This is part 1 in the series: Tour of Our Terraformed Solar System

Until we grow up and invent faster-than-light travel, the Solar System will be our playground. If we don’t kill ourselves first, it’s a good bet that humanity will have a significant footprint in the Solar System in the 100 to 1000 year range: lots of mining, probably a few colonies, maybe a swingset (er, resort world) or two. Perhaps more importantly, faster-than-light travel is not going to be ours anytime soon.*

Time to hop in our space-time ship* and do a quick tour in the mid-distant future, after our species has perfected both sub-light interplanetary travel and geoengineering. We’re going to see what each planet (or its moons) look like as a habitable world for humans, and discuss the history behind how the planet got to that point. A tour of this type also has the advantage of silencing skeptics; none of this “you can’t terraform Pluto, it’s impossible!” We’ll be starting from the premise that it’s already happened, and then work through what had to come first to make it a reality.

There are a lot of planets out there, so this will be a three-part series. Today we’ll be looking at the nice warm inner planets, cozied up to the Sun.


As visitors to this thriving, heat-loving desert world, we’ll be spending most of our time on the cool poles – away from the oven-like deserts, ever-burning jungles and roiling, hypercane-spawning seas of the equator. The poles are cool enough for us outsiders to stay comfortable – even if we’re struck by an errant sunbeam, as the frighteningly large Day-Star peeks out from behind the rim of the protective crater wall. Dome-city museums, the sacred monuments to the First Colonists, and ancient auto-mining relics are all here – and all popular tourist destinations.

There are a few migrating twilight cities as well: massive population centers floating over Mercury’s oceans and hovering over the deserts, always several miles behind the scalding terminator storm. They required expensive upgrades when the planet’s rotation was sped up and the oceans were installed, but the alternative was to abandon the profits from the Solar System’s most lucrative resort-casinos.

How far in the future are we? Oh, we’re a ways out: we’ve had to master the transportation of large comets, to dump enough air and water on this parched world to make it livable. We’ve imported and bred plants to help with air recycling, but they haven’t thrived as much as one would’ve expected, given the abundant light and warmth. This is because our historical planetary engineers needed to transfer enough air from one side of the planet to the other to keep the weather mild,* but not enough to turn Mercury into a greenhouse oven. To that end, they imported comets with the least amount of carbon dioxide (plant-food) and other greenhouse gases possible. It was a delicate balance for the terraformers to achieve – though as a consolation, it was less difficult when they focused only on the habitability of the cooler poles. Air-conditioning the rest of the planet to human-friendly temperatures came much later; there’s some debate whether it’s come at all.

Mercury’s meager magnetic field* wasn’t quite enough protection from the brutal solar wind – a force to be reckoned with at this short distance. In the early days, an entire colony was lost when a massive solar flare combined with a magnetic field vortex to brutally scorch the surface. Luckily, we solved this and two other problems at the same time: slamming comets into Mercury’s equator at an oblique angle gave it an ocean and early atmosphere, sped up its rotation so the days would be a bit more manageable, and (thanks to the increased rotation) boosted its magnetic field.

So why did humans ever bother with this tiny sunburnt world? Didn’t Mercury’s location make it too inhospitable for life? Not necessarily. While radiation and high temperature are indeed problems here, they were not insurmountable. More importantly, Mercury had ICE. Quite a lot of water ice, in a crater on its north pole – and elsewhere. This was a huge lure for the explorers of the inner solar system; early on, water was a key limiting resource. Mercury’s ice wasn’t enough for melting into planet-wide oceans, but it was more than sufficient for the needs of the early colonists.

As an extra incentive, Mercury is the most metal-rich body in the Solar System, and its crust is enticingly thin. The colonies on Mercury’s poles are the oldest after Mars and Luna because of this. It’s also surprisingly easy to get to, seeing as it’s set so deeply into the Sun’s gravity well. Getting out, though… well, there’s a good reason that much of 3000 CE’s planetary survival-horror genre was inspired by the disturbing history of early colonial Mercury.


Terraformed Venus by Ittiz at en.wikipedia
Terraformed Venus by Ittiz at en.wikipedia

It’s the distant future, and we’re visiting Venus during one of humanity’s greatest population booms. There’s a lot of incredible real estate here, now that our distant descendants have finally cleaned the place up and moved it back to its original orbit. The continents didn’t grow up in an ocean, so there are no clean continental shelves. The landmasses are all coastline: convoluted littoral fractals and archipelagos. This combines with the hot sun and rich air to make terraformed Venus a Pandora*-like jungle world. It’s not always the most comfortable place for humans (most of the settlements are in the polar regions, away from the heat), but it’s the lushest, greenest world we could hope for: Earth’s ridiculously fertile twin sister.*

The terraforming consortium still has some work to do; for example, they need to decide whether to permit some natural hurricane formation, how much genetic engineering should be used to adapt Earth plants to Venus’ bizarre season-days, and of course there’s the continued debate over whether to add more magnetic mirrors to the planet’s rings. But this is all just wrap-up and epilogue – the heavy lifting has already been done. And wow, was there a lot of it. Giving Venus a makeover was the project of generations, and there were more than a few false starts.

