All Questions
Tagged with big-bang space-expansion
321
questions
3
votes
1
answer
179
views
Will expanding space rupture an empty box floating in outer space
Under the theory that space itself is expanding, but the space inside of atoms and molecules doesn't expand because nuclear and electromagnetic bonding forces exceed the forces that expand space, ...
- 85
-4
votes
0
answers
46
views
Simple question about finite Universe [duplicate]
If, by Big Bang, Universe was created from initial singularity, with finite "speed" of expansion of matter, shouldnt it be finite as well?
1
vote
3
answers
86
views
Does the fact that we are able to see CMBR implies that universe expanded faster than light?
Supposedly, the universe underwent rapid expansion immediately after the big bang, surpassing the speed of light. If we can detect remnants from that era, does this suggest they moved faster than ...
- 21
0
votes
2
answers
95
views
Could Space and Time Be Decoupled Pre- Big Bang?
The traditional view holds that both space and time emerged together from the Big Bang. However, I'm curious about the possibility that time could be eternal, with no beginning, while space began to ...
- 489
7
votes
3
answers
5k
views
If we consider the spacetime of the universe to be four-dimensional, does the Big Bang lie in its center?
Apologies for the (hopefully now somewhat less) clickbait-y title. Now, of course, I know that the Big Bang did not happen at any point connected to a single point in our current $3$-dimensional ...
- 1,897
1
vote
1
answer
75
views
Are there any observations from the beginning of the universe until the CMB?
The question that concerns my mind is that in the time period before the cosmic microwave background, did humans have any observations or not? I mean, are all the materials mentioned in physics about ...
- 21
2
votes
0
answers
88
views
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
votes
1
answer
128
views
Big Bang Escape Velocity
When our entire section of the universe was in a single hot dark dense state, right before our big bang, what was the escape velocity?
user394592
5
votes
1
answer
608
views
Another universe due to a rogue wave fluctuation
Let us consider our Universe at its heat death state, and the rogue wave phenomenon that is due to improbable superposition of small waves. Is it possible that a rogue wave-like quantum fluctuation ...
- 735
4
votes
3
answers
2k
views
If the observable universe had only one galaxy, how would people know the expansion of the universe?
Hubble measured high redshifted galaxies to discover the cosmic expansion. In a hypothetical universe where only one galaxy exists, would there still be observational evidence for the Big Bang theory? ...
- 195
4
votes
1
answer
892
views
What important milestones happened in the first attosecond after the Big Bang?
I googled "the first attosecond after the Big Bang", but didn't get any relevant results. So, I am asking the question here, in hopes of being more successful. What happened during the first ...
- 1,252
0
votes
0
answers
48
views
Big Bang as stretching space time?
I am still new to researching the big bang so please be patient. I am having trouble envisioning the expansion. As I understand under current theory it is not to be thought of as a singularity ...
- 101
0
votes
2
answers
115
views
Not an "intelligent design" question: How do galaxies collide given the Big Bang? [duplicate]
If all matter began from one infinitesimally small point, and flew outward from there. How can we have galaxies colliding? Did they make left hand turns or something? Or it is possible multiple ...
-3
votes
1
answer
90
views
Why is the cosmic background 4K? Where are the other photons? [closed]
The cosmic background is 4K. Where are the other photons? A 4K photon produced at the big bang is detected by our detector. Time stops for the photon and hence we are seeing the big bang. Shouldn't we ...
- 43
1
vote
1
answer
120
views
Why easiest path from Big Bang to Heat Death is not followed by nature? [closed]
Why after Big Bang it is not going to Heat Death in the easiest path, actually the energy can get distributed uniformly to all directions. Instead we see the energy in Big Bang is being converted to ...
- 179
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
2
votes
1
answer
74
views
Are we surrounded by Big Bang? [duplicate]
Maybe the questions is too stupid to be asked or I do not know the technical words, but I could not find any answer to this question.
Here is how I started to think the title:
First I thought of if we ...
- 23
0
votes
1
answer
98
views
Does The Big Bang Require An Infinitesimal Point, Or Is Another Shape Possible? [duplicate]
Einstein's Spacetime has four dimensions. If the size of one of these dimensions is zero, then the four-dimensional 'volume' - or whatever the corollary to 3D volume is called in 4D - would be zero.
...
- 103
0
votes
2
answers
47
views
Is this the Format of the Observable Universe?
The way I have it is: the Observable Universe looks as follows. In some ball, all the galaxy clusters exist, then in a bigger concentric ball the dark ages exist (no galaxies), then on the surface of ...
- 61
0
votes
0
answers
151
views
Contradiction b/w Big bang theory and conservation of mass
As per the conservation of mass, matter cannot be created or destroyed.
Doesn't this contradict the big bang theory? Like, it states that it all started from a single point. But seeing the massive ...
1
vote
2
answers
85
views
How is Big Bang as a starting point possible?
I have a man-in-the-street question that was probably "predetermined".
If everything around us is co-interacting particles whose source is some infinite small point that started their ...
- 73
12
votes
5
answers
3k
views
What experimental evidence shows that the "explosion" model of the Big Bang with an explosion at a single point of space is wrong?
A popular misconception in the layman public is that the Big Bang was some sort "explosion" at a single point of space, where originally all matter was concentrated and then it "...
- 2,837
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
0
votes
0
answers
48
views
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 ...
5
votes
3
answers
2k
views
How can there be a Big Bang without a singularity?
