travel). Although this would not really violate c either, the effect if it could have been measured would be that even locally things appeared to be getting apart from each other 'faster than c'. Or not?
Thanks!
How would things look like during the inflationary period is more confusing to me though. The rate at which space expanded was huge even in a local context. Without caring to do any math, the space separation which at a certain moment was, say 1,000 km, after a few seconds would have become hundreds of thousands or billions of kilometers, as 'new kilometers got pumped in between'. Even locally, if you tried to measure the speed at which objects receded from each other (ok there were no 'objects' yet but go along with me), you would get apparent superluminal speeds, wouldn't you? (or more precisely, you would not be able to measure it because all the neighbour 'objects' would just disappear from sight with the space between you both stretching faster than the distance the emitted photon traveling at c towards you could travel). Although this would not really violate c either, the effect if it could have been measured would be that even locally things appeared to be getting apart from each other 'faster than c'. Or not?
Thanks!