NASA seeing sprites

From the NASA/Goddard Space Flight Center

A sprite glows red (upper right above the bright white, click to enlarge)) in this image captured by astronauts on the International Space Station on April 30, 2012. Credit: Image Science & Analysis Laboratory, NASA Johnson Space Center

High above the clouds during thunderstorms, some 50 miles above Earth a different kind of lightning dances. Bursts of red and blue light, known as “sprites,” flash for a scant one thousandth of a second. They are often only visible to those in flight above a storm, and happen so quickly you might not even see it unless you chance to be looking directly at it. One hard-to-reach place that gets a good view of sprites is the International Space Station. On April 30, 2012, astronauts on the ISS captured the signature red flash of a sprite, offering the world and researchers a rare opportunity to observe one.

Indeed, sprites are so hard to catch on film, that pilots had claimed to see them for almost a century before scientists at the University of Minnesota accidentally caught one on camera in July of 1989. Since then, researchers aboard planes have occasionally snapped a shot, but it continues to be difficult to methodically film them. So a group of scientists, along with help from Japan’s NHK television, sought them out regularly for two weeks in the summer of 2011.

Filming at 10,000 frames per second on two separate jets, the team recorded some of the best movies of sprites ever taken – movies that can be used to study this poorly understood phenomenon and the forces that create them. By filming from two jets flying 12 miles apart, the team mapped out the 3-dimensional nature of the sprites. Ground-based measurements rounded out the picture.

“Seeing these are spectacular,” says Hans C. Stenbaek-Nielsen, a geophysicist at the University of Alaska in Fairbanks, Alaska. “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.”

During those two weeks, the scientists hopped into their planes in Denver, Colo. each evening and chased storm clouds. Just figuring out which direction to fly next was a full time job, assigned to a single person with a computer watching the weather systems. Once a plane found a hot zone of sprites, however, they often lucked into filming numerous sprites in a row. The sprite’s first flash is usually followed by a break up into numerous streamers of light – figuring out what causes this divergence is one of the key things researchers will try to understand from these films.

The basic understanding of sprites is that they are related to lightning, in which a neutrally charged cloud discharges some of the electricity to ground. Normally negative charge is carried from the cloud to the ground, but about one out of every ten times it’s positive charge — and that leaves the top of the cloud negatively charged. With this one in ten chance, the electric field above the cloud is “just right” to produce the sprite, an electrical discharge 50 miles above the thunderstorm.

Typically the weather we experience on the ground is considered to be a separate phenomenon from the weather that goes on higher up in the atmosphere, in the area known as the mesosphere. The sprites show, however, that some fundamental science connects these two regions, opening interesting physics questions about the interchange of energy between them.

###
About these ads
This entry was posted in lightning, Space, Weather and tagged , , , , , , , . Bookmark the permalink.

28 Responses to NASA seeing sprites

  1. steveta_uk says:

    “pilots had claimed to see them for almost a century before scientists at the University of Minnesota accidentally caught one on camera in July of 1989″

    What were the pilots flying above thunderstorms in 1889? (OK, it says almost, so let’s make that 1895).

  2. Freddy says:

    I’ve always been curious about these sprites, and particularly : which way is energy flowing ? Is it going up or down ?

  3. Autoplan says:

    Literally incredible to catch the sprite on picture — didn’t think that would be possible! Brilliant post, thanks for the read. – Jamie

  4. Emissions from Hansen’s brain…

  5. captainfish says:

    Wait, I thought the science on all things climate and weather were settled?

    What’s with all of you finding new things? What, you think this is science? BAH!

  6. SandyExDerbyNowLimousin says:

    Steveta_uk
    Balloon flights? This from Wikipedia only shows records:

    1783—August—24 m (79 ft); Jean-François Pilâtre de Rozier of France, made the first ascent in a hot-air balloon.
    1783—1 December 1783—2.7 km (8,900 ft); Jacques Alexandre Charles and his assistant Marie-Noel Robert, both of France, made the first flight in a hydrogen balloon to about 610 m. Charles then ascended alone to the record altitude.
    1784—4 km (13,000 ft) Pilâtre de Rozier and the chemist Joseph Proust in a Montgolfier.
    1803—18 July 1803—7.28 km (23,900 ft) Etienne Gaspar Robertson and Lhoest in a balloon.
    1839—7.9 km (26,000 ft) Charles Green and Spencer Rush in a free balloon.
    1862—5 September 1862— about 11.887 km (39,000 ft)—Henry Coxwell and James Glaisher in a coal-gas balloon. Glaisher lost consciousness during the ascent due to the low air pressure and cold temperature of −11 °C (12 °F).

