Hardware Hacking

Cosmic rays are energetic particles originating from deep space that hit our atmosphere at high speed.

There are a variety of sources including our own Sun but most come from interstellar events like Supernova, Black Holes and yet unknown happenings in the outer most reaches of our universe.

Although commonly called cosmic rays the term "ray" is a misnomer, as cosmic particles arrive individually as a primary particle, not as a ray or beams of particles. 90% are Protons, 9% helium and iron nuclei and remainder electrons or other sub-atomic particle remnants.

When these primary particles hit our atmosphere 30km above the Earth’s surface they hit with such tremendous energy they cause a nuclear reaction producing a shower of subatomic particles called pions. The charged pions decay into muons and muon neutrinos whereas the uncharged pions decay into pairs of high energy photons which become the starting points of large cascades of electrons, positrons and gamma rays. The resulting flux of particles at ground level consists mainly of muons and electrons/positrons in the ratio of roughly 75 to 25 percent and hit the Earths surface at near the speed of light ~0.998c...

Another interesting phenom of cosmic rays is that they are an everyday demonstration of Einstein's theory of relativity. This is because a muon at rest will disintegrates in about 2 x 10-6 seconds and so should not have the time to reach the Earth's surface given their travel distance. However as they move at close to the speed of light, time dilation extends their life span as seen from Earth and so can be observed at the surface before they disintegrate.

This is apparently happening 200 times every second, on every square metre, across the entire surface of the earth. With so much energy behind them they pass through just about everything, penetrating deep into the Earth’s surface, without anyone really being aware of their existence.

Below is a segment from an episode the TV program called "Cosmos" with Carl Sagan a legend in my youth, sadly now no longer with us. Although a little out of date, I could never have put the mystery of cosmic rays better.