All Questions
Tagged with big-bang-theory observational-astronomy
7
questions
3
votes
1
answer
109
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Does the Cosmic microwave background (CMB) have an amplitude? Does it vary, like the 'temperature' (wavel./freq.) and the polarization?
Somehow, I have never read about this or thought about, until now...
Does the number of photons from the CMB hitting us from all directions vary at all?
- 5,177
8
votes
1
answer
2k
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Why was the Cosmic Microwave Background (CMB) released at a blackbody temperature of 3000K rather than 30,000K?
If the ionization (or reionization, or Recombination) energy of atomic hydrogen is 13.6 EV, which corresponds to a black body temperature of 30,000K, why did the CMB not begin to appear then?
Why did ...
- 5,177
1
vote
1
answer
111
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Shouldn't the estimate of the universe's age be higher, not lower, after the attractive strength of gravity is taken into account?
From 'Fundamentals: Ten Keys to Reality', by Frank Wilczek :
"Running the movie of cosmic history backward in our minds, we found the galaxies all coming together to meet at a definite time. ...
- 5,177
0
votes
1
answer
144
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Fundamental axioms in LCDM
What are the axioms (if any) behind the LCDM model of cosmology?
NB: axioms, not postulates (e.g., inflation)
user19333
2
votes
0
answers
54
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How the observed deuterium abundance constrains big bang nucleosynthesis?
I know deuterium can be used as a good tracer to constrain the big bang nucleosynthesis. But can anyone tell me the in details how this is actually done?
- 187
9
votes
2
answers
208
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How Good Are the Upper Limits on Heavy Elements?
There are between 90 and 254 stable nuclei all the way up to element number 82. In discussions and graphs about big bang nucleosynthesis nothing above lithium is even mentioned. It's a pretty safe bet ...
- 2,946
4
votes
1
answer
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Why can't we determine the center of the universe [duplicate]
I find this baffling. If we can observe objects moving away from us and each other, than it stands to reason that we can track their paths (relative to each other and ourselves) backward to find a ...
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