If you are caught on a golf course during a storm and are afraid of lightning, hold up a 1-iron. Not even God can hit a 1-iron.Today's astronomy picture of the day is absolutely gorgeous.
-Lee Trevino, golfer who actually has been struck by lightning.
Of course, this is the Icelandic volcano, Eyjafjallajökull, erupting and spewing up volcanic ash. But, of course, the most interesting part of this picture is the lightning, which looks like it both originates and ends in the Volcanic ash itself!
(Image credit for both images above: Marco Fulle, via helicopter.)
First off, I'd like to be concrete about this. The way it looks -- that the lightning originates in the volcanic ash -- is exactly the way it is! This isn't some "lucky shot" by a photographer, either. Check out this picture of Eyjafjallajökull from April 17th.
(Image credit: Snaevarr Gudmundsson, through Universe Today.)
Is it just this volcano? Eyjafjallajökull, it turns out, is not remarkable at all for having volcanic lightning. If we look at some other major recent eruptions, we can see volcanic lightning in the ash there as well. Here's Chile's Chaitin volcano, from its 2008 eruption.
(Image courtesy of National Geographic.)
And here's another one: Sakurajima, from its eruption in 1991.
(Image credit: Sakurajima Volcananological Observatory.)
All told, there have been more than 150 different eruptions over the past couple of centuries where volcanic lightning has been recorded. In fact, I've managed to dig up some photographs of volcanic lightning from before I was born! Here's Mount Vesuvius -- and the accompanying volcanic lightning -- from 1944!
(Courtesy of an old tripod.com website.)
Okay, so now you're convinced that lightning happens in volcanic ash all the time. Yes, it makes for a spectacular picture, but how do you get this in the first place?
Well, what is lightning? You create a big enough electric potential difference between two places, and you can get all of these excess charges to "jump down" to the lower potential. In air, it takes a voltage of about 33,000 Volts (!) to get a spark to jump even one centimeter! Lightning that goes from a high cloud down to the ground can have a voltage difference in excess of a billion Volts!
You can do this because you can get a huge amount of charge separation. For example, in a big lightning strike, you separate out about 1020 electrons! But ash and rocks -- even molten rock -- are electrically neutral, right? So how to we get a big voltage from neutral matter?
Thankfully, the ash that comes out is hot enough so that not every particle is neutral: many are positively charged ions and many are negatively charged ions.
If you can make something push the positive ions differently than it pushes the negative ones, you can create a charge separation! If you get enough charges separated, you can make a large enough voltage to give you lightning!
This should be easy, because when you get charged particles moving around, you make electric and magnetic fields, which is exactly the ingredient you need to separate these charges. As long as these fields are here, differently charged ions are doomed to separate away from one another! And as soon as you get a large enough charge accumulated in different parts of the sky, that's the tipping point, and then you get lightning!
And for those of you who like details with your pretty pictures and explanations, there is some uncertainty as to the exact mechanism that gives you this separation of charge. (Some ideas are here, and some research into the topic is available here.) But this really is lightning from within the volcanic ash! It certainly makes for quite a show, so enjoy it, but enjoy it from a safe distance!
Physical Science
Environment
Comments
Good article. It explains something that had perplexed me; why the 3 people who died of a lightning strike during the eruption of the Paricutin volcano in Mexico (the only volcano whose entire life history has been documented by eyewitnesses) were ascribed to the eruption and not a co-incidental storm.
Posted by: waynerobinson4
| April 20, 2010 2:01 AM
........and i believe this ash has benefits too?
Posted by: teraafirma | April 20, 2010 6:22 AM
I was near the base of Mt. St. Helens the morning of May 18th when it erupted. It was an incredible site to be that close and to be able to see the lightening in the ash cloud. Great pictures!
Posted by: Todd Tomlinson | April 20, 2010 8:54 AM
Interestingly the BBC report about a plane that lost all 4 engines a decade or so ago flying through a volcanic plume, and is one reason why all the flights are stopped over much of northern Europe, mentioned the spectacular show of St Elmo's fire set off by flying through the cloud. (The engines did eventually restart after the plane had lost 3/4trs of its initial altitude and everyone landed safely).
Posted by: Tim Kirk | April 20, 2010 11:42 AM
Thanks for explaining the thing out. On first view i was thinking this could be another one of those spooky government activities.
Posted by: Mani Karna | April 20, 2010 4:10 PM
Fark scientists, you're motherfarking liars.
EXPLAIN MAGNETS. You can't.
Posted by: ICP CLOWN | April 20, 2010 5:09 PM
Nature is amazing, and studying it always makes it more interesting.
Thanks for sharing such a nice info
Posted by: Munir | April 20, 2010 5:10 PM
@2
While some of the most fertile soils can be found around volcanoes, this stuff from Eyja isn't so great. It has lots of fluoride salts which is toxic to vegetation and animal life. Icelandic volcanoes also emit lots of hydrogen fluoride which is an extremely corrosive acid.
zeke
Posted by: zeke | April 20, 2010 6:31 PM
Any Hi-Res (1940x1600) images I can use for wallpaper?
