快猫短视频

Light pollution is a problem in many built-up areas, but certain weather conditions can dramatically amplify it: freshly fallen snow and thick cloud overhead. This combination can make the sky more than twice as bright as a full moon, which may cause issues for nocturnal animals.

Andreas Jechow and Franz H枚lker at IGB Berlin took pictures of the night sky in various locations and weather conditions to measure its brightness. Their aim was to measure the effects of 鈥渟nowglow鈥�, which happens when snow reflects artificial light, such as from street lamps, onto clouds above illuminating the sky.

They took the pictures in a suburb of Berlin, villages within the Arctic Circle in Finland and on the Courland peninsula in Latvia.

In the city suburb of Berlin they found that on a cloudy, snowy night, the sky was 188 times brighter than on a clear night. It was so bright, in fact, that the snowglow was measured to be more than twice as bright as a full moon at the equator, where the moon is brightest. Similar measurements were recorded in the other locations.

The results are eye-opening, says John Barentine at the International Dark Sky Association. This excessive illumination could negatively affect nocturnal creatures by confusing their circadian rhythms, meaning their normal pattern of day to night changes, he says.

We may well be able to mitigate the problem with better outdoor lighting policies and designs, such as dimming or using fewer lights during snowglow, says Barentine.