X-rays could reveal where lightning strikes

Swift · #1 (**permalink**) 22-July-2008, 11:26 PM

I didn't know lightning produces x-rays, let alone that one might use it as a tool to understand lightning.

From R&D Magazine

Quote:

Univ. of Florida and Florida Institute of Technology engineering researchers have narrowed the search for the source of x-rays emitted by lightning, a feat that could one day help predict where lightning will strike.
....

An article detailing the UF and FIT team’s findings appears this week in the online edition of Geophysical Research Letters, published by the American Geophysical Union.

The researchers used an array of electric field and x-ray detectors at a UF/FIT-operated lightning research facility in North Florida to hunt the source of x-rays emitted by lightning strokes. Their main conclusion: As the lightning comes down from the cloud toward the ground in 30- to 160-foot stages known as “steps” in a “step leader” process, the x-rays shoot out just below each step, mere millionths of a second after the step completes.

“Nobody understands how lightning makes x-rays,” says Martin Uman, a professor of electrical and computer engineering. “Despite reaching temperatures five times hotter than the surface of the sun, the temperature of lightning is still thousands of times too cold to account for the x-rays observed.”
...

Dwyer said the research is one more step toward using x-rays to understand how lightning travels.

Jigsaw · #2 (**permalink**) 23-July-2008, 05:28 AM

So, if you want to know which tree it's safe to stand under when a thunderstorm interrupts your picnic, all you need to do is whip out your handy-dandy portable lightning x-ray detector-predictor. And when it starts beeping at your tree, scoot.

TrAI · #3 (**permalink**) 30-July-2008, 01:22 AM

Quote:

“Nobody understands how lightning makes x-rays,” says Martin Uman, a professor of electrical and computer engineering. “Despite reaching temperatures five times hotter than the surface of the sun, the temperature of lightning is still thousands of times too cold to account for the x-rays observed.”

I assumed it had something to do with having electrons moving at high speeds and crashing into stuff, and then I read that nobody understands...

I wonder if a prof. of electrical and computer engineering really is the right person to say what is or isn't known about X-ray emission though... It isn't really in that speciality field... The closest a computer engineers usualy comes to X-rays in their work is if they have a CRT with faulty HV limiting and poor shielding... Come to think of it, CRTs will usualy not get anywere as hot as lightning plasma, even when pumping out X-rays...

slang · #4 (**permalink**) 30-July-2008, 08:15 AM

I have seen speculation that cosmic rays may be involved in creating lightning. I wonder if that might also explain this discovery, if multiple cosmic rays might follow the lightning as a preferred path, and impacting air molecules, thus creating x-rays. I apologize in advance for any gross misunderstandings on my part

Robinson · #5 (**permalink**) 30-July-2008, 04:47 PM

Quote:

“Nobody understands how lightning makes x-rays,” says Martin Uman, a professor of electrical and computer engineering. “Despite reaching temperatures five times hotter than the surface of the sun, the temperature of lightning is still thousands of times too cold to account for the x-rays observed.”

Translation - Martin Uman doesn't know how lightning creates x-rays, and doesn't know anybody who knows.

korjik · #6 (**permalink**) 30-July-2008, 04:54 PM

Heck, if you think x-rays are impressive, some storms make gamma rays. They are called Terrestrial Gamma Ray Flashes (TGFs).

Actually, its thought they come from storms. Still trying to nail that part down. They were kinda accidently found by probes like RHESSI

Robinson · #7 (**permalink**) 30-July-2008, 06:39 PM

Quote:

Originally Posted by korjik

Heck, if you think x-rays are impressive, some storms make gamma rays. They are called Terrestrial Gamma Ray Flashes (TGFs).

Actually, its thought they come from storms. Still trying to nail that part down. They were kinda accidentally found by probes like RHESSI

Cool. Thunderstorms also have vast streamers and energetic jets above them that reach to the ionosphere. Nobody knows yet what the connection between the ionosphere and storms is. But there are some interesting theories.

As an aside:

When I hear "scientist" say they are baffled, don't know, or don't believe, I tend to translate their arcane speech into understandable English.

we are baffled = "we thought we knew everything, but now it is obvious we don't"

we don't know = "we disagree with all theories about the possible cause"

we don't believe = "we disagree with the theory, or we discount all evidence"

I find it hard to believe anyone is still mystified about how x-rays are produced.

korjik · #8 (**permalink**) 30-July-2008, 06:57 PM

Quote:

Originally Posted by Robinson

Cool. Thunderstorms also have vast streamers and energetic jets above them that reach to the ionosphere. Nobody knows yet what the connection between the ionosphere and storms is. But there are some interesting theories.