    Note heights. Presumably there were enough dedicated researchers to go up in a balloon and study storms post 1862?

    Just a thought, I have no evidence.

    Sandy

  7. Edim says:

    “Is it going up or down ?”

    Depends on CO2…

  8. Steve R W. says:

    Gustav Holst playing in the background and reading this thread at the same time.

    Good times.

  9. John Doe says:

    http://www.scientificamerican.com/article.cfm?id=thunderclouds-make-gamma-rays-shout-out-matter

    This month’s issue.

    There’s more in heaven and earth, Horatio…

  10. John Gorter says:

    Souls departing?

    John Gorter

  11. Chuck Nolan says:

    Edim I sure hope you forgot the sarc tag.

  12. SanityP says:

    Not being an expert on these things, I can only speculate to the origin of these sprites and I would think it is kind of an “action-> equal and opposite reaction” thing ?
    Lightning travels to ground -> lightning travels up and beyond upper surface of cloud ?
    KInd of bounce -> rebounce ?

  13. Edim says:

    Chuck, it’s basic physics and it’s been measured with pyrgeometers, the back-sprites. Kidding of course.

  14. guam says:

    Are these sprites “worse than previously thought” if not no problem, if so, a couple of billion in grant funding is probably available!

  15. Bloke down the pub says:

    Sprites have been caught on spy satelites for years now. Does make you wonder how much energy escapes to space by this route.

  16. Tom Davidson says:

    IIRC, the first photo of a sprite was taken from the ground – albeit atop a Colorado mountain looking east across the plains when you can literally see for over 100 miles.
    The solar wind is composed of both positive and negative particles – protons and electrons. The magnetic field of the earth separates these from each other. The electrons have more penetrating power and can follow the magnetic field to ground, while the protons are stopped quickly in the ionosphere. The atmosphere gets charged like a giant condensor with the air in between as the dielectric – at about 100-600 volts per meter. When thunderstorms or solar wind storms permit, the charge difference can ‘leak’ between the ground and the ionosphere. These little leaks would be seen as megalightning bolts (see the white flash in the picture lighting up a piece of the night sky about 20-50 miles wide). Sprites are just the secondary effects induced electromagnetically by the megalightning bolts. The streamers are tertiary effects as the remaining electric charge tries to even itself out.

  17. Peter Hannan says:

    Thanks for this. Sprites and related phenomena are interesting. For anyone who’s interested, here are some articles that I found via Google Scholar:

    Earle R. Williams, Sprites, elves and glow discharge tubes, Physics Today, Nov 2001

    Han-Tzong Su, Rue-Ron Hsu, Alfred Bing-Chih Chen, and Yi-Jen Lee, Lou-Chuang Lee, Observation of sprites over the Asian continent and over oceans around Taiwan, Geophysical Research Letters, Vol. 29, No. 4, 10.1029/2001GL013737, 2002

    Torsten Neubert, On Sprites and Their Exotic Kin, Science, Vol. 300, 2 May 2003

    Yoav Yair, Colin Price, Zev Levin, Joachim Joseph, Peter Israelevitch, Adam Devir, Meir Moalem, Baruch Ziv, Mustafa Asfur, Sprite observations from the space shuttle during the Mediterranean Israeli dust experiment (MEIDEX), Journal of Atmospheric and Solar-Terrestrial Physics 65 (2003) 635 – 642

    Martin Füllekrug and Michael J. Rycroft, The contribution of sprites to the global atmospheric electric circuit, Earth Planets Space, 58, 1193–1196, 2006

    Of course, there’s more, but these are a good start.

  18. MarkW says:

    We didn’t have evidence of these Sprites 50 years ago. Ergo, they are caused by global warming.

  19. Freddy says:

    Bloke down the pub says “… Does make you wonder how much energy escapes to space by this route.”

    Exactly. Or even if it only raises the energy a few dozen miles higher in the atmosphere, rather than all the way to space.
    So, do we have more global warming => more thunderstorms => more sprites => more energy raised to the top of the atmosphere. In which case, we have another negative feedback which, I’ll betcha, is not in any of those silly climate models.
    So, the second question is, what is the order of magnitude of the energy that is transferred by sprites ?
    But the first question is, is that energy moving up or down ?

