Explanation: Have you ever watched a lightning storm in awe? Join the crowd. Oddly, nobody knows exactly how lightning is produced. What is known is that charges slowly separate in some clouds causing rapid electrical discharges (lightning), but how electrical charges get separated in clouds remains a topic of much research. Lightning usually takes a jagged course, rapidly heating a thin column of air to about three times the surface temperature of the Sun. The resulting shock wave starts supersonically and decays into the loud sound known as thunder. Lightning bolts are common in clouds during rainstorms, and on average 44 lightning bolts occur on the Earth every second. Pictured, over 60 images were stacked to capture the flow of lightning-producing storm clouds in July over Colorado Springs, Colorado, USA.
I don't understand how charge-separation comes about in terrestrial clouds. And why does the same thing (apparently) not occur in interstellar clouds? Why don't we see cosmic lightning bolts going from one interstellar cloud to another? Or maybe they do occur, but only on distance scales too short for us to distinguish them with our telescopes?
heehaw wrote:I don't understand how charge-separation comes about in terrestrial clouds. And why does the same thing (apparently) not occur in interstellar clouds? Why don't we see cosmic lightning bolts going from one interstellar cloud to another? Or maybe they do occur, but only on distance scales too short for us to distinguish them with our telescopes?
Reckon the atoms are too far apart, among other things. Wouldn't be surprised if some kind of lightning occurs during star and/or planetary formation.
Just call me "geck" because "zilla" is like a last name.
Thunder contains a somewhat cylindrical initial pressure shock wave along the lightning channel in excess of 10 times the normal atmospheric pressure. This shock wave decays rapidly into a sound wave within feet or meters. When thunder is heard from about 328 feet (100 m) distance, it consists of one large bang, yet hissing and clicking may be heard just prior to the bang (upward streamers). When heard at .6 mile (1 km) from lightning, thunder will rumble with several loud claps.
I've been within 100 meters of several lightning strikes and the above is an accurate description. What I don't understand or believe is how the hissing and clicking can be heard several seconds before the bang. Supposedly the shock wave generated by the lightning is supersonic but quickly decays into an ordinary sound wave. Surely that sound wave should arrive well before the hissing and clicking?
Chris, did you spot this monster storm in the distance?
July is thunderstorm season. We don't tend to have them up high where we are once evening comes, but there are flashes on the horizon much of the night (which my meteor camera also picks up, along with sprites above them). This storm was about 75 km east of me. Without knowing the exact date and time I can't say much else.
Chris
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Chris L Peterson
Cloudbait Observatory https://www.cloudbait.com
Thunder contains a somewhat cylindrical initial pressure shock wave along the lightning channel in excess of 10 times the normal atmospheric pressure. This shock wave decays rapidly into a sound wave within feet or meters. When thunder is heard from about 328 feet (100 m) distance, it consists of one large bang, yet hissing and clicking may be heard just prior to the bang (upward streamers). When heard at .6 mile (1 km) from lightning, thunder will rumble with several loud claps.
I've been within 100 meters of several lightning strikes and the above is an accurate description. What I don't understand or believe is how the hissing and clicking can be heard several seconds before the bang. Supposedly the shock wave generated by the lightning is supersonic but quickly decays into an ordinary sound wave. Surely that sound wave should arrive well before the hissing and clicking?
I can think of at least two mechanisms. In some cases the hissing and clicking may be electrophonic noise, which means you are hearing electromagnetic radiation transduced in some way to sound. That is carried to you at the speed of light. Electrophonic noise is also heard in auroras and large meteors. The second is ordinary sound propagation, but from current paths that are established before the main strike.
Chris
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Chris L Peterson
Cloudbait Observatory https://www.cloudbait.com
<<The Symphony No. 6 in F major, Op. 68, also known as the Pastoral Symphony (German Pastoral-Sinfonie), is a symphony composed by Ludwig van Beethoven, and completed in 1808. One of Beethoven's few works containing explicitly programmatic content, the symphony was first performed in the Theater an der Wien on 22 December 1808[3] in a four-hour concert.
Fourth Movement: Allegro : Thunder. Storm.'
The fourth movement, in F minor, depicts a violent thunderstorm with painstaking realism, building from just a few drops of rain to a great climax with thunder, lightning, high winds, and sheets of rain. The storm eventually passes, with an occasional peal of thunder still heard in the distance. There is a seamless transition into the final movement. This movement parallels Mozart's procedure in his String Quintet in G minor K. 516 of 1787, which likewise prefaces a serene final movement with a long, emotionally stormy introduction.>>
I was on a pier in Tampa Bay when a storm moved in. I came prepared with my camera, but was not really prepared for how close the lightning would be. A particularly close bolt landed about 500 feet away, and the instant it flashed, I heard a 'snap' sound like a static discharge. I got a photo of it too.
Here's a link to it: http://pixels.com/featured/seeking-shel ... rritt.html
This image is quite fantastic. It looks manipulated to a large degree--the contrast between the cloud structures, colors, strange shapes in the center of the huge cloud. Even the overall appearance of the cloud is like nothing I've ever seen before. Is there an explanation for the strong diagonal striations of the clouds? And what are those weird purple shapes in the center?
Chris Peterson wrote:Without knowing the exact date and time I can't say much else.
For general background information, in an email the photographer said "The image was taken on 7-7-16 around 8pm at Palmer Park in Colo Spgs, CO. "
That's about an hour before my camera turns on at that time of year, but here's what my sky looked like from about 9-11pm. All that activity is directly towards Colorado Springs in the east. (You can also see a newish Moon setting in the west (upper right), with Jupiter trailing it, and Mars going in and out of clouds down in the lower right corner.)
20160707_21-23.gif (1.62 MiB) Viewed 4587 times
Chris
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Chris L Peterson
Cloudbait Observatory https://www.cloudbait.com
I was in Colorado at that time and took this picture from just east of Bailey. It was a seriously impressive storm. I've done no image manipulation other than cropping. My location was 39.439300, -105.413331 which is about 50-60 miles north northwest of Palmer Park. My camera says it was 8:28pm local time 7/7/2016. I had been watching it and have pictures from about 8:15pm.
I appreciate seeing a different perspective. As soon as I saw Colorado and July, I had to check the date. I thought I had taken a screenshot of the local radar, but maybe it's on a different computer.
bethkatz wrote:I was in Colorado at that time and took this picture from just east of Bailey. It was a seriously impressive storm. I've done no image manipulation other than cropping. My location was 39.439300, -105.413331 which is about 50-60 miles north northwest of Palmer Park. My camera says it was 8:28pm local time 7/7/2016. I had been watching it and have pictures from about 8:15pm.
I appreciate seeing a different perspective. As soon as I saw Colorado and July, I had to check the date. I thought I had taken a screenshot of the local radar, but maybe it's on a different computer.
This is what the radar caught when this APOD was shot.
Chris
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Chris L Peterson
Cloudbait Observatory https://www.cloudbait.com
Lightning over Colorado
The lightening and its clouds is truly dynamic. Or should I say hurly-burly. 
