Enlarge / Radio observatories like the Green Bank Telescope in Green Bank, West Virginia, are in radio quiet zones that protect them from interference. (credit: The Washington Post via Getty Images)

Visible light is just one part of the electromagnetic spectrum that astronomers use to study the Universe. The James Webb Space Telescope was built to see infrared light, other space telescopes capture X-ray images, and observatories like the Green Bank Telescope, the Very Large Array, the Atacama Large Millimeter Array, and dozens of other observatories around the world work at radio wavelengths.

Radio telescopes are facing a problem. All satellites, whatever their function, use radio waves to transmit information to the surface of the Earth. Just as light pollution can hide a starry night sky, radio transmissions can swamp out the radio waves astronomers use to learn about black holes, newly forming stars, and the evolution of galaxies.

We are three scientists who work in astronomy and wireless technology. With tens of thousands of satellites expected to go into orbit in the coming years and increasing use on the ground, the radio spectrum is getting crowded. Radio quiet zones—regions, usually located in remote areas, where ground-based radio transmissions are limited or prohibited—have protected radio astronomy in the past.

Enlarge / The Milky Way's Galactic Center and Jupiter (brightest spot at center top) are seen from the countryside near the small town of Rebolledo, Department of Florida, Uruguay in August 2020. (credit: Mariana Suarez/Getty Images)

Humans are naturally afraid of the dark. We sometimes imagine monsters under the bed and walk faster down unlit streets at night. To conquer our fears, we may leave a night light on to scare away the monsters and a light over the porch to deter break-ins.

Yet, in huddling for safety under our pools of light, we have lost our connection to the night sky. Star counts by public awareness campaign Globe at Night revealed that, between 2011 and 2022, the world’s night sky more than doubled in artificial brightness. Yet local interventions can create meaningful change.

Light pollution is cutting us off from one of nature’s greatest wonders, harming wildlife and blocking research that could help fight climate change. Stars are more than pretty glimmers in the night sky. They have shaped the mythology of every human civilization. They guide birds on their astonishing migratory journeys. And now we need to do our bit to prevent light pollution so stars can be part of our future.