[remote sensing]
Radiant energy that exhibits both particle and wave phenomena. It can be characterized by wavelength and/or frequency. It ranges from gamma rays, x-rays, through ultraviolet, visible, and infrared light, and out to microwave and radio frequencies. The wave energy model is based on opposing, oscillating electric and magnetic waves that are at 90 degrees to each other and are orthogonal to the direction of propagation. This is primarily used to describe behavior during propagation. These waves move at 3 x 108 m/s in a vacuum, the speed of light. This was defined by the physicist James C. Maxwell in the 19th Century. The particle-based model, introduced in the 20th century by Albert Einstein, is used to describe the energy interaction with matter, where it is described by behavior of the discrete or quantum nature of the photon.
