Phenomenon
Electromagnetic radiation
[Gemet] Emission of any rays from either natural or man-made origins, such as radio waves, the sun's rays, medical X-rays and the fall-out and nuclear wastes produced by nuclear weapons and nuclear energy production. Radiation is usually divided between non-ionizing radiation, such as thermal radiation (heat) and light, and nuclear radiation. Non-ionizing radiation includes ultraviolet radiation from the sun which, although it can damage cells and tissues, does not involve the ionization events of nuclear radiation.
[Wikipedia] In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. This includes: - electromagnetic radiation, such as radio waves, microwaves, infrared, visible light, ultraviolet, x-rays, and gamma radiation (γ) - particle radiation, such as alpha radiation (α), beta radiation (β), proton radiation and neutron radiation (particles of non-zero rest energy) - acoustic radiation, such as ultrasound, sound, and seismic waves (dependent on a physical transmission medium) - gravitational radiation, radiation that takes the form of gravitational waves, or ripples in the curvature of spacetime
Radiation