Beyond Titan - physics and the deep sea

[TokyoStories]

Continuing our crash course in all things deep-sea.

I agree. Also, because it was made up of so many components that we know now were haphazardly stuck together, I’d have thought there’d be very little resistance when it imploded which would make it less likely to warp?

Yes, my (new) understanding is that solid airless components are already at the same pressure as the ocean so are undamaged. It’s things with air in them, like humans, who get obliterated.

@MavisMcMinty @TokyoStories

Thank you both for realizing that people are still interested in learning more. 👏😃

Just checking in.
One of my students has written an article about this-I am insanely envious [grin]

https://www.independent.co.uk/voices/titan-submarine-titanic-dark-tourism-b2362289.html

Will probably not sleep after reading the nutty putty article and watching some you tube. It made me feel panic stricken just watching it:(

Hmm now everyone's changing their tune, the other day people were getting laughed and scorned at by 'science experts' on here for suggesting there'd be any remnants at all because of the implosion...

No, it was explained - along with many other things - on the last thread. Solid things with no air in them can survive ocean pressures. Things with air in them - polystyrene cups, humans - get squashed by the pressure.

I'd think that once it fractures the water will rush in and equalise so no further breakup (other than bits falling of due to breakages). The ocean floor is already littered with wreckage many of which are in big bits (like titanic)

Thanks for the new thread!

Yes the outer hull wasn't going to be compressed, but rather fractured at weak spots at the huge pressure. Hence the large parts being retrieved.

It looks to me like that's an outer cover?
So there's an inner pressure vessel?

With a gap between the 2 that water would get into?

So an implosion in the inner pressure vessel would be the one that imploded?

I am a physicist and did a post grad specialising in aluminium as a material and in particular how it fatigues on aircraft in cold and hot environments as it is mainly bolted and glued together and basically developing new treatments to keep the metal from fatiguing.

I now teach. But occasionally am asked to viva or look over aluminium research as I’m a big nerd in this field and still keep up with it.
https://www.google.co.uk/search?q=youtube+crushing+a+can&ie=UTF-8&oe=UTF-8&hl=en-gb&client=safari#fpstate=ive&vld=cid:ae4463a3,vid:GV0VD4EF2YE
I do this experiment with my 11 year olds to show them about just normal air pressure. Normal air pressure we don’t notice but even a 30 m dive down increases the pressure on you, squashes your lungs to the size of a lemon etc and obviously we have gas in us! And gas really compresses under pressure - this experiment is slightly different Slightly different as basically you heat an empty can with a small amount of water in and then shock it by placing it in cold water and the air pressure buckles it. I do the same with a coke can sellotaped to a vacuum pump which is ancient. It is instant - same effect. Hear one millisecond and buckled the next - the vacuum pump is ancient and maybe on for like 30 seconds. The coke can still remains afterwards. But the people inside - err would be very very compacted.

@TokyoStories just to say thank you for this link on the other thread & reposting for the interested.

https://en.m.wikipedia.org/wiki/Category:Films_with_underwater_settings

So an implosion in the inner pressure vessel would be the one that imploded?

as I understand it - those with more knowledge like @Igneococcus may be wiser is that what happens is that the pressure in the inner shell is much less than the sea,
so if it is breached it implodes (collapses inwards) at huge speed and under massive pressure.
this implosion generates alot of heat which then explodes outwards bursting out of the outer shell which then gets broken and scattered.

No one ever said there would be NO remains of anything - I mean look the Titanic itself is still there under pressure. It's the bodies and pressurised cabin that get anihilated.

Metal gets squashed but will survive if it hasn't been destroyed in an implosion.

Sorry if this was mentioned on the last thread, but what about things like human hair? Would there be any such remains?

Wow! So how does the speed of the can’s implosion compare with the speed of an implosion at 3800 m?

Isn’t there usually intense fire during an implosion? I think any remains get instantly cremated, in fact I watched something where the commentator said in an implosion you “die 3 ways, all in an instant”, although I can’t remember the third way.

Sorry if this was mentioned on the last thread, but what about things like human hair? Would there be any such remains?

Hair burns really easily. So much heat is generated it would be vaporised.

This is a bit brutal but explains what happens.

Sorry, that was to @icelolly12 .

So did the titanic itself not implode because it was full of water when it reached the bottom? Sorry if this has already been asked. I was always awful at science.

I'm guessing it filled with water as it went down.

Maybe some air tight compartments imploded.

Titanic broke primarily when it was at the surface. It started filling with water and broke in two. As it sunk it would start to break up partly due to sinking through the water. As it was already full of water it wouldn't implode, water is essentially uncompressed.

The wreck of the Titanic is compressed at 3,800m down, apparently, all the hollow bits squashed, like the hull and the cabins, as they fell downwards into the pressure. What you see on those ghostly pictures is all the unsquashable bits of the ship.

Indeed solids are already at a high density - the particles are fixed and there is not much room for extension or compression. Some solids are better in tension than compression and vice versa.
Liquids again not much motion in compression or tension but they can transmit pressure eg hydraulic pump or lift
Gases heat them up they expand and volume increases. Cools them down they contract (temperature is another factor here) but pressure x volume is a constant. Double the pressure the volume halves etc

I went on that sub years ago and never even thought about the safety aspect at the time! I don’t think I had to sign anything back then. It doesn’t go that deep though (25 metres I think).

You know when you pump air into a tyre and it gets hot - pressure x volume is proportional to temperature

Increase the pressure as it gets squashed and you're going to increase the temperature massively.

I have a question - anyone still on the Titanic when it went down, what would have happened to them/their bodies as they sank down into all that pressure? Would it have been a gradual squashing, or more violent?

Oh, that’s triggered another question: if it took the tiny lightweight submersible Titan 2.5 hours to sink 3,800m, how long would the actual ship - huge and heavy - have taken?