Timeline for Is the Big Bang defined as before or after Inflation?
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| Jan 10, 2022 at 18:52 | comment | added | Jim | That said, I agree that it is unlikely that he is saying that inflation lasted for no more than $10^{-35}$s. Rather, I think he is merely defining time and the scale factor together. If he defines the Big Bang as a=0 and then defines time as a function of the scale factor, then the result would be a misleading usage of a numerical time around the epoch of inflation. I think his definition of the Big Bang comes before inflation, but I do not think his particular definition of time as a function of $a$ is valid during inflation. | |
| Jan 10, 2022 at 18:47 | comment | added | Jim | I have checked Dodelson. In chapter 1.6 on page 19, he says "We can characterize any epoch in the universe by the time since the Big Bang; by the value of the scale factor at that time; or by the temperature of the cosmic plasma." He then presents a figure (Fig 1.15) that clearly shows inflation at the era log(t/sec) < -35. Given that t is explicitly the time since the Big Bang, he must define the Big Bang as the curvature singularity before the end of inflation where a=0, since t=0 (the Big Bang) would be at $-\infty$ on the timeline; definitively before inflation. | |
| Jan 7, 2022 at 17:20 | comment | added | Jim | I'll have to go and check Dodelson again. I was pretty sure there was a more explicit definition. But perhaps I'm misremembering. Perhaps I misinterpreted. If I find something, I'll add the reference to my question. Nevertheless, he isn't the only cosmologist I've heard using the curvature singularity to mean the big bang, just the most referenceable at the time. | |
| Feb 6, 2021 at 21:47 | history | answered | benrg | CC BY-SA 4.0 |