Posted by: anon4 | April 20, 2010 7:25 PM
If I remember correctly, Pliny described lightening at the 79AD eruption of Vesuvius.
Posted by: Keith Harwood | April 21, 2010 12:04 AM
@5
There is an episode of the TV show "Air Emergency" (NatGeo channel) about the incident with BA009 in 1984 unwittingly flying through an ash cloud. Amazing stuff. The plane was enveloped by a sort of Saint Elmo's fire and was basically sandblasted. May be some clips online.
@8
Icelandic volcanoes generate HF?!? "Extremely corrosive" doesn't even come close to conveying how scary that stuff is.
Posted by: travc | April 21, 2010 6:05 AM
@11 (@8)
"Corrosiveness" as a measure of acidity has actual, literal, extremes. The "most corrosive" acid would be at that extreme, 0 pH. You can't go beyond the extreme here, like you could at the edge of a cliff.
Posted by: tret | April 21, 2010 9:27 AM
Tret #12, corrosiveness is not just determined by pH, the ability to form complex ions is perhaps a little more important than the pH. HF is corrosive because it forms lots of fluoride complexes with metals and can attack oxides. HF does attack glass, not because of pH but because it forms H2SiF6. Low pH doesn't attack glass because SiO2 isn't attacked by it. A useful way of making chemical glassware more chemically resistant is to leach them with HCl. That leaches out the cations from the glass, leaving a layer of pure SiO2. If you then rinse and dry the glassware at a high temperature that porous layer collapses into a pure SiO2 layer that is more resistant to leaching in acid.
Citric acid is a good complexing agent and so if you mix citric acid with just about anything else it becomes more corrosive. Salt water is corrosive because of the complexing ability of the chloride ion, not because of the pH.
Posted by: daedalus2u | April 21, 2010 11:20 AM
Thank you so much for this - explains it in a way I can use in my classroom of primary school pupils. I really appreciate it.
Posted by: Ros | April 22, 2010 2:17 AM
Indeed very interesting, thanx for sharing!
Posted by: Mary Davis | April 22, 2010 4:02 AM
Notable artículo
muy buena explicación sobre los rayos y la separación de las cargas atómicas
Posted by: Marco | April 22, 2010 3:45 PM
It is odd how something so blatant like lightning can not be understood by Academia due to political correctness, when the common man has understood for many years.
It's probably a good thing for evolution that the individual only last for 100 years, so that petty rivalries can be forgotten!
I think the powers that be, are scared that the public can not handle the truth, maybe true...but still sad.
Or just maybe this is one of those unspoken truths that each individual will have to discover on their own.
And when Academia does figure it out, I seriously doubt that the proper credit will be attributed.
The knowledge is there...it's just obscured.
*in a cynical mood tonight*
Posted by: Sphere Coupler | April 22, 2010 10:00 PM
LOL @ ICP CLOWN!! Thank-you so much for making me laugh my ass off for a long time. Also I posted your comment on my facebook so all my friends could laugh at you as well.. Your absolute STUPIDITY has made my day!!. Thank-you so much, moron! Please don't ever change.
Posted by: Rob Mills | April 23, 2010 10:43 AM
I like your explanation, thank you for sharing it. I witnessed Mount Pinatubo erupting, from 8 miles away. I stood on my back porch and observed orange lightning in the roiling ash.
Posted by: Paul Metting | April 23, 2010 1:39 PM
Eyjafjallajökull is a glacier, not a volcano!
Posted by: rijkswaanvijand | April 24, 2010 8:26 AM
Great explanation; I never knew that!
Have a great day
Tony
Posted by: Anthony | April 25, 2010 6:17 PM
Nice collection! The 3rd image the lightning over the volcano is so amazing but at the same time is so scary...
Posted by: hanzel | April 27, 2010 6:23 AM
In your article you wrote:
You create a big enough electric potential difference between two places, and you can get all of these excess charges to "jump down" to the lower potential.
To be theoretically correct, shouldn't this read: "you can get all of these excess charges to "jump up" to the higher potential" as the excess charges jumping are electrons (minus charges)?
The graphic series "charge separation form in ash cloud" supports my question :)
Posted by: Johann | May 18, 2010 3:45 PM
To Rob Mills: the poster listed as "ICP Clown" managed to hoax you a bit. Elsewhere on the internet, the phrase "f**king magnets, how do they work?" is rather well known. Two rappers known as Insane Clown Posse created a video for their latest release, "Miracles", and at about 1:52 in the video one of the rappers relates that he does not understand how magnets work, but he won't ask a scientist, because scientists are reknowned liars. See more here: http://knowyourmeme.com/memes/f-cking-magnets-how-do-they-work
I laughed for different reasons at ICP Clown's post; a rather well constructed proliferation of a meme.
Posted by: Robert | May 20, 2010 4:29 PM
holy craps those pix are so tight
Posted by: alejandro | August 19, 2010 12:49 PM
thats so cool i never knew lightning came out of volcanoes
totaly awsome!!!
Posted by: mimi | September 1, 2010 11:40 AM