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Light pollution frustrates astronomers looking for discoveries


When you look up at the night sky, can you see the stars? If you live in a large city or near one, the answer is probably no. The culprit is not just clouds and weather. It's light pollution, and it's getting worse every year. It's a major challenge for some astronomers as it messes with their views of space. I wanted to learn more about the light pollution problem and to see it firsthand.

PETER PLAVCHAN: So this is our telescope.

HUANG: On a recent night, I went 25 miles west of Washington, D.C., out to George Mason University, to get a look at the night sky with astronomer Peter Plavchan. He's the director of their observatory.

PLAVCHAN: One thing you can't control is the weather.

HUANG: It was overcast, humid, not a star to be seen. It was perhaps a fitting night to talk about another big challenge that blocks the view - light pollution.

So research has shown that the night sky has been getting steadily brighter by about 10% a year for the past 10 years. I wonder, from your perspective, what does that mean?

PLAVCHAN: For as long as human civilization has existed, we've made up stories to describe what we see in the night sky, right? The origins of the myths and the naming of the constellations that we have in the night sky - the night sky has been something that we've always been curious about. So in terms of light pollution and how it's impacting us today, we're taking away that opportunity for people to be curious and to wonder about the night sky.

HUANG: Astronomers worry that great discoveries are more difficult to make since it's harder for them to see into space.

PLAVCHAN: If you go back a century, when Edwin Hubble in 1929 discovered that the universe was expanding, he did that using a 100-inch telescope just north of Pasadena, Calif. And he could not make that discovery today at that same telescope.

HUANG: Some stargazers are trying to bring the dark sky back. Along with Professor Plavchan, I met Eileen Kragie. She's the founder of Dark Sky Friends. It's a nonprofit, and it tries to get local governments to pass rules for, quote, "responsible outdoor lighting at night." These are ordinances to keep as much light out of the sky as possible.

So is your vision for us to kind of get back to a place where the only thing that might obscure your view of the stars is the clouds instead of the light?

EILEEN KRAGIE: Oh, that would be really nice, I think. Yeah. And I think it's important that, you know, people understand that dark skies doesn't mean dark ground and that you can traverse your area safely. I was depressed, really depressed before about this. But I am getting really optimistic because there's people across the globe that are really working hard on this.

HUANG: Professor Plavchan is a little less optimistic. He says there's another growing source that's lighting up the night sky.

PLAVCHAN: With the launch of the increasing proliferation of satellites in low Earth orbit, which reflect a lot of sunlight down to us, we can't escape it.

HUANG: Astronomers are pushing back, calling for caps on night lighting from both below and above.

Pien Huang, NPR News. Transcript provided by NPR, Copyright NPR.