All Questions
110
questions
2
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5
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What is the branch of physics that asks the question 'what was before the Big Bang'?
What is the branch of physics that asks the question 'what was before the Big Bang', assuming the Big Bang is truly what happened at the beginning of the universe? If there could be a better model ...
- 421
2
votes
1
answer
145
views
Common clock reference of Big Bang
Relativity tells us that there is no preferred reference frame, yet current cosmology does operate on the hypothesis that all points in the observable universe originate from the same big bang ...
- 4,892
-2
votes
2
answers
95
views
Since the instant of the big bang, has the progression of the universe been entirely determined?
[Note I am asking up to, but not including, consciousness as this bleeds into philosophy and is a much messier question]
Assuming that the laws of physics have remained constant across space & ...
- 460
1
vote
1
answer
157
views
Why did the Big Bang happen first?
As far as I know, the laws of physics are time-reversal invariant, which means there is no preferred direction of time. The arrow of time emerges with entropy which is a property of macrostates, not ...
- 308
9
votes
2
answers
1k
views
Has the age of the universe changed in 2023?
I teach high school physics and physical science. I was going through the definitions of theory and law when a couple of my students (of different periods) asked about some recent development that ...
- 203
0
votes
0
answers
47
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Theoretical: what is the meaning of nothing? [duplicate]
Before the big bang, there was a point surrounded by nothing (no space or anything). Then the big bang happened and the universe expanded. so beyond the universe's limits, there is nothing? I don't ...
- 1
0
votes
0
answers
48
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Time from big bang to here [duplicate]
New to this so apologies for my ignorance, the simpler the answer the better. Here goes.
Light took 13.5 billion years to get to us from the big bang.
On an imaginary neighboring planet that is much ...
1
vote
3
answers
281
views
Can the age of the universe actually be calculated through Hubble's constant?
I was reading a high-school physics textbook, and it stated that the age of the universe is equal to 1 / Hubble's constant. They even give a derivation: $v = H_{0} D$ and $D = vt$, so subbing in gives ...
- 25
0
votes
0
answers
51
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Was Big Bang the "START" of time? [duplicate]
I know that this question has been repeated a lot. But I still don't understand this concept.
Big bang created matter and space but how could it possibly create time?
If Big bang didn't create time ...
- 77
0
votes
0
answers
34
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Did time have a beginning? [duplicate]
Did time have a beginning in the current scientific consensus? Or has it existed forever?
user361045
2
votes
1
answer
131
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Why is cosmological time unique?
According to the definition I have encountered for the concept of cosmological time, it is defined in the following way:
The cosmological principle states that, at each location in the universe, it ...
- 293
-1
votes
1
answer
77
views
Could an observer in time determine whether time had no beginning or had a beginning infinitely long ago? [closed]
I don't know if this is more a question for mathematicians or physicists (or even philosophers), but what would be the difference between time having a beginning infinitely long ago and time having no ...
0
votes
1
answer
46
views
How does the scale of a cataclysm determine if we can look beyond it?
The textbook I am referring to (Physics for Scientists and Engineers ($9e$), page $1 469$, section $46.11$), has the following paragraph regading the Big Bang:
... This theory of cosmology states ...
- 3,340
3
votes
1
answer
236
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Deriving the age of the universe
I am trying to work out the solution to exercise 8.4 from An Introduction to Modern Cosmology by Andrew Liddle. I could derive the Friedmann equation as below,
$$\dot{a}^2 = H_0^2 \left[\Omega_0a^{-1} ...
1
vote
2
answers
153
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Can the age of the universe be much bigger than 13.8 billion
If observable universe is only a small fraction of the existing universe, does it imply that the age of the universe is much more than 13.8 billion years or the expansion of the universe is much ...
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