If someone has the magical ability to make a vacuum(no or minimal matter/atmospheric pressure) on earth around someone would that person in the vacuum then sh*t their pants? If so would it have to be a perfect vacuum?

A small bit of background. This would be like a spell or magical ability someone had. The question is related to a comedic scene/running theme I thought of while researching a bit about what happens to people in vacuums.

Edit: one of the methods I was thinking of using was like a trap/ritual/device that would be placed on the ground that would create a small vacuum over a certain length of time(maybe long or short) and the vacuum would last for a short time. small particles would be pushed away but people wouldn’t really notice the pushing effect when passing through. Just magic stuff :).

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    $\begingroup$ Well yes, I suppose they might, but then a guy in a rubber mask leaping out at them from behind some bushes might have the same effect if it was unexpected enough .. so these subjects of this sudden event response experiment of yours, do they have any underlying conditions? like incontinence or a particularly nervous disposition? $\endgroup$
    – Pelinore
    Jan 31, 2023 at 22:40
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    $\begingroup$ Decompression will not cause a "brown out." That NASA study exposed a number of chimpanzees to the conditions you are talking about. There is no mention of "soiled trousers." The review of other publications that it includes does not mention anything along those lines, either. Vacuum won't "suck it out." At most, you might have a person with an extreme reaction who messes his pants as a reaction to the surprise. $\endgroup$
    – JRE
    Feb 1, 2023 at 9:43
  • $\begingroup$ Fascinating study. I would have assumed a few seconds of vacuum kill you, but it looks like it's survivable for up to 2 and a half minutes. $\endgroup$
    – Hakaishin
    Feb 1, 2023 at 10:39
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    $\begingroup$ @Hakaishin, "2 and a half minutes" seems kind of long. Sucking vacuum is not like holding your breath. Dissolved gasses (e.g. oxygen) in your blood escape through your lungs very quickly. I've read that you'll lose consciousness within ten seconds (typical) or fifteen seconds (at the most). If somebody could "survive" after two and a half minutes, that doesn't necessarily mean that they would recover full brain function. $\endgroup$ Feb 1, 2023 at 14:18
  • $\begingroup$ I am not sure that surprise (even if extreme and unpleasant in nature) will catalyze an instance of defecation. Maybe a code yellow, in children or the elderly. Has anyone actually witnessed this? $\endgroup$ Feb 1, 2023 at 16:15

3 Answers 3


Not immediately. There would be other grave medical issues that would cause pretty severe results leading to death before any comedic "poopy pants" happened.

For example, gasses dissolved in the bloodstream would bubble into gaseous form like CO2 does in a carbonated beverage when the top is popped. This would cause brain embolisms and severe joint pain from "the bends".

And yes, gasses in the intestine would expand as well, but intestines are flexible so the effects would be a feeling of severe bloating and gas before they would force out any solid matter.

A more plausible scenario might be some strong form of ultrasound broadcast at a specific frequency that would simultaneously relax all muscles while liquifying internal solid waste in a manner similar to how vibrations cause wet sand to become unset and flow in a liquid manner.

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    $\begingroup$ The additional plausible scenario is appreciated. I was actually going to ask you if you had an bout that! Not every idea lands so I'll scrap it for now. The goal was more along the lines of a prank and less along the lines of a brain embolism. $\endgroup$
    – Woli
    Feb 1, 2023 at 2:56
  • $\begingroup$ @Woli, well, maybe not ultrasound, but I have had cars pull up next to me with massive subwoofers and the bass has loosened my stool enough to make me wonder if I'd be able to hold it in! Seriously though, I have heard that there are certain frequencies that cause nausea and can be used to disperse crowds. $\endgroup$ Feb 1, 2023 at 3:27
  • $\begingroup$ I'll take a look at that. That would be an interesting route to go down. I've got some new ideas to look into after thinking on the topic both related to the original question and some different scenarios. Some new inspiration is always welcome. $\endgroup$
    – Woli
    Feb 1, 2023 at 3:54
  • $\begingroup$ Well, there's an effect of fear that can cause a "drop all" reflex hidden somewhere, added to the pressure difference, so I say that the person would first poop then die, if the vacuum exposure would be prolonged. $\endgroup$
    – Vesper
    Feb 1, 2023 at 7:34
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    $\begingroup$ The brown note is a myth... If this guy is asking about the scientific plausibility of vacuum shitting, that probably rules this out too $\endgroup$ Feb 1, 2023 at 14:54


If I understand your question correctly, our hapless adventurer was walking along, minding his/her own business, enjoying the view, keeping an eye out for Kobolds... when suddenly some pestiferous mage stomping away from a three-day loosing streak gambling at the local tavern and nursing a nasty headache from swimming in the worst honey mead he'd ever had decides to return the cosmos to universal balance by sucking our adventurer into a torrid vacuum of death. Let me know if that's too far off what you're imagining.

So, here's the skinny...

According to NASA's bioastronautics data book, the vacuum of space would also pull air out of your lungs, causing you to suffocate within minutes. (Source)

I figure a vacuum there, a vacuum here, a vacuum is a vacuum, so if you think about it, that's no different from dying from something other than an instantly fatal gunshot or knife wound. In other words, other than it would hurt worse than the devil's own thumbscrews, we're not talking about anything unique or special. Putting a pillow over someone's face would lead to the same result. And what is that result? Among other things...

Your muscles loosen immediately after death, releasing any strain on your bowel and bladder. As a result, most people poop and pee at death. (Source)

So, yup, within a few minutes those kobolds lurking behind the bushes will have some free clothing in desperate need of dry cleaning. But the mage will feel better — especially if there's a bonus of popping a few kobolds.

  • $\begingroup$ so yes, but not why you think. awesome +1 $\endgroup$
    – John
    Feb 2, 2023 at 0:08
  • $\begingroup$ Southpark got it right $\endgroup$ Feb 2, 2023 at 0:44

Irrelevant--this very quickly inflicts lethal damage as the air rushes out of the lungs. So long as the vent isn't too big (IIRC 1% of the surface area of your habitat) you simply get the effects of a lack of oxygen, pass out in 10-15 seconds and likely lethal after a couple of minutes (faster than normal because your blood will dump whatever oxygen it has left when it goes through your lungs) but completely reversible if aid reaches you in time.

However, if the hole is too big (and your hole is effectively 100% of the area around them) the air rushes out so fast that it shreds the tissue as it goes. Restoring oxygen won't give you a working lung to breathe it.


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