teleo-codex/inbox/archive/the-mega-earth.md

---
type: source
title: "Colonizing Jupiter"
author: "Isaac Arthur"
url: https://www.youtube.com/watch?v=PQnvjGN91Mg
date: 2017-01-01
domain: space-development
format: video-transcript
status: processing
processed_by: astra
processed_date: 2026-03-10
priority: high
tags: [megastructures, space-infrastructure, isaac-arthur, jupiter, gas-giant, orbital-rings, fusion-candles, europa]
notes: "TRANSCRIPT MISMATCH: File titled 'The Mega Earth' but contains the Colonizing Jupiter episode."
---

## Agent Notes (Astra, 2026-03-10)

Colonizing Jupiter and its moons. Key findings: Callisto as first base (outside radiation belts), Europa's ocean > all Earth's oceans combined, orbital rings at 1g altitude give 318× Earth's living area, fusion candles for gas giant atmosphere stripping. Jupiter system is self-sufficient. See musing for full analysis.

## Curator Notes

Transcript mismatch noted. Part of Outward Bound series. Unique content on orbital rings at planetary scale and fusion candles.

## Transcript

When we talk about the solar system and the
planets and all the distance between them, it’s very easy to forget that most of the
solar system is actually Jupiter and its dozens of moons. So today we continue our look at colonizing
the solar system by focusing in on Jupiter. I’ve pointed out in the past that the asteroid
belt is in some ways a far better prospect for colonization than the inner planets, and
that we focus too much on those inner planets, and something similar applies to Jupiter. Virtually all the mass of the solar system
is in our Sun; of what remains, the majority of it is in Jupiter. If you totaled up every bit of matter in between
Mercury and the Kuiper Belt - every planet and moon and asteroid - you still would not
match the mass of Jupiter. Yet at the same time that mass is mostly useless
to us because Jupiter is not a place we can directly colonize. We are going to challenge that today, near
the end of this episode, and discuss ways to colonize the actual planet. But first we need to consider that Jupiter
is not alone. It has a swarm of large planetoids - 4 of
which, the Galilean moons Ganymede, Callisto, Io, and Europa - are of a size and mass similar
to our own moon or the planets Mercury and Pluto. The eight official planets are also the eight
most massive objects in the solar system, after the Sun of course, but of the next 6,
4 of them are those 4 Galilean moons and the other two our own moon, which we’ve devoted
multiple episodes to discussing the colonization of, and Titan, which was our last episode
in this series. So the importance of these 4 moons in colonization
should not be underestimated. They are essentially planets in their own
right, orbiting a gas giant that’s closer in mass to being a star than a rocky planet. In a way, they’re not so much a part of
our solar system as a miniature one all their own. And if you settled them, the light lag for
communications would be seconds, not minutes or hours like talking between other planets. Travel times are on an order of hours or days,
depending on your drive system, rather than months or even years for interplanetary travel,
and fuel consumption is far lower. At last count Jupiter has 69 moons, and every
single one of them is colonizable. It also has a hundred times as many Trojan
Objects, and a planetary ring. We are interested in every single one of these
objects and, out of them alone, you could build a planetary empire that dwarfs most
of the interstellar ones we see in science fiction. Now in Interplanetary Trade and in previous
episodes of this series we talked about how each of our prior colonies needed something
the others had, and lots of it. But we also talked about how the Earth was
a bit of an exception since there really would only be a demand for precious metals, and
Earth doesn’t really need them anyways - they just wouldn’t mind having them and importing
those can fund solar expansion. The same is also true for Jupiter since this
world and its moons contain all of the raw ingredients necessary to support life, and,
as we discussed in the Interplanetary Trade Episode, you can ship stuff around that mini-solar
system quite cheaply. Indeed, gas giants and their coterie of moons
are better targets for first colonization than Earth-like planets at the interstellar
level and we discussed why in the Life in a Space Colony series episode, Early Interstellar
Colonies. They’ve got rocks and ice and plenty of
oxygen and nitrogen and everything else we need. They also have a ton of hydrogen which is
important if you have a fusion economy, which we tend to assume you do if you are an interstellar
civilization, and of course we already established we had that technology in this series anyways. However it is worth noting that Jupiter, at
5.2 AU from the Sun, is still close enough for solar power to be a marginal option. Out on those moons it’s much dimmer than
