Infrared radiation
Infrared radiation is electromagnetic radiation with wavelengths longer than visible light but shorter than microwaves, occupying the region from roughly 700 nanometers to 1 millimeter. Though invisible to human eyes, we perceive it as heat—every warm object emits infrared energy.
Discovered in 1800 by astronomer William Herschel through careful observation of the spectrum beyond red light, infrared has since become fundamental to modern technology and science. Thermographic cameras detect it to visualize temperature patterns. Astronomers use infrared telescopes to peer through cosmic dust and observe distant star-forming regions. In medicine, thermal imaging aids diagnosis. Industry relies on infrared for materials testing, while everyday devices—from remote controls to heat lamps—harness its practical power.
The relationship between infrared emission and temperature follows mathematical principles, enabling precise measurements across large-scale applications. Unlike X-rays, which ionize matter, infrared safely probes the world through heat signatures.