Linked Questions

21
votes
5answers
7k views

Does red shift evidence necessarily imply that the universe started from a singularity?

We are taught that the universe began as a singularity - an infinitely small and infinitely dense point. At the beginning of time there was a 'Big Bang' or, more accurately, 'Inflation'. The main ...
21
votes
2answers
6k views

How can something finite become infinite?

How can the universe become infinite in spatial extent if it started as a singularity, wouldn't it take infinite time to expand into an infinite universe?
16
votes
3answers
13k views

Is the law of conservation of energy still valid?

Is the law of conservation of energy still valid or have there been experiments showing that energy could be created or lost?
14
votes
7answers
17k views

How can something happen when time does not exist?

I saw this documentary hosted by Stephen Hawkins. And if I didn't get it wrong, it says that there was no time before the big bang, time was created there. So how can anything happen when there is ...
8
votes
4answers
1k views

Is space unending?

Is the space unending, i.e it has no boundaries? If yes, how can a thing exist which is non-ending? Its impossible for me to imagine something like that. Secondly, if its not and has boundaries then ...
6
votes
1answer
577 views

Infinite number of galaxies?

I understand that the current estimate for the number of galaxies in the observable universe is about 100-200 billion. Is there anything in our understanding of physics and the evolution of the ...
6
votes
3answers
2k views

Can we prove that the universe is finite or infinite? [duplicate]

If I say that the universe is finite, how can you say with certain that I am wrong?
5
votes
4answers
1k views

The inner workings of the Olbers paradox

A long time ago I was told that the universe is finite. The provided "proof" (or reasoning), known as Olbers' paradox, was that on infinite universe there would be an infinite number of stars, and ...
4
votes
5answers
933 views

Is the universe bounded?

As I understand it nobody can pinpoint an objective "center" of the universe nor "where" the Big Bang happened. It seems the observable universe is limited by our event horizon at some 14 billion ...
3
votes
1answer
230 views

How could the universe be infinite (what is meant by that)? [duplicate]

I'd like to know what is thought of when saying the universe is infinite. I've read about what is meant when astronomers are speaking of a "flat" universe and I have read that its size is most likely ...
2
votes
0answers
710 views

What was the size of universe at big bang [duplicate]

While self studying cosmology as well as reading around I can't find a satisfactory answer to this question. My thinking is that in principle universe could have started already infinite or as a thiny ...
2
votes
2answers
142 views

How do we know the universe is expanding and wasn't already infinite?

From what I know, the decision that the universe was expanding came from the discovery of the redshift and that other celestial objects, such as galaxies, were moving away from us; the farther they ...
1
vote
1answer
954 views

Is the Universe infinite or it's just expanding to infinity?

According to the WMAP data in the past years we can say that our universe is considered flat or at least nearly flat and we also know that flat universe is allowed to be both infinite or finite in ...
1
vote
1answer
190 views

The universe being finite

I always thought we didn't know if the universe is finite or infinite. However is it true that the universe (not just the observable one) is finite with no boundaries? The articles arXiv:0901.3354 and ...
1
vote
1answer
149 views

Space-time infinite [duplicate]

My apologies if this is a duplicate question. I could not find it. Why do we think space-time itself started at the BB? Or to word it another way, could space-time have always existed infinitely in ...

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