I want to ask a question about a nuclear bomb, specifically about a myth I was told about holding your thumb up to the mushroom cloud to see if you're in range of radiation. Where would this be on topic? Biology, maybe?

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    Can you link to or cite a source that recounts this myth? I don't mean can you do so here, but if you can, you could try Skeptics. (Look at their help center first; they have some special rules.) Commented Aug 30, 2019 at 21:56
  • @MonicaCellio I actually don't have a source, I was told by word of mouth, and being a kid at the time of hearing it, I didn't think to ask, "Where'd you hear that?"
    – user473022
    Commented Aug 30, 2019 at 21:57
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    There are too many factors in play so anywhere you ask it will be a guess (opinion) and likely off topic. There is an online simulator that says 3rd degree burns at 70+km, so running to get behind a metal object would be a better plan than holding your thumb up.
    – Rob
    Commented Aug 30, 2019 at 22:56

1 Answer 1


General answer

Asking about the veracity of (possibly so-called) urban myths is on-topic on Skeptics. Per the help page on scope:

Skeptics Stack Exchange is for challenging unreferenced notable claims, pseudoscience and biased results.

Skeptics is about applying skepticism — it is for researching the evidence behind claims you encounter. It is not for speculation, philosophical discussions or investigating original claims. [...]

If you have a question about the accuracy of public claims made in the media or elsewhere, if you're interested in the evidence behind what you hear or read, then you are in the right place.

I'm guessing the "rule of thumb" you're referring to is the "extend your arm in direction of the mushroom, if your thumb is smaller than it, you're toast"? A claim like this is notable enough to be a fit, and with some research it could be an interesting question.

About your question specifically

It has actually already been asked on Skeptics: Is measuring the size of a nuclear cloud with your thumb an approximate indication of whether you're in the radiation zone?.

Thus, I don't recommend you ask it there, as it would only be a dupe, unless I've misunderstood what you were asking about; in which case, make sure to explain the difference between your question and this earlier one.

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