Who discovered infrared radiation?

Frederick William Herschel (1738 – 1822) was a German-born British astronomer. He discovered infrared light in 1800, according to NASA (National Aeronautics and Space Administration).

In an experiment to measure the difference in temperature between the colours in the visible spectrum, he placed thermometers in the path of light within each colour of the visible spectrum.

He observed an increase in temperature from blue to red, and he found an even warmer temperature measurement just beyond the red end of the visible spectrum.

Within the electromagnetic spectrum, infrared waves occur at frequencies above those of microwaves and just below those of red visible light. Waves of infrared radiation (IR) are longer than those of visible light. IR is a type of radiant energy that's invisible to human eyes but that we can feel as heat.

All objects in the universe emit some level of IR radiation, but two of the most obvious sources are the sun and fire. Slightly more than half of the total energy from the Sun was eventually found to arrive on Earth in the form of infrared.

IR is a type of electromagnetic radiation, a continuum of frequencies produced when atoms absorb and then release energy. From highest to lowest frequency, electromagnetic radiation includes gamma-rays, X-rays, ultraviolet radiation, visible light, infrared radiation, microwaves and radio waves. Together, these types of radiation make up the electromagnetic spectrum.