Light Pollution Dims View Of Comet, Shrinks Our Horizons

 

 STEREO's Heliospheric Imager shows Comet ISON, Mercury, Comet Encke and Earth over a five-day period from Nov. 20 to Nov. 25, 2013. The sun sits right of the field of view of the camera. Credit: NASA/STEREO

This is a reprint of my article that originally appeared in the Hartford Courant.

Comet ISON is barreling toward the center of our solar system, where on Thanksgiving it will slingshot around the sun and head back past Earth.

It's already putting on one of the best shows we've had in a while. Astronomers announced Nov. 14 that the comet had shot up on the brightness scale, becoming barely visible to the naked eye. It may become much brighter.

But you probably won't see it from New Haven, Hartford or Bridgeport. Even if it exceeds current expectations, you'll have to go far afield to catch an unaided glimpse of one of the most dazzling recent astronomical events.

The reason? Light pollution. Lights from Connecticut's dense population, coupled with the state's position wedged between major metropolitan areas, drown out the natural splendor of our skies.

Streetlights, after-hours business signs, outdoor house lights: All these sources of illumination bounce off surfaces on the ground and particles in the air. The light can travel outside of city centers for miles, dimming the sky in rural areas.

Looking at images of Connecticut at night from NASA's Earth Observatory shows the extent of the problem. Everything from Fairfield County up the I-91 corridor into Massachusetts is a big blotch of yellow light. Less prominent blotches cover most of the outlying areas. It's as if someone spilled fluorescent paint all over the map.

Connecticut is actually one of the more light-conscious states, according to Leo Smith, northeastern regional director for the International Dark Sky Association. Over the years, he and his organization have persuaded Connecticut's General Assembly to pass laws requiring municipalities and utilities to adopt shielded lighting that prevents most illumination from escaping upward. As recently as 2009, they worked with Connecticut Light and Power to provide lower rates to towns that shut lights off after midnight.

"When you look at other states in the area, especially in New England, you can't really match Connecticut," Smith said in a phone interview.

There are a few patches of darkness in Connecticut, particularly in the hilly northwest corner of the state. Viewing conditions at the site of the Mattatuck Astronomical Society Observatory in Litchfield, for instance, are relatively clear, except facing south toward the glow of cities located far beyond the horizon.

Smith acknowledged that the state still has a long way to go. Private businesses and homes, which produce plenty of their own light, are largely unaffected by the state laws. And given Connecticut's emphasis on local control, many of the efforts to reduce light pollution must be addressed at the municipal level.

That was what writer and astronomer Bob Crelin did in his hometown of Branford. In a 2002 Sky & Telescope Magazine article, he described his successful campaign to get the town to adopt local zoning ordinances that mandated outdoor lighting standards for everyone.

"I saw no justification for all that light being cast into the sky and couldn't accept it as an inevitable side effect of progress," he wrote.

During his campaign, Crelin found out that a lot of light pollution is "unnecessary and preventable, much of it merely careless waste from outdoor lighting that's poorly designed, overly bright or improperly aimed."

Light pollution is not just a bane for astronomers. We're increasingly living without something the ancients took for granted — a sense of our place in the universe. Crelin noted in a phone conversation that people growing up in light-polluted areas live in a smaller world.

"And when you lose your depth of vision," he said, "you lose your depth of imagination."

Smith's and Crelin's efforts prove that the scourge of light pollution is not inevitable. Every one of us must be mindful of the lighting on our streets, at our businesses and outside our homes. There are simple, practical solutions we can take to restore our skies. If we do, we'll be able to enjoy not only once-in-a-lifetime astronomical events like ISON, but the brilliant displays that play out above us every night.