Personally, I think this has to do with thunderstorms being essentially linear accelerators, vertical SLAC’s if you will. Huge charge differentials from top of cloud to bottom makes for a nice particle slingshot. There’s plenty of opportunity for antimatter (positrons) to be created in energetic collisions from particles coming out of the tops of thunderstorms. Sprites and blue jets for example, may be indicators for energetic particles.
It could also be very energetic photons from lightning as seen in the diagram below. At the high photon energies (twice the rest energy of electrons at 511 keV) and above 1.022 MeV positron-electron pair production may take place. Getting energies of 1.022 million electron volts certainly seems easy enough in thunderstorms. – Anthony
From Sciencenews.org: Signature of antimatter detected in lightning
Fermi telescope finds evidence that positrons, not just electrons, are in storms on Earth
Washington — Designed to scan the heavens thousands to billions of light-years beyond the solar system for gamma rays, the Fermi Gamma-ray Space Telescope has also picked up a shocking vibe from Earth. During its first 14 months of operation, the flying observatory has detected 17 gamma-ray flashes associated with terrestrial storms — and some of those flashes have contained a surprising signature of antimatter.
During two recent lightning storms, Fermi recorded gamma-ray emissions of a particular energy that could have been produced only by the decay of energetic positrons, the antimatter equivalent of electrons. The observations are the first of their kind for lightning storms. Michael Briggs of the University of Alabama in Huntsville announced the puzzling findings November 5 at the 2009 Fermi Symposium.
It’s a surprise to have found the signature of positrons during a lightning storm, Briggs said.
The17 flashes Fermi detected occurred just before, during and immediately after lightning strikes, as tracked by the World Wide Lightning Location Network.
During lightning storms previously observed by other spacecraft, energetic electrons moving toward the craft slowed down and produced gamma rays. The unusual positron signature seen by Fermi suggests that the normal orientation for an electric field associated with a lightning storm somehow reversed, Briggs said. Modelers are now working to figure out how the field reversal could have occurred. But for now, he said, the answer is up in the air.
Recording gamma-ray flashes — which have the potential to harm airplanes in storms — isn’t new. The first were found by NASA’s Compton Gamma-ray Observatory in the early 1990s. NASA’s RHESSI satellite, which primarily looks at X-ray and gamma-ray emissions from the sun, has found some 800 terrestrial gamma-ray flashes, Briggs noted.
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It’s true that there ought to be sufficient energy for pair production, but the atmosphere is also dense enough, even at 100km height, that very few electrons will reach the required energy before a collision resets them to zero KE. You’ll note that they aren’t seeing swarms of these gamma rays.
This will be more fun to think about than the health care bill.
Just to be correct, the photon does not have to strike the nucleus as illustrated above. It merely has to pass close to the nucleus to excite the pair production. The source of the paired particles is not from the “debris” of collision. GK
Having been too close (as in inside) thunderstorms,nothing would surprise me that they are capable of this. When you get a vertical ride from FL200 to FL280 in afew seconds
then spit out-there are some mighty strong forces out there.We humans are insignificant to this planet….
Wondrous and fascinating, just shows how much we have to learn about the science of this earth and the immensity beyond our little planet.
Thank goodness we have solved the science of AGW!?*!
I suppose if we want to be very correct about what people observe here, the picture of a gamma just coming sufficiently close to a nucleus is not right. The researchers are observing not the positrons themselves, but the gamma rays characteristic of a positron annihilating an electron. The two masses in such a collision effectively vanish and the energy, momentum, and parity of the original particles is carried away in one, two or three emitted gamma rays. The instruments detect gamma rays with 0.511Mev energy and the scientists infer that positrons are present.
So where do the positrons come from? If an electron can be accelerated to at least 1.022Mev, as Anthony says, there is enough energy to create an electron, positron pair. However, this is a bare minimum requirement. There must be other particles involved in order to explain the sudden appearance of a unit of positive charge.
There are so few of these gammas observed that perhaps some process other than just acceleration of electrons is involved?
The discoverer of nuclear anti-matter, Antonino Zichichi, seems to agree with Henrik Svensmark and Nir Shaviv,
Climate changes depend in a significant way on the fluctuation of cosmic rays.
http://www.zenit.org/article-19481?l=english
Antonino Zichichi :
http://www.ccsem.infn.it/em/zichichi/short_bio.html
Shocking New Scientific Finding!
Warmer Homes Mean Better Health For Poor People, Study Suggests
ScienceDaily (Nov. 8, 2009) — Being warm enough at home might lead to better health, according to a new review appearing online in the American Journal of Public Health.
http://www.sciencedaily.com/releases/2009/11/091106200738.htm
Gee, if winters were just a little warmer, people would be healthier…..go figure.
The following article is behind a pay-wall, but Goggle’s summary suggests that “The 0.511 MeV radiation is practically completely of atmospheric origin”
E. P. Mazets1, S. V. Golenetskii1, V. N. Il’inskii1, Yu. A. Gur’yan1 and T. V. Kharitonova1
(1) A. F. Ioffe Physical-Technical Institute, U.S.S.R. Academy of Sciences, Leningrad, USSR
Received: 7 August 1974
Therefore one “sees” gammas characteristic of positrons coming from the atmosphere, perhaps from thunderstorms, perhaps independently of them.
Anyway, what I said a moment ago about an electron needing 1.022meV, might not be correct, maybe an electron with kinetic energy of 0.511Mev is the minimum because one has to add enough energy to just create the positron…but then, there is still the issue of the charge.
Gene Nemetz (09:39:42) :
Nice. Thanks.
