We often say we reside on small pale blue dot, and indeed, most of our planet is covered
in Oceans. But there is land down, buried so deep under the water no light ever reaches
it, yet we might come to dwell there one day.
Today we will be continuing our look at the seas: this is part two of our thought experiment
begun in Seasteading and Artificial Islands, so while you don't have to have seen that
first, I would recommend watching it before continuing.
The ocean depths fascinate us and are still largely unexplored, as alien in many ways
as other planets, and hosting some life in greater depths that looks quite alien. Mankind
has been traveling the seas as long as we've history to record it, but until the last century
we couldn't go very deep, just brush the surface.
Humanity has often imagined living in domed cities on the seafloor, and we'll be looking
at how you could do that today, but we'll also be exploring many other options for utilizing
the deep sea, and even discussing how we might make artificial volcanos to make islands.
However, we have to start by acknowledging one key point. A big glass dome on the seafloor
under a kilometer of ocean is not a place most folks would want to live, or even visit.
Even ignoring that you're protected from the water by a glass dome under a hundred
atmospheres of pressure, there's nothing to see. There's no night darker than the
oceans once you get a kilometer deep: sunlight just cannot penetrate down there.
If you want to live down there and see some sea creatures or the seafloor, you need to
have external lights, and in doing that you will attract things that can use light to
live, which means your dome will probably get covered in algae and scum and not be too
fun to look through. And again, there's that pressure issue.
This isn't like space, where the atmosphere difference is 0 and 1, this is 100 to 1, higher
than on the surface of Venus. Every square inch of that dome is under 1400 pounds of
weight, every square centimeter 100 kilograms. We can build stuff that can handle that, that's
about the pressure exerted by someone walking around in stiletto heels, but it's not really
something you want to do with a thin transparent dome. So the glass dome concept for underwater
bases is more likely to be a bunker structure set into the seafloor, that has windows in
rooms that are compartmentalized against flooding if they break.
Now, domes are an option closer to the coast where the seafloor isn't as deep, and the
light still penetrates, but even then, you're likely to use the bunker with windows approach,
not the big glass dome. That has an appeal on airless worlds for agriculture, so you
can grow plants, but for the sea that's not necessary as you can just grow stuff on
the surface of the water anyways and save on the dome. Such bunker windows will also
need wiper blades like your car has, since again they'll get covered in muck quite
quickly. Either algae will grow there or it will fall down to lower depths as marine snow,
the various organic detritus dropped from higher levels that feeds the midnight ecologies
of the Bathypelagic and Abyssopelagic regions. Thing is, most of the ocean does go a lot
deeper than sunlight, or indeed even a kilometer. Most of our planet is ocean and most of that
has an average depth of 3 to 4 kilometers. There's parts that are rich in life, as
sun and nutrients occur together, but that's the minority. Most of the oceans are a desert.
Sure, they have plenty of water, plenty of sun, plenty of nutrients, but in most of the
ocean those last two don't mix much, with the light above, and the nutrients below.
Next week when we dive into the enviroments of space habitats, we'll discuss how the
varying gravity will let us grow trees of stupendous heights, and this is one approach
to terraforming our own oceans, as we might be able to create sea-trees able to grow from
the lowest depths all the way up to the surface, to get nutrients from the seafloor and light
from the sky, like seaweed does at more modest depths. Such a plant would be hard to engineer
or evolve; there's too much distance from light to nutrient, or nutrient to light, and
would need many tricky features to permit the needed strength, energy, and nutrient
movement, but it could be possible. For that matter, we will see today there's a ton
of geothermal energy down on the seafloor, and an organism could be created to make use
of that. One could imagine some massive tree, that
kept the oxygen it makes in buoyant sacs or inflated leaves to help it handle its mass,
setting roots in the ocean floor and spreading its leaves across the surface, but we could
also build skyscrapers or seascapers which might use the same approach, so massive in
size they could only be viewed as arcologies. More on that in a bit. But it's worth remembering
that bioengineering is on the table, for plants and for people too. Mythology is full of mermaids,
and it may be possible to tweak people or our pets to have gills or more modestly, to
handle pressure changes better, if folks really want to live in the seas.
