[Link] Son of low-hanging fruit

post by GLaDOS · 2013-04-04T12:43:03.601Z · LW · GW · Legacy · 1 comments

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Related: Thick and Thin, Loss of local knowledge affecting intellectual trends

An entry I found in the archives on Gregory Cochran's and Henry Harpending's blog West Hunter.

In yet another example of  long-delayed discovery, forms of high-altitude lightning were observed for at least a century before becoming officially real (as opposed to really real).

Some thunderstorms manage to generate blue jets shooting out of their thunderheads, or  glowing red rings and associated tentacles around 70 kilometers up.   C T R Wilson predicted this long ago, back in the 1920s.  He had a simple model that gets you started.

You see, you can think of the thunderstorm, after a ground discharge,  as a vertical dipole. Its electrical field drops as the cube of altitude.  The threshold voltage for atmospheric breakdown is proportional to pressure, while pressure drops exponentially with altitude: and as everyone knows, a negative exponential drops faster than any power.

The curves must cross.   Electrical breakdown occurs.  Weird lightning, way above the clouds.

As I said, people reported sprites at least a hundred years ago, and they have probably been observed occasionally since the dawn of time. However, they’re far easier to see if you’re above the clouds – pilots often do.

Pilots also learned not to talk about it, because nobody listened.   Military and commercial pilots have to pass periodic medical exams known as ‘flight physicals’,  and there was a suspicion that reporting glowing red cephalopods in the sky might interfere with that.  Generally, you had to see the things that were officially real (whether they were really real or not), and only those things.

Sprites became real when someone recorded one by accident on a fast camera in 1989.  Since then it’s turned into a real subject, full of strangeness: turns out that thunderstorms  sometimes generate gamma-rays and even antimatter.

Presumably we’ve gotten over all that ignoring your lying eyes stuff by now.

May you tell others what you see. (~_^)

 

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