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Redshift as evidence of expansion 
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#1
Jan2512, 03:13 AM

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why can we believe that redshift PROOVES expansion of universe when we know that redshift could have been caused due to gravitation.



#2
Jan2512, 03:39 AM

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Are you suggesting that things farther away are progressively more massive so as to create a larger redshift in exactly the pattern that we would expect if these objects were simply moving away from us due to a homogeneous expansion of space?



#3
Jan2512, 04:19 AM

P: 149

well. I guess i wanted to ask that.
So? 


#4
Jan2512, 08:19 AM

P: 53

Redshift as evidence of expansion
I dont think belief comes into it. Its the best explanation for what we can observe.



#5
Jan2512, 11:33 AM

P: 40

The currently accepted model relies on a mechanism, "expanding space", which has no empirical basis. Gravitational redshifting, on the other hand has been empirically verified. 


#6
Jan2512, 02:52 PM

P: 226




#7
Jan2612, 02:27 AM

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#8
Jan2612, 04:37 AM

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#9
Jan2612, 04:46 AM

Mentor
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#10
Jan2612, 02:24 PM

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#11
Jan2612, 02:31 PM

P: 226

Wouldn't this make gravitational attraction impossible? It would be like being in the center of the Earth, all the mass pulling equally each way. 


#12
Jan2612, 02:39 PM

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#13
Jan2612, 11:37 PM

P: 226

Having said that, how does a galaxy form if all gravitational effects are equal in all directions? Local inhomogenity? (I think that's a word). Can't the same effect redshift light? 


#14
Jan2712, 02:04 AM

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The gravity of intervening masses along the route a photon follows across the universe to reach our instruments has zero effect on redshift. They bend the path [ie, gravitational lensing], but, have no effect of frequency. As photons approach a gravitational field, they are blueshifted, as they depart, they are redshifted by exactly the same amount.



#15
Jan2712, 04:06 AM

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#16
Jan2712, 02:05 PM

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#17
Jan2712, 02:41 PM

P: 226




#18
Jan2812, 06:44 AM

P: 476

One of these interpretations assumes that the nature of redshift is not due to space expansion but to gravitational field and obtains a linear law for an universe with a fractal distribution of matter with fractal dimension 2. It seems some recent surveys support a fractal distribution with D ≈ 2, but this is still open. 


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