a typical day on the Earth and is more akin to a cloudy day or a brightly lit house, not
a shadowy twilight place. Ignoring temperature and the lack of air,
plants can grow at the light levels out at Jupiter, though you’d want to boost them
with some supplementary red LED lighting to optimize their growth. Of course they can’t grow on the surface
of some of those moons not just because they are cold and airless but also because they
are bathed in radiation, a serious health hazard to any form of life. Now we have followed our traveler from the
Moon to Mars and back to the Moon then to Venus and back once more to the Moon - or
rather, to Borman station around the Moon - then back down to Earth and back to Borman
Station and off to Saturn’s Moon Titan. However, our traveler doesn’t remember that
last bit. As you might recall the Traveler had cancer
and opted to upload their mind to the huge data repositories built on Titan. As we’ve also discussed in recent episodes
though, uploading your mind is not cut and paste, it’s copy and paste; so the Traveler
copied their mind to a digital format and then found themselves still sitting there
with cancer. Fortunately someone finally cured it so our
Traveler is alive and well and once more taken up with Wanderjahr and at Borman station around
the Moon, still the hub of interplanetary travel. This radiation issue on Jupiter obviously
is especially of concern to our Traveler. Jupiter’s Magnetosphere is enormous, 20,000
times as strong as Earth’s, and it bathes the inner moons in potent radiation in roving
radiation belts that orbit Jupiter. Now Jupiter actually has 4 small moons closer
to it than the Galilean Moons, who are 5 through 8, and only the last of these, Callisto, is
outside that intense radiation zone. We often hear about Ganymede, the largest
moon in the entire solar system; or Europa and its enormous subsurface ocean hidden under
the ice; or even of Io, with its hundreds of active volcanoes spewing matter right into
the Jovian orbit, which is largely responsible for the specific shape and nature of Jupiter’s
Magnetosphere. But Callisto gets skipped a lot, which is
strange since it is bigger than our own moon - coming in third in the solar system after
Ganymede and Titan - and is outside the worst of the radiation, making it the best prospect
for first colonization of Jupiter. And indeed that is where our Traveller will
be going, to a new colony recently established on Callisto. Far enough from Jupiter to mitigate its gravity
well and be safe from radiation, Callisto is a natural choice for the first major base
in the Jovian system. And while Europa’s ocean interests us more,
Callisto itself is believed to have subsurface oceans too. Callisto’s oceans are possibly more likely
to harbor life than Europa’s are, as I will explain later. We don’t tend to think too much about Callisto
as it is cursed by silver medals; it tends to come in second or third on almost any factor
of interest to humans, so it isn’t as well known as other planets and moons. But it has so many areas in which it is almost
the best that it is actually one of the best prospects for colonization in our solar system. Now we are a little less concerned about radiation
here in the late 22nd century, our Traveler’s miraculous cure from Cancer being the very
technology that eases that concern, but we can still hardly go jaunting around radiation-soaked
hellish landscapes without a care in the world. So we will settle Callisto first and because
it is the late 22nd century we will do it in style. There’s far more space-based infrastructure
than there used to be and we have more technology and more practice with alien planets and moons. When we get to Callisto we find they have
already setup their own mass driver, no orbital stations in the traditional sense, it’s
almost a big launch loop ramp with a terminus runway just sitting on pylons high up over
the moon, not orbiting. We just match vectors with it, connect and
roll on down to the surface, decelerating as we go, like a big highway exit ramp. Down at the surface are dozens of domes with
plants inside. We exit the craft and gaze around. The Sun is 5 times further away than on Earth,
so it’s much dimmer, appearing only 5% as bright, but the red-brown light of Jupiter
gives the surface a warm glow. Callisto is tidally locked so Jupiter itself
always dominates the sky on one half of the moon and appears 50 times bigger by area than
the Moon appears from Earth, allowing us to easily identify the constantly changing features
on it, like the Great Red Spot, without even needing a telescope. We smile, pleased we came - this is very different
from anything we’ve seen in the inner system. The lighting isn’t just sunlight, there’s
a red-purple glow of supplemental lighting in the domes. First, because it is far from the Sun, and
