Tour of Our Terraformed Solar System: Jupiter and Saturn

This post is 3 in the series: Tour of Our Terraformed Solar System

Humanity faces a very large problem out past the Asteroid Belt: everything is too damn cold. But don’t worry, there are plenty of other difficulties to overcome beyond something so simple as extreme temperature. There’s the lethal radiation of Jupiter’s magnetic field, the debris of Saturn’s rings, and the lack of solid bedrock – it’s all been replaced with dirty ice. Oh, and don’t forget the toxic ammonia and methane. Colonists didn’t just need a good heating system – a cleanup crew and thorough shielding were important too.

It feels like an entirely different universe out here. The sun is a distant dot, and the planets are large and gaseous – not traditionally habitable by a species that enjoys being pinned to a solid surface by gravity. These enormous gas-balls are anchors for their own miniature “solar” systems: each is orbited by a multitude of (eventually) inhabitable worlds. So we’ll be breaking this leg of our tour into five parts: one trip through each of the four planetary systems, followed by a look at the lonely libertarian paradise beyond Neptune. Each tour takes us farther from the sun – and farther into the future, as the problems-to-profit ratio becomes progressively worse. Since we’re dealing with entire systems full of worlds, we’ll only complete the first two parts in this post – we’re time travelers, but we still need to sleep. For now, let’s see how humanity is tackling the Jovian* and Zohal* systems.

Jovian System (Jupiter)

As we near Jupiter, we’re staring at an angry, stillborn star; a colossal, radioactive ball of gas that comprises the vast majority of the mass in the solar system.* A million or so miles out, we get a good look at the neighborhood. It’s quite a neighborhood: four little planet-sized worlds* orbit this failed star we call Jupiter. They even provide enough gravity to walk without slipping – that is, if it weren’t for all the ice.*


Our first stop is Europa: a large,* mirror-bright moon of Jupiter with a recently renovated ocean. After gorging ourselves on the local seafood, we’re ready to get a good look at our surroundings. As we gaze through an icy ceiling at the great disc of swirled beige and brown that dominates the view, we can see Io, soaring above the banded clouds. Io is a devious little imp of a world constantly buzzing around Jupiter and stoking its rage. This is no mere metaphor: the particles ejected by Io’s volcanoes contribute to a band of deadly radiation in Jupiter’s powerful magnetic field. This is, in fact, the reason there’s ice above us instead of sky; ice does a better job of keeping the Europa colonists (mostly) cancer-free.

We’re visiting at a time when air is being pumped onto the surface and grand radiation-shielding schemes are being implemented, but there’s still nearly a century to go before we’ll see people strolling around on the surface. Not that there will be much of a surface, after the ice melts. Local politicians are still debating whether to liquefy the water-ice crust and turn Europa into a waterworld like its neighbor Ganymede – solid ground, or warm weather?* Meanwhile, us time travelers are debating whether to tell the locals which choice is ultimately made. We decide against it; after all, they got pretty angry a century ago when we told them that they would never find life more complex than self-replicating polymers in Europa’s deep oceans.*

Callisto and Ganymede

Nowadays, these worlds host flourishing human colonies, but it wasn’t always this way. Dozens of previous generations have done a LOT of intense cleanup work – both literally and figuratively – to get these places spec’d for human colonization. Even now, at a time when Mars and the asteroids have been hubs of human civilization for centuries, only the outer two worlds – Callisto and Ganymede* – boast open-air living: Callisto because it’s far enough away from Jupiter’s radiation, and Ganymede because the early colonists found ways to boost its protective, innate magnetic field. Both worlds have been vaguely disappointing: Ganymede is an ocean world with barely a dozen square miles of floating island to walk on, and Callisto has stayed bitterly cold in order to keep a solid surface.* Europa’s government, among others, will have to choose between these two less-than-satisfactory outcomes. In fact, the only world in the entire outer Solar System that’s rocky and dry enough to avoid this iceworld/waterworld dilemma is Io – and it’s a sulfurous, radioactive hellscape, incapable of supporting human life.

The Helioforming of Jupiter

I must say, we’re more than a thousand years out, and yet the Jovian system terraforming just seems so… half-assed. Let’s take a quick trip futureward in our spacetime device* to see what improvements the colonists are able to make.

