The one about Terraforming Mars and Venus
The literal translation for terraforming is “Earth-shaping”. It’s a process of transforming another planet or moon into something that’s more earthlike. What is earthlike? It’s an environment where humans can survive without requiring a spacesuit or an oxygen tank — an environment that can support other plant and microbial life. To understand how this can be done, we first need to understand what makes Earth capable of sustaining life in the first place.
What makes Earth, Earth?
It’s easy to take for granted the qualities that make Earth so suitable for human life: a temperature that’s neither boiling nor freezing, abundant surface liquid water, an essential atmosphere, a protective magnetic field and a relatively stable environment.
Earth is in the goldilocks zone, aka the habitable zone. This is an area of orbit around a star where planetary or moon surface can host liquid water given sufficient atmospheric pressure. Remember, the state of any matter is dependent on both temperature and pressure. A planet’s surface may be warm enough for liquid water to exist, but without sufficient atmospheric pressure the water will just evaporate into space and be lost forever. Mars’s orbit, for example, also falls in this goldilocks zone but Mars doesn’t currently have liquid water on its surface. Earth is the only planet in our solar system to have surface liquid water. Even though Mars doesn’t have any surface liquid water today, it did in its past when its atmospheric pressure was much higher. I have a blog on why Mars lost its atmosphere and water 4 billion years ago, which might be a good read for understanding why Mars is so barren despite being in the goldilocks zone. Because Mars was once so similar to Earth, it’s considered as the best option for terraforming. But just because the goldilocks zone is best for supporting surface liquid water doesn’t mean celestial bodies outside this zone cannot be terraformed to host liquid water on their surfaces.
Ok, so goldilocks zone is a great start as we need liquid water for survival. But that is not all that we need. We also need an atmosphere. There are two things to take into consideration when we talk about atmosphere— pressure and composition. Earth’s atmospheric pressure at sea level is 1 atm. Too little pressure and we may bloat to death. Too much pressure and we may implode to death. Mars that has 0.6% of Earth’s atmospheric pressure will kill you in less than 4 minutes if you venture out without a spacesuit. Dangers of too much pressure can be explained by any trained deep sea diver. At high pressures in deep sea, a harmless gas like Nitrogen, instead of flowing in an out of our blood, starts dissolving in it and causes nitrogen necrosis. Of course, the effects of high atmospheric pressure will differ based on where you are. For example, the high pressures of Jupiter will probably crush you to death before anything else.
But we could die even with all the oceans and adequate atmosphere if it contains no oxygen for us to breathe. Believe it or not, this describes ancient Earth that had oceans and an atmosphere but no oxygen until the arrival of first photosynthetic life — cyanobacteria. Cyanobacteria produced oxygen as a byproduct. Earth is the only planet in solar system with significant oxygen in its atmosphere as well as a protective ozone (O3) layer. This ozone layer helps shield our planet from harmful UV radiation. Earth’s atmosphere also absorbs all of the X rays and gamma rays that the Sun is constantly shooting at us. The molecules in the atmosphere absorb the high-energy photons preventing any from reaching us on the ground. This is why X-ray and gamma ray telescopes are launched in space as these photons don’t reach land based telescopes.
Another thing that has made life possible on Earth is the fact that it’s geologically active. All terrestrial worlds (mercury, venus, earth, mars) have changed since their birth, but Earth is unique in the degree to which it continues to change today. We say that Earth is geologically active, meaning that its surface is continually being reshaped by volcanic eruptions, earthquakes, erosion, and other geological processes. Interior heat is the primary driver of geologic activity, because this heat supplies the energy needed to move rock and reshape the surface. Inside a planet, temperature increases with depth. If the interior is hot enough, hot rock can gradually rise within the mantle, slowly cooling as it rises. Cooler rock at the top of the mantle gradually falls. This process by which hot material expands and rises while cooler material contracts and falls is called convection. At the typical rate of mantle convection on Earth, it would take 100 million years for a piece of rock to be carried from the base to the top. If interior cools enough, convection may stop entirely, leaving the planet geologically dead, with no eruptions or crustal movement.
It all comes down to size. For a terrestrial world, Earth is fairly big. Because of this, it has been able to maintain its internal heat. Mars which is 1/3rd the size of Earth has lost its internal heat (though recent findings suggest it still has some seismic and volcanic activity). Mercury has no internal heat or geologic activity. Venus on the other hand is much similar to Earth in that it has still maintained its internal heat.
