by Chris Peterson » Tue Jan 10, 2023 4:57 pm
johnnydeep wrote: ↑Tue Jan 10, 2023 3:49 pm
Chris Peterson wrote: ↑Tue Jan 10, 2023 2:42 pm
javachip3 wrote: ↑Tue Jan 10, 2023 5:47 am
"The hydrogen in your body, present in every molecule of water, came from the Big Bang. There are no other appreciable sources of hydrogen in the universe."
Really? Many fusion and fission reactions produce free neutrons. Neutron star mergers, supernovas, relativistic jets from black holes, and other cataclysmic events also produce free neutrons. Free neutrons decay with a half life of 10 minutes into a proton, an electron, and an electron antineutrino. A proton is a new hydrogen nucleus. After 13.7 billion years, might not this account for some percent of all existing hydrogen?
Well, given that most estimates suggest that
only a few percent at most of the Universe's hydrogen has ever been in a star, and most of the hydrogen in stars is still there, as hydrogen, I think that it is reasonable to say other sources of the element aren't "appreciable", representing only a very, very tiny fraction of all hydrogen.
Huh. So, 95% or more of the hydrogen in the universe is just floating around as gas in interstellar and intergalactic space? If the following graphic is still accurate, it would imply that about 0.5% / 4% = 1/8 of the hydrogen in the universe is in stars, which would be about 12 percent.
There is a lot of uncertainty in the numbers because there's a lot of uncertainty about how many stars there are. However, even allowing for something on the order of 10% of the hydrogen being in stars, we need to consider that most of the stars that have ever existed in the Universe still do, and are still in their hydrogen fusing phase, and have only fused a tiny fraction of that hydrogen. So compared with the amount of primordial hydrogen, that created as a fusion byproduct remains very tiny.
[quote=johnnydeep post_id=328377 time=1673365759 user_id=132061]
[quote="Chris Peterson" post_id=328376 time=1673361724 user_id=117706]
[quote=javachip3 post_id=328371 time=1673329656]
"The hydrogen in your body, present in every molecule of water, came from the Big Bang. There are no other appreciable sources of hydrogen in the universe."
Really? Many fusion and fission reactions produce free neutrons. Neutron star mergers, supernovas, relativistic jets from black holes, and other cataclysmic events also produce free neutrons. Free neutrons decay with a half life of 10 minutes into a proton, an electron, and an electron antineutrino. A proton is a new hydrogen nucleus. After 13.7 billion years, might not this account for some percent of all existing hydrogen?
[/quote]
Well, given that most estimates suggest that [b][i][color=#0000FF]only a few percent at most of the Universe's hydrogen has ever been in a star[/color][/i][/b], and most of the hydrogen in stars is still there, as hydrogen, I think that it is reasonable to say other sources of the element aren't "appreciable", representing only a very, very tiny fraction of all hydrogen.
[/quote]
Huh. So, 95% or more of the hydrogen in the universe is just floating around as gas in interstellar and intergalactic space? If the following graphic is still accurate, it would imply that about 0.5% / 4% = 1/8 of the hydrogen in the universe is in stars, which would be about 12 percent.
[/quote]
There is a lot of uncertainty in the numbers because there's a lot of uncertainty about how many stars there are. However, even allowing for something on the order of 10% of the hydrogen being in stars, we need to consider that most of the stars that have ever existed in the Universe still do, and are still in their hydrogen fusing phase, and have only fused a tiny fraction of that hydrogen. So compared with the amount of primordial hydrogen, that created as a fusion byproduct remains very tiny.