(Image: ISS/JSC/NASA)
There鈥檚 an unusual red spot in the sky above the southern US. The red splash visible just within the green airglow of Earth鈥檚 atmosphere is a sprite, hanging above the white glow of a thunderstorm raging over Illinois or Missouri.
Advertisement
Sprites are electrical discharges that occur above most major thunderstorms, thought to be triggered by the much hotter lightning emissions beneath.
The image above was snapped on 10 August by astronauts on the International Space Station while flying over north-west Mexico. The moon is visible above the airglow, while the bright patch on the ground roughly below the moon鈥檚 position is Dallas, Texas.
Almost three minutes after the pictured was taken, the astronauts witnessed another sprite near the coast of El Salvador (below). It produced red streaks reaching an altitude of about 100 kilometres. The golden blobs next to it are the result of city lights diffusing through clouds.
(Image: ISS/JSC/NASA)
Earlier this year, a slow-motion video of a sprite helped reveal what sparks these atmospheric flashes, which are among the brightest objects seen in the sky. They can interfere with long-range communications, so a better understanding of how they form could help minimise disruption.
