All Questions
Tagged with redshift general-relativity
8
questions
-2
votes
1
answer
213
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Shouldn't the Friedmann equation take into account the massive extra distance traveled during the time for gravity to travel across the universe? [closed]
I’ve got a question that has been bothering me for the past few years that of the few sources that are only somewhat related to this, none of them say anything about this should be wrong so I can’t ...
- 21
0
votes
0
answers
35
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Is the difference of redshift parameter z able to prove expansion is accelerating in flat FLRW universe model?
Sorry for my bad english, this is not my mother tongue.
Recently, I've encountered a problem in cosmology class that is about FLRW universe.
Assuming that the universe we inhabit is composed of non-...
- 1
1
vote
0
answers
87
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If astronomers didn't know about redshift could we still determine the universe is expanding?
What other evidence is there for the expansion of the universe?
Would the equations of physics look wrong without it?
user51209
8
votes
1
answer
2k
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Is Webb or any near-future telescopes like ELT capable of observing redshift changes to confirm General Relativity?
The (Davis and Lineweaver (2003)) "Expanding Confusion" paper states that "the expected change in redshift due to cosmological acceleration or deceleration is only ∆z ∼ 10^(−8) over 100 ...
- 175
2
votes
2
answers
146
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Could quasars be interior to the event horizon of a SMBH?
My question is prompted by suspicion of three current ideas in astrophysics:
GR predicts a singularity at the center of a BH without regard to QM.
quasar hyper-luminosity is caused by an acretion ...
- 29
1
vote
1
answer
486
views
Cosmological redshift - How do we know it's not caused by the observer's time dilation?
Instead of cosmological redshift being caused by the metric expansion of space, why couldn't cosmological redshift be caused by our perspective moving faster in time? Said another way, if the ...
- 1,005
2
votes
1
answer
203
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Does the redshifting of photons from the Universe's expansion violate conservation of momentum?
The energy-momentum relation,
$$E^2 = m^2c^4 +p^2c^2,$$
lets us derive the momentum of a massless particle:
$$p = \frac{E}{c} = \frac{h\nu}{c}$$
However, the expansion of the Universe redshifts ...
- 8,135
6
votes
3
answers
561
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Heavy star and redshift
A heavy star should look redshifted, due to gravitational time dilation. How is that incorporated into the calculations of distances to the stars, or is it negligible?
How about an entire region of ...
- 1,197