All types of electromagnetic radiation travel at the same speed in a vacuum, which is the speed of light: approximately 3.0×1083.0\times 10^83.0×108 meters per second (exactly 299,792,458 meters per second)
. This includes all forms of electromagnetic waves such as radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays
. The speed is constant because electromagnetic waves propagate through oscillating electric and magnetic fields in vacuum, governed by Maxwell's equations, which determine this universal speed
. In any medium other than vacuum, electromagnetic radiation travels slower due to interactions with the material's electric permittivity and magnetic permeability, which cause the wave to slow down depending on the medium's refractive index
. In summary:
- Speed in vacuum: 3.0×1083.0\times 10^83.0×108 m/s (speed of light)
- Speed in other media: Less than 3.0×1083.0\times 10^83.0×108 m/s, depending on the medium's properties
This speed is the same for every type of electromagnetic radiation regardless of wavelength or frequency when in vacuum
