Austrian-American physicist who was one of the earliest workers in the field of cosmic rays and earned a Nobel Prize in 1936 in physics for his work in recording cosmic ray activity at altitudes as high as 9000 m and discovery in radiation by cosmic rays, where he concluded that the source of the radiation released by cosmic rays are from outer space.  He was also the first to use a Geiger Counter in WW II.

Cosmic Rays:
Definition: Charged particles moving at nearly the speed of light reaching the earth from outer space.  Primary cosmic rays consist mostly of protons (nuclei of hydrogen atoms), some alpha particles (helium nuclei), and lesser amounts of nuclei of carbon, nitrogen, oxygen, and heavier atoms.

 The energy of cosmic rays may be as high as 10^20 electron volts (eV) or more, almost a billion times higher than the highest energy yet produced in a man-made particle accelerator.  Cosmic rays are also used as a source of high-energy particles in the study of nuclear reactions.  On earth, cosmic rays are responsible for 6 to 9 milirem of the average 36 milirem a person receives a year, and they’re also responsible for carbon-dating on fossils as they bombard carbon atoms with nitrogen and causes the carbon to form C14O2  (carbon-14 dioxide), which helps archeologists date back fossils and other remaining objects.

Cosmic Radiation:
Definition: A collection of many different types of radiation from many different types of sources.
Generally, cosmic radiation is referred to the cosmic microwave background radiation, which is consists of extremely low energy photons (energy about 2.78 K) and likely remnants from the time when the universe was only about 200,000 years old.  These photons are too low in energy to be dangerous so they’re harmless. There are also very old neutrinos in the cosmic radiation, but since neutrinos pass through just about everything with no effect they’re just as harmless as the extreme-low energy photons.

Cosmic radiation, however, can be consist of high-energy particles, and they are created constantly by luminous objects in the universe.  Such objects include our sun, stars, quasi-stellar objects and gamma ray bursts are creating photons of different energies constantly, and these objects also produce high-energy massive particles such as electrons, muons, proton and anti-protons.  Higher energy particles such as those are potentially dangerous, but most of those particles never make it to earth as they are often deflected by magnetic fields between the earth and the source, or they interact with other particles, or they just decay in flight.

 The particles that do make it to the earth will interact with the earth’s atmosphere, which acts as a “radiation shield.”  The high-energy cosmic rays bombard living creatures all the time, but they interact and produce particles of much lower energy that impact the earth harmlessly.  Some particles, like neutrinos and muons, interact very weakly on earth that they have no effect on living creatures’ bodies.  On space however, will be another story and that’s when spacesuits and protective covering on spacecrafts come in handy.

The only cosmic radiation that does seriously affects humans, of course, is the UV radiation from the sun, which causes skin cancer.  Although the atmosphere does serve as a shield, UV photons do make it through and therefore bombard people with its high-energy particles, so being aware of UV radiation from the sun is important.