×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

Antimatter In Lightning

Soulskill posted more than 4 years ago | from the doc-brown-can-now-power-his-warp-drive dept.

Earth 169

AMESN writes "The Fermi Gamma-ray Space Telescope, launched last year, detects gamma rays from light years away, but recently it detected gamma rays from lightning on Earth. And the energy of the gamma rays is specific to the decay of positrons, which are the antimatter flavor of electrons. Finding antimatter in lightning surprised researchers and suggests the electric field of the lightning somehow got reversed."

cancel ×
This is a preview of your comment

No Comment Title Entered

Anonymous Coward 1 minute ago

No Comment Entered

169 comments

According to this blinking light... (1, Funny)

Anonymous Coward | more than 4 years ago | (#30013896)

... lightning is made of electro-matter, matter's bad-ass grandma!

Reversing the polarity of the electron discharge? (5, Funny)

BadAnalogyGuy (945258) | more than 4 years ago | (#30013910)

The decay of positrons in the largescale discharge of electronic particles may very well lead to gamma ray emissions, however it is crucial to understand the energy output required to reverse the polarity of the discharge so that we can reproduce the phenomenon in a controlled laboratory.

Or else the Romulans will destroy the Federation.

Re:Reversing the polarity of the electron discharg (5, Funny)

gravos (912628) | more than 4 years ago | (#30013938)

Reverse the polarity? Good god, next you'll be wanting to cross the streams.

Re:Reversing the polarity of the electron discharg (2, Funny)

NoYob (1630681) | more than 4 years ago | (#30013954)

I don't know. But it will explain how a DeLorean can go back to the future.

Re:Reversing the polarity of the electron discharg (1)

ring-eldest (866342) | more than 4 years ago | (#30014006)

Dr. Ray Stantz: Total protonic reversal!
Dr. Peter Venkman: That's bad. Okay. All right, important safety tip. Thanks, Egon.

Re:Reversing the polarity of the electron discharg (0)

Anonymous Coward | more than 4 years ago | (#30014106)

Have they discounted temporal anomalies?

Re:Reversing the polarity of the electron discharg (0)

Anonymous Coward | more than 4 years ago | (#30014122)

There is the theory of the moebius. A twist in the fabric of space where time becomes a loop.

Re:Reversing the polarity of the electron discharg (1, Funny)

Anonymous Coward | more than 4 years ago | (#30015332)

There is the theory of the moebius. A twist in the fabric of space where time becomes a loop.

Re:Reversing the polarity of the electron discharg (4, Funny)

JCCyC (179760) | more than 4 years ago | (#30014188)

You're all off base.The explanaion is much simpler.

Did anybody shout "SHAZAM!" nearby?

Re:Reversing the polarity of the electron discharg (1)

kimvette (919543) | more than 4 years ago | (#30014924)

Many of us wish we could forget ever having been exposed to that show as children. I watched an episode on TV Land a few years ago wondering if it really was as good as I thought it was when I was a toddler. Um, no. It ranks down close to the star wars holiday special. Thankfully I grew out of childhood early enough to avoid having ever developed twisted fond memories of Barney, or even Elmo (Elmo ruined Sesame Street).

Another show I am morbidly curious about is "Wizards and Warriors" - is it as horribly bad as I imagine it was? What about Knight Rider? I've tried watching Knight Rider on Hulu. I can't make it through a single episode. It's horrible.

"SHAZAM"! Ugh. Thanks for bringing back repressed memories. Now I'm traumatized and need to find a good shrink. ;)

Re:Reversing the polarity of the electron discharg (1)

selven (1556643) | more than 4 years ago | (#30014500)

What's a stream? Is it like a subspace tachyon polarization discharge eddy?

Re:Reversing the polarity of the electron discharg (2, Funny)

kimvette (919543) | more than 4 years ago | (#30014876)

Anyone who watches Star Trek knows that any time you want to solve technical problems or achieve new developments, all you need to do is reverse the polarity or invert the phase. Why didn't the folks behind the LHC try this? It's have saved billions of dollars and years of delays! ;)

Re:Reversing the polarity of the electron discharg (3, Funny)

The Grim Reefer2 (1195989) | more than 4 years ago | (#30015016)

Anyone who watches Star Trek knows that any time you want to solve technical problems or achieve new developments, all you need to do is reverse the polarity or invert the phase.

