Red sprites!

October 10, 2017 • 1:00 pm

A red sprite is a type of lightning that’s produced very high in the atmosphere, and very different from “hot” lightning. I’ve never been lucky enough to see one, but here’s a photo sent by reader Hempenstein from FB. The caption was with the original photograph:

Photo by Emily Sutton:   This is incredible. Check out this rare photo by Dramatic sky photography by Paul Smith of red sprites above the line of storms Friday night, near Canton Lake. Red sprites are thought to be caused by a rare and intense type of lighting (positive lightning). KFOR-TV

Here’s what Wikipedia says about sprites:

Sprites are large-scale electrical discharges that occur high above thunderstorm clouds, or cumulonimbus, giving rise to a quite varied range of visual shapes flickering in the night sky. They are triggered by the discharges of positive lightning between an underlying thundercloud and the ground.

Sprites appear as luminous reddish-orange flashes. They often occur in clusters above the troposphere at an altitude range of 50–90 km (31–56 mi). Sporadic visual reports of sprites go back at least to 1886, but they were first photographed on July 6, 1989 by scientists from the University of Minnesota and have subsequently been captured in video recordings many thousands of times.

Sprites are sometimes inaccurately called upper-atmospheric lightning. However, sprites are cold plasma phenomena that lack the hot channel temperatures of tropospheric lightning, so they are more akin to fluorescent tube discharges than to lightning discharges.

Here’s a video of sprites in both real time and slow motion by Scott McPartland, who gives this information:

On May 16th, 2016 I captured multiple, vivid Red Sprites while filming a cluster of supercell thunderstorms off to my northeast. This alternate edit shows these sprites in realtime, and then replayed in slow motion at 1/10th the speed for easier viewing. Camera used was a Sony A7S II with a Zeiss f1.4 lens wide open. ISO of 32000/51000.

 

A few more photos. First, an altitudinal description showing how high these discharges take place (50-100 km) compared to “real” lightning:

And a bit more information:

Sprites are colored reddish-orange in their upper regions, with bluish hanging tendrils below, and can be preceded by a reddish halo. They last longer than normal lower stratospheric discharges, which last typically a few milliseconds, and are triggered by the discharges of positive lightning between the thundercloud and the ground. They often occur in clusters of two or more, and typically span the altitude range 50 to 90 kilometres (31 to 56 mi), with what appear to be tendrils hanging below, and branches reaching above.

Optical imaging using a 10,000 frame-per-second high speed camera shows that sprites are actually clusters of small, decameter-sized (10–100 m or 33–328 ft) balls of ionization that are launched at an altitude of about 80 km (50 mi) and then move downward at speeds of up to ten percent the speed of light, followed a few milliseconds later by a separate set of upward moving balls of ionization. Sprites may be horizontally displaced by up to 50 km (31 mi) from the location of the underlying lightning strike, with a time delay following the lightning that is typically a few milliseconds, but on rare occasions may be up to 100 milliseconds.

In order to film sprites from Earth, special conditions must be present: 150–500 km (93–311 mi) of clear view to a powerful thunderstorm with positive lightning between cloud and ground, red-sensitive recording equipment, and a black unlit sky.

This is a picture of a sprite taken from the International Space station (the sprite is the very faint red bit above the flash).

A sprite seen from the International Space Station (top right, faint red above the lightning).

And an enlargement of the above photo:

Has anybody seen one of these? Now it’s become one of the two meteorological phenomena on my bucket list, along with the Aurora Borealis.

24 thoughts on “Red sprites!”

  1. This is exciting as in mind blowing excitement

    Why is it red – if it’s lower energy, is it because lower voltage / shorter path length?

    Is there an optical phenomenon at play between ground observer and point of discharge?

        1. red = N2
          Blue = O2

          Well, sort of. But they’re also different processes. The red light of the sprites (and also of many auroras) is a fluorescent emission of electrons dropping into ionised nitrogen atoms (or is it molecules – not sure). But the blue-white light of the lightning bolt or arc lamp is primarily thermal emission from the hot plasma cooling. As such, it’s emission is dominated by the physics of “black body” radiation (interacting particles), with only minor contributions from particular intra-atomic electron movements.
          If you have a prism (diffraction grating, CD) which you can view through (reflect off), you should be able to see overlapping images from the emission lines against a background of the smeared-out thermal image.
          When you look at auroras, most are red (nitrogen), but some are green – which is ascribed to (a transition whose designation I forget in) oxygen atoms. Why it’s not always a 4:1 mix of the nitrogen and oxygen lines, I’m not sure – maybe the energy of the incoming particles is sufficient to stimulate the red N fluorescence, but not the higher energy green O fluorescence. (A fluorescing atom receives a photon or impact of variable energy X joules, dumps out a photon of a line-specific energy L, and the atom recoils with X-L joules.)
          There’s a lot of physics in those phenomena!

  2. I’ll have to add that to my bucket list too as well as photographing an iceberg from below the waterline.

    1. Below the water line, or below the iceberg and below the waterline?
      You’d need exceptional visibility to see much in either case – not often the case with surface bubbles. he gorgeous shots on nature programmes are the result of editing down dozens or hundreds of hours of shot footage.

      1. I mean mean dry suit ice diving, well below the water line. So far haven’t found a tour or trip but I’m still looking.

        1. Having dived under ice in a wetsuit (and indeed, in snow melt in a wetsuit), I’d hope for a drysuit too. But my point was about being in an “overhead” environment, where a depth gauge reading of 10m and a distance-to-air-surface of 1000m are perfectly compatible. Rather different from “open water” diving.

        1. 7 to 10 ft (2.3 to 3 m) is good visibility. It’s easy to tell if some of your lights are working in low visibility, but hard to know which one(s) are working. A couple of maniacal Romanian divers I met would keep their lamps taped to lanyards round their wrists, which certainly has some arguments for it.

  5. This is so cool! Not only have I never seen it, I never even knew it existed! It’s gone on my bucket list as well.

  6. So powerful thunder storms, against a clear sky, and at night. I get a couple of those each summer. Hope to see this kind of thing one day.

  8. That is cool, it made me wonder after reading the description of the phenomenon what the ancients would have thought… and how some certain individuals would have used it.

    Shake something, point your spirit stick at that and quickly!
    First, give me that rabbit you have in your hand and perhaps that shiny thing around your neck.

  9. The sprite picture is pretty cool. It was surprising how quick they are, the video was slow motion and yet they were still very quick.

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