  20. Duster says:

    I am far more interested in the fact that it has now been established that gamma ray flashes and beta radiation (free electrons and positrons) are generated within thunderstorms. That implies a lot of energy is being discharged in there. Since thunderstorms are essentially driven by the sun like the rest of the weather (CO2 even in theory only provides a very temporary storage site), how does that work?

  21. highflight56433 says:

    Wise old pilots steer clear of thunderstorms; young bold pilots are listed in the NTSB accident investigation tables.

  22. Caz in BOS says:

    There have been some intriguing UFO reports by very credible aviators. I have often wondered if these pilots experienced some kind of sprite, that appeared to follow the planes because the plane itself was shorting out something in the high atmosphere.

  23. kadaka (KD Knoebel) says:

    From SandyExDerbyNowLimousin on August 15, 2012 at 8:25 am (from Wikipedia):

    1783—1 December 1783—2.7 km (8,900 ft); Jacques Alexandre Charles and his assistant Marie-Noel Robert, both of France, made the first flight in a hydrogen balloon to about 610 m. Charles then ascended alone to the record altitude.

    Wow. I knew research could be dangerous back then, especially for assistants. They didn’t have parachutes at the time. So the hapless assistant must have been thrown overboard as the discarding of ballast!

    Thank you, Wikipedia, for bringing this atrocity to light.

  24. Ian Cooper says:

    I was lucky enough to observe sprites on two occasions in the past 16 months. You don’t have to be in a spacecraft or at any altitude to see them. The perfect conditions for a ground based observer are, an unobstructed view towards the tops of the Cbs where the sprites emmanate from. The best candidate Cb’s are not lone wolves but those that are a part of a chain of such towers.

    The best observer-Cb viewing distance is between 100 – 200 km’s (60 – 120 miles). This puts the brightest part of the electrical storm close to the horizon and therfore easier for the observer to hide from view with a convenient hedge etc. This is important as it means that the eye isn’t distracted by the flashes coming from the bottom of the storm.

    A typical row of Cb’s can stretch up to 100km in length and observations by astronauts show that when an event occurs at one end of the chain it can be directly connected to a similar event at the other end, something that wasn’t known before 1989. Ground observers can see this for themselves. How many of you who see frequent distant thunder storms have noticed widely separated lightning strikes that are almost simultaneous?

    The advent of rain radar on the net means that observers can be prepared for such events as never before. As mentioned in the article most of the sprite appears red, but there is a blue component that is slightly easier to detect by eye. Remembering though that these blue flashes are almost subliminal. The sprites are also bigger than one would expect considering how far away thay are. in a series of images gleaned from a modified security video camera an observer from Queensland, Australia recorded sprites in B&W that were super-imposed on recognizeable southern constellations. The sprites sat at an altitude of between 15 to 20 degrees and covered an area as much as 12 degrees wide by 10 degrees in height.

    The type of thunderstorms that favour sprites are rare here in my part of the North Island of New Zealand. The big advantage we do have here on the Manawatu Plains (the largest flat area in the North Island) is our unobstructed view in all directions, which is ideal for sprite viewing. I have recently had my Canon 450D modified to remove the Infrared Filter for astrophotgraphy purposes. Set at a high ISO rating, a fast F ratio and a long enough exposure I may be able to catch the wee ghosties at the bottom of my garden the next time that they come out to play.

    Cheers

    Coops.

  25. Tibetan monks have recorded seeing them for hundreds of years, the whole myth of dragons is due to the observations, they talk about the energy drawing into the earth during the winter and reappearing again in the spring, and noted the severity of the monsoonal storms related to the occurrence of the “red and blue dragons fighting in the sky” over the most severe storms that resulted in heavy flooding in the lowlands and resultant deaths.

  26. Kelvin Vaughan says:

    Freddy says:

    August 15, 2012 at 1:28 pm

    Bloke down the pub says “… Does make you wonder how much energy escapes to space by this route.”

    Exactly. Or even if it only raises the energy a few dozen miles higher in the atmosphere, rather than all the way to space.
    So, do we have more global warming => more thunderstorms => more sprites => more energy raised to the top of the atmosphere. In which case, we have another negative feedback which, I’ll betcha, is not in any of those silly climate models.
    So, the second question is, what is the order of magnitude of the energy that is transferred by sprites ?
    But the first question is, is that energy moving up or down ?

    I was thinking about this and lightening then it suddenly struck me!

  27. Galane says:

    I can see Sprites any time I want, just by opening my refrigerator door. Unless I’ve drunk the last one. ;)

  28. Brian H says:

    Itz positrons. See accompanying gamma bursts. Anti-Lightning!

Comments are closed.