This episode is sponsored by Brilliant A pristine natural environment sounds idyllic… if you’re on a planet that’s naturally
lush green and blue. But if your planet is just red, dusty, and
airless, nature is going to need some work. You and I live in an era when even a single
human boot print on Mars would be an historic accomplishment, one that we hope with fingers
crossed will happen in our lifetime. However, there may come a time when Mars is
no longer a frontier but is thoroughly colonized and populated. Martian babies will be born, and some Martian
adults will live their whole lives without ever visiting Earth. The geology of Mars will be surveyed thoroughly
and completely quite early on, and preserving its pristine state will become less important
than making Mars a better place for Martians to live. The processes of making a planet more Earth-like
has long been known as terraforming, “Terra” meaning Earth. A term, by the way, that originated in science
fiction before making its way into science. You can of course never really perfectly duplicate
a place nor is that really desirable even where you can, and as channel regulars know,
we have a lot of alternatives for finding extra living space, such as O’Neill Cylinders,
and that’s often been our focus for colonizing and when we do discuss colonizing planets
on the show it’s typically more about how we go about using them and living on them
in comfort, rather than genuinely terraforming them to near-Earth copies. Today though we’ll look at how we’d go
about doing just that, and while in many cases a difference between Mars and Earth would
not be worth the trouble to alter, like its year length and surface gravity, we nevertheless
will bring up the option for changing even those things today. Since there are a lot of factors and options,
many of which we have discussed in more detail in other places, I’ll toss out references
to those if you want more details, beyond that, grab a drink and snack and let’s get
to it. I think there’s this general notion that
you’d start terraforming Mars from one of those early bases and slowly doming areas
over will do ‘something’ that ends in the planet all blue and green. This is really not how you terraform a planet,
and indeed that doming approach, if you’re just expanding by adding dome after dome,
is what we call para-terraforming. You could have bases down on the planet that
you could keep intact through terraforming but you don’t settle a planet while you’re
terraforming it anymore than you start hanging up curtains and moving furniture into a skyscraper
penthouse apartment while they’re still bulldozing and putting in the foundation. Key concept, terraforming is ultra-destructive. You could make structures that could weather
the storm, very literally, as you reshaped that world at a fundamental level, but it’s
actually rather unlikely you’d terraform a planet you’d already settled in a major
way. Just for context, Earth’s got over a billion
cubic kilometers of water in its ocean, and likely more down in the mantle, and while
Mars has less surface area than Earth, that’s about the right zone for what you need to
truck in if you want great deep oceans like we have here. You haven’t got that in its polar ice caps,
and while those if melted would easily supply domes across that whole world, that’s because
you may only need the equivalent of a meter’s depth of water, not kilometers. If you trucked that in as comets, it would
mean dropping several million comets of a size with Halley’s Comet on Mars, which
is actually a bit bigger than the asteroid we think killed the dinosaurs. If you were trying to accomplish that in a
mere thousands years, it would mean dropping such a comet on Mars several times a day. Now, of course you could break those up just
before they hit so they’d burn up more easily in the atmosphere – which Mars doesn’t
really have much of yet – but I should note that quantity and rate would mean you got
around a meter or a few feet of rainfall each year just from that, forgetting about any
normal rain being made by evaporation. So if you want to give Mars water faster than
that, not taking many centuries to do it, you better be ready for non-stop torrential
rain, along with all the erosion and mudslides accompanying it. Or you better be ready for some serious mega-engineering. Like docking those comets in orbit at a host
of orbital rings and slicing them up for transport down to places they can melt rather than plummet
down as ice, snow, or epically large hailstones. Just to put a scale to that, freight trains
typically carry a few kilotons of cargo, so it would take a few hundred thousand of them
to move a cubic kilometer, or gigaton, of water or ice. And if you’re trying for one a day, you’ve
got thousands of trains constantly coming down from orbit and around the ground, hauling
ice, and they complete that project in a mere million years or so. These options probably sound the next best
thing to impossible, and if you’re new to the channel, is why we so often suggest building
things like O’Neill Cylinders instead and why most terraforming plans call for a very
modest approach. If you’re curious by the way, we’ve identified
about 5 million cubic kilometers of ice on Mars, which sounds like a lot, and again it