You forgot to reroute through the main deflector.

of course (0)

Anonymous Coward | more than 4 years ago | (#30013912)

Anti-matter is required to provide so many jigga...

sorry!

just wondering... (0)

Anonymous Coward | more than 4 years ago | (#30013942)

does this mean the LHC is obsolete?

Re:just wondering... (4, Funny)

BadAnalogyGuy (945258) | more than 4 years ago | (#30013950)

The LHC was obsolete [newscientist.com] before it was even constructed.

It never stood a chance.

Re:just wondering... (0)

Anonymous Coward | more than 4 years ago | (#30014014)

I smell onions.

Re:just wondering... (1)

the_one(2) (1117139) | more than 4 years ago | (#30013970)

The purpose of LHC is not to find antimatter (at least not primarily). It's purpose is to find the higgs boson and you don't need LHC to make antimatter

Re:just wondering... (5, Funny)

slarrg (931336) | more than 4 years ago | (#30014028)

I thought it's purpose was eating baguettes.

Re:just wondering... (0)

Anonymous Coward | more than 4 years ago | (#30014624)

no, heating baguettes, to the point of triggering alarms apparently.

doc-brown-can-now-power-his-TIME-MACHINE (0)

Anonymous Coward | more than 4 years ago | (#30013962)

It's Zefram Cochrane who "invented" the warp drive (didn't explain what was used to power it), Doc Brown needed the lightning for his "flux capacitor".

My geekiness is showing.

Crossover (1, Interesting)

gmuslera (3436) | more than 4 years ago | (#30013966)

Now the monster of frankenstein (powered by lightning) was in fact the first asimovian positronic robot (ok, the alpha one, without any law). With that much discussion about who could be the author to write Asimov's stories, maybe the original Mary Shelley could be the one worthy for that task.

Time to modulate the shields (0)

Anonymous Coward | more than 4 years ago | (#30014000)

It's the only way.

Re:Time to modulate the shields (5, Funny)

Anonymous Coward | more than 4 years ago | (#30014038)

What the fuck? You just graduate from the Academy?

Modulating the shields leaves you vulnerable to phased weapon attacks.

"The only way" is to reorient the tractor beam vectors to generate a harmonic subspace bubble around the vessel.

Fucking amateur.

Re:Time to modulate the shields (5, Funny)

Anonymous Coward | more than 4 years ago | (#30014722)

Just to steer the conversation back on topic, your harmonic subspace bubble isn't going to do jack to protect you from the gamma-ray discharge from an antimatter/matter conversion on it's perimeter. In fact it might cause a toroid-effect and trap the gamma-rays inside your shields, interfere with your sensors and might even take some crucial subsystems offline.

Only a combined strategy of cryptographic spread-spectrum modulation of shields combined with aggressive targetted tractor beam vectoring can keep you safe from localized radiation effects and energy weapons. You really need to keep abreast of the technology in these matters or you could leave yourself, your crew, and very valuable data and equipment at risk.

Posted anonymously for obvious reasons.

Re:Time to modulate the shields (1)

Dogtanian (588974) | more than 4 years ago | (#30015014)

"The only way" is to reorient the tractor beam vectors to generate a harmonic subspace bubble around the vessel.

No, the only way is to take off and nuke the site from orbit.

what exactly did they detect? (-1)

TheSHAD0W (258774) | more than 4 years ago | (#30014018)

The article isn't clear about what they say they've detected. If it's the 511 KeV signature of electron-positron annihilation, then yes, it could mean the presence of antimatter; it could also mean the direct conversion of electrons to energy by some other unexplained means.

Either way, it would be a hell of a discovery, potentially leading to matter-to-energy conversion power generation. To hell with fusion power, this is better!

