this post was submitted on 30 Jun 2023
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Explain Like I'm Five

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How fast did the people in it die?

Of course once the sub filled with water they would die instantly because it would reach insane pressures (300-400 ATM or 5800 PSI)

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[–] MrRambunctious@lemmy.world 10 points 1 year ago (4 children)

Less than 4 milliseconds. They didn’t feel a thing.

[–] eating3645@lemmy.world 12 points 1 year ago* (last edited 1 year ago) (1 children)

To add context here, it takes your brain somewhere around 100ms to detect and then another 250 to process pain. So 4ms is not only fast, it's absurdly fast.

To get a sense of how fast it is, go ahead and stub your toe, the time it took to feel it is 100 times longer.

https://www.jneurosci.org/content/26/42/10879

[–] platysalty@kbin.social 7 points 1 year ago (2 children)

I just take solace in the fact that they probably just snapped out of existence instead of having to slowly die in a dark tube over a few days.

I had seen a comment saying human to salsa in 4 milliseconds. ಠ_ಠ

[–] JohnEdwa@kbin.social 4 points 1 year ago (1 children)

And because what failed was the carbon fibre composite pressure vessel, it probably didn't even give any warnings to make them worried. It would be like squeezing a glass bottle, everything will be perfectly fine until it just instantly shatters.

[–] I_Miss_Daniel@kbin.social 3 points 1 year ago

Sometimes glass will give a 'click' as a crack starts. Not sure about carbon fibre though.

[–] RetroEvolute@lemmy.world 2 points 1 year ago

Did some math based on that number since it seemed pretty insane. That would mean that each side of the outer hull would have been moving inward at about 425mph by my estimate. Seems slower than I would expect by that number, but 4ms is hella fast.

[–] ndr@lemmy.world 0 points 1 year ago (2 children)
[–] PrincipleOfCharity@0v0.social 1 points 1 year ago

Physics and math. J/k. I’ve seen similar numbers thrown about. Here is a link to a Quora question What happens to the human body when a submarine implodes from 2 years ago that may be of interest.

When a submarine hull collapses, it moves inward at about 1,500 miles per hour - that’s 2,200 feet per second. A modern nuclear submarine’s hull radius is about 20 feet. So the time required for complete collapse is 20 / 2,200 seconds = about 1 millisecond.

A human brain responds instinctually to stimulus at about 25 milliseconds. Human rational response (sense→reason→act) is at best 150 milliseconds.

The air inside a sub has a fairly high concentration of hydrocarbon vapors. When the hull collapses it behaves like a very large piston on a very large Diesel engine. The air auto-ignites and an explosion follows the initial rapid implosion. Large blobs of fat (that would be humans) incinerate and are turned to ash and dust quicker than you can blink your eye.

[–] lorcster123@lemmy.world -1 points 1 year ago (2 children)

Do you think they died from the water rushing in and hitting them unconscious?

[–] MrRambunctious@lemmy.world 7 points 1 year ago (2 children)

They died by being crushed with enough pressure such that the air inside the sub ignited ie compressed so much it essentially exploded. Death was instant.

[–] fubo@lemmy.world 1 points 1 year ago

Put another way: The matter that made up their bodies was very quickly rearranged into other chemicals; much quicker than the long chain-reactions that make up human thought.

[–] lorcster123@lemmy.world 0 points 1 year ago (4 children)

I know a diesel engine works off compression, but it has a fuel. All fires must have oxygen, fuel, and heat. What fuel would they have in the titan to ignite?

[–] SimpleMachine@lemmy.world 3 points 1 year ago

Everything (including the passengers) inside the sub could have been fuel for combustion had there been time for the reaction to take place. If I remember correctly the interior of the sub could have temporarily been hotter than the surface of the sun during the implosion. Pretty sure just about everything burns at those temps. But the collapse and gas release from the hull happened so quickly I doubt there was time for anything to ignite.

[–] MrRambunctious@lemmy.world 3 points 1 year ago (1 children)

If you compress a gas enough it will get hot enough to ignite. Google “fire pistons”.

[–] Dettweiler42@lemmy.world 2 points 1 year ago (1 children)

It's also why airplane tires are filled with nitrogen instead of air. On landing, the high pressure and heat can cause the oxygen in air to combust.

[–] platysalty@kbin.social 1 points 1 year ago

On landing, the high pressure and heat can cause the oxygen in air to combust.

Phew. Imagine being the pilot to find that out.

[–] CanadaPlus@lemmy.sdf.org 2 points 1 year ago* (last edited 1 year ago)

Ex-people, plastic and so on. With a small room's worth of air it wouldn't have burned long, though.

More significant is just how hot it would get as it collapses. When you suddenly compress an an ideal gas (which air is a lot like) it gets hotter in proportion to it's previous absolute temperature. Room temperature is already 273K, and the pressure down there is hundreds of time larger than at the surface. At some point the law would break down on the way, but you get the basic idea. It was probably as hot as the sun without any help from combustion

[–] intensely_human@lemm.ee 1 points 3 months ago

Water contains oxygen. With enough heat that oxygen becomes free.

[–] CanadaPlus@lemmy.sdf.org 1 points 1 year ago (1 children)

"Rushing" implies something like a wave. The thing crushed flat like the plastic tube it was, and would have done so too fast to even visually track.

[–] lorcster123@lemmy.world 1 points 1 year ago (1 children)

If you were to slowly lower an open glass into the ocean, it would gradually fill with water. So i just think its the same with the sub, albeit faster?

[–] CanadaPlus@lemmy.sdf.org 2 points 1 year ago* (last edited 1 year ago) (1 children)

Sure, but "faster" here means around the speed of sound, and that's fundamentally a different thing from the playful streams we're used to. The thing was waaay down there when it went.

If there was a tiny little hole somewhere that wasn't getting larger, maybe it would slow down enough to just gradually fill the vessel. In that case, though, it would not have imploded. They found it in pieces and the US Navy heard the pop.

[–] lorcster123@lemmy.world 2 points 1 year ago

Yeah I guess if you think of the fact it actually went 'boom' you can imagine the water didnt really flow in but rather flew in very fast. There was probably a huge shockwave that killed them instantly