If X rays can be generated by sticky tape
http://physicsworld.com/cws/article/news/36357
I don’t have a problem believing positrons could be generated in electrical storms.
Next, someone will find dilithium crystals in South Africa.
Or something like this might happen!
Gene Nemetz (09:39:42) :
The discoverer of nuclear anti-matter, Antonino Zichichi, seems to agree with Henrik Svensmark and Nir Shaviv,
He has had a couple of choice things to say about the IPCC too:
“Scientists might not have human behavior to blame for global warming, according to the president of the World Federation of Scientists.
Antonio Zichichi, who is also a retired professor of advanced physics at the University of Bologna, made this assertion today in an address delivered to an international congress sponsored by the Pontifical Council for Justice and Peace.
The conference, which ends today, is examining “Climate Change and Development.”
Zichichi pointed out that human activity has less than a 10% impact on the environment.
He also cited that models used by the Intergovernmental Panel on Climate Change (IPCC) are incoherent and invalid from a scientific point of view. The U.N. commission was founded in 1988 to evaluate the risk of climate change brought on by humans.
Zichichi, who is also member of the Pontifical Academy of Sciences, showed that the mathematical models used by the IPCC do not correspond to the criteria of the scientific method.”
Duct Tape: More than the handyman’s secret weapon!
http://www.youtube.com/watch?v=5QFRSjWVTmY
Hey Kids! With just a couple of rolls of duct tape, you too can be a high energy particle physicist! Or try X-raying the cat, but it helps if you tape it to a plank first!
(Sorry, more Engineer Humor on a Sunday.
I come here for the AGW discussion and this is icing on the cake. Thank you Anthony.
Regards,
Steamboat Jack
How long before AGW is to blame for this as it was not observed before, never mind that Fermi telescope was not there to see it so it must not have happened and AGW cause it to happen. Lets spend some tax money to see if we could stop it from happening.
I also have some doubts that the “linear accelerator” model is viable. The “air” is not good enough vacuum to accelerate them sufficiently. Moreover, they’re probably seeing much sharper 511 keV lines than predicted from positrons created at high velocities, as implied by hugely energetic collisions.
So I prefer to think that some positrons are probably always in the atmosphere, they’re just being collected and/or focused by the lightnings.
See
http://motls.blogspot.com/2009/11/fermi-lightnings-produce-positrons.html
If you google van de graaf generator and positron, you will find several articles. Here’s one:
http://cat.inist.fr/?aModele=afficheN&cpsidt=13831420
Luboš Motl (11:00:51) :
“I prefer to think that some positrons are probably always in the atmosphere, they’re just being collected and/or focused by the lightnings.”
Now why didn’t I think of that? Oh, yeah, the PhD in physics. Didn’t know how much I was missing by studying rocks.
I would have thought the atmosphere would be too dense for this to happen at the altitudes where lightening happens?
Perhaps the huge electric current or the discharge sweeps the ionised air away and causes a vacuum for long enough for the process to happen.
Still lots to learn about our climate – the science will never be settled.
Idle speculation that the gamma rays could originate from space or from the centre of the earth, and lightning is precipitated along their tracks.
How do they measure the direction of travel of these gamma rays? And does the earth absorb them?
Kevin Kilty (09:46:42) :
First lets see where one can get the gamma rays.
There are electrons around nuclei and obviously since thunder storms have high electric fields they are spinning around , as well as the stripped nuclei as ions.
These can become accelerated following the electric lines. They can also be decelerated, against the lines and when this happens ( vortex conditions?) photons come out of the deceleration. Photons can come out also when these energetic charged particles( electrons or ions) whoosh close to the electric field of other nuclei.
If the energy of these photons is in the mev range the photons are gamma rays.
If the gamma ray has an energy over twice the electron mass it can break into an electron positron pair interacting with the electric field , either of the storm or with one of the ions floating around.
The positron will then annihilate with a characteritic spectrum when hitting one of the electrons still attached to the gas nuclei in the atmosphere.
It needs a monte carlo model to get the possible flux out :), i.e. how many one would expect, and model is a five letter word here :).
The first quest is to account for any possible alternative explanations for the gamma rays and their “signature” behaviour.
Then, identify the source of the energy either of positrons or other possible processes.
There is much we don’t know yet.
As an example of gammas generated on gas:
http://accelconf.web.cern.ch/AccelConf/e04/PAPERS/THPLT052.PDF
“Electrons interacting with residual gas atoms in the
storage ring vacuum vessels produce the emission of a
cone of electromagnetic radiation extending from long
wavelength photons down to gamma ray photons at the
energy of the electron beam. The majority of the emitted
radiation energy is in gammas with an opening angle of
1/γ rms, where γ is the relativistic factor of the electrons.”
this is 6 GeV electrons.
****************************
Doug in Seattle (11:13:06) :
Luboš Motl (11:00:51) :
“I prefer to think that some positrons are probably always in the atmosphere, they’re just being collected and/or focused by the lightnings.”
Now why didn’t I think of that? Oh, yeah, the PhD in physics. Didn’t know how much I was missing by studying rocks.
*******************
Well, I guess if one has a strong enough electric/magnetic field, it could tease virtual particles of of the vacuum – kind of like a black hole does.
Luboš Motl (11:00:51) : “I also have some doubts that the “linear accelerator” model is viable. The “air” is not good enough vacuum to accelerate them sufficiently.”
But thunder, I’m told, is caused by air refilling the vacuum created by a lightning strike. Similarly, microscopic vacua may be created by lifting adhesive tape. Tiny adhesive particles may adhere, then release suddenly, like a rubber band.