As an aside:

When I hear "scientist" say they are baffled, don't know, or don't believe, I tend to translate their arcane speech into understandable English.

we are baffled = "we thought we knew everything, but now it is obvious we don't"

we don't know = "we disagree with all theories about the possible cause"

we don't believe = "we disagree with the theory, or we discount all evidence"

I find it hard to believe anyone is still mystified about how x-rays are produced.

It isnt that there is any mystery on how the X-rays are produced. More it is that it isnt known what set of events leads to the production of x-rays.

sabianq · #9 (**permalink**) 30-July-2008, 07:02 PM

Quote:

Originally Posted by slang

I have seen speculation that cosmic rays may be involved in creating lightning. I wonder if that might also explain this discovery, if multiple cosmic rays might follow the lightning as a preferred path, and impacting air molecules, thus creating x-rays. I apologize in advance for any gross misunderstandings on my part

no misunderstanding.

check this out, nobody really knows how lightening is triggered, however, there is a lot of evidence that suggests that cosmic rays are to blame.

http://adsabs.harvard.edu/abs/2004AGUFMAE41A..01B

Quote:

Recent theoretical work, such as that of Gurevich, Milikh, and Roussel-Dupre (1992) and recent observations of X-ray emissions during times of observed elevated electric fields in thunderstorms, such as those by Eack et al. (1996) suggest that the combination of ionization by cosmic-rays and runaway breakdown may well be responsible for initiating electrical discharges in thunderstorms as suggested by Gurevich, Zybin, and Roussel-Dupre (1999).

http://arxiv.org/ftp/astro-ph/papers/0504/0504269.pdf
http://news.nationalgeographic.com/n...ng-rays_2.html
http://www.sciam.com/article.cfm?id=...ause-lightning
http://www-mariachi.physics.sunysb.e..._and_Lightning
http://en.wikipedia.org/wiki/Cosmic_ray
http://www.science-frontiers.com/sf003/sf003p09.htm
http://www.nature.com/nature/journal.../132712c0.html
http://news.softpedia.com/news/What-...ng-77210.shtml
http://www.sciencedirect.com/science...5fcebaaf815294

http://riofriospacetime.blogspot.com...-in-limbo.html

Quote:

The tracks of cosmic rays, striking and scattering particles in the atmosphere, are very similiar [sic] to lightning. Some researchers have suggested that cosmic rays are the cause of lightning!

super interesting!
Cheers!

Robinson · #10 (**permalink**) 30-July-2008, 08:30 PM

Indeed, indeed.

What Max · #11 (**permalink**) 30-July-2008, 08:48 PM

i thought lightning strikes upwards, not downwards....

slang · #12 (**permalink**) 30-July-2008, 09:59 PM

Thanks, sabianq, bookmarked to read when I'm less tired.

ryanmercer · #13 (**permalink**) 31-July-2008, 02:39 AM

That is kinda cool

Thanks for posting that.

Robinson · #14 (**permalink**) 31-July-2008, 03:54 AM

Quote:

Originally Posted by korjik

It isn't that there is any mystery on how the X-rays are produced. More it is that it isn't known what set of events leads to the production of x-rays.

Translation: "it isn't known" = we don't agree with C.T.R. Wilson's theory, or with Alex Gurevich's theories. Well, actually both theories are almost the same.

Robinson · #15 (**permalink**) 31-July-2008, 03:57 AM

Quote:

Each bolt travels at around a third of the speed of light, reaches temperatures as hot as the sun's corona, and carries about 10,000 times as much current as a household circuit. No wonder lightning triggers more than a third of North America's power cuts each year, and kills hundreds of people worldwide.

The sheer electrical power of lightning has had researchers baffled.

http://www.newscientist.com/channel/...mg18624981.200

Translation: researchers baffled = we thought we knew everything but it is obvious we don't

Kaptain K · #16 (**permalink**) 31-July-2008, 04:38 PM

Quote:

Originally Posted by What Max

i thought lightning strikes upwards, not downwards....

Well, yes and no! The "leader" usually snakes upward in fits and starts. When it makes a connection, the main bolt follows the ionized trail back down!

publiusr · #17 (**permalink**) 01-August-2008, 08:55 PM

It doesn't sound like it would give very much warning time.

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