Quote:
Originally Posted by cosmocrazy
What is confusing me about the argument is when we consider time as a reference coordinate then it is measured separately to spacial ones but when we introduce Sr & GR then space time are interwoven and are considered a space-time continuum so the expansion of time is relative to 2 observers in different frame references but not to one in his own? I'm confusing myself now!
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The problem, I believe, is that under SR and GR we have these coordinate transformations that allow one observer to disagree with another observer's choice of space and time axes.
But when you're writing down an equation for the
whole universe, there's no "other observer" to disagree with. As
Occams Ghost has already been told:
Quote:
Originally Posted by matt.o
Occams Ghost - I think you should study the Friedmann-Lemaître-Robertson-Walker metric. You will see that the scale factor only acts upon the spatial part of the metric, and not the temporal part.
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(The "FLRW metric" referred to here is a mathematical description of the behaviour of a whole, dynamic, self-gravitating universe.)
Grant Hutchison