The discoverer of infrared rays was Sir Frederick William Herschel born in Hanover, Germany 1738.
He was well known both as a musician and as an astronomer. In 1757 he emigrated to England where with his daughter Carolina they built a Telescope.
His most famous discovery was that of the planet Uranus in the year 1781.
In the year 1800, Sir William Herschel made another very important discovery.

He was interested in verifying how much heat passed through filters of different colors when observed in the sun.
He noticed that those different colored filters let through different levels of heat. Continuing with this experiment, Herschel made sunlight pass through a glass prism and with this a spectrum was formed (the “rainbow” that forms when light is divided into its colors). By making temperature controls in the different colors of this spectrum, he verified that beyond red, outside of the visible radiation, the temperature was higher.

He found that this invisible radiation above red behaves in the same way from the point of view of reflection, refraction, absorption and transmission as visible light.
It was the first time anyone had shown that there was another form of illumination or radiation that was invisible to the human eye. This radiation was initially called Calorific rays and then Infrared (infra: means below) That is to say below the energy level of red.

Astronomy, medicine, public safety, rescue, electronics, meteorology, process engineering, industrial maintenance, vegetation analysis, the study of ocean temperatures to name a few. It is not only in full expansion but is also emerging as a technology of mass use in the medium term.

. The “heat rays”, as he called them, they behaved like visible light, yet they were not detected by the human eye.
He had discovered infrared radiation.
Sixty-three years earlier, Emilie du Chatelet (1706 – 1749), had anonymously sent to the French Academy of Sciences an essay called “Dissertation on the Nature and Propagation of Fire ”, which included the idea that different colors of light contained different amounts of heat. She wrote that the way
to prove this was to refract light into a line of thermometers corresponding to the different colors of the spectrum – exactly the experiment that Herschel would perform.
She was unable to perform the experiment only due to a lack of thermometers. Her lover, the writer and philosopher Voltaire was using all of his laboratory equipment trying to prove that fire was a form of matter – phlogiston.