In late spring and early summer, at sunset and early twilight, you can see a fantastic sight - noctilucent clouds. They appear high in the atmosphere and can shine almost all night. This year, astronomers are reporting unusually bright noctilucent clouds appearing more frequently and being visible for longer than in previous years. Astronomer, employee of the Space Research Institute of the Russian Academy of Sciences Oleg Ugolnikov tells N + 1 readers about the history of the discovery and study of noctilucent clouds, as well as whether humanity is involved in their appearance.