Electromagnetic Spectrum: The range of electromagnetic waves extending from radio wave to gamma rays.
Electromagnetic wave: A wave that is party electic and partly magnetic and carries energy. emitted by vibrating electric charges.
infrared: electromagnetic wave of frequency lower than 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 wave of other direction.
ray: a thin beam of light.
ultraviolet: electromagnetic wave of frequencies higher than those of violet light.
speed of light: The distance light can travel in a unit of time through a given substance.