
Start of Lightning Bolt Caught on Camera - lelf
http://www.realclearscience.com/journal_club/2015/10/20/start_of_lightning_caught_on_camera_109418.html
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rmcpherson
Great video, the nature article is much more informative than the one linked.

From the nature article, it seems this was the first video of natural
bidirectional lightning, not triggered by rockets or aircraft: "In contrast to
studies of rocket-triggered lightning and lightning initiated by aircraft,
which found delays of 3–6 ms between the onset of negative and positive leader
branches, this natural event exhibited a delay of less than 90 μs (i.e. one
video image)."

This was a negative polarity lightning strike. the most common type. Less than
5% of lightning is positive polarity but they can carry ten times the charge
and exceed a billion volts of potential.

When you read about people surviving lightning strikes it's almost certainly a
negative polarity strike.
[https://en.wikipedia.org/wiki/Lightning#Positive_and_negativ...](https://en.wikipedia.org/wiki/Lightning#Positive_and_negative_lightning)

~~~
omribahumi
Are the positive ones the "bigger" ones?

EDIT: From the linked Wikipedia entry: "Because of the much greater distance
to ground, the positively charged region can develop considerably larger
levels of charge and voltages than the negative charge regions in the lower
part of the cloud."

~~~
TeMPOraL
I didn't know about positive/negative polarity types of discharges, thanks!

Also, having Cloud to Butt extension installed made reading that Wikipedia
quote quite interesting...

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myth_buster
I also like this 10,000 fps video [0] credited to Tim Samaras.

[0] [https://i.imgur.com/W1X1qFI.jpg](https://i.imgur.com/W1X1qFI.jpg)

~~~
heinrich5991
I was wondering how you could talk about a video and then link to a single
image (I think jpg doesn't support animation). But it turns out all of

[https://i.imgur.com/W1X1qFI.jpg](https://i.imgur.com/W1X1qFI.jpg)

[https://i.imgur.com/W1X1qFI.gif](https://i.imgur.com/W1X1qFI.gif)

[https://i.imgur.com/W1X1qFI.png](https://i.imgur.com/W1X1qFI.png)

link to the same GIF. :)

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raverbashing
Ah good thing, so imgur abstracts extensions apparently

Better if you request with .gifv extension, then it's a much smaller (than a
gif) html5 video)

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jrowley
The only issue with gifv is that if you open one on iOS it will pause whatever
music you're listening to at the time. Kind of a bummer and something that
will hopefully eventually get fixed.

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timtadh
Here is the Nature article that this video goes with.
[http://www.nature.com/articles/srep15180](http://www.nature.com/articles/srep15180)
.

~~~
dang
That's obviously more substantive, and HN prefers original sources, but
unfortunately it doesn't include a link to the video, so I guess we'll leave
the URL as is.

~~~
timtadh
It is unfortunately hidden at the bottom as .mov in the supplementary
information section: [http://www.nature.com/articles/srep15180#supplementary-
infor...](http://www.nature.com/articles/srep15180#supplementary-information)
.

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webXL
11k fps. Wow. I will never get tired of watching this stuff.

That got me thinking, is there any theoretical limit to the number of frames
that can be captured in one second?

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skizm
Not that it isn't awesome how fast cameras are, just keep in mind, the clip is
25ms. So at 11,000 fps, that would be 275 images (11 frames per ms). Not sure
if we actually have a camera that can take 11,000 images in 1 second. (I guess
that depends on the resolution)

~~~
rbinv
We do have those, but it does indeed depend on the resolution.

These can do 25k fps at 1280x800 pixels (and 1 million fps at 128x32 pixels):
[http://www.visionresearch.com/Products/High-Speed-
Cameras/UH...](http://www.visionresearch.com/Products/High-Speed-Cameras/UHS/)

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justifier
lightning is enigmatic

and the internet facing community surrounding its research seems divisive

can anyone speak to the sort of research currently being done on the study of
lightning and its initiation?

are there efforts to recreate assumed initial conditions?

thoughts on the source of the huge amounts of directed energy? does the strike
harvest from the vast collection of charged particles within the cloud or is
it created by electrostatic interaction of individual ions, similar to
[http://www.nature.com/nchem/journal/v7/n3/full/nchem.2161.ht...](http://www.nature.com/nchem/journal/v7/n3/full/nchem.2161.html)?

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nosnos
Site down.

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rmcpherson
Direct link to the video:
[https://www.youtube.com/watch?v=4dwBS9nLPbE](https://www.youtube.com/watch?v=4dwBS9nLPbE)

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nosnos
Thanks. Seems to be back now.

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vegabook
a) overloaded site

b) very nice, but is this "Hacker" News? More like Discovery Channel. How is
this interesting from a tech point of view? High FPS cameras. Got it. Got it
long ago.

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wlievens
"High FPS Camera" is a lot more impressive than the latest twitter-controlled
todo-list app or whatever.

