Cosmic Particles:

When you sit in a room with no radioactive material present and switch on a radiation counter with the window of the tube closed, you will observe an occasional click from the device. Few of the particles come from the Earth; there are radioactive elements in the ground nearly everywhere (generally in small amounts). Some of the radiation arrives indirectly from space. The Cosmic particles hit atoms in the environment and such atoms in turn expel other subatomic particles which arrive at the counter tube.

In the early year of 1900s, physicists observed radiation actually coming from space. They found that the odd background radiation rose in intensity whenever observations were made at high altitude; the radiation level reduced whenever observations were taken from underwater or underground. Such space radiation has been termed secondary cosmic radiation or secondary cosmic particles. The real particles from space, termed as primary cosmic particles, generally do not penetrate far into the environment before they collide with and split up the nuclei of atoms. To examine primary cosmic particles, it is essential to ascend to great heights, and as with the UV and x-ray inquiries, this was impossible until the arrival of the space rocket.

Whereas the radiation in the EM spectrum-the IR, radio waves, visible light, UV, x-rays, and gamma rays-consists of photons moving at the speed of light, main cosmic particles are comprised of matter traveling at about, though not quite, the speed of light. At such high speeds, the neutrons, protons, and other heavy particles gain mass as of relativistic effects, and this renders them almost resistant to the effects of the Earth's magnetosphere. These particles arriving in the upper environment come to us in almost perfect straight-line paths in spite of the magnetic field of our planet. By cautiously examining the trails of the particles in a device termed as a cloud chamber aboard a low-orbiting space ship, it is likely to ascertain the direction from which they have come. Over time, the cosmic-particle maps of the heavens can be produced and compared with maps at different EM wavelengths.