is if you’re going the shallow lakes and domes route. My own beloved Lake Erie, just a stone’s
throw from home, is only 500 cubic kilometers and so that’s enough to make 10,000 such
lakes. But it’s only a little more than is in the
Mediterranean Sea. When terraforming planets, we’ll often be
confronted by what is ‘good enough’ where that’s obviously a subjective concept and
where trying to exceed that to truly replicate something Earth-like might require a million
times more effort. Two really good examples of that are day length
and surface gravity. Mars’s day is quite close to Earth’s,
indeed there’s no planet closer to it, being a mere 37 minutes longer than ours. And it is longer, which means you get to have
an extra 37 minutes of sleep, something few of us would object to. But that could be sped up, and is hardly a
high tech process, simply Olympian in effort. You’re talking about needing to add several
thousand, trillion, trillion joules of rotational energy. But if you’re dumping lots of ice down on
a planet at orbital velocities, each gram having several thousand joules of energy on
entry, a trillion, trillion grams would do the trick, which happens to be a billion cubic
kilometers of ice, our rough target number for proper deep oceans. You just have to aim it all to hit in the
same direction so as to add rotation, rather than randomly hitting at every angle. It doesn’t exactly require precise timing
and coordination to get a giant slab of ice to hit a planet in about the right spot. Incidentally, if you had a planet that spun
a bit too fast, shorter days, you could do this backwards in entry direction to slow
it down, and I suspect that would be a more likely terraforming scenario too, as few would
object to an extra hour of sleep but would resent a 23 hour day. Remember the scale of that effort though,
and ask if you really need deep oceans and an exactly 24 hour day, or if lots of nice
lakes and shallow seas and an extra 37 minutes in bed is enough. I suspect most folks will say ‘yes’, even
in some post-scarcity high-automation civilization where robots do all the grunt work, since
even if humans aren’t spending millennia doing the actual lifting, they do have to
wait for the robots to do it instead. A thousand years is a long time to wait on
your contractor to finish the perfect job when he can get something 99% as good done
in 1% of the cost and time, even if cost doesn’t matter to you. Same applies to altering surface gravity,
only scaled up far, far more. As heavy as our oceans are or would need to
be to match that for Mars, you’d still need to bring in around a thousand times that mass
to bring the gravity up to snuff. Martian gravity is only 38% of Earth normal. And no you couldn’t dump asteroids on it,
because the whole Asteroid Belt wouldn’t even make a sizable dent in the amount you
needed, you couldn’t equal Earth’s mass if you used every moon and asteroid in the
solar system. Indeed, all three other rocky planets combined,
Mercury, Venus, and Mars, still mass just a bit less than Earth, and it would seem rather
wasteful to jam them and a few of our larger moons together to make a single planet. You could do that of course, and if you’re
shoving all that stuff together you could arrange to make the new Earth as far from
the Sun as our own but on the opposite side, a Counter-Earth, which has been a popular
idea in science fiction, especially before we had satellites far enough from Earth to
take a peek at what’s behind the Sun. Needless to say, this is very destructive
to the local real estate even by terraforming standards. You could do it slowly, but if you’re adding
a meter a day of new rock to that world, you are talking about centuries of folks going
out and sweeping and shoveling. I’m willing to believe folks might be willing
to put up with heavy rainfall and perpetual clouds for centuries, especially if we picked
our settlers from places like Seattle or London. You might even get a few adventurous souls
hoping to imitate Noah and willing to live there for an expedited process of constant
torrential rain for many years. But I’m thinking having it rain dirt for
centuries would be a non-starter for anyone trying to sell housing there. So again we have to ask what is good enough? Now we do have some tricks for sourcing that
much matter, and actually needing less to achieve the right gravity, that involve using
artificial black holes dumped into the middle of the planet, as we discussed in Colonizing
Black Holes, or ripping the planet apart to reform it into a shell around a gaseous interior,
but those are about the only sane ways to bring gravity up to Earth norm for Mars. Also I love running a channel where dumping
a black hole on a planet or ripping it apart to make a big shellworld can be referred to
as ‘sane’ without the slightest trace of sarcasm. However there’s a decent chance humans and
flora and fauna and pets and parasites can live comfortably in Martian gravity without
any real modification at all, and such modifications, genetic or cybernetic, are certainly not off
the table as pragmatic options. Even for things like hosting a Solar System
Series of baseball or football, where you want the gravity the same as Earth to avoid
