We barely see the stars in Chicago, and that’s dangerous
In the oft-told Bible story, three kings are guided by a bright star to the site of Christ’s birth in Bethlehem.
That was thousands of years ago in the thoroughly un-electrified land of Judah. Try to steer by starlight in modern-day America or Europe or China and you’d have a much tougher time, whether by camel or car.
Since the 1880s, “light pollution” — from streetlights, billboards, strip malls, skyscrapers — has grown so bad that most of the stars above large cities are significantly dimmed or completely obscured. Chicago is a prime offender, having been named America’s most light-polluted town by National Geographic Magazine in 2008.
To a lesser degree, light pollution has become problematic in smaller towns as well.
And the problem isn’t merely an aesthetic one.
“For the majority of the Earth’s history, there was a very regular cycle of light and dark,” says filmmaker Ian Cheney, whose documentary “The City Dark” premieres at 10 p.m. Thursday on WTTW-Channel 11. “And in the last 130 years, we’ve broken that cycle. And as a result, any species — including us — that came to depend on light and darkness as cues for any number of species-specific functions is starting to feel the effects of artificial light.”
Birds become discombobulated and fatally ram into buildings. Pollinating insects — crucial for crop production — veer off course and become easier targets for predators. And nocturnal predators, such as the owls on Northerly Island, might be denied dinner because overillumination screws up their stealth. That means more vermin — rats, for instance — live longer. Presumably, that’s bad.
As the naturalist John Muir put it, “When one tugs at a single thing in nature, he finds it attached to the rest of the world.”
In humans, scientists have discovered, nighttime overexposure to artificial light (by shift workers in particular) causes suppression of the hormone melatonin, which regulates the body’s sleep-related “circadian rhythms.” Low melatonin levels are linked to breast cancer and other ailments. The World Health Organization even declared that artificial night light is a “probable” carcinogen. The American Medical Association recently issued a warning, too.
“It’s another global warming-type thing,” says Larry Ciupik, director of the observatory at Adler Planetarium, where light pollution has long been an impediment to stargazing. “It’s getting worse as the lights increase.”
Until even they fall victim (and Ciupik says that’s not impossible), some of the best spots in America to see stars in all their blazing glory are national parks — where ambient light is distant or nonexistent. For Chicagoans, Weinberg-King and Siloam Springs state parks in southern Illinois are swell spots to view the Big Dipper and Orion’s Belt and scores of other constellations that typically are invisible to urbanites and city-proximate suburbanites. So is the middle of Lake Michigan.
Thursday evening, in fact, two vessels owned by Tall Ship Adventures of Chicago set sail from Navy Pier and Burnham Harbor on so-called “celestial” cruises. The mythology-and-navigation-centric voyages are both sold out, in large part because the Astronomical League convention is in town this week. But general manager Lynn Randall says more might be offered depending on demand.
“Most people, if they’ve lived around the city, have grown used to the night sky the way they see it, not even realizing what they’re missing,” says cruise participant Audrey Fischer, director of the Chicago Astronomical Society and an ardent opponent of light pollution. “How could they care about something they don’t even know is gone?”
Excursions to parks and on lakes, light pollution foes such as Fischer and Ciupik say, are an effective way to augment awareness of an increasingly serious situation whose potentially grave implications are spurring gradual reform.
Cheney says that in Chicago, “perhaps more than in other cities I visited,” building owners and managers are taking steps to shut off unnecessary lights — especially during bird migration season in spring and fall. (Chicago is located along a major migratory flyway.) Ordinances recently were passed regulating light usage in the Cook County Forest Preserve and several county buildings — including the jail, Stroger hospital and courthouses.
Still, there’s a long way to go.
“Maybe the aesthetic nature of it is the starting point,” Ciupik says of light pollution education. “But just because our children won’t see the night sky isn’t the only reason you do this. You do it for your food — literally for survival. And that, I think, is a wake-up call.”