Re:what exactly did they detect? (1, Insightful)

John Hasler (414242) | more than 4 years ago | (#30014072)

> The article isn't clear about what they say they've detected.

Nuclear fusion reactions in the lightning produce positrons which then react with electrons to produce the observed gamma rays.

Re:what exactly did they detect? (1)

TheSHAD0W (258774) | more than 4 years ago | (#30014244)

Umm... This would be hydrogen + hydrogen = deuterium + positron? That makes sense... Though to be generating enough positrons to show detectable levels of gammas from space, that would be a huge discovery.

"other means" would be more than "unexplained"... (4, Insightful)

jeffb (2.718) (1189693) | more than 4 years ago | (#30014074)

If they're detecting 511KeV gammas generated by "the direct conversion of electrons to energy" not involving positrons, then, yeah, it would be a hell of a discovery, seeing as how it would blow away all those stodgy conservation laws and symmetries and whatnot.

Re:"other means" would be more than "unexplained". (0)

Hurricane78 (562437) | more than 4 years ago | (#30014298)

You act as if that would exclude it from being a possibility that one could check.

Sure, it makes it a very unlikely possibility. But should we just never ever check the unlikely possibilities? That would not get us very far, would it?

Remember: In science, NEVER be arrogant, or too convinced of your theories. Because that is usually when someone comes up with proof that you are wrong, and everybody starts to laugh at you. ^^
(Optionally after some decades of denial.)

Re:"other means" would be more than "unexplained". (5, Funny)

mustafap (452510) | more than 4 years ago | (#30014464)

>Remember: In science, NEVER be arrogant, or too convinced of your theories.

Wow, you haven;t been around academics much have you?

I recall an old joke:

"How many PHDs does it take to change a light bulb?
  One to unscrew it, one to pull the chair from underneath him"

Re:"other means" would be more than "unexplained". (-1, Troll)

Anonymous Coward | more than 4 years ago | (#30014956)

Remember: In science, NEVER be arrogant, or too convinced of your theories. Because that is usually when someone comes up with proof that you are wrong,

Please go have a chat with the global warming alarmists and get them to release the raw data and the algorithms they used to "massage" the data and arrive at their results. It'd be nice if global warming were true, and if it really isn't about the money (creating carbon exchanges, similar to stock exchanges).

Re:what exactly did they detect? (2, Informative)

f3r (1653221) | more than 4 years ago | (#30014130)

...it could also mean the direct conversion of electrons to energy by some other unexplained means.

then for that energy we would need 2 electrons, not one.

Either way, it would be a hell of a discovery, potentially leading to matter-to-energy conversion power generation. To hell with fusion power, this is better!

well isn't fusion a way of matter-to-energy conversion power generator?

Re:what exactly did they detect? (2, Interesting)

TheSHAD0W (258774) | more than 4 years ago | (#30014224)

then for that energy we would need 2 electrons, not one.

511 KeV is the mass-equivalent energy of a single electron or positron, and annihilation results in two gamma photons heading off in different directions.

well isn't fusion a way of matter-to-energy conversion power generator?

Yes, but it's not as clean as direct annihilation would be. It generates neutrons which make the materials used for containment radioactive.

Re:what exactly did they detect? (2, Informative)

Ironsides (739422) | more than 4 years ago | (#30014336)

Yes, but it's not as clean as direct annihilation would be. It generates neutrons which make the materials used for containment radioactive.

Depends on the starting elements. Among others, He3+He3->He4+2p+E. No free neutrons generated, only protons and energy.

clean fusion (0)

Anonymous Coward | more than 4 years ago | (#30014380)

Apart from the problem to only get this reaction and nothing else: All current fusion designs have the shortcoming that they have idea how to get the energy out of the plasma, except by neutrons.
There were some initial designs not going that way avoiding the costy tritium and the problem of having to throw the whole reactor in the heavy-contaminated nuclear trash every few years, but currently all I know being researched on is based on trying to make something (preferably some form of carbon) as radioactive as possible.

Re:clean fusion (1)

Ironsides (739422) | more than 4 years ago | (#30014420)

Easy way to get that reaction and only that reaction would be to use only He3 as the fuel source. No other fuel means no other reactions.

