Have you ever been hit by a beam of high energy particles from above?
Surely you have -- it happens all of the time.
Showers of high energy particles occur when energetic
cosmic rays strike the top of the Earth's atmosphere.
Cosmic rays were discovered unexpectedly in 1912.
It is now known that most cosmic rays are
some are helium
nuclei, and the rest heavier elements.
The relative abundance changes with cosmic ray energy -- the highest
energy cosmic rays tend to be heavier nuclei.
Although many of the low energy
come from our Sun, the origins of the highest energy cosmic rays remains
unknown and a topic of much research.
This drawing illustrates
showers from very high energy
Cosmic rays may even be
important to Earth's weather -- common
lightning may be triggered by passing