3 ms·
Neutrinos are weird little things, and pass clean through any sort of matter almost every time. The famous statistic is that you'd need a light-year of solid le
by PhasmaFelis 8y ago
Neutrinos are weird little things, and pass clean through any sort of matter almost every time. The famous statistic is that you'd need a light-year of solid lead just to block half of all neutrinos.
What surprises me about this article is that catching neutrinos tunneling up through the earth is considered surprising. I had thought that neutrino detectors generally caught just as many neutrinos from below as from above; the earth is essentially transparent to them.
To answer your question #2: the detector is no better than anything else at stopping neutrinos (just as detecting their stoppage), but--even though the chance of any given neutrino stopping anywhere in the earth is almost nil--there are so very very many of them that the probabilities add up to a decent number impacting within the detector.
- simonebrunozzi 8y agoThese detectors are underground presumably to remove "noise" from other sources - sorry, I have no source for this, it's just a memory from a physics professor in high school describing such a facility in Italy (Gran Sasso).
- kstr 8y agoNeutrino detectors are mainly looking for (neutrino) events coming from below in order to avoid noise from cosmic rays coming from above. The surprising part is if other particles are observed coming in from below.
- sanxiyn 8y ago> What surprises me about this article is that catching neutrinos tunneling up through the earth is considered surprising. I had thought that neutrino detectors generally caught just as many neutrinos from below as from above; the earth is essentially transparent to them. This is what I thought too, but apparently, the Earth is opaque to neutrinos at energies above 1 PeV. (That is, the Standard Model predicts so.) The article states "The particles had energies that were high enough for the Standard Model to prohibit that kind of careless disregard for matter". Although I think it could have been explained better, explanation is there.