second, because even being about four times further from Jupiter than our Moon is from
Earth, it is still tidally locked to Jupiter. This means that it orbits every 17 days and
that’s how long its day night cycle lasts. Most but not all plants can handle constant
light, but a week of darkness is another story, so being able to provide some lighting in
that period is important. The other moons have this same problem. Only Io, the closest of the Galilean moons,
has a near-Earth length day, at about 42 hours, Europa comes in at 85 hours and Ganymede at
one week. Though the other 4 smaller inner-moons are
really no better, having an effective day length of 7 to 16 hours each. This is okay though because all the radiation
they get encourages us to live under the rock and ice for protection anyway, so all your
lighting is artificial. On Callisto we can employ the same techniques
as on our own moon: Thick glass domes with good insulation and a nice point defense system
for dealing with meteors. That’s important on Callisto which is usually
considered to have the oldest and most heavily cratered surface in the solar system. But Callisto doesn’t need a fusion economy
to run it, it does get enough light for solar to be viable and fission reactors are certainly
possible. Indeed there’s probably good quantities
of uranium and thorium in the smaller moons which might be fairly easy to find and extract. There’s also plenty down in Jupiter, though
that’s harder to extract obviously, but it does mean Jupiter gives off a lot of geothermal
energy, or jovithermal I suppose, vastly more than Earth and indeed more than Earth’s
entire solar energy budget. Hypothetically, you could tap that via Seebeck
generators hung in Jupiter’s Atmosphere, for instance. And Jupiter is a massive dynamo, so one could
also hypothetically tap its rotation directly for electricity. We are assuming fusion as a power source but
it is nice to know there are other options available, and even if solar is a bit weak
out here, we can still play the trick of having cheap parabolic mirrors focusing light on
solar panels or beaming energy in from closer to the Sun. One way or another, Jupiter’s colonization
won’t be hampered by energy concerns. We do still have heat concerns though, even
volcanic Io is much colder than Antarctica and much like as we discussed with Titan,
you have to worry about the places you build melting into the moon. Callisto’s surface is a mix of ice and rock,
it’s like building in permafrost tundra. You don’t necessarily want to go warming
that up. However if you are bound and determined to
genuinely terraform the place, you can make large thin mirrors to bounce enough sunlight
there, and then dome the place over, paraterraform it, so that you can create an atmosphere. Of course gravity is a concern too since gravity
on Callisto is quite low, lower even than our Moon at 12% Earth normal. It’s more massive than the Moon, but less
dense. Even Ganymede is only 14.6% Earth normal,
and Io is the highest, slightly more than our own moon, at 18%. It’s 13% on Europa incidentally, making
Callisto the lowest gravity moon of Jupiter’s major moons, and none of the others have any
gravity of significance. We mentioned back in episode one that we just
don’t know how much gravity people need. We know Earth-gravity is fine, and we know
zero gravity isn’t. Nobody has ever lived in low gravity for more
than a few days so we don’t yet know what the long-term effects of being exposed to
low gravity are. It could turn out to be the case that Callisto’s
low 12% is enough, or that Venus’s near-Earth 91% is not enough. We just don’t know. When discussing Mars’s 38% gravity in the
first episode we opted to assume it would be enough with at most some technological
and medical assistance. We ignored it on Titan because the folks living
there were cyborgs and transhumans. Here I don’t think we can. Now channel regulars know we have a trick
for making gravity: we stick folks in a cylinder and spin it around, using centrifugal force
to simulate gravity by spin. We can’t quite do that here but we can do
something similar. We have to combine the two – real gravity
and spin gravity - when working in low gravity environments. We can’t just ignore the gravity already
present. So if we want to boost it we need to use something
more like a rotating bowl or vase rather than a cylinder. The stronger the local gravity, the shallower
the bowl; the weaker, the closer to being a cylinder we need. Now we do have one last trick if you really
want an Earth-like planet. Last week in Mega-Earths we discussed building
shells around stockpiles of mass, preferably cheap mass like hydrogen, whose surface gravity
would then be the same as Earth. For Callisto or either of the other three
moons, there’s enough mass to make a rocky shell surface and you’ve got hundreds of
