Electromagnetic Spectrum- the range of electromagnetic waves extending from radio waves to gamma rays.
Electromagnetic Wave- a wave that is partly electric and partly magnetic and carries energy. Emitted by vibrating electric charges.
Infrared- Electromagnetic waves of frequencies lower than the red of visible light.
Light year- the distance light travels through a vacuum during one year.
Polarization- the aligning of vibrations in a transverse wave, usually by filtering out waves of other directions.
Ray- a thin beam of light
Ultraviolet- electromagnetic waves of frequencies higher than those of violet light.
Speed of Light-The speed of light in vacuum, commonly denoted c, is a universal physical constant important in many areas of physics.