There are not too many reasons why folks would move to the deep ocean, unlike living on top
of if it, but we did find some, like wanting to be protected from supernovae blasts or
just be as far from other humans as possible without leaving Earth. We'll go over some
of the others as we discuss our options today but it raises a big point we make in the Outward
Bound series, that colonizing a planet doesn't necessarily mean a lot of folks live there.
A factory planet churning out megatons of manufactured goods every minute is certainly
colonized, but might only have a few thousands folks living there to do maintenance. Similarly,
underwater oceanic colonization offers us a lot of resources and benefits, but not too
many for housing. You might retreat there as a refuge from invasion or disaster, or
like many colonists in history, have been exiled or left specifically to get away from
others, but those imply the surface has in some way become hostile to you.
One novel example, as an exception to small groups for science or tourism, or machine
maintenance, is prisons. If you want to build a supermax people can't escape from, even
the Moon is less secure. Worldwide, a little over 1% of the population is in prison, which
probably vastly exceeds the number of folks we'd have engaging in tourism or science
under the sea at any given time. I'm not sure of the practicality or ethics of such
a concept, but it does amusingly fit with our remarks from last time about a lot of
early oceanic colonies being founded by those trying to evade laws back on land.
You can even give them a diver's mix of oxygen and helium, or hydrogen, oxygen, and
helium, instead of oxygen and nitrogen, so that if someone did get out they'd be stuck
for many hours decompressing somewhere you could grab them.
Current mixes and suits still put a fairly shallow limit on diving, but we may improve
both. This, by the way, is one of our options for fairly deep habitats that are classic
domes. You don't have a pressure differential because you put the dome at the same pressure
as the water and change the air mix. Nitrogen becomes a narcotic at high pressures, it's
not just the nitrogen bubble issue for decompression, so you have to remove it for people to operate
at pressures deeper than about 60 meters or 6 atmospheres.
Incidentally, you add one atmosphere of pressure for every 10 meters of depth. That's Earth's
gravity and the density of the material stacking up, and water, has a specific gravity of 1,
or a density of 1000 kg per cubic meter, although salt water is just slightly higher. Gravity
is 9.8 m/s², and 1.03 is the specific gravity for saltwater, conveniently 9.8 times 1.03
equals 10. 10 meters of additional depth adds an atmosphere of pressure in saltwater.
However if you're under rock that's twice as dense, it would be every 5 meters, or if
you're under air, which is about a thousand times less dense, it's about a kilometer.
If you're on Europa, where gravity is only 13.4% of Earth normal, it would be one atmosphere
for every 75 meters. That's one of the appeals of setting up undersea habitats on moons with
subsurface oceans: sunlight is a non-issue at that point anyway, and so are natural air
mixes, so you can spread out a lot more before water pressure becomes a problem.
Oceans are truly huge volumes, you can't really think of them as areas, and we often
talk about using hydroponics to help with food needs on Earth or to grow food in space,
but we often skip aquaponics or aeroponics as options too. We'll skip aeroponics today
as well, but aquaponics is a growing industry, no pun intended, and is ideal for subsurface
ocean farming. We think of floating farms, but there are downsides there, and one of
those is waves. The surface of the sea is choppy, but the
further you descend in the ocean, the more that dissipates. As submarines and fish both
show, your options in the sea are not limited to floating on the surface or rooting to the
seafloor, so you could have farms or cities that just kept themselves slightly submerged,
and indeed they could bob around, surfacing when they wanted or dipping a bit deeper if
the weather was bad. Even at just 50 meters, so long as you're far from shore, you're
pretty safe from even the worst of storms. An aquaponics farm need not stay at a set
depth, you could tow them deeper for nights or bad weather, but planting one at that depth
still permits a solid amount of light to get in and is still shallow enough that divers
could go down without messing with their air mix. Such farms aren't much more than a
bunch of nets and rods to hold some structure, and presumably some ballast to allow it to
keep or change depth, so we're not contemplating anything very fancy.
