AUSTIN, Texas -- Imagine that you couldn't see more than a few stars in your sky. Or never knew what the Milky Way looked like. Would you know what you're missing? And would you even care?
You might think that astronomers are the only ones who care about seeing the stars. Or that only people who are blind or have limited vision don't know what a dark starry night looks like. But, it's a problem we all face.
"The vanishing night skies don't just affect astronomers who study the planets, stars, and galaxies," said Dr. Connie Walker of the National Optical Astronomy Observatory (NOAO) and an advocate of dark skies. "We're all losing our skies to light pollution. In many places, we are raising a generation of people who don't know what the Milky Way looks like. And, light pollution affects the health of many forms of life on Earth -- including humans."
Dr. Walker's remarks opened a session on light pollution at this week's American Astronomical Society conference held in Austin. More than 2,500 astronomers from around the world are here, ranging from undergraduate students to Nobel Laureates. The topics they're discussing range from studies of the sun, moon and planets to explorations of the most distant objects in the universe.
And, they're talking about threats to their work from light pollution.
For many at this meeting -- especially astronomers who observe the universe in what's called "visible" (or "optical") and near-infrared wavelengths of light -- the glare from nearby lights is drowning out the view of objects they want to study. Researchers who use Kitt Peak National Observatory, part of NOAO, deal with the lights of Tucson, Ariz., (60 miles away) and Phoenix (about 200 miles away). Even for some of the newest and most remote observatories in Chile and Hawaii, light glare is a growing issue.
However, the battle for dark skies isn't just astronomy's problem. It's yours, too. Have you ever been blinded by bright lights when driving at night? Or stared at your TV or computer monitor late into the evening? Do you live in a light-bright city where it never gets completely dark at night? If so, then your health can be affected by too much light.
Why is this? Take the TV and computer monitor issue. They emit light that is rich in blue wavelengths. As attendees at the dark skies symposium found out, very recent health studies show that excessive exposure these blue-rich light sources at night hampers or even shuts down your body's production of melatonin -- a substance that helps you sleep and also plays a role in fighting off diseases such as cancer. Researchers are now looking at the links between people who work at night (presumably under bright lights) and higher rates of breast and prostate cancer.
In nature, light glare cuts across the landscape, banishing the darkness. It has devastating effects on wildlife and plants. Recently in Utah, thousands of birds apparently mistook a brightly lit football field for a lake, and came crashing down to their deaths. Newly hatched turtles get confused by lights on their way to the sea in Florida, and they die beneath the wheels of cars, or stranded in yards and parking lots.
Participants in the dark skies workshop discussed three major weapons in the battle against light pollution:
1) proper use of outdoor lighting
2) energy-efficient lighting and
3) limiting your exposure to light at night.
With these, people around the world are figuring out ways to use lights more efficiently to maintain safety, security, and dark skies. The effort is led in large part by the International Dark-Sky Association, a group dedicated to eradicating light pollution and advocating for wiser use of lights.
Other efforts pull together community leaders, families, and students to figure out how much light pollution affects their communities. Beginning on Jan. 14, and extending through April, people are banding together in an event called Globe At Night, to measure the brightness of their local skies and share that information. They recognize that dark skies and dark nights are part of the common heritage of all life on Earth and that the battle to save the night is an important one.