All Questions
18
questions
-1
votes
1
answer
40
views
The centre of what we can now see in the universe
If the JWST has just discovered the furthest away galaxies in one place we can now triangulate to where the centre of what we can see
This is observable and appears not symmetric with everything ...
0
votes
1
answer
146
views
Do symmetries indicate that laws of physics are invariant?
Concerning symmetry in fundamental physics, it is usually said that symmetry indicates that laws of physics are invariant independently of something
For example, time translational symmetry indicates ...
- 2,462
2
votes
1
answer
100
views
Topological phase transitions for the whole universe...?
Physicist Grigory Volovik has put forward some ideas about the universe undergoing a topological phase transition (especially in the early stages of the universe). He published a book called "The ...
- 2,462
0
votes
0
answers
44
views
Effects of anisotropy and non-homogeneity in the universe's symmetries...?
I was reading Philip W Anderson's essay "More is Different" (https://www.tkm.kit.edu/downloads/TKM1_2011_more_is_different_PWA.pdf) and at some point he links the isotropy and homogeneity of ...
- 2,462
1
vote
1
answer
81
views
What if the universe was not uniform...?
In this popular science article, they say that if our universe resulted to be non-uniform (that is highly anisotropic and inhomogeneous) then the fundamental laws of physics could change from place to ...
- 2,462
0
votes
1
answer
105
views
If the universe is infinite, would it be homogenous?
I know, that we can't really know the answer to that, but what is the current state of understanding?
We seem to assume that on very large scales, the universe is homogenous. As I understand it, this ...
- 866
1
vote
1
answer
341
views
What does it mean when we say "The universe is smooth and regular on a large scale"?
I am currently reading "Brief history of time",I have encountered this statement while the book discusses chaotic boundary theory,
according to which the early universe would probably have ...
- 639
0
votes
4
answers
81
views
Homogenous Universe (Earthlike planets?)
The fact that the Universe is homogenous can lead to a conclusion that there are another earthlike planets, or planets like earth are considered as some differences that are allowed in the definition ...
0
votes
0
answers
35
views
Role of isotropy argument in fixing the form of $T^\mu_\nu$ of cosmology (Padmanabhan's book)
The following lines from Gravitation Foundation and Frontiers by T. Padmanabhan (he uses Latin indices for spacetime and Greek indices for space, which is unusual)
The assumption of isotropy ...
- 11.8k
0
votes
1
answer
161
views
Is universe symmetric about a point?
We have a good amount of discussion and theories on the formation of universe.
I want to ask is universe symmetric about a point?
I think that the answer should depend upon the uniformity of ...
- 3,377
0
votes
1
answer
60
views
Is a closed universe symmetric?
Say our universe is closed, at some point in the future it will reach a maximum and then begin to contract, will it return to say the point we are now in exactly the reverse manner? For example, as ...
- 59
2
votes
2
answers
143
views
With respect to what we are saying space is homogeneous or space-time is isotropic? [duplicate]
I don't really understand what we are talking about when we say space is homogeneous. What we are measuring? My notion is: it should depend on the entity and with respect to that entity one can decide ...
- 53
0
votes
2
answers
846
views
Einstein field equations are PDEs or ODEs?
This past semester, I just took an introductory course on G.R., which translates to a lot of differential geometry and then concluding with Schwarzschild's solution. We really didn't do any cosmology. ...
- 303
1
vote
1
answer
159
views
Why doesn't the universe look symmetrical?
If the universe was a dot lets say a point, and that dot expanded equally from all sides, then shouldn't the universe look more symmetric, maybe indentical, from that dot all around?
0
votes
0
answers
36
views
How can the universe be homogeneous and isotropic while it has started with a big bang? [duplicate]
We assume the universe has been shaped by a explosion "Big Bang" but from what I understand explosions make the environment "not" homogeneous and "not" isotropic.
If that's right how can we assume the ...
- 474