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Physicists Pin Down Nuclear Reaction from Moments After the Big Bang
- dragosmocrii 6y agoHow can one have a few grams of deuterium in their body from the time of Big Bang? And how does it make its way in one's body?
- ISL 6y agoThe protons that make up more than half of your mass are also mostly from the big bang. Some of the hydrogen in the world around us is deuterium, again mostly from the big bang. When your body was assembled, and when you drink water/breathe, some of the generally-hydrogen sites in our bodies happen, instead, to be deuterated.
- warent 6y agoAren't 100% of the protons that make up your body from the big bang?
- miemo23 6y agowell neutrons decay in about 10min (avg) into fresh new protons (plus an electron) so perhaps not
- saagarjha 6y ago*free neutrons
- DrAwdeOccarim 6y agoWow, I didn't know that. Do you have a reference?
- magicalhippo 6y agohttps://en.wikipedia.org/wiki/Free_neutron_decay https://en.wikipedia.org/wiki/Free_neutron_decay https://phys.org/news/2020-09-mystery-neutron-lifetime.html https://phys.org/news/2020-09-mystery-neutron-lifetime.html
- DrAwdeOccarim 6y agoTIL. Thanks so much for sharing, this is wild...Reminds me of pair-production. Nuclear physics is so fascinating.
- sandfly 6y agoIs the free electron immediately captured by the H+ particle, or is the energy high enough that this can produce an acidic gas of H+?
- corty 6y agoConservation of momentum dictates that proton and electron will move away from each other. The decay energy might be absorbed by a nearby nucleus in an medium to a large part, leaving only a small momentum for both particles so they can form an atom, but usually it won't. In the average low-density case, the proton and electron will find other partners only after quite some cooldown. In very rare cases most of the energy might also be carried away by the neutrino that is produced as well, so decay to hydrogen is not impossible in a vacuum.
- ISL 6y agoThe energy release in neutron beta-decay is ~780 keV. This should be compared with the hydrogen binding energy of ~13 eV. Hence, there is far too much energy released for the electron to stay bound in essentially any case. If the neutrino carries away all the energy (with momentum conservation soaked up mostly by the recoiling proton), it could re-bind, but that process should be exceedingly rare. In that case, the result would see an (excited, probably) hydrogen atom recoiling away from the invisible neutrino.
- robocat 6y agoHalf-life ~10 minutes, which has a mean of ~15 minutes. Per https://en.wikipedia.org/wiki/Free_neutron_decay https://en.wikipedia.org/wiki/Free_neutron_decay
- p1mrx 6y agoThey're from the big bang indirectly, but they haven't all been protons the whole time. For example: https://en.wikipedia.org/wiki/Beta_decay https://en.wikipedia.org/wiki/Beta_decay
- delibes 6y agoJust being a bit pedantic ... more than half? Atoms typically have more neutrons than protons, and neutrons also weigh slightly more. Surely I'm >50% neutrons by mass?
- marcosdumay 6y agoHydrogen mostly does not have neutrons. You have a lot of those.
- CapriciousCptl 6y agoIt’s probably close to 50%. 80% of your mass is water and carbon. Hydrogen makes up 10% taken by itself but generally didn’t have a neutron which balances out the comparatives rare bigger elements with more neutrons.
- ISL 6y agoAgreed -- I should have gone with "roughly half" or "almost half". As I wrote last night, I incorrectly recalled that n/p is often below 1 -- if I had thought for a moment about high-Z nuclei, the error would have been obvious. A great place for a reader to begin to reach their own conclusions is here: https://en.wikipedia.org/wiki/Neutron%E2%80%93proton_ratio https://en.wikipedia.org/wiki/Neutron%E2%80%93proton_ratio Thank you for the correction.
- deleted 6y ago[deleted]
- manmal 6y agoThere‘s even a recent health fad that claims deuterium is bad for health, and those people also happen to sell deuterium-depleted water.
- simonh 6y agoI suppose that’s one way to lose a little weight.
- shawnz 6y agoIt does have health effects (in huge quantities). https://www.thoughtco.com/can-you-drink-heavy-water-607731 https://www.thoughtco.com/can-you-drink-heavy-water-607731
- vl 6y agoThink about it, it’s a great business: they process water, sell deuterium, and then also sell by-products! :)
- jen729w 6y ago> How can one have a few grams of deuterium in their body. > ... > And how does it make its way in one's body? Just like any other element – it’s around, in parts-per-million, and it finds its way in to your cells as a result. It’s just a non-harmful form of hydrogen. > from the time of Big Bang? Because that’s where the majority of the deuterium in existence was made. Crazy, but true. Unlike most of the heavier elements, it isn’t a by-product of stellar evolution. Extraordinary to think that the Universe is almost fourteen thousand million years old, and most of our deuterium was made in the first twenty seconds. After that, it cooled down and just wasn’t hot enough for fusion to do its work. Physics is mental.
- sethammons 6y agoReminds me of the idea that all the water you drink has already been drank and cycled through dinosaurs n times. https://www.techtimes.com/articles/56727/20150530/you-are-drinking-dinosaur-pee-everyday-heres-why.htm https://www.techtimes.com/articles/56727/20150530/you-are-dr...
