The article references the "Oh-My-God particle, the most energetic particle yet encountered. Here's the late John Walker's excellent piece on that: https://fourmilab.ch/documents/OhMyGodParticle/
That was indeed excellent reading, thank you.
Record-breaking neutrino is most energetic ever detected
71–80 of 137 posts
Re: Record-breaking neutrino is most energetic ever detected
#72For context, 120 PeV is about 10% the kinetic energy of a ping pong ball during typical play.
Does this count as "Americans will measure with anything but the metric system"?
Re: Record-breaking neutrino is most energetic ever detected
#73Earlier quoted context omitted.
The mean free path of neutrinos through lead is around one light-year. So, taking the thickness of the body to be 1/2 a meter, you would expect the probability of any individual neutrino to interact with the body to be ~5 x 10^-17. So you'd ballpark have around a 20--40% chance that a single neutrino interacts with your body. It would probably cause a localized radiation burn. Detectable, but probably not lethal unle…
The mean free path of much lower energy neutrinos in lead is about a light year. The MFP of a 120 PeV neutrino in lead would be something like 10 kilometers, I think.
More like 100 km I'd think but yeah, the neutrino nucleon cross section gets much bigger at high energies
Re: Record-breaking neutrino is most energetic ever detected
#74It looks like they detected a muon and are inferring a neutrino from the fact it went through a lot of solid. Couldn't it be any other weakly-interacting particle though?
It could be beyond the standard model physics but no other standard model particle could work other than a neutrino.
Re: Record-breaking neutrino is most energetic ever detected
#75The article references the "Oh-My-God particle, the most energetic particle yet encountered. Here's the late John Walker's excellent piece on that: https://fourmilab.ch/documents/OhMyGodParticle/
> These calculations involve some elementary but easy to mess up algebra and some very demanding numerical calculations for which regular IEEE double precision is insufficient. If you'd like to double-check these results, be sure to use a multiple precision calculator with at least 30 significant digits of accuracy. So you're saying my iPhone built-in calculator app is going to have problems....? Time to whip out dc…
> So you're saying my iPhone built-in calculator app is going to have problems....?
Your Android phone's built-in calculator app, however, will not. :^)
Re: Record-breaking neutrino is most energetic ever detected
#76Ars Technica has an article, as well, with some additional context/explanation. https://arstechnica.com/science/2025/02/most-energetic-neutr... And an interesting, somewhat related, video from PBS Space Time exploring how supernovas act as particle accelerators (but don't quite explain particles like this one or the 'Oh My God' particle): https://www.youtube.com/watch?v=2sSNWIJbV3Q
Neutrinos “interact with regular matter so rarely that it's estimated you'd need about a light-year of lead to completely block a bright source of them. Every one of us has tens of trillions of neutrinos passing through us every second, but fewer than five of them actually interact with the matter in our bodies in our entire lifetimes.”
They have 1/500,000 the mass of electrons. They interact only through the super short range weak force (and gravity). Nearly 5% of fission energy is expressed in neutrinos.
And, they may be their own antiparticles, meaning they can potentially annihilate each other.
Wild that these things can carry so much energy!
Re: Record-breaking neutrino is most energetic ever detected
#77>Observation of an ultra-high-energy cosmic neutrino with KM3NeT
Re: Record-breaking neutrino is most energetic ever detected
#78It's mentioned in the article that the highest energy ever recorded for a single particle was 320,000 PeV which is about 50 joules, i.e. the energy of a golf ball at 100 mph @_@
That was a cosmic ray proton, which has probably 10 billion times the mass of a neutrino and interacts much more strongly with normal matter. A nuclear juggernaut vs a ninja by comparison.
Most likely a heavier nucleus than a proton too
Re: Record-breaking neutrino is most energetic ever detected
#79Ars Technica has an article, as well, with some additional context/explanation. https://arstechnica.com/science/2025/02/most-energetic-neutr... And an interesting, somewhat related, video from PBS Space Time exploring how supernovas act as particle accelerators (but don't quite explain particles like this one or the 'Oh My God' particle): https://www.youtube.com/watch?v=2sSNWIJbV3Q
Neutrinos “interact with regular matter so rarely that it's estimated you'd need about a light-year of lead to completely block a bright source of them. Every one of us has tens of trillions of neutrinos passing through us every second, but fewer than five of them actually interact with the matter in our bodies in our entire lifetimes.” They have 1/500,000 the mass of electrons. They interact only through the super s…
>Every one of us has tens of trillions of neutrinos passing through us every second, but fewer than five of them actually interact with the matter in our bodies in our entire lifetimes.”
Oh, but those five...
Re: Record-breaking neutrino is most energetic ever detected
#80Earlier quoted context omitted.
Neutrinos can go straight through the Earth, yes, but since they have mass their velocity is less than c.
It’s very close to c though, close enough that it beats sending a signal around the Earth. The drawback is the impractical size and cost of a receiver.
Come on, we gotta convince the finance bros to find building better neutrino beams and detectors.