What are the example of cosmic radiation?

Answer 1

Although there are many forms of radiation with zero rest mass, none of these forms of radiation are at rest. They possess energy and, as a result, also possess mass. The mass of any radiation can be calculated from its energy by the equation m=E/c2 where m is its mass (kg), E its energy (joules) and c its velocity. This is just another way of expressing the equation we have all heard E=mc2.

A good example is light. Although it has zero rest mass, it travels at 2.998 x 108 m/s and has energy. It therefore possesses mass.

The energy of a photon (quantum of light) is determined by its frequency and is given by E=hf where E is its energy, h is plank's constant (approx 6.6262 x 10-34 joule/sec) and f is its frequency in Hertz (Hz).

Suppose we take a microwave with a frequency of 10GHz. The energy of a single photon will be 6.6262 x 10 -24 joules. Further dividing this by the speed of light squared gives the mass of such a photon as 7.3 x 10-39 kg. That is VERY VERY VERY small but it is not zero.

In the end, there are no forms of massless radiation.

Answer 2

Most cosmic rays that we detect on earth are muons. This is because the vast majority of cosmic rays which strike the earth's upper atmosphere are protons, and the collisions with nuclei in the air molecules make a lot of pions. Still with me? The pions then decay to muons and neutrinos. Neutrinos pass right through the earth and are extremely hard to detect; but the muons are quite easy to detect.