Sprites from Space
From NASA’s Astronomy Picture of the Day
An old Moon and the
stars of Orion rose above the eastern horizon on August 10.
The Moon's waning
crescent was still bright enough to be overexposed in this snapshot
taken from another large satellite of planet Earth, the International
Space Station.
A greenish airglow
traces the atmosphere above the limb of the planet's night.
Below, city lights and
lightning flashes from thunderstorms appear over southern Mexico.
The snapshot also
captures the startling apparition of a rare form of upper atmospheric
lightning, a large red
sprite caught above a lightning flash at the far right.
While the space
station's orbital motion causes the city lights to blur and trail during the
exposure, the extremely brief flash of the red sprite is sharp.
Now known to be
associated with thunderstorms, much remains a mystery about sprites including
how they occur, their effect on the atmospheric global
electric circuit, and if they are somehow related to other upper
atmospheric lightning phenomena such as blue jets or terrestrial
gamma flashes.
Image Credit: NASA, Expedition 44