- ars 6y agoThis isn't really totally accurate. A lot of the water in the world is process water, it's created when things combust. And much of the water consumed by plants is turned into carbohydrates which then gets processed back into water after combusting or being oxidized in a animal. I actually highly doubt that any water remains that has never been broken back into its constituent atoms and then combined with other atoms. I suspect the true answer is actually 0% of the water remaining today has ever been in a dinosaur. (I.e the atoms might have been, but not the molecule as a molecule.)
- vl 6y agoAll elements come from somewhere. With the minor exception of heavy element decay, there is no nuclei synthesis on Earth. So elements planet and we consist of were made before, some of them in stars and then spread out though supernovae explosions, and some of them in the Big Bang. Since we have so much heavy elements, our elements are not even from the first generation of stars. AFAIR it’s a third generation of supernovae explosions.
- longtom 6y agoUsually, scientists are extremely careful with extrapolation, the big exception being the big bang, because it sells, I guess, and because it is hard, if not impossible, to verify.
- mr_mitm 6y agoWhat do you mean? There is an overwhelming amount of evidence for the Big Bang. Unless you mean something other than the scientific consensus by the expression "Big Bang". And what do you mean by sell? The Big Bang used to be a fringe interpretation of the equations until the evidence rolled, not because it sounded appealing. Einstein famously introduced the cosmological constant so the equations would allow another interpretation (a static universe), which he just as famously regretted as soon as the expansion was measured.
- StanislavPetrov 6y ago"Scientific consensus" does not equal "overwhelming evidence".
- simonh 6y agoNo, but overwhelming evidence, as we have for the Big Bang, generally does lead to scientific consensus. That’s how science works.
- redis_mlc 6y ago> consensus Sorry, that isn't how science works. In science, a model is created and then verified experimentally. I know global warming is consensus-based, and that's not really science either. No matter how many people you find that say the earth is flat (consensus), it's not.
- treeman79 6y agoYou definitely want people working against the scientific consensus. They will mostly be wrong; but now and then that’s how we get a breakthrough.
- mentos 6y agoThe mass of the observable universe is often quoted as 10^50 tonnes or 10^53 kg So was all of this mass somehow condensed inside a space smaller than a bowling ball? Seems theoretically impossible? Are there any examples of black holes/stars exploding after reaching some critical mass that might resemble the big bang? Is the big bang effectively just a black hole that creates a massive nuclear bomb that starts a new universe?
- svachalek 6y agoThe Big Bang was not an explosion in the conventional sense. When a bomb explodes, even a nuclear bomb, the energy created causes the atoms in the explosive to move violently in all directions. But in the Big Bang, instead suddenly all of those particles got farther apart without necessarily moving. The only real parallel in our current universe is the way the space between galaxies is expanding; nothing on our planet or even within our galaxy (afaik) behaves this way.
- mentos 6y agoOk thank you, so I guess 'big bang' is the wrong imagery. Really its someone stretching the taffy out that all mass sits on, a 'great expansion'. However and wherever mass came from, the idea that mass exists at all is unfathomable. My only way of rationalizing it is that in some higher dimension things 'just exist' and its only because we perceive things in our three dimensions that we believe there must be a start and end to things.
- opwieurposiu 6y agoThere are a couple of details that make the early universe different then a black hole. The first is that, even though the matter/energy density was higher then the Chandrasekhar limit, space itself was expanding at faster than the speed of light so it could not collapse. The second thing is that gravity has negative energy, and matter has positive energy, so the total energy of the universe was exactly zero. Zero total energy is the only amount compatible with our understanding of thermodynamics.
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- Haga 6y agoFrom a certain vantage point the anamolies of the early universe look like a intern in a labcoat caught pressing the wrong button..
- xbar 6y agoWhere is all the lithium?
- deleted 6y ago[deleted]
- gorkish 6y agoBig Bang fusion apparently produces mainly Li-7 which decays to He. There is still a perceived problem with the abundance of Li, Be, and B though when you go charting the observed abundance of all elements. But if the Lithium all decayed, why isn't there more Helium?
- newsclues 6y agoHelium in stars(current and past) doesn’t account for it?
- AnimalMuppet 6y agoThat may be kind of hard to tell. Stars create helium, by fusing hydrogen. That makes it hard to tell how much helium the star started with. (Or so I suspect - I'm not an astronomer.) It's kind of like, in a dynamite factory, trying to tell if there's any dynamite left over from when they blasted to make a hole for the foundations.
- stephenwinter2 6y ago> within the cosmos’s first three minutes Measured with today's clock the cosmos was when Big Bang happened some trillion years older than you think (and Big Bang was an implosion not an explosion). > which helped drive cosmic expansion Cosmic expansion isn't energy-driven at all. http://www.hashsign.eu/html/blog/universe/gravity-and-scaling-of-spacetime-the-long-prevented-leap-of-cosmology-from-1917-to-2017.html http://www.hashsign.eu/html/blog/universe/gravity-and-scalin... "Physics is mental" (jen729w) - cool, equivocal and true