| ¿What are Cosmic Rays? | |||
The discovery of Cosmic Rays dates from the VI century b.C. when Tales of Miletus found about the attraction between the amber and light bodies previously rubbed (electrified), this phenomenon was attributed to the presence of a "soul" in the amber. However Tales noticed that the amber "lost its soul" after a period of time. This enigma was not solved until after twenty five centuries later it was discovered that the presence of cosmic rays was reponsible to unload the charge in the bodies. The official discovery of cosmic rays is dated in the year 1912 when the austrian physicist Hess demonstrated that the number of ions in the atmosphere increases with altitude. |
Figura 1 Appearances of cosmic rays in a nuclear emulsion. |
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Between
1920 and 1930 it was noted that cosmic rays did not come from the Sun
or the stars. In the first case because its intensity was the same during
day and night and in the second case due to the fact that the energy
of the cosmic radiation was comparable with the energy produced by star
light. Nowadays it is known that most of the galactic cosmic rays come
from the birth of supernovas,
objects that mean the end of some masive stars, aproximately 10 times
the mass of the Sun. |
Figura 2 Tycho's Supernova Remnant, watched by the danish astronomer Tycho Brahe in the XVI century. |
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Cosmic
Rays are nucleus of ordinary atoms separated from their electrons
and are characterized for their very high energy, quality that distiguishes
them from the other radiation types. The primary cosmic radiation
is made of protons, In the next figure we show the abundances of the diferent elements in the Solar System compared with abundances of the same elements in cosmic rays:
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particles and heavier nucleus (See 