### ionizing radiation:

Cosmic ray
* Most cosmic rays are very high energy protons and neutrons that are traveling through space
  - come from outside the solar system
  - escape their parent SNRs, filling the galaxy disk and halo
  - have energies between a few million and a few billion electronvolts
* approaching the earth soon interact in nuclei within the atmosphere.
* are a constant hazard while solar flares can be fatal in large doses.
* are atomic nuclei that enter the Earth's atmosphere at nearly the speed of light
  - move through the galaxy at almost the speed of light
* are atomic particles flying nearly at light speed, constantly bombarding the Earth
  - that whip through space at nearly light speed
  - charged particles that bombard the Earth's atmosphere from outer space
* are energetic particles coming from exploded stars in the universe
  - that are found in space and filter through our atmosphere
  - extremely high-energy atomic nuclei which bombard the earth from outer space
  - fast-moving atomic nuclei that bombard the earth from outer space
  - high-energy particles that pervade outer space
  - located in space
  - mainly protons that travel near the speed of light throughout the galaxy
  - more likely to get through to the Earth during periods of low solar activity
  - noticeable even for very short exposures
  - part of cosmic radiation
* are particles - the nuclei of elements in the periodic table
  - that enter the earth's atmosphere from space
  - traveling through space with high energies
  - radiation reaching the earth from outer space
  - relativistic particles and therefore penetrate the heliosphere
* are sub-atomic particles that are moving at a good fraction of the speed of light
  - have been accelerated up to close to the speed of light
  - subatomic particles from space that constantly bombard the earth
  - the fastest matter known to man
  - tiny, subatomic particles that continuously rain down on the Earth's atmosphere
* are very energetic particles that rain down on the earth
  - high energy particles, mainly protons, from outer space
* bombard the Earth's atmosphere constantly
  - atmosphere converting some nitrogen into radioactive carbon
* can pollute all the scales of the wavelet transform
  - seed clouds , trigger lightning , and penetrate commercial airplanes
* constitute a constant stream of particles raining down on Earth.
* create new particles high in the upper atmosphere.
* enter the earth's atmosphere in large numbers every day.
* form a major component of the energy density of the interstellar medium.
* have interested scientists for many different reasons.
* hits increase the noise on the detector.
* influence also on chemical reactions in the atmosphere.
* is ionizing radiation
  - the term given to high energy radiation which strikes the Earth from space
* make extensive air showers in the atmosphere.
* originate from the sun and also from things like exploding stars.
* play a significant role in the natural mutation and evolution of life on earth.
* produce ions in air, which offer a conducting path for the discharge of charged objects.
* provide important information on the chemical evolution of the universe
  - one of our few direct samples of matter from outside the solar system
* radiate from the sun.