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Author Topic: What does redshift of distant objects reveal about expansion of the Universe?  (Read 1245 times)

Offline McQueen

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When looking at the most distant galaxies visible, what is it exactly that is seen ?   When looking at a star that is 13.5 billion light years away, the star or galaxy is being viewed as it was 13.5 billion years ago. It is found that the redshift registers at 1,500,000 kms/sec,  this seems to be perfectly acceptable as the early Universe would have had to expand at several times the speed of light in order to reach its present size, if calculations are made it is found that at this rate (i.e., 5 c ) light travels  31.5 x  106 x 1.5 x 106 = 4.7 x 10 13  kms. per year.  Whereas at ordinary light speed 13.5 billion light years would mean a distance of  1.27  x 1023 kms.  at the same time  moving at 5C the Universe would have travelled   6.35 x 1023 kms in the other direction.  Does this mean that the Universe would have expanded   to a distance of   6.35 x 1023Kms  because of the difference in speed ? Or does it mean that the Universe expanded at FTL for a fraction of that time of 13.5 billion years and then slowed down to ordinary less than light velocities ? It is difficult to imagine how or using what criteria an answer might be reached.


 Furthermore if the oldest galaxies record such high velocities of several times the speed of light due to expansion of the Universe at that time, surely newer galaxies would show a far reduced redshift because they are from a time when the inflationary stage of the Universe was presumably over and faster than light speeds are not possible. It is also a distinct  possibility that it is impossible to detect, now or in the foreseeable future, the change in velocity of a cosmological object  as a result of gravity slowing down or, (with dark energy dominating) accelerating the expansion. Such observations would entail looking back 13.5 billion light years into the past and from there trying to extrapolate, initially  to the present time and then into the future. Thus when looking at stars at such magnitudes of distances of separation from the earth to talk of the Universe expanding, and expanding at exponential FTL speeds,  would seem to be, to put it mildly,  slightly premature.
« Last Edit: 15/04/2016 12:57:01 by chris »


 

Offline quandry

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Universe would have had to expand at several times the speed of light in order to reach its present size
Hmmm. Do you have some foundation for this hypothesis?
 

Offline McQueen

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Hmmm. Do you have some foundation for this hypothesis?

Only the whole Big Bang theory, which states that the Universe started off as a singularity and then underwent a massive inflationary episode during which it reached something approximating its present size.
 

Offline jeffreyH

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After inflation the universe is said to have been the size of a grapefruit so I think you need to do a little more reading.
 

Offline McQueen

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After inflation the universe is said to have been the size of a grapefruit so I think you need to do a little more reading.

If you are right JeffreyH and if your head is as big as a grape fruit, that , according to your research, is how big the Universe would have been after inflation. But according to other theories :

“Cosmic inflation is the idea that the very early universe went through a period of accelerated, exponential expansion during the first 10-35 of a second before settling down to the more sedate rate of expansion we are still experiencing, so that all of the observable universe originated in a small (indeed, microscopic) causally-connected region.”

Please measure your head and decide which option you prefer.
 

Offline arcmetal

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What does redshift of distant objects reveal about expansion of the Universe?

The way I see it:

The redshift of distant objects is an observation made with physical instruments.  It is something we can see.

The expansion of the universe is a conclusion reached at with ideas from men's heads.  It is not an observation.

 

Offline jeffreyH

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After inflation the universe is said to have been the size of a grapefruit so I think you need to do a little more reading.

If you are right JeffreyH and if your head is as big as a grape fruit, that , according to your research, is how big the Universe would have been after inflation. But according to other theories :

“Cosmic inflation is the idea that the very early universe went through a period of accelerated, exponential expansion during the first 10-35 of a second before settling down to the more sedate rate of expansion we are still experiencing, so that all of the observable universe originated in a small (indeed, microscopic) causally-connected region.”

Please measure your head and decide which option you prefer.

Where exactly in that quote does it indicate the size after inflation? I assume it was intended to support your case. From the Planck scale to the size of a grapefruit is an astronomical change or do you not understand that?
 

Offline Prophet12

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The redshift has led science astray the believe 'expansion and now expansion at an ever increasing rate'  What, ever increasing to what? the speed of light???

Expansion is hogwash.   The only explanation of merit is the universe-galaxies-mass is 'contracting at an ever increasing rate'........observable throughout every galaxy which are microcosm of the universe macrocosm.

Hope that helps,
DS
 

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