Talk:Chronology of the universe

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Nucleosynthesis[edit]

RE: At this time, there are about three times more hydrogen ions than helium-4 nuclei.

This is a subtle mis-statement. At the end of the nucleosythesis period, Helium nuclei (almost all He4 and the tiniest amount of He3), account for approximately 25% of the MASS of ordinary matter in the universe - excluding the left over supersymmetric matter.

This proportion is well known. It can be directly observd in various ways, because the proportion of different nuclei only changes in the interior of stars,and in gas clouds ejected by previous generations of stars within galaxies. Everywhere else, the proportion remains almost the same, only disturbed by antiprotons from the decay of the lightest supersymmetric particle. (A topic on which I published a Physical Review Letter with John Hagelin and his student in 1989).

Because most of the hydrogen is in the form of protons, H1, and very little as deuterons, H2 deuterium nuclei, the statement above would mean that the total mass of Helium nuclei (alpha particles) would be 33% more than the total mass of protons (Hydrogen nuclei)!

The sentence would be better rewritten as:

At this time, there are approximately three times more hydrogen ions by mass than helium-4.

Alex Hankey, Physicist — Preceding unsigned comment added by 122.167.131.202 (talk) on 14:30, 24 July 2007

Clarifying the Summary[edit]

I found a number of confusing/misleading turns of phrase in the summary, and corrected them. Unfortunately I forgot to log in until just before the last one - the others show up as IP 81.2.68.136. MrDemeanour (talk) 17:53, 24 July 2015 (UTC)

Inconsistancies Regarding Inflation[edit]

Under Electroweak epoch, text says: Between 10−36 second (or the end of inflation) and 10−32 second after the Big Bang.

Under Inflationary epoch (sub-heading under above) text says: Unknown duration, ending 10−32(?) second after the Big Bang.

In article Inflation_(cosmology), text says: In physical cosmology, cosmic inflation, cosmological inflation, or just inflation is the exponential expansion of space in the early universe. The inflationary epoch lasted from 10−36 seconds after the Big Bang to sometime between 10−33 and 10−32 seconds.

I suggest the authors of this article and the Inflation article get together and workout consistent compatible language.

BuzzBloom (talk) 16:35, 5 September 2015 (UTC)

There seem to be two different theories about when inflation ended. We need to make this clear. Since we cannot see further back than the end of inflation (can we?) there doesn't currently seem to be any way to decide between the theories. Dbfirs 23:46, 13 December 2015 (UTC)

Incomplete Timeline[edit]

There is no mention of what happened before the Big Bang. This needs to be mentioned to complete the time...LINE. Wait... If time is infinite, then how are we here now? This inconsistency should be mentioned, as well.108.85.152.134 (talk) 23:03, 13 December 2015 (UTC)

What makes you think that time is infinite? Dbfirs 23:38, 13 December 2015 (UTC)
Space-time is considered to have manifested together at the Big Bang, hence time did not yet exist before the singularity, at least in this universe. 76.10.128.192 (talk) 04:02, 20 January 2016 (UTC)