science

14307 readers

104 users here now

just science related topics. please contribute

note: clickbait sources/headlines aren't liked generally. I've posted crap sources and later deleted or edit to improve after complaints. whoops, sry

Rule 1) Be kind.

lemmy.world rules: https://mastodon.world/about

I don't screen everything, lrn2scroll

founded 1 year ago

MODERATORS

m3t00@lemmy.world

Joleee@lemmy.world

laverabe@lemmy.world

DeadPand@midwest.social

... "quantum particle creation could play a role in the creation of matter in the universe after the end of an inflationary era" ... (lemmy.world)

submitted 2 months ago by A_A@lemmy.world to c/science@lemmy.world

5 comments fedilink hide all child comments

The way i read it : Our theoretical framework, allowing matter creation (*) provides a possible origin for the universe (without the need of a Big Bang). Also this is quite timely in the actual context of new observations made by the James Webb space telescope that are in tention with classical models.

(*)(after an hypothetical inflatory period, [...or at any time as long as the universe expands...])

title of this post is taken from section : VII. SUMMARY
Of : Cosmological Particle Production: A Review

Preprint :
(2021 December 7 // @ arXiv…)
https://arxiv.org/pdf/2112.02444.pdf

The article has been published in a peer reviewed journal paywall warning.

you are viewing a single comment's thread
view the rest of the comments

[–] nikaaa@lemmy.world 2 points 3 weeks ago* (last edited 3 weeks ago) (1 children)

Our theoretical framework, allowing matter creation (*) provides a possible origin for the universe (without the need of a Big Bang).

If you look at the typical composition of a star today, you will find that it is mostly (99%) hydrogen.

We know that a star burns hydrogen into helium, and therefore the relative fraction of hydrogen in the star's composition decreases annually by a specific rate (let's say 0.0000001%). That means that a star might have an average lifetime of 1 billion years, before its composition changes and it has only small fraction of hydrogen left.

If the universe were created slowly (by a slow process, such as spontaneous particle creation would be), then stars would burn out while they are being created; In other words, we wouldn't see stars that are mostly unconsumed hydrogen, but instead, stars that are mostly already consumed helium, with slow rates of hydrogen being created continuously.

But that would lead to stars having a drastically different composition: instead of 99% hydrogen and 1% helium, we might see 1% hydrogen and 99% helium. That is why I believe a "slow creation" of the universe to be unlikely.

[–] A_A@lemmy.world 1 points 3 weeks ago (1 children)

Maybe I don't follow correctly but what you say would imply that 1 billion years after the big bang (if it was the origin of the universe) there would be no ordinary main sequence Stars left ... (?)

[–] nikaaa@lemmy.world 2 points 3 weeks ago (1 children)

Ok maybe my numbers were a little bit off but the point is: if the universe were created slowly, we'd see clear traces of that. but the evidence points into the opposite direction, that the universe, at some point, was very hot and dense, before stars started forming. So the question is, where would all that matter come from? I deem it's unlikely to all just be "one huge quantum fluctuation", but i'm not sure about that; cosmology is exotic sometimes.

[–] A_A@lemmy.world 2 points 3 weeks ago (1 children)

i like that you were looking for a mechanism to avoid thermal death of the universe.

As for my inspiration : since many years I have read about discrepancies between standard model (including the big Bang) versus observations and I came to believe (with many confirmations as the year goes by) that our current cosmology is incomplete or wrong.

[–] nikaaa@lemmy.world 2 points 3 weeks ago

... and I came to believe that our current cosmology is incomplete or wrong.

Well, yes, I agree with you.