As to "All current fusion designs", that's because we're still trying to make it work in the first place and neutron producing reactions are easier to start with right now. If they could eliminate neutrons from the process now, they would, as it would increase reactor life. Also, energy is not purely extracted by neutrons. If it was, the plasma would heat up indefinitely (Energy, not just neutrons, are produced in fusion) until containment was lost and it exploded. Energy has to be extracted thermally as well.

Re:clean fusion (3, Interesting)

jeffb (2.718) (1189693) | more than 4 years ago | (#30014448)

Well, some of the polywell/Farnsworth enthusiasts hope to harness boron-11/proton fusion. In the most common case, that produces three energetic He nuclei (alpha particles), each carrying two positive charges at several MeV. Surround the reaction zone with collector plates, and you extract the energy directly as high-voltage, low-current DC.

In practice, of course, it's not that simple.

Re:clean fusion (0)

Anonymous Coward | more than 4 years ago | (#30014670)

All the designs I have seen call for tungsten and other LOW activation materials to be used throughout the construction of the reactor, which have very low wear and any radioactive material produced decays within several decades.

Which seems a perfectly acceptable trade off

OTOH, getting energy out, yes it's still a tricky issue, however mostly one of efficiency then fundamental problems.

Re:what exactly did they detect? (1)

Bruha (412869) | more than 4 years ago | (#30014454)

No, of all our technology to produce power it still involves boiling water.

Tapping these nuclear sources directly would be a step forward.

Re:what exactly did they detect? (2, Informative)

Planesdragon (210349) | more than 4 years ago | (#30014574)

No, of all our technology to produce power it still involves boiling water.

Except for internal combustion, photovoltaic solar, molten-sodium solar, hydroelectric, wind, or using an alternator instead of a break to provide resistance to excersie equipment.

Yeah, so, aside from all of those, everything uses boiling water.

Re:what exactly did they detect? (1)

peragrin (659227) | more than 4 years ago | (#30014648)

Molten sodium is used to boil water. Wind and water and internal combustion spin generators other ways. Only photovoltaic is a direct electrical source.

Re:what exactly did they detect? (4, Informative)

Bigjeff5 (1143585) | more than 4 years ago | (#30015072)

Boiling water isn't a direct electrical source either, it's all about energy conversion. The easiest way to convert heat into electricity is to first convert it to kinetic energy. The easiest, cheapest, and safest way to convert heat energy to kinetic energy is to boil water and creat a pressure differential to drive a piston or turbine or what have you. It's very effective, and there isn't any compound likely to do the job better than H2O that isn't also prohibitively expensive.

Heat is the easiest form of raw energy to produce, and if boiling water is the easiest, cheapest, and safest way to convert heat energy into kinetic energy (which is then trivial to convert to electrical energy at very high conversion rates).

Heat engines are also still the most efficient form of energy conversion available to us. A typical modern steam turbine generator will convert close to 50% of the heat energy to electricity, and in some applications can convert as much as 90%. Combustion engines are typically in the 30% range, but getting higher, though they have a theoretical hard limit at 37%. Photvoltaic is coming along, but frankly it's still young and the readily available PV cells compare poorly to combustion and turbine engines. The theoretical limit for a single cell is about 40% efficiency (with light concentrators), but new techniques are working around that limit (they use multiple materials in the cell, effectively combining several cells in one) and the current record is around 43%.

The big problem PV has vs combustion or turbine engines is energy density - the fuel sources the later two methods use are significantly more energy dense than plain sunlight. Sunlight throws a lot of energy everywhere, but only a little in any particular spot. Concentrating it effectively has always been a problem.

Re:what exactly did they detect? (1)

Bigjeff5 (1143585) | more than 4 years ago | (#30015100)

Had a mis-statement, I meant turbine engines are the most efficient form of energy conversion available.

Also, ignore the fragment.

