Yövalopilvet

Yövalopilvet, also known as noctilucent clouds, are rare atmospheric phenomena visible during twilight. They are the highest clouds in Earth's atmosphere, forming in the mesosphere at altitudes of around 76 to 85 kilometers (47 to 53 miles). These clouds are composed of tiny ice crystals that form on dust particles, likely of extraterrestrial origin, such as meteoroid debris.

The distinctive shimmering, electric-blue or silvery appearance of yövalopilvet is a result of sunlight scattering off these ice crystals. They become visible when the sun has set or risen below the horizon for observers on the ground, but still illuminates these high-altitude clouds. The best conditions for viewing them occur during the summer months in the Northern and Southern Hemispheres, typically in the hours following sunset and preceding sunrise.

Yövalopilvet were first observed in the late 19th century and have become more frequent and widespread in recent decades. Scientists are studying them to better understand atmospheric conditions, particularly changes related to climate and the upper atmosphere. Their presence is thought to be influenced by factors such as water vapor content and temperature in the mesosphere, as well as changes in atmospheric circulation. Observing yövalopilvet can be a spectacular experience, offering a glimpse into the delicate and dynamic processes occurring at the edge of space.