Reminds me of Hyperion Tesla trees.
Ultraviolet corona discharges on treetops during storms
51–60 of 69 posts
Re: Ultraviolet corona discharges on treetops during storms
#52Earlier quoted context omitted.
This reminds me of a chat room interaction I had maybe 25 years ago. The other person was adamant that humans can't see the infrared from TV remotes, and I was adamant that I could. It was pretty a widespread belief (even in school science books) at that time that humans couldn't see infrared. Since then more science was done to prove that, in fact, some humans can see some infrared under some conditions. I share tha…
I suppose this also depends on the types of remote controls? There are some where I can see red and some where I cannot.
The faint red glow is actual red light as many IR LED's (esp the ones used in cameras for night illumination) are close to the visible spectrum and have some visible light emission.
Re: Ultraviolet corona discharges on treetops during storms
#53Earlier quoted context omitted.
You can absolutely see corona discharge like that with your eyes. If you come to my day job, and we shut off all the lights in the test room, after your eyes adjust in the dark for a minute, you'll see the soft purple glow coming from the edge our 160kV test rig. Definitely emits UV, but there is enough visible to see it for sure. It comes from the electrons exciting nitrogen in the air.[1] 1. https://commons.wikimed…
> (1:If you come to my day job), and (2: we shut off all the lights) (3:in the test room), (4:after your eyes adjust in the dark for a minute), you'll see the soft purple glow coming (5:from the edge our 160kV test rig). So, 5 different things that make it glow "not coming from treetops". Parent poster wanted to see glowing treetops in a forest, where we might not be adjusted to dark for a minute. You can also see su…
Even a smallish Tesla coil easily produces voltages north of 160kV. I built one using 4" PVC for the secondary with a wound length of maybe ~2 feet of secondary? From memory of the calculations I did at the time I think it was around 350 kV peak? Might have been higher. Threw 24 inch sparks quite easily.
Re: Ultraviolet corona discharges on treetops during storms
#54Earlier quoted context omitted.
The headline suggests that people have seen treetops glowing and it just hasn’t been captured on video before. The actual pictures and video is of something that nobody could have seen with their eyes.
This reminds me of a chat room interaction I had maybe 25 years ago. The other person was adamant that humans can't see the infrared from TV remotes, and I was adamant that I could. It was pretty a widespread belief (even in school science books) at that time that humans couldn't see infrared. Since then more science was done to prove that, in fact, some humans can see some infrared under some conditions. I share tha…
Isn't infrared, by definition, wavelengths beyond what people can see?
Re: Ultraviolet corona discharges on treetops during storms
#55Earlier quoted context omitted.
I suppose this also depends on the types of remote controls? There are some where I can see red and some where I cannot.
The faint red glow is actual red light as many IR LED's (esp the ones used in cameras for night illumination) are close to the visible spectrum and have some visible light emission.
850nm is easily visible, but most remotes are 940nm, which is also visible as a faint purple glow but the source needs to be really bright.
Re: Ultraviolet corona discharges on treetops during storms
#56Earlier quoted context omitted.
The headline suggests that people have seen treetops glowing and it just hasn’t been captured on video before. The actual pictures and video is of something that nobody could have seen with their eyes.
You can absolutely see corona discharge like that with your eyes. If you come to my day job, and we shut off all the lights in the test room, after your eyes adjust in the dark for a minute, you'll see the soft purple glow coming from the edge our 160kV test rig. Definitely emits UV, but there is enough visible to see it for sure. It comes from the electrons exciting nitrogen in the air.[1] 1. https://commons.wikimed…
I’m not saying it can’t be seen, I’m saying that you can’t prove something can be seen by showing me a photo that captures light that I can’t see.
Re: Ultraviolet corona discharges on treetops during storms
#57I once was about 30-50ft from where lightning struck, standing on my porch looking towards my neighbors' house. I didn't see the actual strike happen but I did feel my hair stand on end and then see basically this coming off of the leaves reaching up towards the sky. Little purple tentacles all reaching upwards. But then I got to the point in the article where they seemed to explain this wasn't visible to the naked e…
> I did feel my hair stand on end I've experienced this when a strike hit power lines above my head. I didn't see the actual strike either - my friend a the other end of the driveway said it was right above me, but that sounds a little hyperbolic to me despite the ringing in my ears. I think we'd both be dead if it were that close. Either way, it gave me a lifelong respect for lightning.
Same here! I still love watching it but that moment sent me inside and has definitely made me realize it's better to get inside in some instances!
Re: Ultraviolet corona discharges on treetops during storms
#58There is in fact no photograph of treetops glowing. There is a digital UV-wavelength video of the corona, and a visible-wavelength video of the trees. The paper [1] contains a sole picture with tiny circles indicating where the UV-video detected corona events, overlaid over a frame of the visible-wavelength video. The paper does also contain a video [2] which overlays a somewhat processed version of the UV video over…
That's some weird semantic nitpicking. Wikimedia has a category of "photographs of the Sun": https://commons.wikimedia.org/wiki/Category:Photographs_of_t... Do you think they are not photographs of the Sun because these are not what I see if I look at the sun with my eyes? (In which case I'll see pure white then perma black, I assume.)
Sure, a photo taken in non-visible spectrum is still a photo. And stacking photos taken with different wavelength filters or sensor can also be considered a photo. For example the headline image of the spruce tips taken in a lab is photo. And based on the description of the UV camera in the paper, they did generate UV video of the tree tops.
However, the linked article and associated paper don't have any such photos (or video) of the corona in the treetops. Instead the UV video was processed with a detection algorithm, and then the visible-light photos and video were annotated with graphed dots of where detections were seen. Those dots aren't a photo of the corona by any reasonable definition.
Re: Ultraviolet corona discharges on treetops during storms
#59Earlier quoted context omitted.
That's some weird semantic nitpicking. Wikimedia has a category of "photographs of the Sun": https://commons.wikimedia.org/wiki/Category:Photographs_of_t... Do you think they are not photographs of the Sun because these are not what I see if I look at the sun with my eyes? (In which case I'll see pure white then perma black, I assume.)
Lol. At work, some guy has been pushing a 2-day feature into its 5th week now, with questions like "what do you mean by (database) table?" "Is a database table?" Etc... We have to fill-in RFDs to answer those kind of questions, so the process is massively slow and st...(expunged due to HN guidelines). So yeah, some people really love their semantics and are willing to do whatever it takes to keep it that way. [You ca…
wrong thread?
Re: Ultraviolet corona discharges on treetops during storms
#60Fun fact. Lightning strikes stimulate fungi to produce more mushrooms. Some shiitake and nameko cultivators in Japan have started using electrical shockwaves and gotten dramatically improved yields (sometimes over 200%). Interestingly enough the idea came from Japanese folklore rather than this science It's possible that this is an evolved response. Lightning hitting a tree will turn it into bark which is an excellen…
Ozone: the fast life history signal for the mycelial mind!