When cosmic rays, especially high-energy galactic cosmic rays, strike Earth's atmosphere, they often produce a cascade of secondary sub-atomic particles called an "air shower". This diagram depicts an incoming cosmic ray (in red, at the top) and the resulting air shower which includes protons (green), neutrons (orange), pions (yellow), muons (purple), photons (blue), and electrons & positrons (pink). An actual air shower may consist of millions of particles, depending on the energy of the initial cosmic ray.
Windows to the Universe original artwork by Randy Russell using a photo courtesy UCAR (Nicole Gordon).

Cosmic rays from space hit Earth's atmosphere all the time. When a high-energy cosmic ray enters the atmosphere, it can cause an "air shower". The cosmic ray hits a molecule in the atmosphere and "breaks up", producing lots more sub-atomic particles. A real air shower can make millions of particles. This picture shows a simple version of an air shower. The cosmic ray (in red, at the top) makes lots of other particles, many with odd names. The sub-atomic particles shown here include protons (green), neutrons (orange), pions (yellow), muons (purple), photons (blue), and electrons & positrons (pink).
Windows to the Universe original artwork by Randy Russell using a photo courtesy UCAR (Nicole Gordon).

Cosmic rays from space hit Earth's atmosphere all the time. When a high-energy cosmic ray enters the atmosphere, it can cause an "air shower". The cosmic ray hits a molecule in the atmosphere and "breaks up", producing lots more sub-atomic particles. A real air shower can make millions of particles. This picture shows a simple version of an air shower. The cosmic ray (in red, at the top) makes lots of other particles, many with odd names. The sub-atomic particles shown here include protons (green), neutrons (orange), pions (yellow), muons (purple), photons (blue), and electrons & positrons (pink).
Windows to the Universe original artwork by Randy Russell using a photo courtesy UCAR (Nicole Gordon).

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