What would happen if a neutrino hit the nucleus of an atom in my body?

If I understand correctly, neutrinos pass through objects and rarely interact with the atoms.

But let’s say a high-energy neutrino begins to go through my body and then hits the nucleus of an atom in my body. Would I feel it?

You would not feel it - way too small an impact (you don’t feel the cosmic rays that impact you either). Inverse beta decay would occur - converting a proton to a neutron and a positron. Depending on what kind of atom the proton was in, this might result in a new radioactive atom in your body - but probably not a big deal, as you already have radioactive atoms throughout your body.

If it happened inside of one of your eyes, you might see a tiny flash of light. I’ve seen estimates that probably one or two people on the planet “saw” supernova 1987a this way.


There’s an interesting xkcd What If question on the topic.

I read once that this is likely to happen about once in an average lifetime.

So, you’re going to need to eat a lot of bananas.

I seem to recall reading somewhere that the higher the energy of the neutrinos, the more likely they are to interact with nuclear matter. So if one could artificially produce a beam of extremely high energy neutrinos they could be used as a weapon with potentially limitless penetration. Anyone else know about this?

Your body is bombarded by cosmic rays and other particles all the time. (Not to mention radiation from outgassing radon, especially in the basement). As mentioned, you might see a flash if it’s in your eye (and presumably, you’re in pitch dark). The neutrino detector in Sudbury Ont. deep in the mine has a large number of tubes to amplify the flash so it can be detected. It’s not a major event to get hit by a neutrino. Nuclear collisions with other particles happen all the time and nothing will happen unless you are bombarded by an excessive number of them.

So if a neutrino hits a carbon-12 nucleus (one of the more common atoms in the body), it converts one of the protons to an neutron, resulting in boron-12. Looking up boron-12 on Wiipedia, I find it’s radioactive, with a half-life of about 20 ms, usually emitting a beta particle, resulting in … carbon-12. So basically it results in the emission of an electron & positron, which, if they happen to meet up, will mutually annihilate and produce gamma rays. Which, if you’re on your deathbed, could be the final thing that pushes you over the edge. All die, Ooooh the embarrassment!

[quote=“dtilque, post:10, topic:913225, full:true”]. All die, Ooooh the embarrassment!

I recognize that reference!

I recognize that reference!

I guess I still don’t understand quotes…

Quote tags need to each be on their own line.

And it would be extraordinarily difficult to weaponize neutrinos. Even at high energies, the probability of each one interacting with a human body is 1 in bignumber, so your weapon would need to use bignumber times as much energy as is needed to kill a single human. It would literally be easier, instead of trying to penetrate through whatever shielding is present, to just blast away all the shielding before blasting the target.

Ahhh. There’s an XKCD for everything.

You’re really underselling bignumber here. You should read that referenced what-if from Randall Munroe. Bignumber is like “supernova level of explosion”.