But most importantly, interior heat is also responsible for Earth’s global magnetic field. Internal heath causes the liquid metal in Earth’s outer core to move up and down (convection). It’s important to note this movement of electrons in the liquid core is different from the convection of rocks in the mantle I mentioned earlier. — but the physics of all convections is the same.
The result of all this is that electrons in the molten metal (liquid Iron and Nickel) move within the core in much the same way as they would move in an electromagnet, generating Earth’s magnetic field.
This field is SUPER important in making a plant habitable. Earth’s magnetic field builds a magnetosphere — a protective shield — around Earth. The magnetosphere shields us from the energetic particles of solar wind and cosmic rays that are constantly bombarding us. Whatever particles that make it through this shield are directed towards the poles where they collide with atmospheric molecules creating the beautiful auroras. Without our magnetic field, the high energy particles will strip away our atmospheric gas and our atmosphere will be lost forever to space. This is exactly what happened to Mars when it lost its magnetic field about 4 billion years ago. These particles can also cause genetic damage in living organisms. One of the biggest terraforming challenges is generating a magnetic field. Without resolving this problem any successful terraforming of a planet will only be temporary. And it would only be a matter of time before the charged particles of solar wind and cosmic rays strip off our human generated atmosphere (unless the planet has a reallyy strong gravity). If you could figure out how to heat up a planet from the inside or create an external magnetic field then you might want to pitch your idea to NASA or Elon Musk.
Lastly, a bearable temperature is important for survival. You would think Earth is just the right temperature because it’s in the goldilocks zone. But Mars which is also in goldilocks zone has an average surface temperature of -80F! So, how is earth so warm? It’s because of the greenhouse effect. Greenhouse gases on Earth like carbon dioxide, ozone and water vapor trap the infrared radiation that reaches Earth from Sun. The gas molecules bounce the photons around rather than letting them escape, heating up the planet.
Without these greenhouse gases, our Earth’s average surface temperature would be 0F instead of 58F. But too much of it can lead to global warming. Venus is a living example of what’s called a runaway greenhouse effect. Its thick atmosphere is 98% carbon dioxide which is an excellent greenhouse gas. Venus has 200,000 times more CO2 in its atmosphere than Earth. In fact, Earth actually has about the same amount CO2 but its mostly trapped in the rocks rather than being in the atmosphere. And this makes all the difference by baking Venus at a scorching 880F!
These factors — atmospheric pressure and composition, abundant surface liquid water, a nondeadly surface temperature range, and a protective magnetic field — are what we have to align with Earth’s to terraform a planet.
By using many different mechanisms that already exist, and others that are still theoretical, we will attempt to terraform Mars and Venus. Of course, we can theoretically terraform any planet or moon or even stars and black holes! Of course terraforming stars and black holes would be a bad idea but it’s doable. Given enough time and resources, any planet or moon with a strong enough gravity to hold on to its atmosphere can be terraformed. Some of the best candidates in our solar system other than these two are Saturn’s moon Titan and Jupiter’s moon Europa. I chose to describe terraforming Mars and Venus because of their complete opposite challenges. This way we get to explore the entire spectrum of terraforming.
While picking a suitable planet or moon to terraform, it’s important to keep in mind that places with gravity that’s significantly lower or higher than Earth will have health implications. Humans over several generations may evolve to suit better to a different gravitational environment, but, the initial starter generations may experience health issues. It might also be wise to pick a body that already has an internal heat generating magnetic field.
We will now explore how the most promising Mars and the searing hot Venus can be terraformed.
TERRAFORMING
MARS
*The chart above may not be visible in dark mode”
Compared to Earth, Mars has almost no atmosphere. And whatever atmosphere it does have is made almost entirely of CO2. So, there’s no question of breathing on Mars. And we will need a spacesuit to keep us pressurized. Also, without the atmosphere we will get the full blunt of radiation coming from Sun including X-rays and gamma rays. Mars is also 1/3rd the size of Earth so the gravitational attraction humans will feel there will be much less. Mars has lost its magnetic field. And unless we generate one for it, all our terraforming efforts are to be lost in several generations. Oh, and let’s not forget global dust storms. But Mars does have a similar rotation rate to Earth so our days will be of similar length. Mars also has a similar tilt as Earth, giving it seasons.