I have read to Sean Carroll that he says that the Big Bang model is correct, but the Big Bang event is incorrect, so what is the difference? And everyone knows that the Big Bang model is linked to ...
- 51
0
votes
0
answers
55
views
Big Bang and where do we stand relative to it? [duplicate]
Maybe dumb question, not sure, but I would need some help here to understand.
https://theglobestalk.com/james-webb-telescope-see-back-in-time/
So according to physics we can look back in time ...
1
vote
3
answers
278
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
74
views
Why is it surprising that the universe was in an extraordinarily low-entropy state right after the big bang? [duplicate]
So I don't understand why it's surprising that the universe in an extraordinarily low-entropy state right after the big bang?
The way I see it the second law of thermodynamics forbids almost anything ...
- 1,389
13
votes
4
answers
2k
views
Why can't we run the laws of physics backwards and forwards in time infinitely?
So assuming we know all the laws of physics in differential equation form, and I have an estimate for the current large scale state of the universe (whatever standard assumptions/data cosmologists use ...
- 1,224
0
votes
1
answer
28
views
LCDM epoch or point where it fails
Nobody denies the currently success of the LCDM of cosmology. Recently, I wondered myself if there is a point or epoch (beyond the space-time singularity) where it breaks down. Does it fail at phase ...
- 6,611
0
votes
0
answers
43
views
When was the Higg's particle created after the Big Bang?
Was the Higg's particle created with the Bag Bang?
- 11
1
vote
0
answers
33
views
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
2
votes
1
answer
131
views
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
0
votes
1
answer
499
views
Has it been proven the fine-structure constant (FSC) changes with time?
I have heard this claimed over and over, even that the FSC was 1 at the Big Bang. Is there any actual consensus among scientists that this is so?
- 804
1
vote
2
answers
470
views
Isn't the universe older than 13.8 billion years? [duplicate]
To preface this, I'm not an expert, I'm just an avid astronomer with little mathematical knowledge.
I was watching a video that was explaining the cosmic scale and how the observable universe is only ...
- 299
1
vote
2
answers
95
views
Time dilation between now vs right after the Big Bang should imply the universe is much older than 13.8 bn years? [duplicate]
The universe is said to be 13.8 bn years old. But if we go back in time towards the Big Bang singularity time will slow down more and more and eventually stop because of the density of the singularity....
- 11
2
votes
1
answer
319
views
Size of the universe 13 billion years ago
When wee look at the sky in opposite directions, we can see early galaxies that were formed about 13 billion years ago. At that time, the distance between two such galaxies at the opposite ends of the ...
- 466
-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
2
answers
88
views
"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
views
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
2
votes
1
answer
171
views
Particle horizon in an empty universe
So in this thread,
Can space expand with unlimited speed?,
the author Pulsar made amazing diagrams of different horizons and paths for a benchmark model that describes our current universe, and gave a ...
- 161
-4
votes
1
answer
120
views
Cosmos at minimum 250x bigger than our observable Universe, so why then the need for a Big Bang?
Please correct me If I'm wrong but does not the BB only refers to our light speed limited observable Universe (OU) from our home position?
Also it is estimated that the Cosmos is minimum 250 times the ...
- 4,170
0
votes
1
answer
83
views
Is a meter constantly getting bigger? [duplicate]
If the bigbang is the start of the expansion of space everywhere then does that mean that a 1 meter ruler is bigger tomorrow than it was today?
Does this apply to the size of atomic particles and ...
- 973
1
vote
1
answer
88
views
How could proper distance today be infinity in a curvature only Universe when the age is finite?
So for a curvature only universe, the Friedmann equation becomes
and we get the solution $a(t) = t/to$, and $to = 1/Ho$.
If we calculate the proper distance today we will get
As $z-> infinity$, ...
- 161
3
votes
0
answers
77
views
Confused about size of the universe in the past
From Wikipedia, I got that the photons of the cosmic microwave background radiation originated when the spherical volume of space which will become the observable universe was 42 million light-years ...
user338734
4
votes
1
answer
663
views
Why don't we see the big bang?
excuse my understanding, my brain is melting.
So I understand that pictures of far away objects is like viewing the past.
and I think I pretty much get that the big bang was in every direction since ...
- 973
3
votes
1
answer
86
views
How can we still see the CMB? [duplicate]
May seem stupid but i cant wrap my head around it. if a star explodes we eventually see it when the light gets here. but once its got here we see the event and the star is now gone, we cant see it ...
-1
votes
1
answer
113
views
Is HD1 Galaxy a potential Big Bang theory killer?
I have heard some first explanations of why the farthest ever galaxy discovered about 13.27 Bly away the HD1 appears so UV active and about the population III stars inside this galaxy made only from ...
- 4,170
0
votes
2
answers
113
views
If there was an infinite amount of matter at big bang to form an infinite universe how it was possible for a so huge amount of matter to expand?
If there was an infinite amount of matter at big bang to form an infinite universe how it was possible for a so huge amount of matter to expand? Is it better to think that the universe is spatially ...
- 467
1
vote
1
answer
55
views
Higher order terms in Big Bang derivation
You can easilty proof that an SEC fluid gives a big bang by looking at the second Friedmann equation:
$$
\frac{\ddot{a}}{a} = -\frac{4\pi G}{3}(\rho + 3P) \le 0
$$
This implies that $\ddot{a} \le 0$ ...
- 351