Earth’s worth of hydrogen just down in Jupiter itself. You could also fix its spin to be 24 hours
while pumping that in and use orbiting shades and mirrors, or ones back at Jupiter’s L1
point, to boost the light. And between the 4 main moons there is actually
plenty enough rocky mass to construct many such shells, not just 4, but that’s a lot
of work and I would say more than it’s worth but we never really know what the effective
price point for Earth-like living space will be when considering high-tech post-scarcity
civilizations. They might have automation so good that planet-building
is fairly cheap, or they might be so efficiency minded that they live a strictly post-biological
existence on computer chips. As for Callisto, while its surface resembles
our own moon quite a lot, it is a bit different. As you dig down beneath it’s rocky ice lithosphere,
many dozens of kilometers, we think you might hit a deep salty ocean, one which may or may
not have a decent amount of ammonia in it too, and which would probably be deeper than
any ocean on Earth, before returning to an icy-rock mixture and possibly a small silicate
core. Unlike Earth, it’s a lot easier to dig very
deep on Callisto, no major issues with pressure and heat, so boring a tunnel down into that
hypothetical ocean might not be too hard. You can do some interesting things there too
but we’ll discuss those in regards to Europa in a moment instead. Once settled on Callisto our Traveler finds
they are something of a celebrity, having been all over the solar system with every
new colony. So we are brought in to discuss the future
of Jovian civilization. For the outer moons, and indeed even those
inner 4, things are simple enough: they will follow the colonial model of asteroids by
boring a hole inside for a rotating habitat and mine and expand as the situation demands. For Ganymede the situation is somewhat the
same as Callisto, but you almost have to live underground because of the radiation. It is also likely to have an oceanic layer
between the surface rock and ice and the center. Io is another story. It tends to get written off as non-viable
for colonization but that might be a little too pessimistic, and as we noted in our discussion
last time about Titan, colonization doesn’t necessarily mean terraforming. It would not be hard to put an orbital ring
around Io with connected habitats folks lived in and a tether reaching down to the surface
to conduct mining operations. In this regard Io could serve as an industrial
hub, supplying huge amounts of raw materials and manufactured goods to the rest of the
Jovian mini-system. Again, with the low gravity and close distances
it is actually viable even with 21st century rocket technology to ship around goods and
people between all these moons. But let’s consider Europa next. Europa is often considered the best candidate
for any other life in our solar system, especially anything more complex than some lichen on
Mars or floating microbes on Venus. Data from NASA's Galileo mission strongly
indicated that Europa has a liquid ocean under its ice-shell that has more water than in
all of Earth’s oceans combined and is more than 100km deep. Water was one of the main reasons that life
evolved on Earth and many scientists believe it might be a necessary element for the creation
of life. There are some issues when it comes to life
evolving on Europa, though. One is that the most recent research suggests
that an action of having alternating periods in, as Charles Darwin put it, “warm little
ponds” of wet and dry were likely required to create the conditions for unicellular life
to evolve on Earth. For that there needs to be land where a nutrient-rich
soup of chemicals can pool that is alternately covered by ocean water and then dried out. There is no such land on Europa. Another problem is that Jupiter's radiation
belts regularly sweep across the surface of Europa, which would sterilize any life on
its surface, including any in those warm little ponds. That is, if it is life as we know it from
Earth. Finally, the temperature of those ponds is
unlikely to be warm, meaning that biochemical reactions slow down and decrease the chances
of life evolving from the soup. Now as mentioned, both Callisto and Ganymede
probably have those underground oceans just like Europa, so if you find life on one you
might find it on the others. Indeed as close as they are and as low as
their gravity is I wouldn’t rule out that if one had it the others might too, even with
those frozen surfaces and radiation belts as a likely barrier to cross-pollination. This means in all three cases we want to be
careful to keep our eyes open for signs of life; it’s not very likely, but if we find
life under the ice on any of these moons it will shakeup our view of the cosmos a lot. If that life exists, though, it’s likely
to be very different from the life that evolved on Earth. But even if it was a simple bacterial life
