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JTP3167
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Is time dilation a factor in the calculation of the expansion speed of the universe?
General Relativity is fully accounted-for.JTP3167 said:Is time dilation a factor in the calculation of the expansion speed of the universe?
H_A_Landman said:Some of the evidence for dark energy is that very distant objects are less red-shifted than we expected.
H_A_Landman said:Since, as the universe has evolved, matter has fallen deeper and deeper into gravitational wells (planets, stars, galaxies, galaxy clusters, superclusters, ...), one would expect that modern observers are on average at lower gravitational potentials than ancient observers.
H_A_Landman said:So when we look back in time, we are also (on average) looking UP a gravitational gradient
H_A_Landman said:I don't think Peter's answer addresses this
H_A_Landman said:So to sum up, there should be an effect of the type I proposed, but it appears much too small to affect the observations significantly, let alone explain them away.
H_A_Landman said:That would change the question to something like: "Was the rate at which matter descended into gravity wells (and hence got time-dilated) faster in the early universe than it is now?".
H_A_Landman said:This seems plausible since matter was closer together back then
H_A_Landman said:and was starting from a higher-potential state
I think this paper analyses the effect you are describing or something very similar.H_A_Landman said:So to sum up, there should be an effect of the type I proposed, but it appears much too small to affect the observations significantly, let alone explain them away.
Isn't it the shape of the magnitude vs. redshift curve (because we can only infer distance from redshift)?PeterDonis said:it is the shape of the redshift/distance curve over a wide range of redshifts, which shows the expansion rate of the universe accelerating as of a few billion years ago (more precisely, as of the corresponding redshift).
GeorgeDishman said:Isn't it the shape of the magnitude vs. redshift curve
GeorgeDishman said:(because we can only infer distance from redshift)
GeorgeDishman said:I think this paper analyses the effect you are describing or something very similar.
Time dilation is a phenomenon in which time appears to pass slower for an object or person moving at high speeds or in a strong gravitational field compared to a stationary object or person.
Time dilation is accounted for in calculating expansion because as the universe expands, objects and light are affected by gravitational fields and high speeds, which can alter the perception of time. Therefore, time dilation must be considered when calculating the rate of expansion of the universe.
Time dilation is accounted for in calculations by using the theory of relativity, specifically the equations developed by Albert Einstein, which take into account the effects of gravity and high speeds on time. These equations are used in cosmological models to accurately calculate the expansion of the universe.
No, time dilation is not a constant factor in calculating expansion. It varies depending on the object's or light's velocity and the strength of the gravitational field it is experiencing. Additionally, as the expansion of the universe continues, the effects of time dilation may change.
Time dilation is crucial in understanding the expansion of the universe because it allows us to accurately measure the rate of expansion despite the effects of gravity and high speeds. Without accounting for time dilation, our calculations would be significantly less accurate and could lead to a misunderstanding of the expansion of the universe.