Click Here to Read: How to spot these electric-blue clouds that form at the edge of space Forming 50 miles above Earth’s surface, noctilucent clouds offer a rare glimpse into one of the least-understood layers of the atmosphere By Stefanie Waldek on the National Geographic website on June 11, 2026.
Noctilucent clouds, Kuresoo bog, Soomaa National Park, Estonia. Image: Martin Koitmäe. Public Domain via Wikimedia Commons.