From: utzoo!decvax!harpo!eagle!allegra!don
Newsgroups: net.physics
Title: cosmic rays
Article-I.D.: allegra.1247
Posted: Fri Apr 22 17:26:00 1983
Received: Mon Apr 25 06:15:04 1983

Subject: high energy particles

Gravitational and nuclear processes in space don't produce particles
with really impressive enegies (a few Mev).  Occasional cosmic rays
have energies that are far beyond what any man-made accelerators can
produce.  I forget the exact numbers, but the comment about the tennis
ball is often used to illustrate.  Convert a foot-pound to
electron-volts and you will have a ballpark figure.

These particles are not created with these energies, but are
accelerated by moving magnetic fields in space .  The super high energy
particles are thought to be extragalactic since particles cannot get to
those energies by bumping around within the galaxy.