arguments over home team advantage and records, you do have options like making a big deep
bowl shaped stadium and spinning it, to combine local and spin gravity to achieve the Earth-norm,
and cities could be made as such too. In the absence of the right gravity you’ve
also got a problem with the right atmosphere, getting it thick enough and made of the right
stuff and keeping it from flying away. That last is not actually a gravity problem,
more gravity helps for keeping atmospheres longer – they all leak incidentally, even
ours – but it mostly comes down to a lack of a real magnetosphere. With that Mars could hold an atmosphere, and
even our Moon probably could. But there’s more to it than simply dumping
air down or baking oxygen out of the rocks. In this case it isn’t such a big issue for
transport though. Air does have weight but it is pretty light
compared to things like oceans. Trucking air in from other places is no mean
feat, but this is an example where going beyond ‘good enough’ isn’t that restrictive. A couple notes, Mars has plenty of oxygen,
oxygen is the third most plentiful element in the Universe and it’s easy to forget
that just about everything we think of as rock or dirt has a ton of oxygen in it, a
third of Earth’s mass is oxygen and very little of that is in our air and any rocky
object will be similar, and any icy object is almost entirely oxygen, as H20 might be
two hydrogen and one oxygen, but oxygen masses 16 times as much as hydrogen and makes up
89% of the mass of water. So you don’t need to bring oxygen in for
air but most of what we call air is nitrogen. No we don’t need that to breathe but our
plants do. You can pressurize domes to normal Earth atmosphere
even though they’re only a few meters, not kilometers high, and thus use very little
nitrogen, which Mars hasn’t got a lot of as best we can tell, but if you want to grow
plants outdoors you need that nitrogen in bulk and probably need to raid Venus or Titan
for it. Now you also don’t need full pressure to
walk around in, indeed we routinely under-pressurize space suits so they leak less, leakage is
always faster the bigger the pressure difference on the sides of a crack or seam. So we go with pure oxygen a lot for suit mixes
and a lower pressure inside that suit. But if you want that regular pressure and
air on Mars, you actually need to use more air per unit of surface area than Earth has,
as pressure outside a sealed suit or a can is essentially weight of air over you, and
the same mass of air on Mars has less weight, so you need more air to get the same pressure,
and since there is less gravity yanking it down, it’s going to rise up even higher
toward space than our atmosphere does. Another option is to use a denser mix of gases,
possibly using a gas like Sulfur Hexaflouride which is an inert, non-toxic gas that is a
potent greenhouse gas and is 5 times heavier than air. It also has the effect of lowering the tone
of your voice, which may mean we come to think of Martians which live in such an atmosphere
as having deep voices. That is going to result in some very different
weather patterns but they’d still be fairly analogous to Earth, especially in contrast
to the current weather there, which is dust storms. It also means all your orbiting objects need
to orbit higher not to be getting dragged on by the atmosphere, and furthermore, it
also negates some of the advantage Mars has over Earth to a spacefaring civilization,
since its low gravity and minimal atmosphere make launching from ground to orbit much easier. You need to launch higher and through more
air, though it would still be easier than on Earth. Of course speaking of orbits, and of weather,
which is largely driven by the Sun, which Mars gets less off, we should talk about the
orbital infrastructure that has to come with terraforming Mars. One critical difference in colonizing planets
as opposed to getting off one, you always build your orbital infrastructure up before
and during building your civilization up, not after, as we did here on Earth. It’s easier to get into the orbit of Mars
than to land there. Truth be told it makes more sense to put a
space station around Mars or on one of its tiny moons before we set a base up on Mars,
though I can’t imagine us bringing ourselves to make the long trip there to drop off a
station then follow that up with a later mission to plant a flag down on the surface. Key point though, if you’re doing big stuff
down on Mars, you’re doing it with a space and orbital industry in play and in a big
way, so you might as well look to that for options for dealing with the magnetosphere
and low temperatures. Folks like to ask about drilling a hole down
into the Martian Core and setting off nukes to spin its core up to make a magnetosphere,
and honestly that’s not a logical approach. Especially as you’re talking about sending
down so many nukes to get that job done that it would make the whole cold war arsenal look
like a package of firecrackers. While that is admittedly not that big a deal
when we’re talking about trucking in whole oceans its still overkill for no effect. As it turns out we actually know how to make
magnetic fields without using a billion, trillions tons of spinning molten metal, and an electromagnet