Without an atmosphere full of greenhouse gases to retain infrared radiation coming from Sun, Mar’s average surface temperature is -80F. So, for the first several generations that live on Mars, the main mission would be to warm up the planet, raise atmospheric pressure, and make Martian air breathable. How do we do that? Well, by using greenhouse gases we can accomplish two of the three things: increase air pressure and warm the planet. Easiest would be if you could find the greenhouse gases on Mars itself rather than lugging it from Earth.
ACCOUNT OF MARTIAN GREENHOUSE GASES
Though Mars lost quite a bit of its atmosphere to space, a significant amount got bound to various elements on ground. The most accessible CO2 reservoir is in the polar ice caps. These ice caps also have frozen water. There are several proposals for how the polar ice cap CO2 can be released. The best leading proposal is to have two well positioned giant mirrors directing all of Sun’s energy on the ice caps. This will sublimate the CO2 into its gas form. To make this even more effective, albedo reduction may be adopted where the ice caps will be covered with dark dust increasing sunlight absorption. Dust from Mars’s moons Phobos and Deimos, which are amongst the blackest bodies in solar system will be ideal for the albedo reduction. Orbital mirrors with about 50 mile radius will be required. Carl Sagan had even proposed covering the ice caps with dark extremophile lichens. Not only will the lichens help the polar ice cap heat up faster, these microorgnanisms will produce their own CO2. But they would have to be lab treated as there are only a handful of microorganisms that can withstand the harsh environment of space. Releasing all this CO2 will raise Martian atmospheric pressure to about 4% of Earth’s and raise the temperature from -80F to -70F. Water vapor is a great greenhouse gas as well. Though we rather leave the frozen water in ice caps to form lakes as Mars warms up, we may have to direct it towards building the atmosphere instead. Some CO2 is bound to rocks on Mars as carbonate minerals. This would be hard to release as breaking down of carbonates require temperatures greater than 575F. This will require a lot of energy and resources. It will add another 2% to the atmosphere. There’s also CO2 dissolved in Mar’s crust. Because the gas is so widespread throughout the crust, any significant CO2 release will require heating of the entire planet. Releasing all of this would add another 1–2% of CO2 to the atmosphere. And still quit a bit of CO2 got buried deep inside Mars. This will be hardest to access but also the area with most CO2. Releasing all the CO2 from here might get us up to 30–40% of Earth’s atmospheric pressure but it’s still not quite enough. But it’s possible that with this amount of CO2 may trigger a runaway greenhouse effect like on Venus. The warming up of planet would increase volcanic outgassing (the biggest volcano in our solar system is Mount Olympus on Mars), making the atmosphere even thicker. But that would take millions of years.
Ok, so Mars doesn’t really have much of anything other than CO2 which is also not enough. We might just have to bring our own. One of the most powerful greenhouse gas, thousands of times stronger than CO2, is chlorofluorocarbons (CFCs) — infamous for their destructive effects on Earth’s ozone layer. We can use Fluorine based gas which is safer for ozone layer. Because the compounds are easily destroyed by photolysis, they are extremely short lived. Maintaining the temperature will require continuous production of CFCs. So, we will have to build production factories on Mars. And let’s just say that we will need a LOT of CFCs.
Another possible greenhouse gas is Ammonia (NH³). Problem with this is that it won’t stay as ammonia for long. It will break in Nitrogen and Hydrogen gas within a few hours. So, it may not warm the planet but Nitrogen is a great filler gas. Earth’s atmosphere is 70% Nitrogen. Filler (buffer) gas help reduce Oxygen toxicity. A crazy proposal for getting Ammonia to Mars is by bombarding it with comets from Kuiper belt. We could send many drones that would each nudge an ammonia rich comet towards Mars. Their precision will have to be dead on considering Earth is right next door. Also we would need about 10,000 comet. And Kuiper belt is really far away. Comets are mostly gas so won’t damage the Martian surface much; instead the gas will sublimate up and get caught by Mars’s gravity.