We fast-forward a few millennia, and the results are disorienting. The Solar System doesn’t have one sun, it has three: Jupiter and Saturn (or Zohal, as it’s known now) have joined Sol in the exclusive star club. We’re right next to one of these acolytes of fusion: Jupiter is swollen, red-hot, and sports four little blue and green worlds.*

Jupiter is made up of all the right bits to be a star – it was just too small to ignite under its own gravity. But that’s like saying a torch is too cold to ignite under its own heat. Of course it is. The winning formula for setting that torch on fire? Just add human intervention. Hydrogen is tricky fuel, but deuterium* is a bit easier. There’s enough deuterium in Jupiter’s makeup to burn for hundreds of thousands, possibly millions, of years. In galactic time, this is barely a blink – but considering that all of human civilization has taken place in the last ten, maybe hundred thousand years, that’s plenty of time. We could easily repeat all of human history from agricultural societies onward on all four Jovian worlds ten times over before there was a problem.*

The New Galilean Planets

Of course, setting Jupiter on fire only solved two problems: getting enough heat and light to the surface of its four worlds. Luckily, by now Jupiter’s newfound solar (er, Jovian) wind has helped disperse some of its radioactive ring, and advanced shielding and cleanup systems take care of the rest. But the four Galilean planets still have a few quirks, to put it mildly. A quirk shared by all four is their tidal locking: one side faces the enormous Jupitersun, while the other receives only meager, intermittent light from Sol. This isn’t a deal-breaker for habitability – it just means that each of the four worlds has its lukewarm “Earth-like” zone in a different place. Innermost Io is only habitable on its dark * side, Europa’s Earth-like temperatures are on its rain-soaked twilight rim, Ganymede sports a balmy tropical ring of eternal dawn, and distant Callisto is only barely Earth-like at the very center of its day-lit bullseye.

The three outer worlds are covered with massive floating islands – though much of Callisto’s surface has remained frozen, due in part to the powerful corporate lo-grav-ski-resort lobby.* The inhabitants of all four worlds experience all the modern terrestrial amenities, from locally customizable gravity and weather to the best radiation shielding money can buy. Io is still jokingly referred to as a hellscape – which is only true of its oven-like Jupiter-facing side. Of course, the looming mining* and radiation shielding equipment looks positively diabolical, which supports the “infernal” vibe.

Jupiter has a handful of other moons as well, but nothing big enough to be of interest; they’ve been private resorts, trading posts, pleasure worlds, micronations and mining stations – but never hubs of civilization. The innermost moons were towed out of the way when Jupiter was helioformed, to keep them from vaporizing into explosive comets or new, even-more-radioactive rings.

We’ve seen everything of note here – it’s time to leave Sol even farther behind and see what’s happening in the Zohal System.

Zohal System (Saturn)

Place names are funny things – uninhabited rocks and seas (and planets) can have all sorts of names in all different languages, but once somebody lives there, they usually get to pick their own name. After a cultural group of Persian descent colonized the moons of Saturn, the common name for the planet sixth furthest from the sun became Zohal.

However, this isn’t a planet, it’s a star. Such a pity; the rings have largely evaporated,* and the court of little snowball-moons were all towed to safe distances, except for Mimas – which is quite literally boiling away.* Titan, Saturn’s single planet-sized world – which once boasted a unique and remarkable hydrocarbon climate – is now a doppelganger of Earth*. It probably shouldn’t come as a great surprise; humans do have a spotty record of respecting natural heritage.

Hmm, let’s dial it back a few centuries, shall we? What did this place look like before Zohal was set on fire?*

Unignited Zohal

Ah yes, now everything as it should be – the gorgeous rings, the snowball moons dotted with research stations, even the orange hydrocarbon haze of Titan.

The Snowball Moons

The moons large enough to be of interest are, from innermost to outermost:

  1. Mimas, Death Star clone and greatest shepherd of the rings
  2. Enceladus, ever-venting plumes of salty snow; promising sub-surface ocean
  3. Tethys, even less dense than water; made almost entirely out of ice. Also looks a bit like the Death Star when the light hits its big crater just right
  4. Dione, a moon with an entourage of lesser moons; has curious ice cliffs
  5. Rhea, the biggest besides Titan – massive enough to walk on but otherwise boring
  6. Titan, the big one; plenty to talk about here
  7. Hyperion, a potato-shaped, porous sponge of dirty ice; a great place to hide until the authorities melt it down
  8. Iapetus, a black side, a white side, and an enormous ridge around the equator that makes it look like a walnut
  9. Phoebe, a captured anomaly with a pitch-black surface

Humans in this time have recently discovered primitive bacteria on Enceladus, and biochemists everywhere are having a field day. But if anything that just makes the moon a worse candidate for colonization; contaminating the Solar System’s only other source of life* would be a big no-no. So let’s skip past Enceladus and the rest of the snowball dome-cities to the heart and soul of the Zohal system: Titan.


