Did the hydrogen in my body come from the Big Bang?

Which, if it did, would imply that all hydrogen did but I’m only concerned with “mine”.

Everything in the universe came from the Big Bang.

Yes, I understand that. I also understand that elements heavier than Beryllium didn’t form until later. I’m just wondering if hydrogen could be formed later as well.

The only place other than the Big Bang that produces protons (the nucleus of most hydrogen) are some rare radioactive decays and fission reactions, along with some high energy processes that produce proton-antiproton pairs.

There are also some very rare nuclear reactions that produce deuterium (such as in very, very low mass stars), but it’s not a stretch to say that more than 99.9% of the hydrogen in your body comes – untarnished by any further processing – from the Big Bang.

(I am an astrophysicist.)

But those heavy radioactive elements come ultimately from ancient fusion reactions (i.e. hydrogen.)

Yes, but in astrophysics this phrase has a specific meaning that’s different from “ultimately can be traced back to the big bang.” When we say “comes from the big bang” we mean that it’s pristine, and hasn’t been transformed from something else.

I think, what they’re trying to say, is yes.

Oh, so it’s all about you

Wow, even the Big Bang is about you!

You’re forgetting one of the most common nuclear decay processes around: the emission of a neutron. Free neutrons decay with a half-life of around 11 minutes, producing a proton and an electron. Which together make up a hydrogen atom.

This form of decay causes one of the hazards of storing high-level nuclear waste. Hydrogen (along with helium from alpha decay) will build up in tanks storing liquid high-level waste. These tanks have to be monitored for pressure and vented before it gets too high.

Even with hydrogen from neutron emission and decay, I think it’s still safe to say that the overwhelming majority of hydrogen in the Universe is primordial. There just isn’t enough radioactive material around to come close, even if every radioactive atom emitted a neutron (which they don’t; alphas and betas are much more common).

Oh, sure. No argument. Didn’t mean to imply otherwise. I was just saying that proton as a decay product is not as rare as ethansiegel indicated.

[quote=“dtilque, post:9, topic:550824”]

How radioactive would this hydrogen be? What does H break down to, if at all?

Not radioactive at all. That hydrogen is no different from any other hydrogen, and it’s completely stable. Deuterium (hydrogen with an added neutron) is similarly stable. Tritium (with two added neutrons), however, is fairly radioactive, but I don’t think it is produced from radioactive waste like dtilque mentioned.

Tritium is a radioactive waste product; old-style nuclear power plants produce tritiated water.

The tritium, however, decays into Helium-3, not into hydrogen, so unless you’ve literally been drinking the wrong water, you shouldn’t have any in you.

Neutron emission, BTW, is an extremely rare decay (as compared with the three major types: alpha, beta, and gamma decays), and usually occur only with man-made elements, not with the natural ones. Neutron emission - Wikipedia

For the record, proton emission is also possible, but is even rarer.

Hydrogen is the simplest element. It contains one proton and one electron. If it loses the electron it still can be considered a hydrogen ion.

As a single proton there’s nothing simpler for it to break down to, unless protons themselves can break down. That’s been a controversial subject for decades. Certain Grand Unified Theories predict that over a very long time scale, even protons will break down.

A positron is a positive electron.

10[sup]36[/sup] is a ridiculously long time, about 10[sup]26[/sup] times as long as the universe has been in existence. Still, with so many protons some would presumably be breaking down at any given time. The problem is that experiments can’t find any.

Until some better experimental proof comes along, you can assume that your Hydrogen is stable and will not break down at all.

If nothing else, you’ll get neutrons from spontaneous fission, especially if you get critical fission going (which can happen in nature).
And I don’t know all that much about grand unification theories, but I would expect that if the positron + pi[sup]0[/sup] decay is permitted, then a neutrino + pi[sup]+[/sup] decay should also be permitted, and have approximately the same amplitude. Unlike the positron channel, where all the energy ultimately ends up in photons (assuming there’s an electron in the vicinity for the positron to annihilate with), the neutrino channel would end up sinking most of the energy into neutrinos of various sorts (a mu neutrino/antineutrino pair and an electron neutrino/antineutrino pair).

However, hydrogen is flammable. If it mixes with oxygen, it can go boom!

The hydrogen’s still there, though, as part of the molecules. And Nars was asking about the hydrogen in his body, which is for the most part hydrogen which has already gone boom.

I’m pretty sure MEBuckner wasn’t responding to Nars. This response was part of the discussion of the danger of the hydrogen produced by radioactive decay of stored waste. It’s not radioactive, but it is dangerous because it 1) builds up pressure and 2) is inflammable.