Sometimes in the winter, the sky is very bright. When it’s very cold, often the humidity is very low. Various scientists are finding for the reason behind it since centuries. But now, scientists claimed that they have finally solved the mystery of bright nights.
Scientists suggest that the effect is created by slow-moving, high-altitude atmospheric waves. When such waves merge together and amplify the light from naturally occurring airglow, gas atoms that aren’t usually visible.
The airglow light is formed by various chemical reactions taking place in the upper atmosphere. It also involves the green tinge in the air that happens when oxygen molecules split apart by the Sun join together again.
Scientists primarily collected the data on spikes in airglow light and matched it with records of atmospheric waves. They found a link between them.
Although, bright nights have always been rare occurrences. In fact, they are hardly ever seen today due to the effects of light pollution on the night sky. According to the data, bright nights only occur once a year in the places where they are noticeable.
Earlier in the 1st century, the phenomenon of bright nights was mentioned by Pliny the Elder. Later on, other pieces of evidence are found in only research papers and newspapers.
Lead researcher Gordon Shepherd said, “The historical record is so coherent, going back over centuries, the descriptions are very similar. Bright nights do exist, and they’re part of the variability of airglow that can be observed with satellite instruments.”
Scientists found that when the airglow mixed with weather-driven atmospheric waves, bright nights could last for several nights in a row. It even can create light up to 10 times brighter than normal.
Jürgen Scheer, from the Instituto de Astronomía y Física del Espacio in Argentina, said, ” “This study is a new approach to the old enigma of what makes some night skies so remarkably bright, and the answer is atmospheric dynamics.”
“We now have a good idea which dynamical phenomena are behind [airglow] events of extreme brightness.”
Shepherd said, “It’s worth thinking about if you’re ever a long way from civilization and notice the nighttime light is stronger than it should be.”
“Maybe it’s an almost dead question. I’m having the last word before it dies.”