All Questions
7
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60
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Why is the age of the universe $=D/v$, despite that $v$ is not constant with time?
I am watching a series of lectures by the Noble prize laureate Brian Schmidt and Paul Francis and in this episode (at 4:20) they make the simple assumption that a galaxy receding from us due to the ...
- 157
1
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0
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54
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How is the expansion of the universe measured if redshift depends on the expansion itself? [duplicate]
To me this seems like a bit of a chicken egg problem.
Based on the redshift of light (plus the assumption that physics worked the same way back then and there as it does now and here), we can ...
0
votes
1
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55
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How do you know that objects are accelerating from each other in space?
I know that Hubble redshift comes from the relation between the distances of objects and the Hubble parameter:
$$H_0 = \frac{\dot{R}}{R}.$$
But how we differentiate between redshifts effects from the ...
- 84
3
votes
2
answers
720
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Does the universe lose energy when spacetime expands?
When reading about the Big Bang you’ll commonly hear that the universe began “cooling down” soon after. However, if we assume the universe is a closed system, would that thermal energy not continue to ...
- 203
3
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2
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142
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Can Hubble law be explained by galaxies moving away from one point at random constant speeds?
Let’s put a lot of material points at coordinates (0,0).
Let’s give them completely random velocities.
Let’s evolve this system for some time ...
- 276
2
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2
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532
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Is the expansion of the universe really accelerating? Or does it just look like it?
I pulled this quote from an article on the Hubble Constant:
"...for example, if the Hubble Constant was determined to be 50 km/s/Mpc, a galaxy at 10 Mpc, would have a redshift corresponding to a ...
6
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3
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166
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How do you explain cosmological red shifting in terms of gravitons?
We know that the photons from the big bang are continually being red shifted and losing more and more energy. In terms of the graviton view, how would you explain that? Where is the energy going?
Are ...
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