form, that would provide a treasure-trove of genetic information that we could possibly
incorporate into our own genetics or make use of industrially and that could be an economic
driver for the Jovian colonies too. If it is life as we know it, then that will
also have repercussions as it then means that Panspermia is probably real. Panspermia is the hypothesis that life exists
throughout the Universe, distributed by meteoroids, asteroids, comets, and planetoids. As I mentioned earlier, Callisto is possibly
a better bet for finding life on it than Europa is because Callisto is located largely outside
of Jupiter’s radiation belts, has solid rocky surfaces, and therefore may be able
to provide us with those alternating wet and dry primordial ponds. The only real issue is that it does not have
the tidal stresses that Europa does so any heating of the oceans will have to be driven
by radioactive decay in Callisto’s core and by sunlight, not through gravitational
tectonics. In the absence of life though, Europa represents
an unusual colonization approach. Under the ice is ocean, and in a fusion economy
it would be possible to float large fusion reactors that gave off photosynthetic light
to warm the seas and let us transplant photosynthetic organisms and our whole marine ecology there. You could put the reactors near the surface
and hang a chain of lights down, what I referred to as vertical reefs in our discussions of
Rogue Planets or enhancements to Earth itself. Or you could simply let them float like submarines
around the depths with large wire frames around them with lights and nutrients till they became
meandering ecosystems fueling an entire marine ecology. Submarine archipelagos. With Europa’s far weaker gravity diminishing
the buildup of pressure with depth, and with light coming from the reactors and not the
Sun, such marine life would be far more vertical. Human habitats and farms could exist on these
submarine archipelagos too, and people might journey around in personal submarines rather
than automobiles or small private spaceships. It’s hard to overestimate the amount of
civilization and colonization that could be done around Jupiter. It has immense resources and a good mixture
of them so that while it might trade with other planets, it doesn’t really need to. Yet what about the planet itself? In a fusion economy hydrogen is immensely
valuable but also not really in short supply, but the preferred fusion methods, beyond simple
vanilla hydrogen which is much harder, would be either deuterium or helium-3, and Jupiter
is a great source for both, which are not easy to find in quantity elsewhere. Though one doesn’t need a lot for fusion,
entire national economies can run their electricity off the energy in one small tank of deuterium
for quite a while. To harvest that we might scoop it up with
ships, giant airships that descended and opened their bays and shot out of the atmosphere
before they got too heavy and slowed down. This may be the best method early on, and
your ship probably needs to be as big as a fusion reactor can be made small, so that
it can be powered by what it is collecting. We obviously don’t have fusion reactors
for spaceships but it’s unlikely you couldn’t make one suitable for that use, and of course
if you can’t make one at all, you don’t need to try scooping up gas from Jupiter. If you do have a fusion economy then you probably
want not just these scoops but big tanker refineries floating around sucking in gas
and probably refining out the deuterium or helium-3 from it for pick up. However at the bigger scale, when you need
billions of tons, scooping with ships is maybe not ideal. Folks often want to hang tethers down and
just suck material up, either straight from the atmosphere or from our huge flying refineries,
but space elevators are a dubious proposition even on Earth, and tethers on Jupiter require
far more length and are under 253% of Earth gravity. We have an option for this though. The orbital rings we’ve discussed before,
the ultimate in cheap mass movement of material off a planet. You build an orbital ring just above the atmosphere,
or even down in it just a little to gain protection against meteors but still be above wind. From here you can safely lower down far shorter
tether to scoop up gas and retract them up to the ring. Above that you can have yet another ring,
either several layers or two more, one more circular ring out where gravity has dropped
to Earth Normal, and another elliptical one connecting the two. Jupiter has a radius of just under 70,000
kilometers, more than ten times Earth’s. To get to a place where gravity is the same
as Earth, you would need to be 1.59 times further away, 41,000 kilometers above the
planet. That is probably much too long to stretch
any single space elevator tether, so you need either multiple rings each connected to the
