Standard patterns of radiation distribution about their source. The term radiation applies primarily to the transport of energy by acoustic, elastic, electromagnetic, or gravitational waves, and extends to the transport of atomic or subatomic particles (as represented by quantum-mechanical wave functions). The time dependence of radiation waves is generally analyzed into sinusoidal components with constant frequency ν and wavelength λ (equal to the wave velocity divided by ν), radiation sources being generally smaller than λ.