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Witnesses of nuclear explosions have described their hands becoming transparent, and that they could see the bones. For example, see here. How does that happen?

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    $\begingroup$ Supported on this video . I disagree with the premise of the question. $\endgroup$
    – user190081
    Sep 11, 2018 at 16:31
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    $\begingroup$ you should give a link to the video that claims this $\endgroup$
    – anna v
    Sep 11, 2018 at 16:41
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    $\begingroup$ Everything has the potential to be "transparent" to certain radiation. Your hands are already transparent to neutrinos, X-rays (partially), gamma radiation... it turns out they're transparent to sufficiently bright light also. Test it out with a torch. $\endgroup$ Sep 12, 2018 at 10:15
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    $\begingroup$ Experiment for you: In a dark room, cover a flash light with your fingers. Your mobile phone's flash light should be sufficient (if any). $\endgroup$
    – phresnel
    Sep 12, 2018 at 11:47
  • $\begingroup$ I think I read about this in Richard Feynman's book "Surely you're joking, Mr Feynman?". I read it a long time ago, but I think I remember a passage where he talks about witnessing the first nuclear test, and not wearing the safety glasses he was given because he was observing from behind a pane of glass, which would block the most dangerous UV radiation. Here's where my recollection is more hazy: he either spoke about himself covering his eyes with his hands, OR he recounted stories from soldiers who had done so; and the experience was an afterimage of the hand's skeleton. $\endgroup$
    – Aaron F
    Sep 13, 2018 at 11:46

2 Answers 2

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Have you never seen the bones of your hand when covering a flash light at night? Imo it was just a very bright light over a large area and trying to shield the eyes the bones were seen.

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  • $\begingroup$ That was my best guess as well. Will see if the question produces an idea that is better then that. It would be interesting to reproduce (not just with a flashlight, but with a light source equivalent to what those people experienced. ) $\endgroup$
    – radon
    Sep 11, 2018 at 17:51
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    $\begingroup$ @annav You might be surprised. It's hard to compare a deposited energy density to an energy flux, but if I'm reading the Synlight press material correctly, they can achieve intensities of the order of 10 MW/m$^2$ for extended periods of time, so they'd be able to deposit that energy density (though maybe only on a small target?) in a small fraction of a second. You certainly don't want to put human test subjects there, but it looks doable to me. $\endgroup$ Sep 11, 2018 at 18:32
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    $\begingroup$ @radon why do you need "a better idea"? A bright enough light shines right through one's flesh and skin. Nuclear explosions are bright. Mystery solved. $\endgroup$
    – IMil
    Sep 11, 2018 at 22:58
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    $\begingroup$ Or just use brighter and brighter lights until you can extrapolate what would happen in extreme light. You don't really need to match nuclear explosion level of brightness on the initial testing. $\endgroup$
    – Nelson
    Sep 12, 2018 at 1:05
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    $\begingroup$ @jkej "Clear image" may be an exaggeration or a false memory. High levels of stress tend to do this to you. Like, for instance, when nuclear bombs go off in your vicinity. $\endgroup$
    – IMil
    Sep 12, 2018 at 23:08
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Skin and flesh are of different ability to stop light. Extremely bright light can be detected through a thin layer of skin.

Also, a nuclear weapon releases electromagnetic energy all up and down the spectrum. Different wavelengths have different ability to penetrate. Here is a guy showing interesting effects with infrared.

https://www.youtube.com/watch?v=QaKxCMPLhTE

His example is a lot of fun because the wavelengths he is using penetrate but don't do any harm. The radiation released by a nuclear weapon includes wavelengths that are very harmful. But they can penetrate and scatter. When they scatter there is some tendency for them to scatter to lower wavelengths which are then visible.

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    $\begingroup$ In the video you cite, the person is using an IR camera, he mentions "Quite bright but you have to use an IR camera; you will not see anything with bare eyes. " $\endgroup$
    – radon
    Sep 11, 2018 at 16:41
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    $\begingroup$ @radon but he didn't use a nuclear bomb as a light source ! $\endgroup$ Sep 11, 2018 at 19:18
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    $\begingroup$ @MartinBeckett You aren't going to see IR, even if a nuclear bomb is releasing it. $\endgroup$
    – forest
    Sep 13, 2018 at 0:50
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    $\begingroup$ Scattering doesn't change wavelength of incident light, only direction. A tiny fraction of the energy of a nuclear bomb is going into visible light, though it is likely still enough to appear as a very bright strobe and for this existing visible light to pass in a detectable amount through the flesh of a hand. $\endgroup$ Sep 13, 2018 at 6:44
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    $\begingroup$ @forest Depends on the kind of infrared. There isn't a hard cut-off, the eye just gets gradually less sensitive. If your (near) IR source is bright enough you definitely can see it, it just might not be eye safe (but nobody has claimed that nuclear bombs are eye safe ...). $\endgroup$
    – etarion
    Sep 13, 2018 at 8:31

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