87

You can see octopodes crawl out of a tide pool and into a neighboring pool with little difficulty. octopodes have been known to crawl out of a tank in an aquarium and have the crab in the tank next door for dinner. They have even been known to shut off lights that bother them in their tank at an aquarium. They have been documented crawling out of their tanks,...


75

Octopodes are not going to colonize land the same way we've colonized space - they're going to colonize the land the way we've colonized the sea. Penguino has done a pretty good of addressing how different it is for humans to go to space versus octopodes coming ashore. But there is a parallel that's much closer to shore (so to speak). An octopus' ability ...


51

What you described is an old invention:the wax tablet. Spermaceti from sperm whales is just one of many waxes your underwater people could use. Some of the fishes also contain significant quantities of wax. If you need only a short-term solution, animal fat would also do the job. I couldn't find any seaweed that secretes waxes, so I hope your underwater ...


45

Bubble curtain. https://www.eurotrib.com/comments/2012/9/6/165418/5127/3 Depicted - an oil rig with a circumferential bubble curtain to reduce underwater noise. https://en.wikipedia.org/wiki/Bubble_curtain A bubble curtain is a system that produces bubbles in a deliberate arrangement in water. It is also called pneumatic barrier. The technique ...


36

You would die quite instantly. L.Dutch's answer is accurate if you do the shift on a reasonably short timescale. But if you do it really fast, which I'm getting the impression is your goal, the story is a bit worse. It is true that most of the body is solid or liquid, and thus basically non-compressible. Only the air volumes will be squished. However, ...


33

There are a few issues that need to be considered separately: Constructing water-filled environments for a water-breather to reside in on land isn't a significant technical issue. The manufacturing requirements for a salt water pool or aquarium are far simpler to achieve than for an air-filled canister to be used in a vacuum. Getting onto land from the sea ...


33

A bubble curtain is a decent idea, but for something more static, that doesn't require continuous power... A sponge wall. You want a series of baffles that will allow water to pass through, but will choke and disorganize the flow, absorbing and dissipating shockwaves. Sponges will do that just as well in water as spongy materials do in air to absorb sound. ...


26

Braids of seaweed. The ancient Inca used knotted fibers, or quipu, to record events and information. With enough effort, seaweed could be manipulated (slicing then braiding) into thin cords, which could then function in a similar way as quipu. I wouldn't be sure about the lifespan of these cords -- it depends on the manufacturing process -- but these ...


25

Kraken Can't drop depth charges if your ships have been eaten.


21

Would this underwater civilization be possible during the Bronze Age? No. First thing off: They use sand to desalinate the water to drink. Sand might be good at filtering out particles suspended in water. But salt is present in water as a solution, sand does nothing to it. Else every beach would be as good as a fresh water lake. They build ...


17

You don't have to go back in time very far to reach a point where marine-derived hydrocarbons pretty much made the world go round. The catch being that you have to kill rather intelligent, large and dangerous predators who share your environment. Enter the sperm whale, whose head is filled with an extremely useful collection of waxes and oils which may be ...


16

Pressure will act on the fluids in the body, thus gases and liquids. Liquids Well, liquids are practically non compressible, meaning that even applying large pressures they won't change in volume in an appreciable manner. So blood vessel, eyes, brain, etc. will not be severely affected. Gases Gases are contained mainly in the lungs, intestine and stomach....


15

They need to be able to breathe, so an airlock leading into a section of ocean wouldn't be useful Well, not so much. Freediving is very much a thing, after all, and has been for quite a considerable length of time. People have been able to variously dive to over 100m, swim hundreds of metres and hold their breath for about 10 minutes (probably not all three ...


14

I would say that for both humans and your octopodes, Space is a much tougher frontier. Without going into the details, I would like to direct you to a few factors that may come into play. Space as it were, is extremely dangerous for both humans and octopodes. Radiation, extreme temperature changes, micro gravity, and the vacuum of space. In comparison to ...


14

You would find it near impossible to push someone out, let alone trow him out. To "push" 80 kg man out against 10 MPa pressure would need around 800 kJ of work and a push of 50-100 tonnes if you go head/legs first. Maybe your dome can make pockets to eject or you have special building with "airlocks" to trow him in and fill it full with water. How happy ...