There’s also the option of using Methane as a greenhouse gas (CH4). There is evidence of Methane pockets under the surface from Curiosity’s data. We could try mining that. Worst scenario, we could also try importing Methane from Titan which has plenty. Plus it’s closer than Kuiper belt. Some bacteria also produce Ammonia and Methane. But we will have to at least partially terraform the planet before most microorganisms can survive there. Or with CRSPR and future of genetic engineering we may be able to manufacture just the right microorganisms.
Latest research shows that Silica aerogel can warm the planet by mimicking Earth’s greenhouse effects. The researchers show that a two to three-centimeter-thick shield of silica aerogel could transmit enough visible light for photosynthesis, block hazardous ultraviolet radiation, and raise temperatures underneath permanently above the melting point of water. Silica aerogels are 97 percent porous, meaning light moves through the material but the interconnecting nanolayers of silicon dioxide infrared radiation and greatly slow the conduction of heat. These aerogels are used in several engineering applications today, including NASA’s Mars Exploration Rovers.
In the best case scenario, the warming of the planet may take about 100 years. After which the water that’s frozen underground will fill in dried up river beds again. We also need Oxygen. Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE), placed inside the latest Mars rover, Perseverance, will produce a small amount of pure oxygen from Martian CO2 in a process called solid oxide electrolysis. Based on the success of this experiment, we can set up large scale models of this. If our planet by this point has a decent atmospheric pressure and CO2, we can also place cyanobacteria in Martian soil to help produce oxygen. It’s cyanobacteria that billions of years ago triggered the Great Oxygenation Event on Earth changing its entire ecology. But this method will take 100,000 years to make Mars’s air breathable.
Next, we need vegetation for nutrition as well as for more oxygen. But in order to grow anything in Mars’s soil we will have to rid it of its perchlorates which is extremely toxic. This could be done with the right bacteria that can survive on Mars and breakdown the toxins.
It will take time. A lot of time and a lot of resources to terraform Mars. It won’t happen for many generations. But it’s definitely doable. Many scientists have recommended biodomes instead. These domes will be just like Earth. But outside the domes will be the same deadly barren Mars. Some people may not prefer a world with boundaries. I personally think the biodomes are a great idea to have our Martians feel at home while they do the hardest jobs of their lives. But there will eventually come a day when they would be able to step out of these domes and breathe fresh air on Mars. Of course, people who don’t want the Mars life anymore will always have the option of coming back on Earth with the next spacecraft (which should fly every 2 years because of Mars’s Opposition). Having biodomes will also eliminate the need for genetically modified organisms. We could just have cyanobacteria ingrained in the ecosystem of the domes.
But we still haven’t resolved one big problem. Mars’s missing magnetic field. It’s not clear how we would go about restoring Mars’ magnetic field, but we might be able to build an artificial one. Previously NASA scientist Jim Green proposed a concept of placing a magnetic dipole satellite with a 1–2 tesla magnet placed in an orbit between Mars the Sun. This would provide a magnetosphere protecting Mars’s atmosphere from harmful solar radiation. The satellite would have to be placed in one of the Lagrange points. The Lagrange Point is a location of gravitational equilibrium that ensures the structure remains between Mars and the sun. This isn’t easy but definitely possible.
Elon Musk in not crazy for starting so early. He is brilliant for giving humanity a head start on an extremely difficult problem.
BUT WHY TERRAFORM IN THE FIRST PLACE?
I know many people who believe that the main reason we want to terraform other planets because we have almost broken Earth. Then why not just fix Earth? Wouldn’t that be a hundreds of magnitude easier than terraforming an extreme planet? Yes, of course that would be easier — IF the many proponents of fossil fuels and the many more disbelievers of global warming stop adding hurdles. But that’s not it. This is not the only reason we want to terraform.
Earth has faced 5 extinctions in its history. We are currently amidst the 6th one. There are many many reasons for extinctions from Earth’s natural albeit a bit dramatic internal homeostatic mechanism (ice ages) to the possibility of collision with asteroids (like the one that killed the dinosaurs). We are also not always the best of people. There are wars, fight for nuclear power, exponential increase in technology, election of corrupt officials in power. Based on current trends, it only seems like a matter of time before there is a third world war that thanks to our advanced technology will completely destroy Earth. We could be struck with another pandemic with a much higher mortality rate. Then we have the problem of an ever growing population on limited land and resources. Given the vastness of the cosmos, it only seems like a matter of time before something goes wrong. And considering how far we have come as humanity on planet Earth, it will be the saddest story ever if we extinguished before anyone even knew we existed.
