Re: btw
Cosmic rays are high energy radiation from space. It is often used purely for the massive particles (which includes neutrinos, btw), but not always and it's a relatively recent distinction in any case. The particles need not be fundamental either - nuclei up to and including iron are found in the flux (esp. for E < ~10^15eV)
Exactly: if not solely for massive particles then it includes photons (there aren't many other massless ones we can detect), so the story becomes, "cosmic rays have similar energy to other cosmic rays of similar energy". Knowing they are making an unstated distinction for nuclei separate to neutrinos and gamma is rather crucial to understand what's going on.
Biting the hand that feeds IT
