All Questions
Tagged with electromagnetic-radiation cosmology
55
questions
53
votes
4
answers
12k
views
Red shifted to what?
I searched and found a lot of questions and answers about red shift here but none with the answer to mine. (sorry if it is there somewhere and I did not find it.)
Everyone is saying the light from ...
- 611
18
votes
3
answers
2k
views
Is the amplitude of the Cosmic Microwave Background (CMB) correctly predicted or just its spectral shape?
I see this beautiful graph of the CMB in Wikipedia
Apparently the measured data-points match the theoretical curve for black body radiation very exactly and the discrepancies and error-bars are simply ...
- 2,403
18
votes
2
answers
4k
views
Did the big bang create an infinite number of photons?
We will always be able to see the cosmic microwave background (CMB) at about [the age of the universe] light years away.
Always.
Does that mean that infinite photons were created at that time? If ...
- 781
15
votes
1
answer
4k
views
Why can’t you see at the start of the Big Bang?
I’m quite confused with regards to photon emission throughout the creation of the universe.
From what I’ve heard, there was no light (of any frequency) in the universe until 300,000 years after the ...
- 2,356
14
votes
1
answer
4k
views
What percentage of the mass/energy of the universe is in the form of electromagnetic waves? [duplicate]
Is there any theoretical framework or model that would lead to a prediction, either precise or approximate, about how much or what proportion of the universe's total mass is in the form of photons, or ...
- 533
11
votes
3
answers
3k
views
If we have a cosmic microwave background should't we also have a cosmic radio wave background?
I'm a layman in physics, but here is what I understand:
What we see in the sky with naked eyes is a map of electromagnetic waves in the frequency visible to the human vision.
But that kind of ...
- 111
10
votes
1
answer
1k
views
What fraction of the universe's energy is contained in photons?
From each point in the universe, the light of billions of stars, galaxies, supernovae etc. can be detected. So there seems to be a lot of energy/momentum "in flight".
Is it possible to ...
- 347
10
votes
2
answers
973
views
Do photons and cosmic rays radiate energy through gravitational waves? If not, why not?
Due to the mass-energy equivalence, both matter and EM radiation bend spacetime, and both are capable of forming singularities (black hole, white hole/kugelblitz). In light of this, why do photons ...
user40753
9
votes
4
answers
2k
views
Do photons make the universe expand?
I have a problem understanding the ideas behind a basic assumption of cosmology. The Friedmann equations follow from Newtonian mechanics and conservation of Energy-momentum $(E_{kin}+E_{pot}=E_{tot})$ ...
- 10.1k
8
votes
3
answers
2k
views
How much light is there in space and how heavy is it?
Our night sky is filled with stars. On a dark night a significant fraction of the sky is light. This light, we are told, has been in transit for many millions of years. There must therefore be quite a ...
- 219
7
votes
3
answers
2k
views
Where does the light of the Big Bang come from?
I'm wondering whether the residual light of the Big Bang comes from one particular direction and what possibilities do we have to detect its position?
- 422
7
votes
0
answers
323
views
Trying to reproduce curves with angle of CMB anisotropies as a function of distance and curvature parameter
I am looking for a way to get, by a simple numerical computation, the 3 curves on the following figure:
For this, I don't know what considering as abcissa (comoving distance ?, i.e
$$D_{comoving} = ...
user87745
6
votes
4
answers
2k
views
Accelerating Expansion of Universe - Why Not Caused by Radiation?
As I understand it, dark matter and dark energy are used as an 'explanation' for how universe expansion is accelerating; because without it gravity would be expected to cause a long term shrinking.
...
- 181
6
votes
4
answers
598
views
Which one is more fundamental in nature: matter or radiation?
I am following a geometric perspective on abelian gauge theory as done in the lecture notes by Timo Weigand, chapter 6, pp 165-167, here:
http://www.thphys.uni-heidelberg.de/~weigand/QFT1-13-14/...
user56963
6
votes
1
answer
348
views
How does the Cosmic Microwave Background give us information about the Big Bang?
I was reading about CMB after this new breakthrough last week and I could not figure this out. The CMB did not exist before the epoch of Last Scattering. They were just photons which were formed at ...
user42733