Brighter Skies

The stars are vanishing. Don’t worry, they’re all still there. It’s just that most of us can’t see them. And a recent study says the problem is even worse than expected.

The problem is called skyglow. It’s a glare caused by streetlamps, billboards, and other outdoor light sources. A lot of their light shines up into the sky. It reflects off of molecules and particles in the atmosphere, filling the sky with light.

Scientists have used instruments aboard satellites to try to measure that light. In 2017, for example, a satellite found that light pollution around the world was increasing by about two percent per year.

But the satellite wasn’t sensitive to the wavelengths produced by LEDs, which today make up a huge fraction of the outdoor-lighting market. And the satellite couldn’t pick up the light that was being scattered from side to side.

So a scientist in Germany teamed up with Globe at Night — an online network of volunteers. They kept an eye on the night sky, and compared what they saw to charts showing different levels of skyglow. And what they reported was a lot worse than what the satellite saw. Around the world, skyglow is going up by almost 10 percent per year.

One researcher described it this way: If a child is born today in a city where you can see 250 stars at night, by the time it turns 18, it’ll see just 100 stars. The rest will be hidden by the glow of the not-so-dark night sky.
 

Script by Damond Benningfield