Deadly Skies 
[SFX: fireworks sounds]
Bright lights will be popping all across the country tonight -- fireworks to commemorate Independence Day.
But the bright light won't end when the last of the fireworks fizzle. Everything from streetlamps to garden lights will continue to fill the night sky with a bright glow -- the glow of light pollution.
It's bad for professional astronomers and casual skywatchers alike because it overpowers the stars, robbing the night sky of much of its beauty and drama.
But for many species of life, it's not just bad -- it's deadly.
Many migrating birds, for example, navigate by the Moon and stars, and the glow of the rising and setting Sun. But bright skyscrapers and other light sources can confuse them. They fly toward the light -- and kill themselves when they splatter into the buildings. Some cities require that the lights on skyscrapers be turned down during migration seasons.
Light is a problem for baby sea turtles, too. When they hatch, they head toward the brightest light. On dark beaches, that's the sea, which reflects the light of the Moon and stars. But on developed beaches, the light is from streets or buildings. The turtles head inland and perish.
And even the firefly is at risk. It uses those little flashes of "lightning" to attract mates or warn off predators. Bright lights interfere with those signals, chasing off one of the great joys of summer nights.
But there are many steps we can take to limit light pollution.
You can find details at mcdonaldobservatory.org/darkskies.
Script by Damond Benningfield, Copyright 2010