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Comment by japhyr | Hacker News Reader

This is fascinating. I've only ever really though of antimatter forming in the early universe, at the edges of black holes, and in particle accelerators. I love the thought of them forming in thunderclouds as well, and I'm quite curious to hear about the followup investigations.

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Never would have thought the A-10 could become an instrument of science

Thundercloud, not Thunderbolt. There's a big difference.

No they're literally flying an A-10 into the storm to try and measure things.

> the US National Science Foundation even plans to fly a particle detector on an A-10 ‘Warthog’

wow I missed this the first time reading it. Are A-10s cheaper to operate than a G-V? (costing at least 8,000 per hr)

> Are A-10s cheaper to operate than a G-V? (costing at least 8,000 per hr)

Not necessarily, but they're a hell of a lot more robust. Thunderstorms are a really violent environment and no place for an executive jet.

and it looks like work has been underway to use an A-10 for just this purpose for a while. http://en.wikipedia.org/wiki/Fairchild_Republic_A-10_Thunder...

found some hourly cost of ownership data: A-10 17k per hour, G3 32K per hour. (compared to <6K for a civilian G3)

http://nation.time.com/2013/04/02/costly-flight-hours/

And besides, nothing says you mean business by making your appearance in an A-10. Gets them everytime.

"The jet will also have its nose-mounted, 30-millimeter cannon removed, opening up more space for scientific instruments."

http://blog.ametsoc.org/uncategorized/plane-has-combative-at...

Given that it's an A-10, it might be more accurate to say that the cannon is having its aircraft removed.

    Given that it's an A-10, it might be more accurate
    to say that the cannon is having its aircraft removed.

wow, no kidding...

http://en.wikipedia.org/wiki/GAU-8_Avenger#/media/File:GAU-8...

I'd love to have been present at the first conversation where that became a plan. "Well, what's tougher than the plane we've already got? Wait.... What's the toughest plane in the sky? An A-10? Right. Who do we have to talk with to get one of them?"

I'm a surprised that the plan isn't to use a UAV. Small things can be really tough, are subject to smaller gradient-driven forces, and, if the airframe comes apart, a brave pilot won't have to die.

Thunderstorms can the thought of as being driven by one of nature's particle accelerators. The electric fields in thunderstorms can run up to at least 100 kV/m and maybe more, so getting potential drops well into the mega-volt range over relatively short distances is not too difficult: http://science.ksc.nasa.gov/amu/journals/jamc-2008.pdf

Electron-positron pairs require an energy of just over 1 MeV to be created (the energy of a single electron charge dropping through a potential of 1 MV). So there is more than enough energy kicking around to generate pairs fairly copiously (positrons are always produced with a companion electron in this kind of process, although they may be produced alone in certain types of radioactive decay.)

The interesting part of this work is it seems there was a large volume where there were a lot of positrons, and the specific mechanism capable of producing that situation is not known. Really interesting science in an extreme and transient environment!

Bananas are a weak source of antimatter [0]

[0] http://en.wikipedia.org/wiki/Potassium-40

So are human bodies. I can't remember the math right now, but several times an hour your body will produce a positron.

Some antimatter particles are easy to make locally. For example many radioactive isotopes decay by positron emission (also named positive beta decay). http://en.wikipedia.org/wiki/Positron_emission Most of the times the positron just collides with an electron and emits a pair of 511eV photons.

For example, this is applied in a common medical procedure: Positron emission tomography (PET) http://en.wikipedia.org/wiki/Positron_emission_tomography

Positrons are way more common than that, i.e. only in the early universe, black holes, particle accelerators. They are emitted in a kind of radioactive decay, and are the basis of PET scanners.

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