Neutrinos are inoffensive. They have no electrical charge and they travel at the speed of light, or nearly. Whether they are weightless or have a finite but small mass is one of today's unsolved problems. The contribution now awarded consisted among other things of transforming the ghostly neutrino into an active tool of research. As well as in cosmic radiation, neutrinos, which belong to the moon family, can be produced in a multistep process in particle accelerators, and this is what the prizewinners utilized.
Suitable accelerators exist in some few laboratories throughout the world.
Since all matter is transparent to neutrinos, it is difficult to measure their action. Neutrinos are, however, not wholly inactive. The rarity of such direct hits implies that a single neutrino of moderate energy would be able to pass unhindered through a wall of lead of a thickness measured in light-years. In neutrino experiments the rarity of the reactions is compensated for by the intensity of the neutrino beam. Even in the first experiment, the number of neutrinos was counted in hundreds of billions.