The Rings of Venus
Terraforming is the modification of a planet in such a way that terrestrial life can thrive there. One should not underestimate such an enterprise. The terraforming of Venus or Mars is a huge project that will take centuries, if not millennia. But on which of our two neighboring planets is such a project the most promising? They both have their pros and cons, but on this page I mainly want to talk about Venus.
This closest planet in our solar system looks suspiciously like Earth, at first glance. With a diameter of 12,104 kilometers, Venus is only a few percent smaller than Earth (12,757 kilometers). Gravity is also only a fraction less: 0.9 g. That similarity is very striking when you consider that the planets orbiting our sun vary enormously in size, from the dwarf Mercury to the giant Jupiter.
As a child I was fascinated by this twin sister of the Earth. I even drew a map, not based on any scientific knowledge, with seas, continents, mountain ranges and wave currents. The map also shows the assumed time zones and the climates according to Köppen, which I just learned about in geography class.
Unfortunately, around the same time, scientists began to understand that in many other ways, Venus doesn’t really look like our homeworld. Spaceships like the American Mariner 2 and the Russian Venera probes revealed that the planet isn’t exactly paradise. In fact, with an average temperature of 462 °C, an air pressure about 90 times higher than on Earth, an atmosphere with an awful lot of CO2 and a thick cloud cover from which sulfuric acid rains, Venus looks more like hell than hell itself.
Moreover, Venus rotates very slowly around its axis, which makes a day last more than 116 earth days. That also makes Venus a less pleasant holiday destination, let alone a nice place to emigrate to.
The ideas about terraforming, making other planets more habitable, have therefore always focused mainly on that other neighboring planet, Mars. That world ain’t much like paradise either. But the Red Planet can be terraformed, so to speak, on a rainy Sunday afternoon, compared to Venus.
Mars is only a small planet, however, so Venus remains the jackpot for terraformers. But how would you handle that? Be careful: we are going to think big. Very big. Fasten your seatbelts and suspend your disbelief!
First of all, the hellish temperature has to drop by over 400 degrees. This requires a planetary-sized sunshade to be placed at one of the so-called Lagrange points where the gravitational pull of the Sun and Venus are in balance.
The L1 point is about one million kilometres out, roughly one percent of the distance to the Sun. As a result this parasol has to be even bigger than the planet itself. Such an engineering project is far beyond our current capabilities. But with some advances in rocket science, robotics and asteroid mining, work could start later this century.
Furthermore, there is very little water on Venus. And water is an indispensable ingredient in every recipe for a livable world, so it has to be imported. Fortunately, in the outer regions of the solar system, there is an abundance of asteroids made up largely of water ice. Send them at the right angles to Venus and the planet will rotate a tiny bit faster with each impact. Two birds with one icecube!
Manoevring large rocks through the solar system is also far outside the grasp of current technology. But the principle is simple: build a rocket motor on the asteroid’s surface that uses some of its mass as fuel and push the rock out of its orbit. It’s of course recommendable not to apply this technology on a large scale until it’s hundred percent reliable. When you send many thousands of large icecubes to the inner solar system, they have to cross the Earth’s orbit. And you don’t want a single one of them to accidently crash into the homeworld.
There’s also stuff we’d rather get rid off: carbon, for example. A lot of carbon. If you shoot that into space at the right angle, the planet will rotate a little faster with every shot. And since it’s a shame to waste all that material, let’s build a nice Saturn-like ring system out of it. With their shadows, these Rings cool the areas around the equator. That’s not a luxury because Venus is a lot closer to the sun than our own planet.
And at night the Rings bring light in the darkness; that also comes in handy because Venus has no moon. And though all those impacting asteroids and ejected carbon may speed up the planet’s rotation quite a bit, an Earth-like 24 hour day and night cycle may not be attainable. So it’s good to have a source of natural light to brighten up those long Venusian nights.
That will be an amazing sight. A majectic arch in the night sky, partly in the shadow of the planet itself. Dancing in the Ringlight…
Summarizing it this way, it actually sounds like a piece of cake. But there are still a few challenges. For example, what do we do with other unwanted stuff in the atmosphere, such as hydrochloric and sulfuric acid? And what can be done about the relatively weak magnetic field? What will be the exact composition of the new atmosphere? Can argon and helium, readily available, take the role of inert gasses instead of the rare nitrogen? Can we create an ozone layer that protects life from solar radiation?
