On the Hunt for High-Speed Sprites

Air glow (along with a lightning sprite) is visible in this image from the International Space Station. Credit: NASA

A bright red sprite appears above a lightning flash in a photo captured from the ISS

Back on April 30, Expedition 31 astronauts aboard the ISS captured this photo of a red sprite hovering above a bright flash of lightning over Myanmar. Elusive atmospheric phenomena, sprites are extremely brief bursts of electromagnetic activity that are associated with powerful lightning discharges, but exactly how and why they form isn’t yet known — although recent research (along with some incredible high-speed video) is shedding new light on sprites.

Although the appearance of bright high-altitude flashes above thunderstorms have been reported by pilots for nearly a century, it wasn’t until 1989 that a sprite was captured on camera — and the first color image of one wasn’t taken until 1994.

So-named because of their elusive nature, sprites appear as several clusters of red tendrils above a lighting flash followed by a breakup into smaller streaks, often extending as high as 55 miles (90 km) into the atmosphere. The brightest region of a sprite is typically seen at altitudes of 40-45 miles (65-75 km).

Because they occur above storms, only last for a thousandth of a second and emit light in the red portion of the visible spectrum (to which our eyes are the least sensitive) studying sprites has been notoriously difficult for atmospheric scientists. Space Station residents may get great views but they have lots of other things to do in the course of their day besides sprite hunting! Luckily, a team of scientists were able to capture some unprecedented videos of sprites from airplanes in the summer of 2011, using high-speed cameras and help from Japan’s NHK television.

Chasing storms over Denver via plane for two weeks, researchers were able to locate “hot zones” of sprites and capture them on camera from two planes flying 12 miles apart. Combining their videos with ground-based measurements they were able to create 3-dimensional maps of the formation and evolution of individual sprites.

Based on the latest research, it’s suggested that sprites form as a result of a positive electrical charge within a lightning strike that reaches the ground, which leaves the top of the cloud negatively charged — a one-in-ten chance that then makes conditions above the cloud “just right” for a sprite to form higher in the atmosphere.

“Seeing these are spectacular,” said Hans C. Stenbaek-Nielsen, a geophysicist at the University of Alaska in Fairbanks, Alaska, where much sprite research has been conducted. “But we need the movies, because not only are they so fast that you could blink and miss them, but they emit most of their light in red, where the human eye is relatively blind.”

An example of how energy can be exchanged between lower and higher regions of Earth’s atmosphere, it’s been suggested that sprites could also be found on other planets as well, and may provide insight into the exotic chemistries of alien atmospheres.

Read more on NASA Heliophysics here.

Main image: Image Science & Analysis Laboratory, NASA Johnson Space Center. Inset image: the first color image of a sprite  (NASA/UAF.) Video: NHK.

Bolt from the Blue: Giant Flash of Lightning Seen in Saturn’s Storm

An enormous storm that wrapped its way around Saturn’s northern hemisphere during the first half of 2011 wasn’t just a churning belt of high-speed winds; it also generated some monster flashes of lightning as well — one of which was captured on camera by the Cassini spacecraft!

Check it out…

The image above was created from Cassini raw images acquired in red, green, and blue color channels and assembled to create a somewhat “true-color” image of Saturn. The image shows the storm as it looked on February 25, 2011, a couple of months after it was first noticed by amateur astronomers on the ground. (The circle at upper left illustrates the comparative size of Earth.)

Read: Studying Saturn’s Super Storm

These images were acquired by Cassini almost two weeks later, on March 6, the first showing a bright blue flash of lightning within the storm, along the eastern edge of a large eddy. The second image, taken 30 minutes later, does not have any visible flash.

Because the flash was only visible in blue light (and there was no red channel data) the images are false color. Near-infrared replaced the visible red channel.

Based on the image resolution (12 miles/20 km per pixel) the size of the lightning flash is estimated to be about 120 miles (200 km) wide — as large as the strongest lightning seen on Earth. And like on Earth, Saturn’s lightning is thought to originate deeper in the atmosphere, at the level where water droplets freeze.

Although the 2011 northern storm was a great feature to observe, this wasn’t the first time lightning had been spotted on Saturn. Cassini had observed flashes on the ringed planet in August of 2009 as well, allowing scientists to create the first movie of lightning flashing on another planet.

Since its arrival at Saturn in 2004, Cassini has detected 10 lightning storms on Saturn — although with up to 10 flashes per second and eventually covering an area of 2 billion square miles (4 billion sq. km) the 2011 storm was by far the largest ever seen.

Image credits: NASA / JPL-Caltech / Space Science Institute. Top composite by J. Major. Video: JPL

Lightning From Space!

Photo of Earthly lightning seen from orbit by ESA astronaut Andre Kuipers


Here’s an amazing shot of a flash of lightning within storm clouds over west Africa, captured from orbit by ESA astronaut André Kuipers aboard the ISS.

