On neutrinos

I've been thinking a lot about neutrinos. Those strange ghostly particles that might be there and might not be there. Millions of them, popular science writers never hesitate to tell us, pass through our bodies every second. Or do they? When confronted with the existence of such a strange and mysterious entity what should we think? Sir Arthur Eddington, when asked if he believed that neutrinos really existed, replied that he had no doubt that scientists would produce observations to support their existence. Do you follow? He explained: (I am paraphrasing here) "Imagine a sculptor before a block of marble who says, there is a head of man hidden in this block of marble and with this chisel I will reveal it". Cowan and Reines had to put their ears, figuratively speaking, to the walls of a nuclear reactor to hear one for the first time.

I remember too Bob Shaw's science fiction novel A Wreath of Stars, which I read sometime in the last century, back in Ireland. Shaw imagines a parallel universe composed of neutrinos existing somehow contemporaneously with our own. (I know, scientific accuracy was not a strong point of this novel). Special glasses worn by mine workers revealed this mysterious demi-monde. A black neutrino star burning in the mid-day sky. Ghostly shapes passing through walls which were really lost souls from this neutrino universe. Weakly interacting. How can something which is so unreal be real? But half a dozen or so neutrinos were detected in the depths of the Earth after supernovae 1987a exploded, the first time neutrinos were ever detected from a star other than or own.

I thought about all of this as I was swimming my habitual midday 1.5 kilometres at the local swimming pool. Even I was energetically doging old-age pensioners swimming half as fast as me or being overtaken by Aryan super-beings swimming ten times as fast I realised that I was, in fact, a neutrino! A weakly interacting particle. One kilometer of lead, even, would not stop me. Sailing through buildings and trees and houses and people and kilometers and kilometers of rock and earth, out towards interstellar space, the cold empty reaches between the stars. Interacting weakly. I understood, at last, my place in the world. I guess Glenn Gould was a neutrino, too...