Invisible Light

Maxwell's equations predicted invisible forms of light waves, like x-rays and radio waves.

Not only did Maxwell infer from his theory that light was a kind of electromagnetic wave, he also predicted that there were many other kinds of electromagnetic radiation, besides visible light.

Maxwell was right. In 1888, Heinrich Hertz discovered the existence of radio waves. This discovery led to an invention that has changed our world—the radio. However Hertz died aged 36, before Nikola Tesla and Guglielmo Marconi had realised this invention.

Radio waves are not the only other kind of electromagnetic wave. X-rays, microwaves, infra red, ultraviolet and gamma rays are all invisible forms of electromagnetic radiation.

We use many of these electromagnetic waves everyday. X-rays help doctors see inside our bodies, microwaves communicate between our mobile phones and satellites, and infra-red switches open our doors.

All of these kinds of waves are described by Maxwell's equations.