Sad to say, the planet named after a goddess of love did NOT love us back. Venus seemed built to keep humans out: a sort-of anti-terraformed world covered with boiling sulfuric acid and metal snow. It boasted the hottest surface of any known world* and the most overtly toxic, corrosive atmosphere.

Venus was terraformed late. It would’ve been exceptionally difficult early on, with no immediate payoff; the early explorers decided that mining probably wouldn’t be worth it, and the gravity is too high to get the goods off-world easily. Venus’ problems became its strengths in the long-run: its perfect gravity (just enough lower than Earth that you’re noticeably lighter, but not light enough to be a problem) and its close-but-not-dangerous proximity to the Sun make it an ideal human world.

Before we finally managed to tame it, there wasn’t much humanity could do with Venus besides, well, failed terraforming attempts. Even during the final stages of this last, successful terraforming attempt, orbital and upper-atmosphere habitats were safer and more Earth-like than any location on the planet’s wretched surface. Most other worlds have some early mining sites, terraforming stations, or colonies that became sacred ground or tourist traps – but not Venus.

Non-Scientific Sidenote

The closest is the now-destroyed hideaway of self-proclaimed supervillain “Professor Love”, who built a giant atmospheric ejector and threatened to spray Earth with Venus’ harmful greenhouse gases if Earth’s governments didn’t give in to her demands. She even proved that she could eject the Venusian atmosphere into space, and some of this gas was collected by Earth. Over the course of a few hundred years her plan may have worked – but orbital bombardments work significantly faster than interplanetary spray guns. The biggest winners, of course, were the media.

But Venus does have a physical record of its terraforming. Chief among them are the impact craters from humanity’s centuries-old comet bombardments – the source of both Venus’ oceans and its barely-sufficient rotation*. The fissure lines from our initial, mostly-failed attempts at moving the world to a colder orbit are apparent as well. Not to mention the sprawled wreckage of the first attempt at a planetary solar shield, and the flecks of the first failed ring. Yet these reminders of humanity’s string of failures are mostly limited to the steamy equatorial jungles; our pole-hugging colonists aren’t troubled by them. Today’s colonists are generally too awed by the gorgeous rings*, the constant aurorae*, and all the free land to fret over whether this is just the latest in humanity’s string of doomed terraforming attempts.


Earth by NASA/Goddard Space Flight

Earth in the distant future… is not exactly an original sci-fi setting. But once we had the tech to live on Venus, Mercury, and the outer moons, we fixed up Earth exactly how we like it. Pollution? Cleaned up. Radiation? Buried. Temperature? Well-regulated. Shorelines? Restored to their pre-industrial levels. Hurricanes? Steered safely away from cities and ocean colonies. Poverty? Well… we’ll see.

This is still where the bulk of humanity lives; even in the distant future, after we’ve ruined the planet with nuclear apocalypses and planet-wide evil empires multiple times over, this was still a great place to pick up* and* start over*. We evolved here, and no world can ever be as Earth-like as Earth. The planet feels like a utopian – if overcrowded – paradise when we visit. After all, we recovered from multiple planet-wide disasters and domesticated hostile worlds — the troubles of Earth have seemed insignificant by comparison. First-world problems have a new, much more literal meaning.

But there’s something not quite right here. Something is different…ah, the view has changed! There are more satellites: Earth-orbiting and near-Earth habitats were some of the easiest options for early space colonization, and some are old enough to be sacred heritage sites by now. But there’s something else. Has that big greenish-blue thing in the sky always been there? What is that?

Yes, we’re visiting far enough in the future that the moon has been terraformed. It may seem a bit over-the-top, considering that we’re so close to a perfectly habitable world. In fact, if nothing horrible happened to Earth, humanity might not have bothered with the Blue Luna project; the moon’s small size made the undertaking a bit tricky to say the least. But let’s take a quick detour to this new blue marble – it’s sure to have an interesting history.

Luna: Earth’s First (and Still Best!) Moon

By lttiz (Daein Ballard) at en.wikipedia
By lttiz (Daein Ballard) at en.wikipedia

“But we can’t terraform a world with such low gravity!” bellowed the original naysayers. Wrong. Air leakage is more a function of ionizing radiation from the solar wind; a magnetic field is more important for preserving atmosphere than high gravity. Even then, the equilibrium timescale here is geologic – or generational, at fastest. When the first terraformers dumped air onto the moon,* it stayed there long enough for their grandkids to breathe it. Humanity had a bit of maintenance to do thereafter, but our species is used to dealing with upkeep. After the last oxygen extractor was built, the comet-wrangling schedule got nice and lenient; we only need to dump extra nitrogen and water down every few centuries. The induced magnetic field from the ionosphere is enough to keep the surface radiation livable – though radiation meds are still included in standard Loony multivitamins. The Loonies don’t seem to mind the fact that their world will die soon after they do; it’s a point of pride that Luna’s biosphere is (at least on very long timescales) fully dependent on humanity for its survival. This isn’t mother nature, it’s daughter nature – and she’s a beautiful but fragile thing.

