Pions and muons were discovered using these and the showers they create are detected by the current Auger Project.
A proposed upper bound on the energy of these entities is the GZK limit, but the recent discovery of the so-called "oh-my-god particle" has called this into question. Postulated by Hess to explain electrometer readings, their name was coined by Millikan who, believing they were photons, debated Compton, who correctly held that they are charged particles. Pions and muons were discovered using these and the showers they create are detected by the current Auger Project. For ten points, name this form of highly energetic radiation of indeterminate origin that comes from space.
A proposed upper bound on the energy of these entities is the GZK limit, but the recent discovery of the so-called "oh-my-god particle" has called this into question.
{cosmic ray}s