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Why do cosmologists assume that inflation began shortly after the Big Bang, rather than at the exact start?
Somehow, I have never come across an explanation of why cosmologists claim that the alleged inflation of the very early universe occurred not at the Big Bang, but very shortly afterwards (~10^-36 to ...
1
vote
0
answers
33
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How can scientists deduce the number of types of neutrinos, or 'effective number', from Planck satellite data?
Is it related to the way they deduce the Hubble constant from Planck data?
Would more types of oscillating and mixing neutrinos mean faster or slower expansion of the universe?
Would a fourth mass ...
2
votes
1
answer
853
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What is the 'scale factor' equation for a dark-matter dominated universe?
The Friedmann equations can be solved exactly in presence of a perfect fluid with equation of state
$${\displaystyle p=w\rho c^{2}} \qquad p=w\rho c^2$$
where ${\displaystyle p}$ is the pressure, ${\...