Our fear to remain unknown is so strong that both Pioneer and Voyager spacecrafts that were launched with intention to maybe one day leave the solar system were equipped with a memorabilia of Earth.
But that’s not enough. Voyager won’t even go through the Oort Cloud for another 20,000 years. And it will be 40,000 years before it flies by the next closet star, Alpha Centauri. So, the probability that some alien will come across our earthly messages is extremely low. And then we don’t even know if they will be able to interpret it.
It makes sense that we spread our eggs in multiple baskets so we don’t all go extinct at once. If we don’t terraform, other option should be orbiting cities like in Ellysium. But in case of an asteroid collision, a floating city in orbit may not be safe either. But it will still be a great solution to our rising population problem.
VENUS
Terraforming Venus was first proposed by Carl Sagan. It will require a complete opposite approach than what we had to employ with Mars. Looking at the chart above, we can see why. Mars has 0.6% of Earth’s atmospheric pressure and Venus has 90 times the pressure of Earth’s atmosphere. Mars’s average temperature was a freezing -80F and Venus’s average temperature is a burning 890F. Venus is also very different in the sense that it has a 243 Earth days rotation. This means that on Venus you get about 120 days of sunlight followed by 120 days of night. It’s super hot either ways. A day on Venus is longer than a year. This slow rotation also accounts for a lack of magnetic field despite a hot internal core. Venus also experiences rains of sulphuric acid. It has an extremely dense and poisonous atmosphere. Doesn’t make sense why scientists would want to terraform such a place. But some scientists do believe that it will be easier to terraform Venus than Mars. Let’s see if that’s true.
To begin terraforming Venus, we will have to cover three bases:
1. Reducing Venus’ surface temperature significantly
2. Eliminating most of the planet’s dense CO2 and sulfur dioxide atmosphere via removal or conversion to some other form
3. The addition of breathable O2 to the atmosphere
And as Mars’s freezing temperature is related to its lack of atmosphere, Venus’s boiling temperature is due to an excessive CO2 in its atmosphere. So, just by removing CO2 we not only reduce atmospheric pressure but also cool down the planet.
Carl Sagan had suggested using photosynthetic bacteria to breakdown the CO2. But he proposed this in 1961 when the truth about Venus’s ultra dense atmosphere was still hidden. Later he conceded his proposal because microorganisms from Earth would not be able to survive on the surface of Venus. Although, they may be able to survive in higher levels of the atmosphere where both pressure and temperature are lower. Otherwise, we might have to bioengineer bacteria that not only survive but flourish on Venus’s surface. There is another problem that breaking CO2 into organic molecules requires Hydrogen which is rare on Venus. Like Mars, Venus also lacks a protective magnetosphere. Without this protective shield, all the Hydrogen in the atmosphere got stripped by solar winds and lost in space. So, genetically engineered photosynthetic bacteria may not be enough but they are definitely a start as they will also help with adding Oxygen in atmosphere.
Another way to remove CO2 from atmosphere is by creating carbon sinks on the planet — a method that scientists are exploring for fixing the greenhouse effect here on Earth. These carbon sinks sequester CO2 into carbonate minerals. There are many options for carbon sinks. On Earth, the best and biggest carbon sinks are the rocks. CO2 from the atmosphere reacts with the rocks and minerals to form carbonates like Calcium Carbonate which is the main ingredient in limestone. Many approaches to terraforming therefore focus on getting rid of carbon dioxide by chemical reactions trapping and stabilising it in the form of carbonate minerals. The Calcium and Magnesium oxides on Venus’s surface would be great candidates to react with CO2 and Sulfur Dioxide. Estimates have shown that if we use up all the Calcium and Magnesium oxide on Venus, we would reduce the pressure and temperature by half. To convert the rest of the carbon dioxide in the atmosphere, a larger portion of the crust would have to be artificially exposed to the atmosphere to allow more extensive carbonate conversion. It’s either that or bombard Venus with asteroids full of these sequestering minerals. This is typically a slow process. On Earth, it takes hundreds of thousands of years. But it’s believed that the process can be significantly expedited by using catalysts such as Polystyrene Microspheres.