Going deeper you'd have to start supplementing sunlight with artificial light, and that's
a power issue. That could easily end up a non-issue in the future as we get better energy
sources like fusion or the power satellites we discussed some months back, but the oceans
offer us some power options too. We discussed some surface options last time, but deep down
has two of interest to us. First, there's fission. As we improve our
reactor designs to better utilize the fuel we put in them, better recycle the materials
used in and around them, and access new fuels like Thorium, we get access to a vast supply
of energy from fissile materials, enough to last us as long as civilization has already
been around at least. But people still don't like it in their backyards, and they certainly
don't like the waste there. Remote undersea nuclear plants are a handy option in that
regard, and water is one of the best shields against radiation. Dumping radioactive waste
in the sea is actually banned by International Treaty under the London Convention, but mostly
relates to some rather contemptible practices at the time, and ocean floor disposal, particularly
into subduction zones where the materials will get dragged down into the planet's
mantle, holds some good options for disposal of wastes which might not be recyclable and
be radioactive for very long periods. Of course it's also a potentially awesome
place to find such materials too. Most of the Earth is underwater, and the seafloor
is a lot closer to the mantle than the continental surfaces are, and not just because the seafloor
is deeper. The Moho discontinuity, the boundary between the crust and the mantle, is typically
closer under the sea, 20 to 90 kilometers below the surface of the continents, but only
about 5 to 10 kilometers beneath the ocean floor.
Beyond mineral wealth, that makes it a great place for geothermal power, and as we get
better with superconductors, we may well start to move all our power generation off Earth's
lands to the seas and space. Such power lines would be one of many examples of infrastructure
networks we might run on, or maybe in, if we buried them just under the ocean floor.
We already lay fiber optic cables that way, and we may do power or pipelines, but we may
also do transport. Elon Musk's hyperloop passenger transport
system, love it or hate, has popularized the notion of vacuum trains, or near vacuum trains,
but the concept is much older and I regard it as something of an inevitability. Hypersonic
or suborbital flights may be on the table in even the near future, but ultimately you
can't have craft moving through the atmosphere over land at such speeds, the sonic booms
would be ruinous and that's very fuel intensive. You can set up a transport network using orbital
rings, see that episode for details, but those are essentially vacuum trains in space. When
flying you accelerate and as you gain altitude the atmosphere thins, letting you speed up
with less air resistance. Go high enough and it causes no drag or booms and you can accelerate
as fast as you please. However, a vacuum train, or near-vacuum train
like the Hyperloop, on ground or buried under it, offers the same option, and maintaining
a vacuum deep underwater is no harder than maintaining one atmosphere of pressure there.
Here's the cool thing, much like a launch loop, when you've no air in the way you
can accelerate as fast as folks can comfortably handle, and even if that was just 1 gee, you
would hit Mach 1 in 35 seconds, and Mach 10 in 6 minutes. Such a Mega-Chunnel would permit
travel from New York to London in half an hour, and you could leave right from a station
in the middle of the city. You don't necessarily half to stop accelerating at that speed either,
same as the burn and flip method we discuss with spaceships, a vactrain, essentially a
spaceship, can potentially accelerate the whole way, flipping half way through. And
if folks don't mind a bit more acceleration, or you're sending priority cargo, you are
looking at being able to get anywhere on the planet in half an hour or less.
But you have to have a track and it has to be pretty straight, beyond the curvature of
the Earth, indeed as we discussed in Orbital rings that does impose a maximum velocity
because you are turning with the sphere of earth, and we can cheat and turn upside down,
so that centrifugal force from turning is counteracted by Earth's gravity, and it
works as well underground or undersea as in space. You tear through the tube at insane
speeds upside down at 2g, walking around on the ceiling for the trip, and in doing so
can achieve twice the speed satellites fly over at while still feeling like you're
under normal gravitational force, albeit to an outsider upside down. Needless to say building
such a network would not be cheap, but only in the context of normal highways. We've
million of miles of roads and track after all, these are harder to build and pricier,
but we're getting much better at boring tunnels.
Key thing to recall about vacuum trains though isn't just that they can get you across
the oceans very quickly, it's that it could get you from Chicago to Detroit in minutes,
or Atlanta to Houston, it's not just for globe-spanning trips, however our interest
is in those big people pipelines under the sea today so we'll save discussing huge
underground networks of them for later in the series.
