All Questions
Tagged with big-bang-theory expansion
18
questions
2
votes
2
answers
241
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Expansion rate of an infinite universe at the Big Bang
If the universe is infinitely large, then any two arbitrarily distant points must have been arbitrarily close together at some earlier point in time. Doesn't that mean that the expansion rate of the ...
- 123
2
votes
1
answer
146
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Strange plot in Max Tegmark book, Our Mathematical Universe
In Max Tegmark's book, Our Mathematical Universe, we can find (in chapter 5, figure 5.3) the following (horrible and poor quality) plot that is supposed to highlight the extreme sensitivity of the ...
- 189
2
votes
1
answer
355
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Because the Universe is expanding, what is it taking up?
It is my understanding that the universe is expanding and that matter takes up space. While the universe only contains small percent of matter, wouldn't expansion indicate that the universe is ...
- 129
1
vote
1
answer
867
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How can something infinitely big have expanded from an infinitely small?
Please help me reconcile what I see as contradicting theories:
The universe began with the Big Bang and expanded from an infinitesimally small point.
The universe is infinite.
How can something ...
- 11
5
votes
1
answer
414
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Why is the Cosmic Microwave Background evidence of a hotter, denser early Universe?
In his book Gravitation and cosmology, Steven Weinberg says that CMB makes it "difficult to doubt that the universe has evolved from a hotter, denser early stage".
In my understanding, the ...
- 1,002
1
vote
0
answers
80
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Expansion of space - how do we end up with an unobservable region?
I've just been answering a question on this issue,in physics SE,and realised that my answer conceals a point I don't myself understand.
I understand that
The expansion of metric isn't affected by ...
- 1,030
2
votes
1
answer
136
views
Is it fruitful to search for a correlation between rates of in-falling matter in black holes and the expansion rate of our universe? [duplicate]
To my understanding, white holes are hypothetical objects that are time-reversed black holes; black holes gravitationally "suck in" matter whereas white holes "spit" matter back out. As such, I think ...
user15317
4
votes
3
answers
1k
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How can the universe be expanding faster than speed of light? [duplicate]
So the story goes like this:
A long time ago, 13.799±0.021 billion years to be exact, something happened. It was a big bang, loud explosion and universe came to existence. It grew and grew, and now ...
- 701
-1
votes
1
answer
214
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Why is the CMB not simply travelling parallel to us? [closed]
When we look to the distant farthest reaches of the universe we see light that was emitted at the big bang 14 billion years ago. But the universe was tiny back then so that light, which is only ...
2
votes
3
answers
257
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Is it just the observable universe that is expanding?
Is it possible that it is just our observable part of the universe that is expanding, in the time that we exist, and other parts are both expanding and contracting at different rates and times?
Would ...
- 149
-1
votes
1
answer
483
views
Isn't the date of the Big Bang a bit bogus?
If I understand correctly, the date of the Big Bang is an extrapolation of acceleration of the universe's expansion through time based on the erroneous assumption that the universe is approximately 13 ...
- 19
4
votes
2
answers
240
views
Was the Universe expanding before the beginning of inflation?
My point of view is that first there was the Big Bang singularity, and then the period of inflation which resulted in the observable Universe becoming many times bigger. But was the Universe expanding ...
- 559
2
votes
2
answers
455
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How do we know the universe's expansion is speeding up?
Please forgive my ignorance, I am not an astronomer, just an interested layman.
The further away a galaxy is from us, the faster it is moving away from us. But the galaxies we see exist in the ...
- 23
4
votes
1
answer
1k
views
Big Bang / Big Crunch cycle?
I've been reading some of Stephen Hawking's work on the theory of the expansion (and ultimate contraction) of the universe and was curious if anyone has every hypothesized that the universe has ...
- 143
1
vote
1
answer
174
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If the speed at which the universe contracts in reverse time decreases over time, then how did scientists arrive at a date for "The Big Bang"?
If the speed at which the universe expands is constantly increasing (just like a derivative), then the opposite must also be true: the speed at which the universe contracts in reverse time is ...
- 11