The idea of a red sky at night used to invoke beautiful images of vibrant sunsets, the product of warm sunlight bathing the sky near the horizon. The adage of “red sky at night, sailor’s delight” refers to a calm night ahead; a red sunset suggests a high-pressure system in the west is bringing calm weather. But red skies at night have taken on a new meaning in recent decades. As outdoor lighting becomes increasingly prominent, our night skies are gradually turning from black to red.
This discovery came from a team of scientists led by Christopher Kyba from the Freie Universitaet and the Leibniz Institute of Freshwater Ecology and Inland Fisheries. The scientists were tracking the effects of cloud cover on light pollution when the realized the color of the night is changing. Their report, entitled “Red is the New Black,” was just published in the journal Monthly Notices of the Royal Astronomical Society.