Talk:Big Bang

make page: pre-explosive state (cosmogony)

• the Before the Big Bang [pre-explosive state] theories

According to most physicists the term "precosmic state" is wrong (even that state is one period of the cosmic state/wavefunctional evolution of the universe), because space-time pre-existed (see: Stephen Hawking) necessarily (even in a different state in some theories).

The common theory is that our surrounding causal subluminal sphere was a spot (but not of exactly zero volume), and the whole spacetime/universe was still infinite (actually potentially infinite for each observer as it is now; because there is no IMMEDIATE causal connection outside each arbitrary observer's causal sphere [but there is some relay of causality; not only the central region exists in the causal spheres]) but denser.

I suggest you try posting a request at: 'Wikipedia:Requested articles/Natural sciences#Astronomy and cosmology'. Thanks. Praemonitus (talk) 15:22, 6 June 2021 (UTC)

Baryogenesis issue

At first glance there seems to be a conflict between these two sentences:

• ...leading to a very small excess of quarks and leptons over antiquarks and antileptons—of the order of one part in 30 million.
• ...a mass annihilation immediately followed, leaving just one in 10¹⁰ of the original protons and neutrons, and none of their antiparticles.

Am I missing something? Shouldn't the two values be the same, or some simple ratio thereof? They differ by >300. Praemonitus (talk) 17:47, 24 December 2020 (UTC)

One part in 10^10 is an underestimate, I think, but I also believe the Kolb & Turner 30 million to one number may be out-of-date as well. billion to one is indicated here. In principle, this can be calculated from the CMB photon density as described in rough detail at Baryon asymmetry (but maddeningly not actually calculated using the observed values at that article). I could dig up old notes on the subject, but I agree that we should try to get the consistent fraction decided upon. jps (talk) 01:45, 4 April 2021 (UTC)

Here is a rough estimate for 100 million to one as the correct ratio relying on the standard treatment of the asymmetry: [1]:

This ratio remained constants[sic] during the expansion of the universe and was therefore the same in the early, hot universe. When the universe was very hot, all particles were relativistic, and g_∗S ~ 10². Therefore η ~ g_∗Sn_B/s ~ 10⁻⁸, and assuming there were about as many baryons as antibaryons as photons (n_b ∼ n_¯b ∼ n_γ), this gives (n_b − n_¯b )/n_b ~ 10⁻⁸. Now assume that all the baryons were quarks, i.e. no nucleons had been formed yet, and we can conclude that for every 100 million antiquarks there were roughly 100 million and 1 quark. A tiny asymmetry but with important consequences!

Getting more accurate than this estimate is model dependent and will change with the precise choice of baryogenesis model, I believe. jps (talk) 17:28, 4 April 2021 (UTC)

Now fixed both here and at baryogenesis. g* is important, friends! jps (talk) 13:15, 6 April 2021 (UTC)

Semi-protected edit request on 26 May 2021

In the section on History - Development, there is a line referring to the accelerating expansion of the universe, ending with the "[citation needed]" statement. Here is the text fragment: Cosmologists now have fairly precise and accurate measurements of many of the parameters of the Big Bang model, and have made the unexpected discovery that the expansion of the universe appears to be accelerating.[citation needed] I propose adding the citation:

• Riess, A. G.; Filippenko, A.V.; Challis, P.; Clocchiatti, A.; Diercks, A.; Garnavich, P.M.; Gilliland, R.L.; Hogan, C.J.; Jha, S.; Kirshner, R.P.; Leibundgut, B.; Phillips, M.M.; Reiss, D.; Schmidt, B.P.; Schommer, R.A.; Smith, R.C.; Pyromilio, J.; Stubbs, C.; Suntzeff, N.B.; Tonry, J. (1998). "Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant". Astronomical Journal. 116: 1009-1038.

• Perlmutter, S.; Aldering, G.; Goldhaber, G.; Knop, R.A.; Nugent, P.; Castro, P.G.; Deustua, S.; Fabbro, S.; Goobar, A.; Groom, D.E.; Hook, I.M.; Kim, A.G.; Kim, M.Y.; Lee, J.C.; Nunes, N.J.; Pain, R.; Pennypacker, C.R.; Quimby, R.; Lidman, C.; Ellis, R.S.; Irwin, M.; McMahon, R.G.; Ruiz-Lapuente, P.; Walton, N.; Schaefer, B.; Boyle, B.J.; Filippenko, A.V.; Matheson, T.; Fruchter, A.S.; Panagia, N.; Newberg, H.J.M.; Couch, W.J. (1999). "Measurements of Omega and Lambda from 42 High-Redshift Supernovae". Astrophysical Journal. 517: 565-586. Sivertz (talk) 15:41, 26 May 2021 (UTC)

 Done in revision 1025326597, I added DOI and arXiv links. TGHL ↗ 🍁 00:08, 27 May 2021 (UTC)

Semi-protected edit request on 31 May 2021

The Big Bang Is not formed by an sigularity but formed when one Ununoctium atom and its anti paricle blasted and the annihalte so these annahilation expanded the universe. Sanjay007123456 (talk) 00:35, 31 May 2021 (UTC)

To editor Sanjay007123456:  Not done: please provide reliable sources that support the change you want to be made. P.I. Ellsworth  ed. ^put'r there 03:05, 31 May 2021 (UTC)

Semi-protected edit request on 20 June 2021

In the part "Hubble law and expansion of space", it is said that D is the comoving distance and that it varies as the universe expands (precisely "The theory requires the relation {\displaystyle v=HD}{\displaystyle v=HD} to hold at all times, where {\displaystyle D}D is the comoving distance"), but this is inconsistent with the definition of comoving distance, which by definition does not vary with the expansion. Also, following "Cosmology" from Weinberg, one has v = H*l, where l is this proper distance, since from FLRW metric, one can consider a fixed time so that proper distance is given by l = a(t)*ksi, where a(t) is the scale factor and ksi the comoving distance. When time-differentiated, it yields the above formula, namely v = H*l, q.e.d. 128.179.161.200 (talk) 08:32, 20 June 2021 (UTC)

 Done: I've fixed it. Not sure why it said comoving. ‑‑Volteer1 (talk) 01:46, 21 June 2021 (UTC)

time in the young universe

A point is a mathematical concept and does not exist in physics because it has no dimensions. This causes difficulty in understanding what was first in the universe. It seems that then most was foreseen of what since has been realized as p.e. the carbon atom is in reality a very complex thing while it allows many forms of life. Biologist do not reflex much about this and easily can stick to gradual changes as observed in history on Earth. Evolution of species took much time and this is rather well registered. But measuring of time is connected to real objects and threse where not present in the early universe with its plasma facies. So the duration of early phases of the universe is uncertain. Also existence of black holes can be questioned since stillstand of time contradicts fast processes in the beginning. May be black holes are just big masses in plasma condition? See more on www.janjitso.blogspot.com.