7 ms·
The 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
by ISL 6y ago
The 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]