They're a good way to get your feet wet in deep sea colonization though, because all
those vac trains and fiber optic trunk and power and pipe lines need maintenance and
need outposts along the way for safety reasons. As we said, with any colony operation whatever
the main purpose is you want secondary industries to help move marginal operations into profitable
zones, and geothermal power or aquaponics or a fission plant or even an undersea supermax
prison are options there. But mining is likely to be a big one, and
can maybe get even bigger. We always talk about mining asteroids or moons, but every
asteroid and moon in our solar system has less combined mass than Earth, and most of
that is in the mantle and core, and again the Moho discontinuity, the edge of the mantle,
is a lot closer on the seafloors. Trying to mine the mantle, sometimes called
Moho Mining, is a lot easier said than done, even in the context of mining things millions
of kilometers away in space, and we'll discuss it more down the road, but it is theoretically
doable, essentially boring a hole down into the magma below. We have materials that can
handle those temperatures, and while the pressures involved make that much harder, it's not
impossible. Let imagine for the moment though we took
such a material and made a big straw, with one end poking down into the mantle and the
other all the way up to the surface, and let it fill with air, not water. Straw is an apt
analogy as you now have a huge pressure differential and magma can rise up. We might refine this,
extracting what materials we want, and dump the spill around our lava straw, building
an artificial island in the process. Indeed, we might use such an approach along with good
earthquake modeling to relieve the pressures that cause earthquakes, volcanic eruptions
where we don't want them, and so on. These, especially as uncontrolled events, are not
your friend when engaging in massive planetary engineering projects. Needless to say the
mineral wealth and the raw power available by steam turbines using this heat might make
for major industries too. But the ocean floor alone offers a lot of
mineral wealth and we mentioned an idea last time of a Jellyfish Habitat where most folks
live in a main facility on or near the ocean surface, while long tentacles scraped the
seafloor for minerals and nutrients and moved the place around or anchored it.
We'd talked about lighting those tentacles to provide for ecosystems it might haul along
with it, but you need not necessarily move such a thing either. We said near the beginning
that you wouldn't want to live under the sea very deep because there's nothing to
see unless you light it, and we just discussed a straw many kilometers long buried in the
mantle and reaching to the surface which could become a habitat of it's own, much like
oil rigs. Let us instead imagine a skyscraper, built
on the ocean floor and all the way up into the skies. You could put windows on such a
thing so long as you compartmentalize every section against flooding if one shatters,
and indeed all the air, surrounded by water, provides a strong buoyant force that would
relieve a lot of the weight and compression normal skyscrapers face, letting you get away
with a thicker skin. One could give it tendrils too, just cords floating out from the side
giving some light and attracting and boosting the local ecology, so now you can see it and
there's plenty to see, and it provides some food for those living inside.
This is very like the arcology notion we've often discussed, vast buildings in which whole
cities live and farm their own food, vertical farming and mega-skyscrapers essentially.
And like many such structures, it benefits from being bigger. We said in the arcologies
episode that you'd generally make them wide and use the middle for farming and manufacturing,
folks would live on the outer edge, with a better view. Depending on how safe those windows
are and how good the view is, you might reverse that in deeper waters, or stick to it, but
you could have vast columns or cones of arcologies rising up from middle of the oceans, and not
just to the surface either, but far above. Indeed if we get good enough with our materials
or active support systems we've discussed before, these could be space towers too, one
might imagine Earth in a few centuries sporting mega-arcologies that rooted themselves all
the way down to the mantle and all the way up to space, from Moho discontinuity to Karman
Line. Such a structure would have, by normal building standards, about 40,000 floors, and
a big cone or needle shaped one just 10 kilometers in radius, quite small for an island, would
have an internal floor space equivalent to a small continent, and one could build tens
of thousands of such structures each housing billions in comfort. As we mentioned in the
Ecumenopolis episode, Planet-Wide cities, the follow up on arcologies, finding room
for trillions of people on Earth, if you have the energy, doesn't involve paving over
everything. Indeed you'd be enhancing and empowering locally ecosystems if done properly,
the problem is getting rid of all the heat. Far future stuff, that, but that's what
we look at here, and I be remiss if I didn't mention one other approach to colonizing the
oceans, which would be to drain them. We have a lot of water, indeed we have a lot in the
mantle too, not just the oceans, and it's precious stuff in space but arguably mostly
in the way down here. Almost all the ecology happens in the first hundred meters or so,
as does the evaporation that fuels our rain supply and weather systems. Last time we mentioned
a scenario in which we might start building many skinny and long islands across the oceans
and even cutting canals into the continents, you can do the reverse too, drain those seas
out and cut deep lakes and smaller seas as cisterns while making new land on what used
to be the ocean floor, and moving much of that water into habitats built in orbit around
Earth. One need not go all-in on this either, water levels have been much lower in the past,
that's how our ancestors could walk to the Americas or Australia, and one might decide
to restore that, leaving a very different looking planet.
