What If Every Solar System Planet Was Habitable? | Unveiled

VOICE OVER: Noah Baum WRITTEN BY: Caitlin Johnson
Humanity has hopes to one day visit Mars, but what if every single solar system planet was safe for us to live on? In this video, Unveiled imagines a far-future reality when all the planets are habitable - from the searing plains of Mercury to the icy world of Neptune. We could see an entire space network emerge, held together by the asteroid belt. And we could even start to look beyond the Oort Cloud, out into the rest of the universe...

What if Every Solar System Planet was Habitable?

Statistically, there are billions of potentially habitable planets out there in the wider universe. And we have every reason to hope (or expect) that at least one of them has conditions similar to Earth. But those planets are all impossibly far away… so what would happen if liveable worlds were a little closer to home?

This is Unveiled, and today we’re answering the extraordinary question; what if every solar system planet was habitable?

To be considered “habitable”, planets have to meet certain criteria. For one, they have to be in the “habitable zone” of a star system; Not too close to the sun but also not too far away, otherwise they’re too hot, like Venus is now, or too cold, like Mars. They also have to be big enough to sustain a molten core, they have to have an atmosphere, they’re preferably rocky and NASA also says it’s best if they have large bodies of liquid water.

So, factoring all of those requirements in, aside from Earth none of the planets in the solar system are currently habitable. From Mercury through to Neptune, some tick some of the boxes but none tick all of them - even though there are suspicions that Mars may have done long ago. Something would have to drastically change to make them all liveable – be that with the actual planets, with the sun, or perhaps even with life itself.

As we are now, there’d be plenty of stumbling blocks even if every other planet could host life. So far, we’re yet to travel further than our own moon… So even if we could walk, talk and breathe elsewhere, technological restrictions could mean that we’d never get the chance to do so. However, knowing for sure that a readymade, new home awaited us on somewhere like Mars would make space travel that much easier. Long-distance astronauts wouldn’t need to plan for building habitats in extremely hostile conditions; we wouldn’t have to take a water supply other than what was needed on the trip; and we might not even need a food supply if other-worldly crops were edible. All of which means that spacecraft would be lighter, smaller and able to travel faster, the journey times would be reduced and suddenly we’d be an achievable distance from a lot of other places.

Such a life is the dream for many scientists and stargazers, to the point that it is something that we’re working on - even if we are at the very early stages right now. So, perhaps this hypothetical plays out in the far-future, at a time when the other planets are habitable but only because humans have gone there already and terraformed them. Here, the problem of travel is eliminated right away, seeing as we’d clearly already have the tech to get us to distant places. Exactly how we’d have terraformed every individual planet, though, is another matter entirely…

Perhaps we’d find a way to control the climates on the inner planets Mercury and Venus, or to somehow steer them away from the sun and into the habitable zone. Mars is already in that zone, but we’d need to have seriously strengthened its atmosphere before it could be considered liveable, perhaps by somehow heating up its outer core to improve its magnetosphere. Then there are the outer planets, which would be even more complex seeing as these gas and ice giants don’t have a defined “physical” surface in the same way as the terrestrial planets do. In fact, most scientists believe that the giants’ moons actually have much more potential than the planets themselves, like Jupiter’s Europa, Saturn’s Titan, or even Uranus’s Miranda.

They’re all extremely theoretical ideas, though… so what if it isn’t the planets that need to change to accommodate human life, but human life itself? Organic life is very adaptable, evolution has proven that time and time again, so could we one day find a way to specifically accelerate the process? To effectively optimize humans to withstand the heat of Venus, survive the lack of Martian atmosphere or somehow live within the clouds of Jupiter? The prospect of “designing human beings” is a pretty scary one, and many consider it wildly unethical… but advocates argue that its actually humanity taking control of itself. Here, it’d fast-track humans into populating alien worlds… even if it did blur exactly what being “human” means.

But, who’s to say that a fully habitable solar system would only be populated by humans, anyway? If all the planets around the sun just so happen to be habitable, and if all of those habitable worlds developed within a similar time frame as our own, then we could find ourselves in this alternate reality living side-by-side with a wealth of other alien races. Whether we’d call anything that isn’t human “alien” in these circumstances is debatable, though, given that we’d all be very much aware of one another.

In either case, over time we’d have developed a communication web all across the solar system - much like we have all across the world today. Our collective histories would be full of iconic moments involving journeys and discoveries made from planet to planet; of trade deals brokered between inter-planetary allies; and of pioneering efforts to develop interstellar space travel beyond the Oort Cloud. In this existence, Alpha Centauri is what Mars is now; the nearest “other” world to the one which we all know.

In building connections between planets, we’d see a wide spread of space stations acting as checkpoints between worlds - or even repurposed asteroids that we’d somehow managed to control. The asteroid belt itself could become a vital link between the inner and outer planets, bridging the gap between Mars and Jupiter. In general, the solar system would look a very different and much, much busier place.

Our shared technology would advance at a super-fast rate, with planets trading resources and specific regions of the solar system becoming known for particular products - like Jupiter with hydrogen, or the asteroid belt with precious metals. Ferrying between planets, moons and checkpoints, we’d see gigantic cargo ships for industry and sprawling cruise ships for tourism - with some beings living out their whole lives in the space between worlds. But the crème de la crème for open solar system designers and engineers would still be a generation ship, ready to venture beyond the pull of our own sun and into the realm of another. And generation ship building would perhaps naturally be biggest business on Neptune, the farthest out of the planets, as well as all across the Kuiper Belt.

The one dark cloud and ominous by-product across all of this inter-planetary, seeming paradise? War. The prospect of all worlds uniting to make best use of the solar system and to one day venture beyond it is exciting… but would it really transpire? Or would one planet, or one group, try to claim dominion? Could all of those well-meaning trade pacts turn into strategical alliances, as the solar system becomes split by its riches, its beliefs and its ambitions. Very quickly, Earth and everything else could find itself in the midst of a “space war”, pushing armies into battles along frontlines all around the sun. The terraforming work and inter-planet bonds long forgotten; the cross-world comradery and scientific collaboration a thing of the past.

Whether a fully hospitable solar system means humanity spreading out on its own, or the emergence of other solar system life forms, there’d be a balance to strike. Would this wider history mimic Earth’s own records, tarred with cross-border fighting, invasions and territory claims? Or could we instead build something friendlier, more cohesive and beneficial? If our star system opens up but only to humankind, then the playground of life just got a lot bigger. If the other planets were just always lived on by other types of being, then our friendships and connections just got infinitely wider. It would be the basis for something extraordinary. And that’s what would happen if all the solar system planets were habitable.