Neutrinos are the most abundant particles in the universe. Trillions upon trillions of neutrinos are streaming through you as you read this text.

Where all these neutrinos come from?

Neutrinos come from heaven and earth:

They are produced in large numbers in the explosion of a dying star called supernova. Antineutrinos from Supernova 1987A: 1,000 million/cm2 were emitted over the course of several seconds.

They are produced in the fusion processes in the Sun – solar neutrinos. Solar neutrinos: 10,000 million/cm2/s

They are produced in Earth in radioactive decays of radioactive elements such as uranium 238U, thorium 232Th and potassium 40K – geoneutrinos. Geoneutrinos: 1 million/cm2/s

Neutrinos that are left-over from the Big Bang explosion – relic neutrinos. (330 cm-3 everywhere in universe)

Our own bodies emit neutrinos from radioactive decay of potassium 40K that is naturally present in our bodies – 340 million/day.

In nuclear reactors as byproducts of fission – 1020 neutrinos/cm2/s in the average nuclear plant.