04/01/2023
The Sun is producing only a third of the neutrinos expected
Hold up your thumb. 100 billion neutrinos are passing through your thumbnail every second. 8.5 minutes ago they were in the heart of the Sun.
Solar neutrinos are a by-product of sunlight-generating nuclear reactions. When Ray Davis set out to detect them with 100,000 gallons of cleaning fluid down a mine in South Dakota, he expected to confirm the standard picture of the Sun.
Instead, he found only a third of the expected neutrinos, something that was not only confirmed by later experiments but led to his Nobel Prize.
Neutrinos are ghostly subatomic particles existing in a weird quantum superposition – akin to an animal that is simultaneously a cow, a pig and a chicken.
As they travel from the Sun, they flip between being an electron neutrino, a muon neutrino and a tau neutrino, which is why experiments sensitive to only one type pick up a third of the expected number.