Astronauts aboard the International Space Station are snapping photos of Earth at night, and the images are telling a troubling story.

Using the photos, a citizen science project called Cities at Night has discovered that most light-emitting diodes (LEDs) — which are touted for their energy-saving properties — actually make light pollution worse. The changes in some cities are so intense that space station crew members can tell the difference from orbit.

Tech Insider previously reported on Milan, Italy's LED light pollution, and have since received other before-and-after images of major metropolitan cities that have made the switch. We've turned astronauts' photos into animations, below. The results are as astonishing as they are mesmerizing.