All Questions
27
questions
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
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
-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
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 ...
2
votes
2
answers
236
views
If CMB came from the big bang, how come we got to where we are before the CMB arrived? [duplicate]
I have read that the cosmic background radiation was formed 380,000 years after the big bang, when stuff changed from being opaque to light, because of free electrons, to becoming transparent.
However,...
- 145
4
votes
3
answers
2k
views
Where did the CMB come from? What is due to the matter/antimatter annihilation? Or perhaps the radiation released when the electrons decoupled?
Where did the CMB originate from? I get that at the beginning of the universe, by the Big Bang theory temperatures and pressures were too high for matter to exist, and even if it did, it would just ...
- 521
2
votes
1
answer
112
views
Is cosmic background radiation consistent with the Cosmological Principle? [duplicate]
Is the observation of cosmic background radiation really consistent with the cosmological principle? It implies that there is a "special" rest frame of motion with respect to the big bang. ...
- 804
22
votes
4
answers
4k
views
Why does CMB radiation propagate towards us?
There is something with CMB radiation that does not sit well with me... It seems very counterintuitive that we are able to see it. If CMB radiation formed at the early phases of the universe, would it ...
- 563
5
votes
1
answer
687
views
How does the Planck satellite's detailed map of the CMB lead to a value of the Hubble constant, $H_0$?
Cosmologists have put great faith, it seems, on the cosmological model that led to a value (of 67) of the Hubble 'constant', after carefully peering at Planck's map of the cosmic microwave background.....
- 4,509
10
votes
3
answers
2k
views
Since the CMB is the oldest thing we can see, how do we know for sure what happened before the CMB?
I keep wondering about how can we be so sure about what happened before the CMB, given that it is the oldest thing we can actually see.
It seems like we are very confident about what really happened ...
- 101
29
votes
2
answers
4k
views
Why is the Cosmic Microwave Background evidence of a hotter, denser early universe?
In his book Gravitation and Cosmology, Steven Weinberg says that the Cosmic Microwave Background (CMB) makes it "difficult to doubt that the universe has evolved from a hotter, denser early stage&...
- 1,421
1
vote
2
answers
297
views
Where does the 379,000 year recombination prediction of the Big Bang theory come from?
The Big Bang theory postulates that recombination happened 379,000 years after the Big Bang.
However, I have never seen a single statement as to how this number came about.
I don't imagine they ...
- 4,191
2
votes
3
answers
503
views
Why can we see the cosmic microwave background radiation?
This radiation (CMBR) is said to have its origin at the surface of last scattering that exposed itself when the big bang universe had expanded for less than a million years.
In order to see radiation ...
- 176
0
votes
2
answers
583
views
How do we know the age of Cosmic microwave background? [duplicate]
How do scientists know the age of the CMB? And how does it correlate to the age of universe?
- 1,005
1
vote
1
answer
398
views
Big Crunch vs Big Rip vs Heat Death vs Conformal Cyclic Cosmology... What's the Most Common View? [closed]
I just saw that Penrose recently published a paper on Conformal Cyclic Cosmology and it made me wonder, what exactly is the consensus view these days? I first heard of Penrose in connection with Orch-...
- 187