August 9, 2013 - Space.com
When the Perseid meteors streak across the sky this weekend, they will leave a trail of celestial pollution in their wake, sprinkling a layer of gases high up in the atmosphere.
This pollution doesn't pose a threat to Earth. If anything, it's a gift to scientists: Astronomers will fire powerful lasers into the gassy Perseid meteor shower debris, creating artificial stars that help researchers snap clearer photos of the cosmos.
"One of the gases left behind by meteors is sodium, which collects in a layer about 60 miles (90 kilometers) above the Earth," Chad Trujillo, head of the Gemini Observatory's adaptive optics program, said in a statement.