Lightning is a common sight from Space Station, creating a constant light show for the astronaut and cosmonaut crew members. On average, lightning strikes the ground somewhere on Earth 100 times each second, and there are 5 to 10 times as many cloud-to-cloud flashes as there are ground strikes. That adds up to about 40 to 80 million flashes of lightning every day around the world! Considering that the ISS orbits Earth 16 times a day — and from quite a high viewpoint — it stands to reason that lightning is spotted quite often.

So although it may not be rare, lightning still makes for dramatic photos — especially to those of us here on the ground!

For more information on André and his ongoing long-duration PromISSe mission, visit the ESA site here.

Image credit: ESA/NASA

ISS Soars Over Stormy Africa

Comet Lovejoy can be seen in the video rising just right of the Milky Way.

Here’s a quick but lovely little gem: a time-lapse video taken from the ISS as it passed above central Africa, Madagascar and the southern Indian Ocean on December 29, 2011. The nighttime flyover shows numerous lightning storms and the thin band of our atmosphere, with a layer of airglow above, set against a stunning backdrop of the Milky Way and a barely-visible Comet Lovejoy, just two weeks after its close encounter with the Sun.

This video was made from photos taken by Expedition 30 astronauts. The photos were compiled at Johnson Space Center and uploaded to The Gateway to Astronaut Photography of Earth, an excellent database of… well, of astronauts’ photos of Earth.


The site’s description of this particular video states:

This video was taken by the crew of Expedition 30 on board the International Space Station. The sequence of shots was taken December 29, 2011 from 20:55:05 to 21:14:09 GMT, on a pass from over central Africa, near southeast Niger, to the South Indian Ocean, southeast of Madagascar. The complete pass is over southern Africa to the ocean, focusing on the lightning flashes from local storms and the Milky Way rising over the horizon. The Milky Way can be spotted as a hazy band of white light at the beginning of the video. The pass continues southeast toward the Mozambique Channel and Madagascar. The Lovejoy Comet can be seen very faintly near the Milky Way. The pass ends as the sun is rising over the dark ocean.

There are lots more time-lapse videos on the Gateway as well, updated periodically. Check them out here.

Video courtesy of the Image Science & Analysis Laboratory, NASA Johnson Space Center.

News Flash: Cassini Captures First Movie of Lightning on Saturn

NASA’s Cassini spacecraft has captured images of lightning on Saturn, allowing the scientists to create the first movie showing lightning flashing on another planet. “Ever since the beginning of the Cassini mission, a major goal of the Imaging Team has been the detection of Saturnian lightning,” said team leader Carolyn Porco in an email. Porco said the ability to capture the lightning was a direct result of the dimming of the ringshine on the night side of the planet during last year’s Saturn equinox. “And these flashes have been shown to be coincident in time with the emission of powerful electrostatic discharges intercepted by the Cassini Radio and Plasma Wave experiment,” Porco added.

The sound in the video approximates the electrostatic discharge signals detected by the instrument.
Continue reading “News Flash: Cassini Captures First Movie of Lightning on Saturn”

How Close Was That Lightning to the Shuttle?

Lightning strikes close to the launchpad at Kennedy Space Center on August 25, 2009. Credit: NASA, Ben Cooper. Click the image for access to a larger version.

If you’re wondering why the first launch attempt for space shuttle Discovery was scrubbed early Tuesday morning, here’s your answer. Yikes! But what a gorgeous picture! And of course, the second launch attempt early Wednesday morning was called off when instrumentation for an 8-inch fill and drain valve on the shuttle’s external tank indicated the valve had failed to close. But yesterday, the valve functioned correctly five times during launch pad tests, NASA said. That means NASA will likely go ahead with a launch attempt at 04:22 GMT (12:22 a.m. ET) on Friday. But the anomaly remains unexplained, so it will be up to the mission management team to decide if the shuttle can fly as is, or if engineers need to know more about the issue. The decision won’t be made, however until the MMT meets Thursday afternoon, just hours before the scheduled liftoff time. As the saying goes, there’s a million parts on the shuttle and if only one is not working….

UPDATE: Launch now is targeted for no earlier than 11:59 p.m. Friday, Aug. 28, to allow engineers more time to develop plans for resolving the issue with the valve.

See below for a close-up of the lightning shot, to see how close it actually came to the shuttle.

Lightining strikes close to Discovery on the launchpad on Aug. 25, 2009. Credit: NASA/Ben Cooper.  Click image for access to larger version.
Lightining strikes close to Discovery on the launchpad on Aug. 25, 2009. Credit: NASA/Ben Cooper. Click image for access to larger version.

Discovery’s 13-day mission will deliver more than 7 tons of supplies, science racks and equipment, as well as additional environmental hardware to sustain six crew members on the International Space Station. The equipment includes a freezer to store research samples, a new sleeping compartment and the COLBERT treadmill. The mission is the 128th in the Space Shuttle Program, the 37th flight of Discovery and the 30th station assembly flight.

Hat Tip to absolutespacegrl on Twitter!