Much of the region was underwater thousands of years ago when glaciers clogged up the natural outlet of Lake Michigan, creating what geologists call glacial Lake Chicago.
Two islands peeked out of the cold waters at the lake’s south end. One is still known as Blue Island. The other, a place that stood out for its natural diversity and unusual topography in an otherwise flat landscape, was called Mount Forest Island.
Neither, of course, are still islands. But the scenic and natural wonders on display on Mount Forest Island made it among the first land purchases by the nascent Forest Preserves of Cook County, when 80 acres were acquired in 1916 in Palos Township for $10,605, according to a history of the preserves published in 1965. By 1918, the Palos Preserves had grown to 2,370 acres and was still growing.
Now at 15,000 acres and the district’s “largest concentration of preserved land,” according to Openlands, part of the area is once again an island, though not because of its elevation.
Rather, it’s an island of darkness. That might sound like the title of a horror film, but in reality, it gives the area a sought-after global designation.
Late last month, the International Dark-Sky Association designated the Mount Forest Island portion of the Palos Preserves the newest Urban Night Sky Place.
Though the International Dark-Sky Association sounds like it could be villainous antagonists in the imaginary “Island of Darkness” film, the designation is being celebrated by fans of nature and sky watchers alike.
One of the reasons are those ominous connotations that go along with the concept of darkness.
More Top Picks Adhd Homework Tips For Parents Fighting Nightly Battles
Ken Walczak, a senior manager at the Adler Planetarium in Chicago who has been involved with the Palos Preserves effort since it began three years ago, often works with high school students from the city and its close-in suburbs.
On a field trip a few years ago to the Indiana Dunes National Park, “some students literally were afraid to get off the bus,” he said.
“They were like, ‘there’s no lights out there, it’s scary,'” Walczak said. “They’re so used to streetlights being everywhere, they think if there’s no streetlights, it must be dangerous.
“That’s the importance of the Palos Preserves,” he said. “It’s a place you can realize there is a natural night without pervasive lights.”
The designated Urban Night Sky Place is a roughly 6,600 acre triangle bounded by the Des Plaines River, U.S. 45 and the Cal Sag Channel. That also corresponds to the geological boundaries of Mount Forest Island.
Mary Busch, a program specialist with the Cook County Forest Preserves who worked with Walczak on achieving the designation, said the criteria were “stringent,” involving retrofitting facilities to shield lighting and convert many to LED while making sure they emit light on the correct spectrum.
But by far the biggest thing the Palos Preserves have going for them is the foresight of the Forest Preserve District’s founders to acquire and protect so much land, both within Mount Forest Island and surrounding it.
A project by Alder’s Far Horizons Stratonauts program where students designed and created light sensing cameras and deployed them to the area indicated the region emits “nearly 1,000 times less light than downtown Chicago,” according to a Forest Preserves news release.
The Palos Preserves is the largest of the three Urban Night Sky Places that have been designated so far, Busch said. The other two are Timpanogos Cave National Monument near Salt Lake City, Utah, and Valle de Oro National Wildlife Refuge located 7 miles south of Albuquerque, New Mexico.
Busch said the Urban Night Sky requirements aren’t quite as stringent as rigorous as those needed to become an International Dark Sky Place, which are in remote areas far removed from cities and their inherent light pollution.
Those are the kinds of places “where you can see the Milky Way from horizon to horizon,” Walczak said.
You’re not going to get that at the Palos Preserves, or anywhere near Chicago. There’s simply too much light pollution. But that’s the point of the Urban designation.
“Most people live around cities,” he said, “and most people don’t have the means to travel for a week to a mountainside somewhere. So this designation address(es) the reality of where people are and where they live.
“But it also offers a way to experience nature at night that’s really foreign to people.”
One impediment to that is the Forest Preserves’ policy of closing at dusk.
While they’re not planning on opening the Palos Preserves 24/7 because of security and other concerns, Busch said they already average at least one nighttime program per week there, and there are opportunities to spend the night in cabins, tents or RVs at Camp Bullfrog Lake.
“But we want to provide more free access too,” Busch said. “It’s ever expanding. We’re planning to partner with Adler where they can lead programs along with our naturalists.”
That would be right up Walczak’s alley.
“Once you feel what it’s like to be there at night, you realize how precious it is,” he said. “The Forest Preserves are the last bastion of protecting the night.”
Dark skies are something of a passion for Walczak, who grew up in Munster, Indiana, as an “astronomy nerd, always in my backyard with my telescope.”
These days his bucket list involves spending a night in the darkest spot in each state.
“I’ve done 12 so far and still have a lot to go,” he said.
For the record, the darkest accessible place in Illinois is Siloam Springs State Park in the western part of the state, where the closest town of any size is Quincy, about 30 miles away.
“That is about as dark as it gets,” he said. “I was amazed at the view. You’re still in the Midwest — and the Midwest is notorious for light pollution in general — but I did see that iconic Milky Way from horizon to horizon. There were beautiful skies there.”
Even the remote environs of the Shawnee National Forest in southern Illinois are brightened by cities such as Carbondale, Evansville, Indiana, and Paducah, Kentucky, Walczak said.
It doesn’t take much light to dim the power of nature’s sky show, it turns out, and Chicago has plenty. In another experiment, students in his program measured light in a line reaching nearly 100 miles from the center of Chicago. The glow to the north could be detected as far away as the environs of Lafayette, Indiana, they found.
“Turn a bunch of streetlights on in Chicago, and you don’t realize how far that goes,” he said.
More Top Picks Best Chew Necklaces For Sensory Needs
From the Forest Preserves perspective, having dark skies, even if they’re only somewhat dark when compared to truly remote areas, is important for people, and wildlife too.
“Urban and suburban kids miss out on the experience of a truly starry night,” Busch said. “So we’re trying to bring that back and preserve the night. It’s a way to protect the natural rhythms of people and animals.
“I just love nature, and a dark sky is part of that you don’t often see if you’re in urban or suburban areas. Being in the Palos Preserves, at least in proximity to Chicago, you get a taste of a beautiful night sky.”
Landmarks is a weekly column by Paul Eisenberg exploring the people, places and things that have left an indelible mark on the Southland. He can be reached at [email protected].