We could also try thinning Venus’s atmosphere manually. You could try pulling it into space but Venus has a similar escape velocity to Earth so that would be a bit impractical. Also such violent bombardments could cause more volcanic outgassing adding back to the atmosphere we just removed.
Venus is also much closer to Sun than Earth so it receives almost twice as much sunlight. We could possibly try cooling the planet by creating ginormous solar shades. The solar shades could also be helpful as power generators. Venus could also be cooled by adding reflectors in the atmosphere. These reflectors would form a solar shield. If done right, these reflectors could also be used to transform the atmosphere.
Venus also lacks water both in its atmosphere and its surface. So, we need a way to bring in enough sustainable liquid water — which again won’t be easy. Several ice moons of Jupiter and Saturn have more water than Earth even. Some of the craziest ideas have involved crashing these on Venus. It’s one thing to change orbits of asteroids and comets and another to move big moons bound to giant planets. This would require enormous amounts of energy. You may be thinking why can’t we just produce our own water, like Moxie on Mars Perseverance rover that will be making Oxygen. Well, because like Moxie, no human technology is at that scale yet that we can produce and entire atmosphere of the planet. And if we don’t add these ingredients fast enough, they may not stick long enough before getting lost in space again.
What about Venus’s 4 month long dark nights?? I don’t know about the feasibility of increasing its rotation. Increasing the rotation of Venus to an Earth-like solar cycle would require about 1.6 × 10²⁹ Joules (50 billion petawatt-hours) of energy. The difficulty of that tasks is in the same realm as generating an internal source of magnetic field for a planet. Again as in almost all other cases, colliding with some other celestial object might help here as well. We could also potentially utilize space mirrors to direct sunlight on the surface during night time. These mirrors will have to orbit with the planet so that they are always pointing towards the night side. This is called a geostationary orbit. On Earth, communication and weather satellites are placed in this orbit. But because of Venus’s extra slow rotation, its geostationary orbit will be that much higher which means the mirrors will have to be that much bigger.
Protecting our newly created atmosphere will require an artificial magnetosphere. We could use the similar technology we discussed in terraforming Mars of placing a strong magnet between the orbit of Mars and Sun. But we will always have to take this magnet into account whenever we launch anything in that direction of space or our satellites and spacecrafts will get redirected towards the magnet.
Lastly, similar to Mars’s temporary solution of bio-domes, at Venus we have artificial mountains dubbed “Venusian Tower of Babel”. It has been proposed that an artificial mountain could be built on the surface of Venus that would reach up to 31 miles into the atmosphere where the temperature and pressure conditions are similar to Earth that a colony could be built on its peak.
IS THAT ALL?
We probably should also have rules and regulations in place for this new world. For example, if a crime were to happen on Mars who would ensure justice? Are law officials on Earth responsible? But even at light speed, information transfer between Earth and Mars can take anywhere between 7–20 minutes. That may not be ideal if the situation on hand is grave and urgent. But if law officials are in Mars then who sets the laws? There are a lot of ethical issues that would have to be resolved before establishing a community on a different planet.
Can the first humans to reach another planet start touching things? Or are we going to have to quarantine till we can absolutely be sure there’s no life on that planet lest we contaminate it.
Even the most basic thing as time is not an easy concept when we talk about other planets. Take Venus for example where a day is longer than a year. Even Mars which has a relatively similar rotation to Earth will lag behind if we use Earth’s clocks there. We might need a Martian clock where every second on Mars is equal to 1.027 Earth seconds. It may not seem like a big difference but over time it will accumulate. Also, a year on Mars is twice as long as an Earth year. We might want to use an Earth calendar out of nostalgia so we can celebrate our holidays together with the fellow Earthlings. But the seasons associated with it would make no sense. It will make more sense to use a separate Martian calendar.
Is everyone socially and economically equal on the other planet? Or will social hierarchy take place again?
There’s a very great trilogy on terraforming Mars. Interestingly, in second book when Mars’s is beginning to terraform, the second generation youth start rebelling to keep Mars the way it is. What are the chances that this will happen in real life too? It’s such a great book that the biggest contender for future Mars flag is a reference to this trilogy.
Here’s another flag contender that shows Mars as a way station between Earth and stars:
And that’s all you need to know (and some more) about terraforming. Hope you enjoyed the post!