Meteorologically, 21st century Titan is a carbon-copy* of Earth. It has seas, rain, and a thick atmosphere! And that would be wonderful if humans drunk methane and breathed nitrogen and enjoyed temperatures of -180° Celsius.* Since humans tend to prefer their water liquid and their air oxygenated, Titan was a bit of a fixer-upper. But humanity didn’t want to completely eradicate Titan’s unique hydrocarbon weather – so the colonists of this era made a compromise: cloud cities in Titan’s modified upper atmosphere, dome cities on the still-frigid surface, and methane weather everywhere else. This compromise wasn’t made out of respect so much as resource concerns; specifically, it would take decades to properly harvest all of Titan’s valuable – and toxic – hydrocarbons.* On no other outer-system world is the pre-colonization cleanup work so difficult – and yet so profitable. In the meantime, the cloud cities are decent enough places to live. The weather is still a bit cold – okay, a lot cold – but strapping on insulated wingsuits and soaring through the sky by flapping one’s arms…that makes up for a lot.*

Rings Are the New Asteroid Belts

A tour of Zohal wouldn’t be complete without a look at the rings. No, they won’t be terraformed – not ever. Even in alternate futures where they aren’t blasted into space by the stellar wind of an ignited Zohal, there’s no great way to turn person-sized chunks of ice into livable habitats. And yet, even as Titan has just barely been terraformed, there are thriving communities here.

Saturn's rings close-up: ring particles! Artist’s impression of the rings of Saturn, observed from just above/within the plane of the ring. Image by NASA/JPL/University of Colorado

So why bother to live in the rings? Titan has resources and decent gravity, Enceladus has primitive life that needs to be studied, and some of the other moons have some decent snowboarding and mountain-climbing. Indeed, the rings are patently dangerous. Popular scifi depictions of asteroid belts with their densely-packed, careening space rubble are nothing like the real asteroid belt – but they’re a LOT like Zohal’s rings. When smugglers, criminals, and daredevils need to escape, hide, or perform death-defying maneuvers for their gasping audience, they’ll be weaving between icy boulders in the rings at breakneck speeds.* The larger moonlets hide entire colonies of Ring Rats – refugees and pirates that raid Zohal’s atmospheric hydrogen-extractors and terrorize the dome cities of nearby moons. There’s a good chance that, as beautiful as the rings are, the pirate-weary Zohal colonists weren’t sad to see them evaporated.

There are a few other curios and attractions here, such as the Dusk Temple of Phoebe, the Star Wars theme park on Mimas, the impossibly large solar-harvesting reflectors that warm balmy Rhea, and Zohal’s enormous, abandoned deep-atmosphere extractors from the metallic hydrogen rush of ’49. But we’ve seen enough tourist traps. We should rest awhile, and relax aboard an old-model freighter headed farther out. In a month, we’ll start the final leg of our Solar System tour at the most awkwardly named planet: Uranus.

P.S. Our bills are paid by our wonderful patrons. Could you chip in?



  1. George

    Hey I love this as I’m working on a sci-fi RPG without FTL drives so it is limited to our solar system. I love the idea of turning Jupiter and Saturn into mini suns, but I was wondering what if any source material was used for this article. I ask because I want to look into what effect it would have on the inner planets and why would both need to be suns would not a Jupiter sun provide warmth to the Saturn moons too?

  2. gmhs

    Not much. The new jupiter star would be about one thousand times less powerful than the sun, and the orbit would go from far away to a bit closer, not enough to do much in terms of heat. Light, however, would be different. Jupiter’s light may even light up the dark side of Earth to full moon levels when at its closest. (2010 and 2061 from the Space Odyssey series cover it well)
    I’m exited to see what you come up with, George.

    • gmhs

      Oops, forgot to use the reply button.

  3. Rob

    Hi! really like your series, very informative and inspiring for world building.
    I just read up on Eyeball Planets and was looking at the Galilean planets: Callisto is an Icy eyeball-eternally lit in the center surrounded by ice, Ganymede and Callisto are Hot eyeballs, and Io is something unique. When you talk about the night/say/superday cycle are you talking about periods when Sol and the other planets are in view, basically making things super bright?

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