Cosmics for High School Teachers
The following is intended for an audience of High school teachers and their students.
What is a Cosmic Ray
Cosmic rays are particles originating outside the earth which hit the Eartch's atmosphere. 90% of the particles are protons. 9% are alpha particles (a helium atom without its electrons). 1% are electrons.
Solar and Galactic
Solar cosmic rays originate from the sun and have energies between 10 to 100 kilo-electron volts (keV = 1.6 e-16 Joules = amount of heat your body produces in 1e-18 seconds [1/1000 femto-seconds]). Galactic cosmic rays are in two categories; either galactic or extragalactic. Galactic Extragalactic cosmic rays flow into our galaxy having energies beyond 10e15 eV (amount of energy your body creates in 1/1000 of a second). They are very rare with only 1 entering a square meter on the earth's surface per year.
Primary and Secondary cosmic rays
Oh-My-God- Cosmic rays
About 15 protons having an energy of 10e20 eV have been seen by the University of Utah's Fly's Eye Cosmic Ray Detector. ( the first publication Physical Review Letters, 22 November 1993, http://arxiv.org/abs/astro-ph/9410069)
Particles of this energy could light up a 40 Watt light bulb for a whole second.
At a January 12, 2005 conference of the American Astronomical Society, particle physicist Glennys Farrar presented a paper tracing five similar very-high-energy cosmic rays, all of which were detected between 1993 and 2003, to a pair of colliding galaxy clusters 450 million light-years from Earth. Farrar speculated that the clusters' powerful magnetic fields could become warped in the collision, accelerating charged particles to the extreme energies astronomers have observed. [edit]