Interesting for the meteorologically inclined, if you didn't already know: red sprites and blue jets are upper atmospheric discharges associated with thunderstorms. Like the lightning you're used to seeing, that lights up a cloud from within, or snakes down to touch the ground, sprites and jets are electrical discharges -- just way up high.
Sprites are predominantly red, enormous but weak flashes appearing directly above an acitve thunderstorm system and tend to coincide with the more familiar lightning flashes. They appear to prefer areas of a thunderstorm that are starting to decay. Sprites tend to cluster, don't last very long, and are damn hard to see. So, don't waste your time unless you happen to be hanging around the Earth's atmosphere at around 65-75 km in altitude, over a thunderstorm actively discharging lightning, and you've got some serious low light level equipment on you.
Now, blue jets stream from the top of the electrically active core regions of thunderstorms -- so where red sprites are observed in decaying areas, blue jets like it where the action is still hot. They appear at lower altitudes, hanging around at 40-50km, and flow up and out in a cone-like shape.
Interestingly enough, gamma-ray bursts have been observed over thunderstorm regions at altitudes of greater than 30km. Related? Maybe.
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