Re:what exactly did they detect? (1)

ceoyoyo (59147) | more than 4 years ago | (#30014554)

Fusion releases the binding energy of the fused nucleus. It's like what happens in a chemical reaction except the mediating force is the (residual) strong force instead of the electromagnetic force, so you tend to get more energy. That amount of energy is still very small compared to the total energy represented by the mass of the reactants. It's not really matter to energy power generation because the mass that gets converted to energy is not really "matter" but rather potential energy. You're talking about a process where you actually take some matter and convert it entirely into energy.

Take a simple fusion reaction, 2H + 2H -> 3He + n.

Look at the mass balance of that equation:
delta mass = 2*(mass of 2H) - (mass of 3He + mass of n)
= 2*(2.0141 u) - (3.0160 u + 1.0087 u)
= 0.0035 u.

In contrast, if you found some kind of total conversion method you could convert the entire mass of the reactants into energy. That is, instead of 0.0035 u converted into energy you'd have 4.0282 u -- the total conversion reaction yields more than a thousand times the energy of the fusion reaction.

Re:what exactly did they detect? (4, Informative)

Bigjeff5 (1143585) | more than 4 years ago | (#30014790)

From the first paragraph of the article:

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.

In other words, they have detected 17 gamma-ray flashes due to lightning, and some of them have the signature of antimatter (i.e. the electron-positron annihilation).

I'm not sure how that's not exactly what you're saying they didn't say. Just because they didn't say 511 KeV? If 511 KeV is the signature of electron-positron antimatter collitions, and they've found the signature of antimatter collisions in some (not all) of the storms, wouldn't that suggest they are seeing 511 KeV bursts?

Here's more:

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.

It seems pretty specific about what they are seeing, it is simply stated in a high-level language that the common interested-but-not-knowledgeable reader can understand.

This is essentially an online science news magazine, not a journal for published papers seeking peer review. They are only going to give you the gist of the information at a high-level, and from there if you have better knowledge of the subject you should have an automatic deeper insight into what they might be seeing.

It's not like it's some amature job either, the space telescope was built to find this sort of thing, so finding these signatures is not like some wack job pop-sci company pushing nonsense in a press conference to attract investors before folding in a few years.

Wait, I'm confused... (0, Redundant)

d3ac0n (715594) | more than 4 years ago | (#30014020)

Does this mean that Star Trek style warp drive only works in an "Electric Universe" physics model? Or does it mean that we don't have to worry about crossing the streams once we reach 55mph?

Great Scott!

Not that surprising (4, Interesting)

tylersoze (789256) | more than 4 years ago | (#30014044)

Apparently they've detected gamma ray energies up to 20 MeV from thunderstorms, so given that amount of energy involved I wouldn't think it's that surprising that electron-positron pairs might be created in the process since an electron only has a mass of .511 MeV. The thunderstorms are basically operating like natural linear accelerators.

Re:Not that surprising (1)

astar (203020) | more than 4 years ago | (#30014724)

hmm, no chance that it is something useful, like maybe a more efficient way to produce positrons?

Re:Not that surprising (0)

Anonymous Coward | more than 4 years ago | (#30014960)

Who are you, John Galt?

reversal schmersal (4, Insightful)

Anonymous Coward | more than 4 years ago | (#30014052)

Antimatter in lightning does not suggest that the electric field got reversed; that's nonsense. The electric field is a vector, and it can point in any direction.

What it does suggest is either that the few positrons created or brought by cosmic rays are somehow concentrated by lightning, or that the strong electric fields in lightning are actually pulling a few positron-electron pairs out of the quantum electrodynamic vacuum. The first explanation is probably ruled out unless positron decay gamma rays are also seen all over in the atmosphere, just not as densely concentrated as in lightning.

The second explanation is perfectly possible, if the electric fields in lightning are simply strong enough over large enough volumes of space. Any potential difference greater than 2 m c^2/e will in theory produce positrons and electrons from nothing; this is called 'the Schwinger Effect'. But the rate is ridiculously low unless the field is enormous, and it has not yet been observed. Relatively straightforward calculations would allow one to estimate what sort of electric fields lightning would need to involve, for the observations to be due to the Schwinger Effect.

