How big is the universe?

rod

Oct 22, 2019
2,594
1,073
5,560
The cosmology calculators will show a vastly larger size to the expanding universe. Example, LAMBDA - Calculators (nasa.gov)

The comoving radial distance is where an object would be today relative to Earth. Look back time distance or light-time distance is commonly used when presenting distances using redshifts but not much on the comoving radial distances told to the public. The CMBR z~1100 places the edge about 46 billion light years away, thus the diameter some 92 or 93 billion light years from earth frame of reference. However, this is 4D space expanding (not 3D space) where all objects with redshifts 1.4 or larger are traveling faster than c velocity in a hyperspace coordinate relative to earth. Apparently mass and galaxies in hyperspace are assumed to expand faster than c velocity when you dig into things here but near each other, moving slower than c velocity. This should be told to the public clearly.
 
Jun 1, 2020
2,266
1,836
5,060
"While the estimate of 92 billion light-years comes from the idea of a constant rate of inflation, many scientists think that the rate is slowing down."

Who and how many think the expansion is slowing? DE was introduced to explain the SN evidence demonstrating the expansion is accelerating?

Rod stated: "However, this is 4D space expanding (not 3D space) where all objects with redshifts 1.4 or larger are traveling faster than c velocity in a hyperspace coordinate relative to earth."

Yes. For me, I like to use my magic wand and freeze the universe, then go measure it. This is the distances the article gives as well as you.

It's interesting, as you mention, that at z = 1.4 the break point for photons coming our way come from a region traveling at or very close to the speed of lilght. But, for clarity, this applies to photons from that region that begin their travel to us today. Billions of years ago, photons from that region were not having this problem. Is this correct?
 

rod

Oct 22, 2019
2,594
1,073
5,560
Helio, you asked in #3, "It's interesting, as you mention, that at z = 1.4 the break point for photons coming our way come from a region traveling at or very close to the speed of lilght. But, for clarity, this applies to photons from that region that begin their travel to us today. Billions of years ago, photons from that region were not having this problem. Is this correct?"

If you work with the cosmology calculators like the example I showed or others, e.g. Cosmology calculator | kempner.net

The reported distances presented to the public is the look back time or light time distance. The comoving radial distance based upon 4D space and hyperspace, place the object much farther away then look back time distance today so when z=1.4 or larger, the comoving radial distances are more than 13.8 billion light years distance from earth. We cannot see those objects because it would take light longer to reach earth than the postulated age of the universe (using Special Relativity). More info on 4D space expansion I posted in this thread earlier, Our expanding universe: Age, history & other facts, https://forums.space.com/threads/our-expanding-universe-age-history-other-facts.53627/

A comment from someone I know well versed in GR math. Why this is not made clear to the public I do not understand.
 

ASK THE COMMUNITY

TRENDING THREADS

Latest posts