Astronauts have captured two jaw-dropping Earth-based light shows from their lofty perch in space.
One of them is incredibly beautiful, the other incredibly rare.
In case it isn’t obvious, the beautiful one is up there. It’s an aurora that astronaut Scott Kelly photographed it on Saturday evening. Or whatever time of day an astronaut calls it — one full “day” on the International Space Station lasts 90 minutes, half in darkness and half in daylight.
Here’s Scott Kelly (not to be confused with his identical twin-slash-astronaut brother Mark), who seems a little bewildered by what he saw up there:
Kelly brings up the sun because that’s what causes auroras.
High-energy particles sometimes spew out of the sun in droves, then get trapped in Earth’s magnetic field. The field eventually funnels the particles toward the North and South Poles, where they slam into the atmosphere. Boom! Auroral light show.
But that’s not the only amazing sight astronauts captured this week.
On August 10, an astronaut was casually photographing a massive thunderstorm over Central America, as one does flying 17,500 mph over the planet 200 miles up.
Here’s the image, with the moon in the upper left:
Upon closer inspection, space writer Jason Major saw a big red sprite:
Below is a closer look at this oddity.
Note the tendrils (purple) rising from the thunderstorm (bright white/blue) up toward the flash of the sprite (red), sort of like an electrical puppeteer and marionette:
Red sprites are enormous.
This one, like the handful of others astronauts have captured, probably rises up 50 miles and stretches a few miles wide.
They’re also rare rarely photographed: They last all of a few milliseconds and are essentially never seen from the ground (because a big, fat, scary thunderstorm is usually in the way).
Red sprites are akin to gigantic red lightning that shoots upward. Steve Cummer, a Duke University engineer who’s studied sprites for years, summed up how they form quite nicely in a National Geographic News story I wrote a few years ago:
“They’re sparks created in the upper atmosphere, well above a storm cloud, that follows lightning below the cloud,” Cummer said. “The [lightning] charge creates an electric field and, when it’s big enough, it drives a spark that propagates upward.”
And sprites aren’t just a curious phenomenon. They might play an incredibly important role in shaping the composition of the air we breathe. Here’s Cummer again:
“What sort of chemistry is happening, and how long does it last? That we don’t know yet.”
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