If a neutrino do not interact with anything and can pass through a light year of lead, how humans manage to detect them?
In: 6
With a lot of difficulty.
Neutrino detectors [tend to be really, really big](https://www.businessinsider.com/super-kamiokande-neutrino-detector-is-unbelievably-beautiful-2018-6).
Usually giant water tanks (some using heavy water), buried deep underground, surrounded by detectors that look for interactions between neutrinos and stuff in the water.
Neutrinos do interact with things, but only via the weak interaction (and gravity, but only in negligible amounts). That detector linked above is the [Super-Kamiokande detector](https://en.wikipedia.org/wiki/Super-Kamiokande) in Japan; a tank containing 55,000 tons of water, 1,000m underground, with 13,000 light detectors around it. Specifically it detects Cherenkov radiation which is a weird thing you can get when neutrinos interact (weakly) with electrons or the nuclei of atoms.
About 10^11 neutrinos pass through each square centimetre of the Earth’s surface each second. The Super-Kamiokande detector (with a surface area of over a thousand square metres) detects about 8 per day.
We detect neutrinos with a lot of difficulty, by having really big detectors, and knowing that huge numbers of neutrinos pass through every second.
Latest Answers