Astronaut Don Pettit has shared an image taken by his colleague Matthew Dominick. It shows a very rare atmospheric phenomenon called a sprite.
Sprites are huge electrical discharges that occur in the mesosphere above severe thunderstorms. They appear as glowing red-orange flares. While ordinary lightning forms at altitudes of up to 16 km, sprites are born at altitudes of 50 to 90 km. They reach up to 60 km in length and up to 100 km in diameter.
The earliest reported observation of sprites dates back to 1886. In 1925, Nobel laureate Charles Wilson theorized that electrical breaches could occur in the upper atmosphere, and in 1956 he witnessed what may have been a sprite. But their existence was finally proven only in 1989, when sprites were first captured on camera.
According to astronaut Don Pettit, who published the image, the height of the photographed sprite is 60 kilometers and the base is 5 to 8 kilometers high. The color change from blue to red occurred at about 20 km. For comparison, the height of the visible boundary of the atmosphere is 120 km.
However, not everyone agreed with this assessment. According to some observers, the base of the sprite photographed from the ISS was actually over the horizon. In this case it was much higher and should have reached the edge of the Earth’s atmosphere.
Earlier we told you about how scientists investigated another rare type of lightning called green ghost.
