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Expansion rate and corollary 
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#1
Jan3013, 09:34 AM

P: 20

If dark matter is accelerating the expansion of the universe, then how fast did the universe start expanding at the point of the Big Bang ?
The preStandard Candle model of the Big Bang held that the expansion rate had always been declining and by backward interpolation, must have been very much faster at the BB. But if the reverse is true, how did the BB even happen  if the expansion rate was slow to zero ? I've never heard anyone ask this question, as yet. 


#2
Jan3013, 10:41 AM

Mentor
P: 11,589

Currently, expansion is accelerating  but some billion years ago, matter dominated and acceleration was slowing down. Expansion was quicker in the early universe.
We have a calculator here, and some nice graph showing the evolution of the size of the universe which I do not find at the moment. 


#3
Jan3013, 06:59 PM

P: 20

:) 


#4
Feb213, 12:51 PM

P: 5,632

Expansion rate and corollary



#5
Feb213, 01:01 PM

P: 5,632




#6
Feb213, 05:03 PM

Astronomy
Sci Advisor
PF Gold
P: 23,108

There is a much plainer graph of the scalefactor over time that is here http://ned.ipac.caltech.edu/level5/M...s/figure14.jpg It shows slowing down until around year 7 billion and then speeding up after that. I didn't have room in my signature for it, but I already had a different figure from the same article in my signature http://ned.ipac.caltech.edu/level5/M...es/figure1.jpg so I get it by clicking on that (which is "Figure 1") and then changing the 1 to a 14. 


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