around the planet or placed between Mars and the Sun at the Lagrange point is an option. There’s often a desire in fiction or discussions
of the future to make a terraformed planet somehow absent of technology after the process
is done, I think that’s part of the objection folks often have about orbital habitats like
the O’Neill Cylinder too, but an artificial magnetic field like that, even if it broke
down, would not result in the planet outgassing its atmosphere in mere minutes or even centuries. That’s more than enough time to fix the
problem, even if somehow things got so bad that a handful of survivors had to rebuild
and repopulate the planet and rediscover the technology too. Terraformed planets are going to require maintenance
too, and the more terran you want the place, the more maintenance is going to be needed,
even for stuff like the local ecology. If you’re wondering about how much power
it takes to run a magnet around Mars, or put a big magnet at the Martian L-1 point with
the Sun, the usual figure is about a gigawatt, which is fairly trivial even by modern standards,
let alone that of any civilization thinking about transporting many quadrillions of tons
of matter to a planet or dumping million of megaton atomic devices down into its core,
and whose uranium or plutonium could easily run that magnet’s powerplant for millions
of years. Of course there’s also a giant fusion plant
on hand too with the Sun right there and that’s a handy thing, since giving Mars enough light
to be comfortably warm will take way more juice. It’s a popular notion to suggest we could
just release a lot of greenhouse gases there to raise temperatures, but that’s a non-ideal
patch. Just as a reminder, Carbon Dioxide in large
concentrations has a lesser known effect of making the people breathing into lethargic
morons, and it kinda defeats the purpose of terraforming a planet if you need a breathing
mask and air scrubber when outside. Other greenhouses gases are certainly options
but water for instance, while a great greenhouse gas, has this tendency to form clouds and
to fall down, and if you’re aiming for high concentrations, that rather spoils the option
of going on walks on the Martian lands or having a picnic. Methane is a great greenhouse gas, and is
actually odorless it just tends to be produced by processes that aren’t, it’s also flammable. We have plenty of others like Ozone or Nitrous
Oxide, but my feeling is that folks would not want any of these in their air in large
enough quantities if there was an alternative. Which there is. The notion of building a great big lens at
the Martian L-1 or a whole lot of orbiting mirrors can strike people as a huge effort
but it really isn’t. Indeed it’s probably the easiest manufacturing
process involved in the whole terraforming effort, as mirrors and lenses are very thin
things. We were talking about dropping many millions
of cubic kilometers of water and air on the planet, in contrast a mirror as thick as the
one in your bathroom but with a volume of a single cubic kilometer of glass or aluminum,
would fold out to be as big as most countries, and we can make mirrors a heck of a lot thinner
than the one hanging on your wall or medicine cabinet. Not that you’d make a single mirror or lens,
you’d do a ton of them, and you’d have to be replacing, re-polishing, or recycling
them occasionally, but I’d be surprised if it took as much effort to build and maintain
enough of those to heat Mars up to tropic weather and keep them up till the Sun expanded
to produce that effect on its own in a few billion years took anything like as much effort
as trucking in all that air and water did. And if you’re putting in all this orbital
or Lagrange point infrastructure, you might as well put in power satellites and keep your
industries mostly up in orbit, no point despoiling the planet you just invested huge amounts
of effort into turning green. It’s also way easier and faster than moving
the planet. Of course it’s not Springtime on Mars unless
you’ve got trees and grass blooming new leaves and flowers, and that takes us back
down to the ground, because we also have to make all our soil. This is another case where what we can do
in domes is a lot easier than planet-wide and in the open. Given sufficient mastery of biotechnology
we can probably tailor us up some lifeforms that could cheerfully live in a vacuum stuck
to the side of a desolate airless asteroid, so cooking up something that can live on Mars
is almost certainly doable long before we have sufficient power and automation to be
thinking about these kinds of mega-engineering approaches to terraforming we’ve discussed
today. That does require advanced tech, whereas most
of what we’ve discussed thus far does not, it’s huge but simple, like the pyramids
or the Great Wall of China. In a dome, you can pressurize and light it
and mix up some basic dirt that’s not toxic for plants to live in. While the gravity is lower we already know
plants do fine in lower gravity, but things change when you’re talking about an open
and planet-wide ecology. We can’t ignore all the biogeochemical cycles
that help us deal with a lot of nutrients flowing down out of dirt and into the bottom
of the ocean, we can’t ignore that the rock on Mars is not chemically the same as what