Again, such things are why we call this the Earth 2.0 series, as they fundamentally change
the planet, whether for better or worse is an ethics question we'll skip here, though
certainly a worthy one for contemplation, for the series we'll just lay out the options
that might be on the table, and where they might not be something we want to do on Earth,
the galaxy is full of other worlds we might employ such techniques on.
Or in our daydreams too. As I said at the beginning, the ocean depths fascinate us and
are still largely unexplored, alien places. Mankind has been traveling the seas as long
as we've history to record it, but until the last century we couldn't go very deep,
just brush the surface. We often talk about the Golden Age of Science
Fiction and 'the classics' written in the middle of the 20th century, but it goes
back before then and one of the true classics is Jules Verne's "Twenty Thousand Leagues
Under the Sea", our book of the month. It chronicles a trip around and under the oceans
in the submarine Nautilus, appropriately sharing a name with the actual Nautilus, a craft built
in 1800 that's usually considered the first practical submarine. Indeed it was also the
name of the first nuclear-powered submarine, which also first transited under the North
Pole in 1958. Verne's Nautilus, which he chronicled the
voyages of 150 years ago, sets out in the 1860s for a trip around the world. Initially
our narrator for the tale joins an expedition hunting the Nautilus, thinking it a Sea Monster,
not a submarine making a long journey. The commander for this 20,000 League journey is
Captain Nemo, a fascinating character that also appears in another of Verne's novels,
the Mysterious Island, and has shown up in many of the tribute works to Verne, like the
League of Extraordinary Gentlemen. Needless to say this story has been adapted to film
and TV many times, both good and bad, but the book is still amazing even now.
It's dated a bit in its science and technology, needless to say. However, that's not only
part of its charm but also a plus. It is so easy for us to forget that science and technology
and the drive for contemplating the future is not something new, and that we had already
accomplished so much by the mid 19th-Century. While hardly without their faults, there is
so much to admire about our ancestors and such works let you immerse yourself in the
world as they saw it, and the future as they saw it. What they got right and what they
got wrong, always something to keep in mind as we ponder our future here on this channel.
There are many audio adaptations and performances to pick from, and if you'd like to grab
a free copy of the audiobook from Audible, you can listen to a sample of each first and
find the narrator whose voice you like the most. I think I saw a dozen or more to pick
from, and I noticed one was done by Harlan Ellison, that fantastic and flamboyant author
who sadly left us a few months back. I had a chance to attend a talk by him many years
ago and he's always a pleasure to listen to and he narrated quite a few audiobooks.
Another thing I like about Audible, if you find a narrator you like, you can easily pull
up other stories they've read, and it's often a good way to find new authors you enjoy
too. If you'd like to grab a free copy of "20,000
Leagues Under the Sea", by whichever narrator you enjoy, just use my link in this episode's
description, Audible.com/Isaac or text Isaac to 500-500 to get a free book and 30 day free
trial, and that book is yours to keep, whether you stay on with Audible or not.
Next week, we'll be back up in space in "Environments of Space Habitats". We'll
discuss O'Neill cylinders and other space habitats, focusing on their environments,
ecology, and weather, which we'll see is not just inside but also outside in the not-quite-void
of space. And two weeks from now, we'll be teaming
up with the SENS Research Foundation, to discuss extending the human lifespan, a topic we've
discussed before here in terms of its implications for civilization, but this time we'll dig
deeper into the biology of aging and the science of how to slow it down. Way down.
For alerts when those and other episodes come out, make sure to subscribe to the channel
and hit the notifications bell. And if you enjoyed this episode, hit the like button
and share it with others. Until next time, thanks for watching, and
have a Great Week!
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