Infrared a wave and like its quantum particle, the photon. Infrared radiation was discovered in 1800 by astronomer Sir William Herschel, who discovered a type of invisible radiation in the spectrum lower in energy than red light, by means of its effect on a thermometer. Slightly more than half of the total energy from the Sun was eventually found to arrive on Earth in the form of infrared. The balance between absorbed and emitted infrared radiation has a critical effect on Earth's climate. Infrared radiation is emitted or absorbed by molecules when they change their rotational-vibrational movements. It excites vibrational modes
Ultraviolet (Light My Way) naked eye and ultimately unknowable to the human intellect." Conversely, Steve Stockman, author of "Walk On: The Spiritual Journey Of U2", sees "Ultraviolet" as being about Bono's wife Ali Hewson, and "how when he feels like trash, she makes him clean," but says there is good reason to interpret the song as being just as much about God. The song's title supports this view: indigo and violet rarely appear in song lyrics as frequently as other colours, while ultraviolet represents an unseen wavelength beyond the visible spectrum. As such, the title evokes the image of black light or an invisible