• TitanLaGrange@lemmy.world
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    1 year ago

    what I’m wondering is what would it look like if a human in the deep sea was suddenly exposed to those pressures, as would happen if a submarine rapidly pressurizes?

    Kinda depends on how fast ‘rapid’ is. Consider that the pressure difference between the outside and the inside volume of the sub represents a potential energy. At a depth of 4km for a sub that size you’re talking about the energy equivalent of about 50 kilos of TNT (thanks to Scott Manley’s live stream for the estimate ).

    That’s a lot of energy even if the release is relatively slow, which means that the forces pushing things around as everything comes to equilibrium are quite large. There might be a rate at which the forces are low enough to not significantly damage a human body, but also fast enough that the people won’t drown before the target pressure has been reached. As a guess, an average untrained person under normal conditions could probably last at most 2 to 3 minutes before beginning to drown (an extremely well-prepared person can last 24 minutes 37.36 seconds, the current underwater breath hold record), so that’s like 22 psi per second (equivalent to a descent rate of about 45 feet per second or 30 mph, pretty damn fast).

    I’m skeptical that this would be survivable, and at a minimum it would be extremely painful. As the pressure increases the air in the lungs would compress collapsing the lungs. That alone isn’t a huge problem, breath-holding free divers experience that. However, as the air is compressed the volumes in the skull (nasal sinuses and inner ears) could no longer be pressure-equalized by forcing air into them, so the surrounding tissues would be pressed into them. As anyone who’s flown while congested can tell you even a few pounds of pressure is extraordinarily painful. At 22 psi per second I suspect the forces would at least tear nasal sinus and inner ear tissues, and possibly crack skull bone.