The term ray (as in optical ray) seems to have arisen from an initial belief, due to their penetrating power, that … See more

Of primary cosmic rays, which originate outside of Earth's atmosphere, about 99% are the bare nuclei of common atoms (stripped of their electron shells), and about 1% are solitary electrons (that is, one type of … See more

Cosmic rays attract great interest practically, due to the damage they inflict on microelectronics and life outside the protection of an atmosphere and magnetic field, and scientifically, because the energies of … See more

After the discovery of radioactivity by Henri Becquerel in 1896, it was generally believed that atmospheric electricity, ionization of the air, was caused only by radiation from radioactive elements in the ground or the radioactive … See more

The solar cycle causes variations in the magnetic field of the solar wind through which cosmic rays propagate to Earth. This results in a modulation the arriving fluxes at lower energies, as detected indirectly by the globall… See more

Early speculation on the sources of cosmic rays included a 1934 proposal by Baade and Zwicky suggesting cosmic rays originated from supernovae. A 1948 proposal by Horace W. Babcock suggested that magne… See more