https://imagine.gsfc.nasa.gov/science/toolbox/history_multiwavelength1.html

He found that the thermometer that was seemingly out of the light had the ... to discover the higher-energy (shorter wavelength) light in the electromagnetic ...

https://en.wikipedia.org/wiki/Electromagnetic_spectrum

The first discovery of electromagnetic radiation other than visible light came in 1800, when William Herschel discovered ...

https://en.wikipedia.org/wiki/Electromagnetic_radiation

Electromagnetic radiation of wavelengths other than those of visible light were discovered in the early 19th century.

https://socratic.org/questions/how-was-invisible-electromagnetic-radiation-discovered

Mar 20, 2016 ... The recognition of the forces as part of the electromagnetic spectrum of radiation may have started with James Clerk Maxwell.

https://www.britannica.com/biography/Heinrich-Hertz

electromagnetic radiation · radio wave. Heinrich Hertz, in full ... In 1883 he began his studies of Maxwell's electromagnetic theory. Between 1885 and 1889, ...

https://www.britannica.com/science/electromagnetic-radiation

Electromagnetic radiation, in classical physics, the flow of energy at the universal speed of light through free space or through a material medium in the form of ...

https://www.olympus-lifescience.com/en/microscope-resource/primer/lightandcolor/electromagintro/

Infrared light, which lies beyond the longer red wavelengths of visible light, was the first "invisible" form of electromagnetic radiation to be discovered.

https://www.khanacademy.org/science/physics/light-waves/introduction-to-light-waves/a/light-and-the-electromagnetic-spectrum

Planck's discovery that electromagnetic radiation is quantized forever changed the idea that light behaves purely as a wave. In actuality, light seemed to have ...

http://astronomy.swin.edu.au/cosmos/E/Electromagnetic+Radiation

Examples of electromagnetic radiation are visible light, radio waves, X-rays and ... They discovered a strong relationship between the properties of electricity and  ...

https://www.slideshare.net/mobile/bleonacoba/history-of-electromagnetic-waves-discovery

Perhaps the greatest theoretical achievement of physics in the 19th century was the discovery of electromagnetic waves.