Re:reversal schmersal (2, Funny)

Anonymous Coward | more than 4 years ago | (#30014150)

quantum electrodynamic vacuum

positron decay gamma rays

You're good!

Re:reversal schmersal (-1, Offtopic)

Anonymous Coward | more than 4 years ago | (#30014174)

Yeah, you better post all that fact and expert information as AC! This is Slashdot, we'll not have any of that shit in here.. If we ever catch you in person, you'll be so deep in karma-pithole that no positive comments will ever escape again.

Let it be the last time,
Slashmob

Re:reversal schmersal (1)

boudie2 (1134233) | more than 4 years ago | (#30014314)

A lot of people don't know that Schwinger himself was also very entertaining at dinner parties, and a bit of a lothario. Hence the term sha-wing!

Re:reversal schmersal (0)

Anonymous Coward | more than 4 years ago | (#30014362)

Nothing to do with swinger parties then?

Re:reversal schmersal (1, Funny)

Hurricane78 (562437) | more than 4 years ago | (#30014332)

reversal schmersal

the Schwinger Effect

Aaahh... a bit of German makes every scientific topic cool.
We only lack a "färbottenärr Krruppstahl Gammastrrahlänn-Krriegsmaschinenapparraturrr" in there somewhere. Jawohl! ;)

Wundabar! Jahaha!

Re:reversal schmersal (0)

Anonymous Coward | more than 4 years ago | (#30014812)

Insert lame-ass Wayne's World reference here.

Re:reversal schmersal (1)

drinkypoo (153816) | more than 4 years ago | (#30015492)

It's always been my understanding (well, since I was a pre-teen or so) that lightning is not a one-way process. My understanding is that the current flow does indeed reverse several times during a strike, that it's A/C and not D/C. Commentary?

Been looking a long time (2, Informative)

Anonymous Coward | more than 4 years ago | (#30014064)

Researchers have been looking for the tell-tale 0.511 MeV photons for decades in lightning storms. The idea is that a lightning channel could act like a natural particle accelerator. So electron-positron pairs could be created. But they have never been seen before from what I understand. But maybe these particles were created in much larger lightning bolts or perhaps the emissions are preferentially directed upwards into space ... dunno. Very interesting.

Jigawatt (0)

Jojoba86 (1496883) | more than 4 years ago | (#30014092)

Not that surprising, with all those jigawatts of energy in lightning...

Re:Jigawatt (-1, Flamebait)

Anonymous Coward | more than 4 years ago | (#30014110)

A nigga that just stole something generates 1.21 niggawatts.
If only there was a way to harvest this energy on a powerplant scale.

Re:Jigawatt (0)

Anonymous Coward | more than 4 years ago | (#30014842)

There is! Use the hot air from all the racist redneck fucktards to ignite and burn all the niggers.

This was first observed in 1971 (5, Informative)

mbone (558574) | more than 4 years ago | (#30014132)

It’s a surprise to have found the signature of positrons during a lightning storm, Briggs said.

No, it's not.

There is a long history of observations and theorizing about gamma ray flashes from lightning strikes and ball lightning, starting in the early 1970's :

Is Ball Lightning caused by Antimatter Meteorites? [nature.com]
D. E. T. F. ASHBY, C. WHITEHEAD, Nature 230, 180-182 (19 March 1971).

This has also been observed in connection with "sprites [harvard.edu] ".

And from thunderclouds [arxiv.org] without lightning [arxiv.org] .

Oh, and it's also been observed from space before :

RHESSI Observations of Terrestrial Gamma-Ray Flashes [harvard.edu]

Now, not all of these reports include a positron annihilation signature at 511 KeV. But, 511 KeV emissions were explicitly reported from lightning in the 1970's [nature.com] . And, considering that lightning / thunderstorm related gamma rays are routinely observed with energies up to 10 MeV, there is plenty of energy to create positrons, and so I wouldn't be surprised if all of these reports included the positron annihilation line (or, at least the ones with sensitivity in that energy range).
 

