

Thunderstorms create antimatter - ubasu
http://www.nasa.gov/mission_pages/GLAST/news/fermi-thunderstorms.html

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ghshephard
The Fermi Gamma-ray Space telescope orbits at 550 km - I'm not sure how large
its Gamma-ray Burst Monitor is, but, it's probably on the order of magnitude
of a square meter.

From the graph, a TGF creates an additional 80 impacts per microsecond. Under
the (admittedly incorrect) presumption that a TGF is omnidirectional, that
would suggest a TGF is emitting enough positrons to cause in 10^-6 seconds an
increase of 80 impacts on the 1 meter section of the surface of a sphere with
a 550 * 10^3 meter radius.

If I don't munge the math, that would suggest each of these TGF is emitting
approximately:

    
    
       4*Pi*(550*10^3  )^2*80 /(1*10^-6 )
       3*10^20 positron emissions per TGF that make it to the LEO of the satellite.
    
    

Divide as appropriate to account for the likely (per the article) non-
omnidirectional nature of the burst (they tend upwards)

Not sure how many are normally absorbed in the atmosphere, or, in fact, if
10^20 is a significant number of positrons - but I'm thinking it would be
interesting to mount a TGF detector near, or above, a frequently hit lighting
target (Empire State Building gets around 100 Hits per year)

Checking Wikipedia - it turns out that lightning has been a well known source
of Gamma Rays for at least 15 years - I read about the observations of the
Compton Gamma Ray Observatory in 1994 - and compared it to the more recent
discovery by the Fermi Gamma Ray Space telescope. It's hard to see what they
discovered that was different this time around.

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gammarator
What's new here is the direct observation of a spectral feature--the well-
known 511 keV line--which corresponds to annihilation of the positrons
produced by the TGF with electrons. Gamma-rays and electrons had been observed
before, but it wasn't known that positrons were produced as well.

Compton didn't observe it because its energy resolution was too coarse, and
RHESSI (another satellite which has detected many TGFs) doesn't have enough
collecting area to do spectroscopy.

There are current ground and airborne experiments looking for high energy
emission from lightning.

(I'm a gamma-ray astrophysicist who works with these satellites on other
sources.)

~~~
juiceandjuice
Where do you work? I handle the astroserver at SLAC.

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cryptoz
And thunderstorms just got even more badass.

What are the potential implications from this discovery? Since it is so
expensive and difficult to create antimatter on Earth (and it only lasts for
less than a second), the obvious question to ask is if we can capture or study
the antimatter produced in thunderstorms?

That would be amazing.

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acconrad
For some reason I feel this is only going to reduce the significance of anti-
matter. I remember first hearing about it as some ominous "substance" that
only exists in the emptiest depths of the universe. If it happens all of the
time on earth, I'm sure we'll be able to conclude that anti-matter is as
common here as it is elsewhere in the universe, and won't exhibit any super-
interesting properties that we once thought it did.

~~~
jerf
What super-interesting properties are you thinking of? Antimatter has been
pretty pedestrian for a while now.

~~~
lukev
Hm. I'm not sure I'd go so far as to say it's _pedestrian_. Well understood by
theoretical physicists, perhaps. Inherently, though, it's still pretty damn
interesting.

~~~
jerf
Interesting scientifically, sure, just like electrons and protons and
Newtonian physics and all sorts of other things. But there's not much mystery
to it. I agree with uvdiv, acconrad was almost certainly thinking dark
matter/energy.

~~~
chc
Or he's been misled by, like, every work of science fiction ever. They almost
all portray it as the sort of mysterious, otherworldly stuff he's describing.
I've known a lot of people who were kind of disappointed to learn that
antiparticles are uncommon, but not _that_ uncommon.

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SpacemanSpiff
I wonder if this phenomena is at all related to red sprites and blue jets
<http://en.wikipedia.org/wiki/Blue_Jets>

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athom
I just realized, doesn't Jupiter have constant lightning storms a couple of
orders of magnitude more violent than ours? Just imagine the sort of animatter
generation _those_ might be driving!

We gotta get another probe out there! Unless maybe we've got something that
could pick up the signs back here...?

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po
I was more interested in the concept of the magnetic mirror point, which I was
unaware of until now:

<http://en.wikipedia.org/wiki/Magnetic_mirror_point>

<http://en.wikipedia.org/wiki/L-shell>

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juiceandjuice
I work for this experiment!

I think I'll have to play around with this data tomorrow.

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spenrose
Is the antimatter arsenic-based?

