This week, people in at least 17 states may have a chance to catch a glimpse of the northern lights, which are usually seen in Earth’s northernmost regions.
The Geophysical Institute at the University of Alaska in Fairbanks expects increased aurora activity Thursday in Midwestern states such as Minnesota, Wisconsin, Michigan and Indiana.
The aurora will be visible “low on the horizon” across Chicago, with the city’s light pollution making it difficult to spot.
The colorful spectacle occurs when particles from the sun collide with particles of gas in Earth’s atmosphere. According to the Institute of Geophysics, Thursday’s high aurora forecast is due to a solar storm, when there is more particle activity.
When particles collide with nitrogen and oxygen in the atmosphere, they gain energy that is released in the form of light. Depending on the energy intensity, gas particle type, and altitude, the colors range from a vibrant green to an intense purple.
The dancing lights occur around the North and South Poles because the sun’s particles travel along the Earth’s magnetic field lines. In the northern hemisphere, the lights are known as the aurora borealis. In the southern hemisphere, it’s the aurora borealis.
Between now and 2025, the lights will be visible in more of the northern hemisphere, the institute says, because of the sun’s 11-year cycle difference, which indicates how sunspots change over time. We’re approaching the peak year of 2025, when the chances of seeing the aurora borealis at lower latitudes will be highest.
This particular cycle was much more intense than expected, said Michelle Nichols, director of general observation at the Adler Planetarium in Chicago.
“It’s beyond expectations, which is great, and that’s great for us,” she said. “This means we may get a chance to see things a little more often than the last several solar maximums.”
The best location, Nichols said, is an area with dark skies, which wouldn’t be possible with city lights. In Illinois, there is the Green River State Wildlife Area about two hours west of Chicago.
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But for the best views, Nichols suggests traveling to northern Wisconsin, Minnesota, North Dakota, northern Michigan, or the Upper Peninsula. Even after traveling, there is no guarantee that the lights will match expectations.
“It’s very, very, very difficult to anticipate them,” she said. “They may become stronger or weaker than expected.”
The strength of the aurora is measured in Kp, and ranges from zero to nine, with nine being a strong geomagnetic storm. Thursday night forecast for Kp level 6.
According to the Geophysical Institute, the best time to view the Northern Lights is between 9 p.m. and 3 a.m., but Nichols said that’s also not guaranteed.
Despite all the uncertainty with Thursday’s light show, Nichols said it makes her happy that more people have been interested in the night sky, whether it’s the northern lights or the upcoming eclipse.
“I’m really glad people are interested in looking at the sky,” Nichols said.
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