one above and below, or you need an elliptical one to stretch the distance. However up at that top one you could walk
around – under a dome – and feel just like you were back on Earth. Indeed, as we discussed last week, one option
for colonizing Jupiter is simply to build many orbital rings at this distance, each
turned at an angle, to create a shell around the planet, then add dirt and water and air
and have a planet with 318 times the living area of Earth. It would be cold, but you can provide artificial
lighting either by many orbital mirrors or an artificial fusion-powered sun orbiting
the planet once a day, geocentrically. Jupiter is known as the solar system’s vacuum
cleaner. It is the most massive object in our solar
system with the sole exception of the Sun and it deflects or captures a lot of the comets
and asteroids that would otherwise head for the inner solar system. Without Jupiter, considerably more comets
and asteroids would bombard the inner planets, including Earth. We can be extremely grateful that we have
a big brother keeping watch over us and dealing with those icy and rocky playground bullies
that would otherwise pound us. There will come a time, though, when humans
will have colonized the entire solar system, including the Oort Cloud. The Oort cloud is currently where most of
our comets are found. We will discuss how that can happen in our
next episode in the series. When we have tamed it all, rogue bodies will
be all but eliminated and we will outgrow the need for our planetary big brother to
protect us here in the solar system. One possible future for Jupiter is to remove
all of the gas from Jupiter. Down under it all we believe is an immense
core of heavier elements several times more massive than Earth. If we stripped that all away we might have
a rather nice planet below, especially if we moved it closer to the sun and took its
moons with it. For this purpose we have a device known as
a fusion candle. There’s a few ways to do this but I’ll
describe the one’s Jeremy rendered for the episode since they are the only such animations
in existence. You build yourself a giant fusion reactor,
with an intake nozzle to suck in gas and two propellant nozzles, one pointed down and one
pointed up. When you turn it on the upward nozzle hurls
huge amounts of high velocity gas out of a rocket engine, shooting it fast enough to
escape the planet’s gravity. That would make the fusion candle drop down
into the planet very fast, so the second down-pointing nozzle thrusts the whole candle up to compensate. This is one time when you definitely want
to burn the candle at both ends! You build a ton of these, when they are on
the right side of the planet they are on full power, otherwise they hover, so that all your
push is in the right direction, and it shoves the planet like a giant spaceship, using its
massive atmosphere for power and propellant. By this means you can strip off a gas giant’s
atmosphere and relocate the smaller remnant to the inner solar system. That would be a rather pitiful ending for
our big brother planet and I prefer a more exciting option of making the Jovian system
into an interstellar spacecraft, taking that whole planet and its moons on an interstellar
journey to another solar system. It has the fuel and resources to travel at
solid speeds across the interstellar void for millions of years if it needs to, and
it is one example of how you might send an intergalactic colonization effort, a notion
we will examine more at the end of the year. That interstellar spacecraft Jovian system
could even undergo a further evolution. Jupiter is too small to become a star, but
that doesn’t need to stop us. We can pick up other exo-Jupiters - Jupiter
sized planets that have been expelled from other star systems or ones that we have flown
out of other systems using fusion candles. We gather several of these Jupiters together
in interstellar space and fuse them into a super-Jupiter. This super-planet, once it reaches a critical
mass, will itself become a star about which we can build a custom-made solar system with
our super-Jupiter as its star. Speaking of getting out into deep space though,
our next episode in the series will focus on colonizing not planets but the endless
swarms of small icy bodies out beyond the main solar system, in our next episode in
the Outward Bound series, Colonizing the Oort Cloud. After that we will turn inward, and talk about
Colonizing the Sun. Not Mercury or making a Dyson Swarm, but the
actual Sun itself. Next week though we will head back to our
discussion of artificial intelligence and look at the well known science fiction concept
of a Machine Rebellion, and the week after that we will examine the notion of networked
intelligence and Hive Minds. For alerts when those and other episode come
out, make sure to subscribe to the channel. 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!