Scientists discover the ‘invisible’ 8th colour of the rainbow
Washington: Researchers have identified an invisible eighth colour in the rainbow, a discovery that could have wide-ranging implications on the nature of military camouflage and modern espionage.
The discovery of the new ‘basic’ colour in the spectrum of light was made by physicists at the Randall Monroe University in West Virginia, who were investigating the properties of ‘slow light’; packets of photons that are fired through a cloud of ultracold sodium atoms, colliding with the light and slowing it to roughly 17 mph.
This light was then funnelled through a series of carbon nanotubes in which the angle of incidence (the measure of how far the light beam deviates from aiming ‘straight on’) was enough to bounce the photos back on themselves, effectively ‘bunching’ the light waves together.
“Really, all it took was a bit of lateral thinking,” said Dr Flora Padyolis, a professor in elementary wave physics at the institution and a lead author on the new study. “If you imagine the spectrum of visible light as analogous to sound waves with each named colour corresponding to a musical note, then what we’ve done is to approach the problem from an entirely new angle, taking what people previously thought was a C natural and listening to it like a B sharp,” she said.
Experts say the colour, which has yet to be named, can be thought of as the first addition to the traditional spectrum since Isaac Newton first successfully split white light using a triangular prism in 1671.