While visiting the Temple of Armstrong, the ground shakes so violently that all the pilgrims still learning to walk in low gravity fall to the ground.* As we pick ourselves up, the locals just grumble; we can hear them complain that these moonquakes have been getting worse ever since they had the oceans installed. Something about iron oxidation and crustal swelling; it’s a problem they can mitigate but never really fix.

There are more items on our travel docket: Luna is chock full of thousand-year-old sacred sites and tourist traps. Dome cities, carefully restored resort hotels, mining sites, and plenty of ancient flags – some housed in temples, others surrounded by meticulously preserved, pre-terraforming lunar soil. We even visit a historic site beneath the ocean; it was important enough to preserve under great domes. Last on our list are giant landscape drawings so large, they can only be seen from orbit: the logos of the ancient megacorporations.

Mars: The Planet Formerly Known as Red

Terraforming Mars by Daein Ballard on Wikimedia Commons
Terraforming Mars by Daein Ballard on Wikimedia Commons

Ah, Mars. Humanity’s first vacation home – and escape valve. It took longer than certain optimistic scifi authors believe, but terraforming Mars was eminently doable. It was half-assed at first; the deep craters and canyons were just barely habitable for the better part of a century before we got serious about adding oceans and breathable air. Even then, it took another century or two after that to bring life to the high plateaus – and even now, the tops of the great supervolcanoes are complete dead zones.

We’re visiting Mars at a sooner time than any of the other worlds: it’s less than a millennium away. Humanity has been mining and colonizing the asteroids for centuries, and there have been dome cities on Mars for longer than anyone can remember – but only recently has Mars become a little blue-and-green Earth-twin.

There’s all sorts of interesting politics and history to consider, but we’re here to study geography.* What does the planet itself look like, and how do the colonists like it?

This place has a lot of carbon dioxide in the air – enough that us visitors feel a bit dizzy and out of breath until we finally acclimate to it. This gas – and just a pinch of sulfur hexafluoride* – is more than enough to keep the whole planet toasty warm. Mars needs a cozier air-blanket than Earth, but the planetary engineers didn’t have to go to extremes; most of the carbon dioxide was already here, and anyway, we aren’t in a sunless cryogenic hellscape yet. (Wait till we get to the outer planets; those are a bit insane.) The sun is noticeably smaller and fainter, but there’s still plenty of bright daylight for growing crops and the like.

The geography is a bit bizarre. There are no continents per se, just a giant northern ocean and an equally large southern landmass, interrupted only by a few strange canyons and two large inland seas.

Since we’re less than a thousand years in the future, humanity’s technology isn’t efficient enough to clean the salt out of the entire planet’s soil – life will just have to adapt to the world’s unusual chemical makeup. But the farmlands that grow Earth-sourced crops are fully desalinized, and the nastier chemicals like peroxides are all taken care of.

While the world is finally just about Earth-like, the centuries-long piecemeal colonization process has had an unfortunate side-effect: Mars’s sacred heritage sites are all at the bottoms of oceans. The Hellas Deep and the deepest places of the Great Northern Ocean were the best sites for early colonists; the pressure there was even high enough for liquid water! It’s ironic, really; now these early colonies have more water than they can handle. Other heritage sites (like the canyon-bottoms, and the lower northern “ocean”) are underwater as well; the most important historical treasures and dome-houses were transported to safety before the floods came, but the sites themselves are lost. The oldest preserved places of cultural significance are some of the robotic landing and mining sites, and a handful of underground tunnel cities dug above current sea-level – but they aren’t much to look at.

Even though this world is finally a friendly blue-green, there’s still a smattering of red and white. The highest parts of Olympus Mons and the Tharsis plateau are never going to be properly terraformed; they’re just glaciers and bare red rock. Olympus Mons is the Solar System’s tallest mountain. The Martian atmosphere would have to be ridiculously, poisonously thick at sea-level for humans to be able to breathe normally at the top of Olympus Mons. People climb the mountain all the time, but they make the pilgrimage to the Solar System’s highest summit in spacesuits.

The key Martian industries at this point are mining and ecology tech, wrapping up the last terraforming tasks and trying to figure out how to balance this new ecosystem. It’s going to take some work – the biosphere definitely hasn’t reached equilibrium yet, and species diversity is very low.

Another early human colonization target is just next-door – we’ll only need to jump forward in time about four weeks. Why four weeks? Because that’s when my next post in this series goes live on Mythcreants. See you then!

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