Either way, terraforming Venus is a job that will take hundreds or even thousands of years to complete. But the reward is immense: a second Earth with seas and oceans, continents and archipelagos. It may take a few centuries (or maybe millennia) but then you really have something in your hands. Enough time to work out the details.
The funny thing is: we can already draw a world map of Venus as it will appear from under that thick cloud cover. The topography of the surface has been scanned at a detailed level through radar. And almost every hole and bulge has been named by the IAU, with the catalog of Earthly goddesses and heroines as the main source. The result is a mix of exotic tongbreakers with more familiar names. Al-Taymuriyya, Snegurochka and Kokyanwuti alongside Artemis, Phoebe and Dione.
The exact coastlines will of course depend on the amount of water that can be imported, but there will be two continents: Ishtar in the Northern Hemisphere and Aphrodite around the Equator. And there are countless islands, peninsulas and mini-continents; the new Venus will be a perfect playground for water sports lovers.
It is hard to predict at this stage how the climatic zones and landscapes will spread over the continents and islands. Those zones are a result of the atmospheric circulation which in turn depends on things like the air pressure and the final rotation speed we can give the planet.
On Earth there’s a pattern of low pressure at the equator as well as at 60 degrees latitude and high pressure at the poles as well as at 30 degrees latitude. That’s why the Amazon is a jungle and the Sahara is a desert. On Venus, with probably a slower rotation, potentially a thicker atmosphere, certainly more heat from the Sun and of course the cooling effect of the Ringshadow, we will most likely see a different pattern.
But let me make a speculative prognosis.
Tropics and subtropics
The areas around the equator, which are in the shadow of the Rings for part of the year, will have a rather temperate, subtropical climate. Relatively cold winds will cool down also the areas just outside the shadow.
To the north and south of this comparitively mild zone are tropical rainforests that dwarf the Amazon. A little further from the equator we may also find some more arid climates and even an occasional desert. But after terraforming, most places on Venus are close to water and the proximity of the sun will generate plentiful rainfall. So those barren lands will be rare.
Warm poles, cool highlands
The polar regions will have a pleasant, Mediterranean climate. But with one rather remarkable aspect: the large Sun hovers all year round just above or just below the horizon. That’s a consequence of the axial tilt of the planet, which is just 2,7 degrees (compared to Earth’s 23,4). The blue and golden hours, popular among photographers, will take up most of the day. It’s not hard to imagine the slogan in the holiday brochures: The Land of Eternal Sunrise. That this Sun will rise in the west, as a result of Venus’ retrograde spin, is just a minor peculiarity.
It gets really cold only in the highlands of Ishtar, about five kilometers above sea level. And on the summit of Maat Mons, a shield volcano eight kilometers high, right on the equator, Venus’ own Everest. If you’re into skiing, I recommend you head for Mars.
Flora and fauna
It is going to be a nice job for the biologists, ecologists and landscape architects of the, say, twenty-eighth century, to select the right animals and plants for the new world. They will need the help of genetic modification or more traditional breeding methods to create species that are adapted to the conditions on the new world.
But it won’t be just a matter of planting some heat-resistant trees. Or releasing a few bio-engineered elephants with night vision. The creation of a vital ecosystem may take a few more centuries, in which bacteria, lichen and insects pave the way for more complex species.
The end result of the Venus terraforming project will be a spectacular world, living and breathing. A true sibling of Terra, with familiar features yet different in many ways. The outcome of a daunting enterprise, but definitely worth the hard work and patience.
Lord of the Rings
This transformed Venus would be a perfect setting for a multi-season series on Netflix or a similar platform. In this epic story, the protagonist travels from their native land in the southern polar region, where the ring system is not visible, to a mythical city on the equator, right below the Rings. That journey would take the viewer through many scenic locations with colorful cultures and fascinating lifeforms. Since we most likely won’t live long enough to see the terraforming of Venus completed – to put it mildly – such a television drama would at least give us a sneak preview.
Anyway, writing a novel, although simpler than terraforming Venus, is a tough job so that will take a while…
UPDATE: I elaborated this blogpost into an article in the magazine of the Dutch Spaceflight Assocoiation, which can be read here, from page 4.