Light pollution describes artificial light that makes our night brighter than it naturally should be: street lights, parking lot lights, electric signs on buildings. While much is used to deter crime and prevent car crashes, we need to find a way to reduce it and to return to a darker night.
Experts say that the number of fireflies is dwindling. In addition to habitat loss by urban sprawl and industrial pollution, they theorize their decline is also due to light pollution. Lightning bugs need darkness to attract mates by illuminating their bodies.
Light pollution affects the natural rhythm of other species.
In the spring robins are chirping at 3 a.m., when -- except for the artificial light -- it's still dark outside. And rabbits, who are naturally active at dusk, still hop around at night.
In cities like Chicago, which has nearly 200,000 streetlights, lamps can confuse birds, which may mistake skyscraper lights for the Northern Star, a celestial guidepost in migration. The birds circle buildings until they exhaust themselves and crash.Humans are also affected by light pollution.
An Israeli study published earlier this year found that women who live in heavily illuminated neighborhoods are more likely to get breast cancer, hypothesizing that too much light at night may interfere with the brain's production of a tumor-fighting hormone.When I worked nights as a copy editor, I read a story about female night-shift workers being diagnosed with more breast cancer. The same hypothesis was given.
So save some money and energy, and turn off those lights.
(The photos show Sydney, Australia, before and during "Lights Off Australia" in 2007.)