13

As a starting point here is a video of an egg at 6,000 bar video 1 bar is 10 meters, so we are 60,000 meters underwater. So if you look at the egg from the outside there is nothing wrong with it. The shell withstands the pressure just fine. Once the egg is cracked open all the proteins have congealed, and the egg is "cooked" but from the outside it is just ...


11

Bottom feeders A bottom feeder is an aquatic animal that feeds on or near the bottom of a body of water... In the aquarium, bottom feeders are popular as it is perceived that they will clean the algae that grows in the tank. Generally, they are only useful for consuming the extra (fresh) food left by overfed or clumsy livestock https://en.wikipedia.org/wiki/...


11

Underwater domes will probably be located deep in the oceans. If you are under one of the major oceanic currents, then all you need is some dynamite. Find a school of fish far enough from home for a blast to be safe and... well, blast. The fish will all die or be stunned, and they will float to the surface where a ship can gather them. mostly sink to the ...


11

What would she look like after a few hundred years of submersion? Like a really big lobster. Regular lobsters live in the sea, and can live to over 100 years old and still look just like lobsters. They just get slightly bigger and slightly heavier after each moult. Normal crustaceans stop moulting eventually (perhaps due to sensescence, or perhaps due to ...


9

One major advantage that octopodes have in colonising the land, is that they can already make short stints out of the water without any specialised equipment. This is very much not true of humans in a vacuum. A question asked on Biology SE details the ability of an octopus to survive out of water, and another source details that coming out of the water to ...


9

the engine simply evaporate water in a chamber, then uses the pressure to push water and/or vapour at the rear in order to create thrust. If you just pick water from the depth you are and evaporate it, you will not get any additional pressure. The vapor bubble will just last until it cools down and collapse. This will have a very low efficiency. It's called ...


9

Two factors are important here one, there are consistent currents, strength is less important than consistency. two, sea floors are not, generally, flat on a large scale. Taken together this means that getting sewage downhill and/or down current away from a city should be possible and even practical making it "someone else's problem" which is what ...


9

Wouldn't it make more sense if they just migrated to a tunnel network that was underground but had sea access. As in tunnels that terminate at caves and those caves have pools in them with flooded tunnels leading out to the sea. Then perhaps your people could develop something like a breathing helmet made of leather sealed with pitch or resin or similar ...


9

Fish traps are a convenient way to catch fishes and other sea creatures. A fish trap is a trap used for fishing. Fish traps can have the form of a fishing weir or a lobster trap. A typical contemporary trap consists of a frame of thick steel wire in the shape of a heart, with chicken wire stretched around it. The mesh wraps around the frame and then ...


9

Physics Question: I do not think the pressure underwater changes when the surface freezes. Pressure is created by weight, and freezing does not change weight. You could say that liquid gases of former atmosphere add to weight, but again, turning atmosphere into liquid does not change its weight, or the pressure it creates. For engineering problem, ...


8

They could use clicks and whistles like a dolphin, or they could also communicate through bioluminescence like a bobtail squid. They could also cummunicate through whale song.


8

It's blue, Sir Since most people can't barely hold a minute, and 99% of the population won't exceed a mere five minutes, they're dead. Very very dead. (if you take 10-ish minutes). The duration for reanimation after loss of consciousness and oxygen is around 3 minutes if I remember correctly. So barring the pressure problem necessiting a full analysis (that ...


8

Would an deep sea lava river be feasible? Yes, but it wouldn't look as impressive as a lava river on land. Most of Earth's volcanism actually happens underwater, in mid-ocean ridges. We can't usually see them, and they are under several kilometres of water, so they're not as famous as volcanic eruptions in populated areas like Hawaii. Here is an impressive ...


7

You're not going to evaporate the water, you're you're going to displace it. That actually makes it both easier, and no more possible. The thing with displacing the water is that the easiest direction to displace it in is upwards. In any other direction there's something fundamentally in the way. Operation Wigwam is the closest I can find to what you're ...


7

Depending on the level of scientific realism you want, it should be possible to enable rod and reel "sport" type fishing activity from your underwater dome (even if the dome itself is kept at surface pressure, i.e. the humans inside aren't "saturation divers" spending long periods at depth pressure. First, you need a "waldo" type manipulator system. These ...


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