Please allow me to simplify this dimension question by replacing 3 with 2.
Ibix and Kimbyd above recognize the issues, but I see no experiment. Others
outside of Physics Stack have proposed theories and experiments, but
it is not proper to review them here.
Thus . same question:
we now live...
Motivated by some apparently intractible unsolved problems, I see cosmology
as a beautiful mathematical description of a strongly flawed paradigm.
This forum wisely does not allow laying out alternate paradigms, so I try to
ask questions to guide my immature understanding , in the spirit of...
OK...I guess I am hooked on this.
Your hypothetical example seems to violate conservation of energy. That is, a single flash contains a finite amount of energy E,
but if a viewer sees even a diminished glow forever, eventually the integrated energy entering his eye will exceed E.
I appreciate...
Peter
You write:
>>Btw, it helps a lot to use the PF quote feature
Good idea, but I do not know how to use this feature. Hence I have improvised this substitute device.
You write (in response to my assumption that the surface of last scattering was a 2-sphere):
>>I have no idea why you would...
Peter:
I am grateful for your feedback, but I feel I should take a couple of cosmology courses here at UW-Madison before continuing this thread. I am currently taking a related physics course. However, here are some parting comments.
[1] I had assumed that the surface of last scattering (S)...
Thank you for your patience...I am not a trained cosmologist. I have replied to you point-for-point, but the time dimension is a struggle for me.
You write:
>>The "point-like start" ... is not a feature of our actual current best-fit model
Accepted. The logic in favor of S³ does require a...
Peter Donis:
Here is another neat topological way to convince yourself that the universe must have the topology of S³.
First, consider the universe starting with us now, extending out (and backward in time) to the surface S of last scattering (at which CMB was produced). We see this surface...
PeterDonis:
Sorry to post this question twice. I feared that I had posted incorrectly the first time.
On the issue...
Is it not true that the big bang thesis posits a point-like start to our universe which we are
currently researching, limited by our ability to "see" before the origin of CMB...
A Play. Title: Unseen Shapes (the "balloon analogy" revisited)
Scene 1: You are in what appears locally to be an isotropic Flatland (E²). You look around in every direction. Far away objects
are rather dim, and you suspect that beyond your range of vision, there is more. Indeed, the...
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New
Phinds:
I appreciate your interaction, but it is time to say goodbye.
The statement "There IS no "outside" is completely unverifiable, unless you define "universe" to make it true. I proposed a different definition of "universe", perhaps implying a different metric, and a...
Phinds:
I appreciate your interaction, but it is time to say goodbye.
The statement "There IS no "outside" is completely unverifiable, unless you define "universe" to make it true. I proposed a different definition of "universe", perhaps implying a different metric, and a different...
Frankly, I am finding this discussion unhelpful, but I will respond once more...
I do not see any implication of a preferred direction or location. If you see it, show me where it is.
I did not claim the universe was a sphere or ball, but I did claim that at each time, t, the...
I am not a physicist, but let me try to "defend" the quoted concept above.
At any time t, the universe has a size or diameter d(t). We do not know what d(t) is equal to for any time t, though I have seen various estimates for small values of t. That said, we probably agree that at least for the...
The question, please, makes no assumption about the "center of the universe". The only assumption is that the older universe was smaller, and the observer today must therefore be outside the boundary of that older universe. No specific location of anything is assumed. All locations are merely...
Several questioners ask if the Hubble red shifts could be gravitational red shifts rather than space-expansion red shifts. I understand why the answer has generally been "no". However, can I try this variation of the question...
Red-shifting is apparent mostly for distant galaxies, which are...