it is on Earth and not something you could just throw in box with air and water and light
and some seeds and micro biota and expect to get healthy plants from. You are going to have to make every last inch
of soil on that planet, and you might decide the easiest and most sustainable approach
is to plow up several meters everywhere you go, throw that into giant mobile separators
to get the basic chemistry and soil particle size and shapes right, dump it into huge bioreactors
full of nutrient and bacteria, bake down a layer of ceramic or foil to act as a liner
to keep lower layers of Mars from contaminating that new soil, then dump the slurry back down
again in layers as you start getting plants and roots in there so all the stuff doesn’t
mudslide on you as you start the weather and rains going. Again, terraforming is a very destructive
process even when done right. Especially if you want to do it fast, and
since even fast is a process of centuries, that’s probably the path you’ll go, especially
since you are not going to even try terraforming planets unless you’ve got so much power
and automation that you don’t really need to try to be frugal about manpower. Keep in mind though that’s why we often
say rotating habitats are better, since, ironically, it is actually easier to build and terraform
a big metal can than a genuine existing planet, even adjusting for the size differential of
living area. You go beyond domes, you’re going all in
for a project that will dwarf any endeavor we’ve ever done before, and indeed probably
all of them combined, before you ever see your first oak tree blossoming there that
hasn’t been so gene-hacked that it probably has less relation to a terrestrial oak tree
than you or I do. We can’t ignore all the ecological cycles
that even once in place in simple form, are not going to mimic Earth too well. A tree might grow just fine in low Martian
gravity, indeed it might grow far better and get you trees that sneered at little redwoods,
but that sort of thing really affects all the ecology going on under its majestic branches
and canopy. You can probably force it to mimic Earth,
but this is an example where not only would ‘good enough’ tend to come into play,
but likely be viewed as a bonus feature. There’s probably a trillion planets out
there in this galaxy that are as amenable to terraforming as Mars is, and doubtless
at least many thousands will be close enough to Earth in almost every variable of lighting,
gravity, calendar, etc that most folks wouldn’t notice without careful measure, so for all
the others, why bother making carbon copies? Better perhaps to make every planet unique,
where you terraform only the low-hanging fruit or those aspects we really need to feel at
home, once we’ve adjusted to our new home, mentally or even physiologically. In that light, of course, we might often find
that expediting our own adaptations, or going beyond what evolution or even biology would
permit, might be a path that is easier or offers us more uniqueness options than terraforming,
what we call bioforming. And of course that’s something we arguably
have already done extensively with a lot of life on Earth, even our best friend, the dog,
just ask the poodle. But for Mars, the first world we think to
terraform, and arguably our closest sandbox to experiment and perfect our technique on,
I think we can’t really all say we’ve terraformed it, brought spring to a desolate
and dead world, until any regular old modern human could take their regular old modern
dog out onto the Martian prairies and forests with a Frisbee and a picnic basket, and in
no more gear than a t-shirt, shorts, and hat. For me, that’s ‘good enough’, and while
getting there would take a long time, and an incredible amount of work, as we are essentially
building an entire world, as we saw today, it can be done, if we want it bad enough. We were talking today about how you need to
generate a magnetosphere on Mars to keep the air in and adjust pressure and how that’s
going to work out as a thicker and taller atmosphere than on Earth because of the lower
gravity. Things like this can be counter-intuitive
sometimes and it helps to have a background in the sciences to grasp it, and if you want
to learn more about pressure and how it works, there’s a good quiz on it over at Brilliant,
as well as courses on magnetics if you want to understand how those help keep atmospheres
in and how much energy it would take to run one for a whole planet. Brilliant is a problem solving website and
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challenges in the archives and access dozens of problem solving courses. So next week we’ll be celebrating SFIA’s
fifth anniversary by returning to one of our favorite topics, the Fermi Paradox, to look
at the role that Extinction might play in either limiting the number of intelligent
civilizations that arise or ending them after they’ve arisen as galactic players. The week after that, we’ll return to the
Alien Civilization series to look at the popular concept of Ascended Aliens or other examples
where an advanced civilization might simply lose interest in our Universe, or at least
it's more primitive occupants, in Aloof Aliens. For alerts when those and other episodes come
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