Astronauts captured a red sprite from their vantage point on the International Space Station. The vibrant jellyfish is part of a thunderstorm that raged over Mexico in early August.
Red sprites are bright flashes that happen directly above thunderstorms with more mundane cloud-to-ground or intracloud lightning strikes. The sprites are brightest at an altitude of 65 to 75 kilometers (40 to 46 miles), but can extend as faint wisps as low as 30 kilometers and as high as 95 kilometers (18 to 59 miles). The sprites are red at the highest altitude, fading to blue at lower altitudes. The largest sprites cluster together in a clump of tendrils up to 50 kilometers (31 miles) across, looking vaguely like red glowing jellyfish.
Red sprites above a thunderstorm in Mexico on August 10, 2015. Image credit: NASA
The sprites flash for only a few milliseconds, making them extremely difficult to photograph. This in turn makes them difficult to study, although we’ve learned a lot since the first time sprites were documented in 1989. They retain the whimsical name “sprite” in part because that captures the fleeting nature of the phenomena without committing to any particular physical process to create them.
Although photographs of the atmospheric phenomena are rare, astronauts on the International Space Station have a perfect view for checking out the millions of lightning strikes that hit the Earth every day. This photograph was taken late on August 10, 2015 above Mexico. It also contains a view of the moon, the green haze of airglow, orange city lights, a wide white splotch of dense lightning flashes.
Update August 24, 2015: NASA has released an annotated version of this photograph.