Above: " Supernova explosions, like the one that created the expanding Crab Nebula (pictured), may be the source of galactic cosmic rays" NASA
"Cosmic rays are atomic nuclei and electrons that streak through the Galaxy at nearly the speed of light. The Milky Way is permeated with them. Fortunately, our planet's magnetosphere and atmosphere protects us from most cosmic rays. Even so, the most powerful ones, which can carry a billion times more energy than particles created inside atomic accelerators on Earth, produce large showers of secondary particles in the atmosphere that can reach our planet's surface."
"Most researchers are betting that cosmic rays come from supernova explosions," says Jim Adams of the NASA/Marshall Space Flight Center. When massive stars explode they blast their own atmospheres into space. The expanding shock waves can break apart interstellar atoms and accelerate the debris to cosmic ray energies. Cosmic rays are subsequently scattered by interstellar magnetic fields -- they wander through the Galaxy, losing their sense of direction as they go."
Jim Adams, NASA/MSFC: "The radiation dose rate from Galactic cosmic rays inside a spacecraft in interplanetary space would be about 1.1 Sv/yr, but here on Earth its only ~0.0003 Sv/yr. The atmosphere and the magnetosphere are responsible for the dosage reduction mainly because the intense flux of lower energy cosmic rays never reach us. Also, secondary particles from the higher energy cosmic rays, the muons and electrons, do less biological harm than the parent cosmic rays would."
Complete article by NASA
Galactic
Cosmic Rays in the News:
An unusual space traveler named Fred is orbiting Earth aboard the International Space Station. His job? To keep astronauts safe from space radiation.
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