Re:This was first observed in 1971 (5, Funny)

Anonymous Coward | more than 4 years ago | (#30014220)

Did you stumble into this forum by mistake? Come back when you have some baseless conjecture or a conspiracy theory.

Re:This was first observed in 1971 (0)

Anonymous Coward | more than 4 years ago | (#30014226)

Pair production in energetic plasmas is well known. Example:

http://www.springerlink.com/content/c7m0606n40840552/

So why not in the highly energetic plasma created by a lightning strike?

Re:This was first observed in 1971 (2, Informative)

mbone (558574) | more than 4 years ago | (#30014330)

Why not indeed ?

This sounds reasonable to me :

The lightning associated gamma rays can be inferred as due to bremsstrahlung associated with electrons released moments after the return stroke and the likely radiation associated with radioactive decay products in the interactions of protons generated in the lightning with the atmospheric constituents

(from Jayanthi et al., 2006 [harvard.edu] ).

Although the previous reports of lightning induced fusion from Slashdot [slashdot.org] are intriguing.

Re:This was first observed in 1971 (2, Informative)

mbone (558574) | more than 4 years ago | (#30014302)

I am in Japan, and jet-lagged - I mean to say

Now, not all of these abstracts report include a positron annihilation signature at 511 KeV.

I have read these papers (and others) and IIRC 511 KeV reports are fairly common, but I don't have them in front of me to be sure.

Re:This was first observed in 1971 (2, Interesting)

calidoscope (312571) | more than 4 years ago | (#30015086)

And, considering that lightning / thunderstorm related gamma rays are routinely observed with energies up to 10 MeV, there is plenty of energy to create positrons, and so I wouldn't be surprised if all of these reports included the positron annihilation line (or, at least the ones with sensitivity in that energy range).

Considering that pair production starts becoming significant at gamma energies above 5 MeV (threshold 1.022 MeV), I would be very surprised if there weren't some 0.511 MeV gammas from thunderstorms. It is also likely that the positrons could be formed by interaction between high energy electrons and matter.

I would think that the gammas are produced in conjunction with sprites (cloud to ionosphere) rather than normal cloud to ground strokes.

Electron-Proton Collisions? (0)

RAMMS+EIN (578166) | more than 4 years ago | (#30014196)

Is the radiation you observe when a positron is annihilated different from what you would see if, say, an electron collided with a proton?

Re:Electron-Proton Collisions? (1, Insightful)

Anonymous Coward | more than 4 years ago | (#30014222)

If an electron collided with a proton, you'd see hydrogen.

Re:Electron-Proton Collisions? (1)

Winckle (870180) | more than 4 years ago | (#30014232)

Well you wouldn't 'see' it. :)

Re:Electron-Proton Collisions? (5, Informative)

mbone (558574) | more than 4 years ago | (#30014432)

No, you don't get annihilation from electrons and protons.

You do get radiation, if things are energetic enough. If the electron becomes bound to the proton, you get emissions at one of the Hydrogen lines.

If, for example, the electron went all the way to the Hydrogen ground state, you would have emissions at the limit of the Lyman Series [wikipedia.org] , up in the hard UV at 91 nanometers.

If things are more energetic, you will get electrons and protons combining to form free neutrons. These will decay [gsu.edu] (this decay is called beta decay) and release gamma rays at 782 KeV, but since the half life of free neutrons is 10.3 minutes, this will be really spread out in time and hard to see. Free neutrons have been directly detected from lightning strikes, so some of this is presumably going on.

Re:Electron-Proton Collisions? (1)

RAMMS+EIN (578166) | more than 4 years ago | (#30014522)

So you are saying that electron-proton collisions probably do occur, but do not lead to the observed gamma radiation TFA mentions?

Re:Electron-Proton Collisions? (4, Informative)

mbone (558574) | more than 4 years ago | (#30014576)

Electron-proton collisions will not lead to a 511 KeV line. That's due to electron-positron collisions.

