Streetlights, Not the Biggest Contributor to Light Pollution, Study Shows

For many years, people believed that streetlights contribute the most to light pollution, but a recent study has shown that it is not the case, Universe Today reported.

Light pollution is an excessive, misdirected, and obtrusive artificial light that washes out the starlight of the night sky and the archnemesis of astronomy as it spoils both enjoyment and professional study of the celestial bodies in the universe. Besides, light pollution also brings adverse health effects and waste energy.

Over half of the world's population are now living in cities, and three out of four cities have never experienced the wonders of the pristine dark skies yet due to light pollution that people believed is mostly caused by the streetlights. But contrary to that, research suggests that streetlights contribute less than 20% of light pollution as a whole.

Modern Civilization Creates Light Pollution

In an effort to make modern civilization safe during night time, humans have invented streetlights that light at night. Also, cars, billboards, sports stadiums, and store displays and signs have become abundant.

But the more humans turn on the light at night to make movement possible, the lesser access they have with the skies that ancient people knew and loved. Thus, making it disadvantageous for astronomers who study the universe.

The greater observatories from the past centuries are now facing the problem of growing light pollution from cities that forces astronomers to build telescopes in some of the most remote and hostile areas of the world.

So what to do about it? For decades, it was assumed that streetlights were the culprit behind the light pollution, but it seems not to be the case after all. Researchers found that light pollution is basically everywhere, and they lazily spray their light in all directions, even in the sky.

Therefore, streetlights are not the biggest contributor to light pollution, which hampers the research activities of astronomers.

Streetlights Only Make Up 20% of Light Pollution

In the October 2020 issue of the journal Lighting Research & Technology, research has painted a new light regarding the cause of light pollution.

The research team used the Suomi National Polar-orbit Partnership Satellite (NPP) to take pictures of the night skies in Tucson, Arizona, which recently upgraded their streetlights to work smartly that could adjust its brightness over the course of the night.

City officials have allowed to dim the streetlights to only 30% of their maximum brightness and then crank it up on the following nights. The researchers then compared the amount of light pollution appearing on the satellite photos.

They found out that nothing much has changed and that only 20% of the city's overall brightness could be attributed to streetlights. The results of the study were confirmed by a ground team that also measured the amount of light pollution during the experiment.