In the 50 years Anthony Harris has admired astronomy, he said he’s seen the northern lights in Chicago only about five times. It’s unlikely that he’ll add to his total this week.
“I’d say probably once every 10, 20 years you’ll get an aurora that’s bright enough to see in the city. It used to be more frequent, but Chicago’s light pollution with the new LEDs is overwhelming,” said Harris, the vice president of the Chicago Astronomical Society.
While scientists previously predicted that people in more than a dozen states including Illinois could glimpse this week an aurora borealis, also called the northern lights, an updated forecast shows that this picturesque display is unlikely. The lights would have been visible low on the horizon in Chicago but more challenging to spot due to light pollution, according to the earlier forecasts.
Astronomy lovers and experts across the city say this development isn’t surprising. Michelle Nichols, director of public observing at Chicago’s Adler Planetarium, called the original forecasts from the Geophysical Institute at the University of Alaska-Fairbanks, which were three days out, “an eternity for aurora predictions.”
“Not surprisingly at all, the strength of the forecast geomagnetic storm is lower than before, so the prediction area does not now include Illinois,” Nichols said, adding that they probably won’t be visible in southern Wisconsin either.
According to the Geophysical Institute, particles from the sun colliding with gas molecules in Earth’s atmosphere cause the northern lights. The altitude of the collisions, type of gas molecule and intensity of the energy determine the lights’ color, which can include anything from green to pink to blue.
Aurora strength is measured using Kp numbers. While zero is calm, nine is a “major geomagnetic storm.” Harris suggests checking the Kp numbers right before you plan to head out to view the lights. A Kp of five or above means there’s a geomagnetic storm.
The best time to see the lights are from 9 p.m. to 3 a.m., according to the Geophysical Institute, and dark, clear skies are optimal. They were most recently seen in Illinois in April.
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“Unless it’s really going to be high off the charts and a really intense display, it’s very unlikely that you’re going to see the aurora borealis in the city,” Harris said.
For people who might be interested in aurora chasing or stargazing, Harris recommends heading out to Green River State Wildlife Area, a wildlife restoration area about two hours west of the city. He said a comfortable lawn chair, planetarium app, binoculars and warm clothes are essential supplies for the trip.
“Plan for a night of stargazing and sharing with friends,” he said. “If you’re lucky you’ll see an aurora, if the aurora is a no-show, then you’ve spent a night under the stars with friends and family.”
Harris isn’t the only astronomer who was disappointed, but not shocked that the northern lights aren’t making an appearance in the city. While attending the University of Chicago, Aster Taylor made weekly trips to the roof of Ryerson Hall to observe the stars and galaxies through a telescope as president of the school’s Ryerson Astronomical Society. One time they even observed the Andromeda Galaxy — the nearest large galaxy — in the South Side during winter.
Because Taylor, 22, is living in California before attending the University of Michigan this fall to pursue a graduate degree in astronomy, they were “sad to miss” what could have been “an incredible event that you almost never see.”
A silver lining, Taylor said, is that some people seemed to become more interested in astronomy this week.
“You have no idea how many times I have told somebody that I study astronomy and they go ‘Oh, so what’s your star sign,’” Taylor joked. “I think it’s a good thing for people to have a better understanding of the world they live in.”
