All Questions
37
questions
2
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0
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88
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A problem on cosmic inflation
I analyze inflation in this following scenario: Suppose that at some very early epoch, $t_1 ≤ t ≤ t_2$ (where $t_1 ≪ t_2 ≪ t_r$ and $t_r$ is the time at the recombination epoch), the universe resides ...
- 131
1
vote
1
answer
89
views
Duration of inflationary epoch
Why is it thought that the inflationary epoch of the universe lasted approximately $10^{-30}$ seconds and why did it take the inflaton (assuming its existence) to release the energy contained itself ...
- 495
1
vote
0
answers
33
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Can we infer the size of the whole universe from its expansion rate? [closed]
If the universe inflated to 100 billion km in its first second, that suggests only 1/160,000 of it was observable from any point at that moment. The expansion rate slowed after that, of course, but ...
- 384
0
votes
2
answers
88
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"What" was expanding during the Inflationary epoch?
I know, space. But in my opinoin, space makes only sense if there is something that experience things like position and distance. A universe without anything that require position and distance to ...
- 793
9
votes
2
answers
4k
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Why do we need inflation?
wiki (https://en.wikipedia.org/wiki/Inflation_(cosmology)) says that immediately after BB there was expansion at speed greater than $c$, what makes this necessary, what would happen if expansion took ...
user337596
0
votes
0
answers
77
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What if cosmological inflation never stopped?
If inflantionary theory is correct, the universe ceased to expand after just $10^{−32}$
seconds. Imagine a scenario where cosmic inflation never actually stopped.
At the extremely accelerated ...
- 2,987
6
votes
4
answers
431
views
Did the universe need the presence of matter and radiation to start expanding?
I have read this question:
Hence it is not possible that photons generated by stars is contributing to dark energy.
Could photons generated from the many trillions of stars be some how contributing ...
- 29k
0
votes
1
answer
75
views
A fire at the end of inflation?
In their article at bigthink.com "Surprise: the Big Bang isn't the beginning of the universe anymore", the writer articulated an alternative theory that suggests inflation didn't begin at a ...
- 11
10
votes
4
answers
3k
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So Universe Expansion is accelerating, it already did with the Big Bang, so what came in-between?
So scientists are finding that the Universe is expanding at an accelerating rate.
It is said 'Dark Energy' is the cause. Ok.
But the Universe expanded at a reaally accelerated rate just after the Big ...
- 111
0
votes
1
answer
55
views
How do you know that objects are accelerating from each other in space?
I know that Hubble redshift comes from the relation between the distances of objects and the Hubble parameter:
$$H_0 = \frac{\dot{R}}{R}.$$
But how we differentiate between redshifts effects from the ...
- 84
1
vote
2
answers
131
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If the universe is expanding at an accelerated rate, was it stationary at some point in time and contracting before that?
If the universe is expanding at an accelerated rate it would mean that the more we go in the past, the slower the speed of expansion must have been. Provided the acceleration was always non-zero and ...
user283752
0
votes
1
answer
102
views
In the big bang model did the universe reach its current size in less than one day? [closed]
I read that the Inflationary Epoch is posited to have lasted $10^{-32}s$. That seems quite quick.
In the big bang model did the universe therefore essentially reach the size it is now in less than ...
- 255
1
vote
1
answer
139
views
How was matter in other parts of the universe affected by the Big Bang and inflation in an infinitely sized universe?
I'm trying to understand how the idea of an infinite universe with presumably infinite matter works with the Big Bang and inflation.
I understand that if the universe is infinite, then it's always ...
- 199
10
votes
4
answers
2k
views
Is Big Bang Theory the only one to explain the creation of the Universe?
Is Big Bang Theory the only one to explain the creation of the Universe?
I have read about Big-Bang Theory explaining the creation of Universe. Is there no other theory to explain the creation of ...
user262759
1
vote
1
answer
172
views
Early Universe Flatness Problem
My question is about the curvature of spacetime in the early universe (Plank era)
https://en.wikipedia.org/wiki/Flatness_problem
Based on data from Wilkinson Microwave Anisotropy Probe, in order to ...
- 11