Re:Electron-Proton Collisions? (1)

Lehk228 (705449) | more than 4 years ago | (#30014404)

well to start with electrons and protons don't destroy each other. if they were somehow forced together and you threw in an anti-neutrino maybe you could force the reverse of a neutron decay and make them into a neutron, but first you would need to figure out how to force them all together and how to convince the quarks involved to shuffle identities.

so if it's even possible within the laws of physics it's probably at least a thousand years before we can do anything like that, and i don't see any reason to be doing it in the first place since it's pretty easy to find neutrons so why try to make them?

Isn't scientific discovery great? (0)

Anonymous Coward | more than 4 years ago | (#30014204)

I think all our hopes and dreams are found right here in this solar system.

Whoa there, cart before horse? (2, Interesting)

Ancient_Hacker (751168) | more than 4 years ago | (#30014436)

Could it be the other way around, that cosmic rays trigger lightning? So the timing is just a coincidence?

Re:Whoa there, cart before horse? (1)

John Hasler (414242) | more than 4 years ago | (#30014544)

No. These observations were made with a telescope. That means that they know what direction the gamma rays came from. Cosmic rays don't come up out of the Earth.

Really surprising? (0)

Anonymous Coward | more than 4 years ago | (#30014462)

Let us see.. the electric field that gives rise to lightning discharges measures, what, 100 MV? In that field electrons and singly charged ions could, in principal, be accelerated to energies up to 100 MeV. The rest mass of an electron is 0.51 MeV, the rest mass of an electron-positron pair thus is 1.02 MeV. No, most electrons and ions would not attain these energy levels due to collisions etc. but some might get up to the required level to generate e-p pairs. The p will annihilate some e and, voila, you have your 1.02 MeV gamma photons.

See a lightning strike as in particle accelerator with an in-situ target.

Is it just me (0)

Anonymous Coward | more than 4 years ago | (#30014656)

or is anyone else having a hard time differentiating between real science and star trek jokes?

Re:Is it just me (1)

eric-x (1348097) | more than 4 years ago | (#30014788)

I'm using a -3 funny modifier, the problem is that not all "jokes" are modded funny. It would be much better if the poster could mod his/her own post to indicate the intention of the post.

positrons vs electrons (1)

Skapare (16644) | more than 4 years ago | (#30014658)

And they can tell this is the decay of a positron and not an electron by what means? Shouldn't they have the same energy wavelength?

Re:positrons vs electrons (1, Informative)

Anonymous Coward | more than 4 years ago | (#30014902)

Um, because electrons don't decay, douchington?

The forums are full of scientists (0)

Anonymous Coward | more than 4 years ago | (#30014726)

I find it so funny that, everytime a piece of news is posted here about someone discovering something fascinating to the scientific community, there's always a group of people that already knew about it/didn't find the discovery so relevant/etc. These people usually write long posts with technical vocabulary unfolding the misteries of the discovery to everyone, which makes me wonder why they are not working in these laboratories already where they could have solved these misteries long ago (or maybe I'm wrong and some of them already are working there).

Re:The forums are full of scientists (1)

jack2000 (1178961) | more than 4 years ago | (#30015142)

Often these discoveries are in the context of "discovering this or that phenomenon in practice" and not in theory. They aren't discovered as a new phenomenon, rather a confirmation of theoretical work. As this kind of theoretical work is often though and studied in academic environment you'd often get those people to "explain" what has happened to the unwashed masses.

Cross section of lightning? (4, Interesting)

jasno (124830) | more than 4 years ago | (#30015030)

Does anyone know what the cross section of a lightning bolt looks like? I've always wondered if forces akin to the skin-effect are trying to spread out the electrons while it's constrained in a tube of plasma. Is it round? Is it a sheet? What's the electron density like? What sorts of pressures would you expect in the center of a bolt?

Just curious... but I'm unable to find a google hit and too dumb to simulate it.

Load More Comments
Slashdot Account

Need an Account?

Forgot your password?

Don't worry, we never post anything without your permission.

Submission Text Formatting Tips

We support a small subset of HTML, namely these tags:

  • b
  • i
  • p
  • br
  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>
Sign up for Slashdot Newsletters
Create a Slashdot Account

Loading...