Researchers at the Adler Planetarium are looking at whether the switch from sodium to LED street lights in Chicago is reducing or increasing light pollution.
Michelle Nichols, the Adler's director of public observing, said the sodium lights created in orange glow in Chicago's night sky. The sky might appear clearer since the switch to LED, but Nichols said it's unclear whether the new lights are making it easier or harder to see some objects in the night skies, such as planets and stars.
"The human eye is most sensitive to blue light, and LEDs give off a lot of blue light," Nichols said.
Nichols said the planetarium will send up high altitude balloons over Chicago with equipment to measure the levels of light pollution from LED street lamps.
She also said more homeowners and businesses are switching to outdoor LED lights, which tend to be brighter and increase light pollution.