Terraforming Venus

Terraforming VenusWhen you hear the word “terraforming”, the planet that most likely springs to mind is the planet Mars. In recent decades, Mars has captured the public imagination, and the red planet is considered to be the most likely target for any terraforming efforts within our Solar System. But it wasn’t so long ago that scientists and science fiction writers alike considered Venus to be the most agreeable subject for our terraforming ambitions.

Venus has long been considered to be Earth’s twin, and it is thought to have once had an atmosphere comparable to our own (before runaway global warming turned it into one of the hottest places known to man). So, instead of trying to heat Mars, should we really be trying to cool Venus?

The following information on the terraforming of Venus was provided by Dmitriy Ivashchenko and was first published on the Mars Terraforming Corporation Facebook page…

The terraforming of Venus is the hypothetical process of engineering the global environment of the planet Venus in such a way as to make it suitable for human habitation.

Why Terraform Venus?

Venus after terraforming:

Ideally, terraformed Venus could be a planet with a warm and humid climate. It’s estimated that if the Venusian atmosphere had composition identical to the atmosphere of Earth, its average temperature would be about +26 ° C (on the Earth it’s +15 ° C)

Current conditions on Venus:

The average temperature on Venus is currently + 467 ° C (Venus is the hottest planet in the solar system), the atmospheric pressure is about 93 atmospheres (bar), the composition of the atmosphere is carbon dioxide – 96 % , nitrogen – 3.5% , carbon monoxide and sulfur dioxide – 0 3%, oxygen and steam – 0.12%.

The attractiveness of colonization:

Venus is the twin sister of our planet: the diameter of Venus 12104 km (95 % of the diameter of the Earth), the mass is 4.87.1000000000000 billion tons (81.5 % of the mass of the Earth), the acceleration of gravity 8.9 m / s ² (91 % of the earth gravity).
Venus is the nearest planet to us in solar system.
Venus gets a lot of solar energy, which potentially could be used for terraforming.

Difficulties of colonization and terraforming:

  1. Venus is very hot; the average temperature on the surface of +467 ° C (hotter than Mercury).
  2. Pressure on the surface of Venus is 93 atmospheres.
  3. The atmosphere of Venus is 97% composed of CO2.
  4. Venus has virtually no water, so it must be delivered there by artificial means. For example, by means of comets or asteroids, or by synthesizing water (e.g. from atmospheric CO2 and hydrogen).
  5. Venus rotates in the opposite direction to the Earth and the other planets of the solar system, the axis of rotation is nearly perpendicular to the plane of the orbit (176°). Because of this unusual combination of directions and periods of rotation and revolution around the Sun, a single day – 24 hours here on our planet – lasts 117 Earth days on Venus.
  6. The magnetosphere of Venus is much weaker than the Earth’s. In addition, Venus is closer to the Sun than the Earth. As a result, during the terraforming (by decreasing the mass of the atmosphere), the level of radiation on the surface of the planet will likely be higher in comparison with the Earth.

How to Terraform Venus

The methods of Venus terraforming:

1. Solar screens between the Sun and Venus
Screens should be installed in the Lagrange point between Venus and the Sun. However, it should be remembered that this equilibrium is unstable, and to hold it in the Lagrange point, we will need to correct its position regularly.

It is assumed that such “umbrellas” can dramatically reduce the flow of solar energy reaching Venus and, as a result, reduce the temperature of the planet to an acceptable level. Moreover, by sufficient shielding from the sun the temperature can be decreased to such extent that the atmosphere of Venus will freeze and substantial part of it will fall on the surface in the form of dry ice (solid CO2). The result will be a significant drop in pressure and additional (by increasing of albedo) cooling of the planet.

One of the options for such project could be the installation of ultralight reflective mirrors, the light from which can be used for simultaneous heating of the colder planets (for example Mars). The screen could also be used as gigantic photo cell for mega-powerful solar power station.

2. Bombardment by comets or water-ammonia asteroids.
The amount of water that would need to be delivered to Venus is enormous. For example, to provide a suitable hydrosphere on Venus requires at least 100,000,000 billion tons of water, which is about one hundred thousand times more that the mass of Halley’s Comet. The required icy asteroid should have a diameter of 600 km (6 times smaller than the diameter of the Moon).

Aside from icy comets and asteroids, a large amount of water can be delivered from some moons of Jupiter and Saturn, as well as from Saturn’s rings.

Delivery of water to Venus by means of asteroid bombardment solves one problem but creates new ones. Here are some of the problems this could create:
– First, a large asteroid strike could lead to the destruction of the planet’s crust and create even more life-threatening conditions, so we should probably use a lot of weaker strikes.
– Second, the rocks of Venus have an enormous heat capacity and relatively low thermal conductivity, so the process of cooling in any case will last for many years.
– Third , the current temperature of the surface layers of the atmosphere is far above the boiling point of water. Consequently, without substantial cooling below +300 ° C (at 90 Earth atmospheres) free water could not exist on the surface of the planet. Water will be present in the atmosphere as water vapor, which is also a greenhouse gas. However, the clouds of dust, raised by strikes, will contribute to decreasing of the temperature, creating the effect of  a “nuclear winter”.

3. Delivery of terrestrial algae or other organisms to Venus
In 1961, Carl Sagan suggested introducing chlorella to the upper atmosphere of Venus. It was assumed that with no natural enemies, the algae would start multiplying exponentially and break down a lot of carbon dioxide relatively quickly. As a result, the Venusian atmosphere would be enriched by oxygen. This in turn would reduce the greenhouse effect and decrease the surface temperature.

4. Neutralization of the acidic atmosphere
Shock spraying of metal meteor in the atmosphere can bind sulfuric acid into salt with liberation of water or hydrogen (depending on the exact composition of a meteor). Asteroids like (216) Kleopatra could be used for this process. Perhaps the plutonic rocks of Venus also have suitable composition. In such a case it is sufficient to use a hydrogen bomb with sufficient power to simultaneously cause the “nuclear winter” effect and to bind acid by means of dust.


Article by Dmitriy Ivashchenko of the Mars Terraforming Corporation

Edited by Mark Ball

  • http://dtkrippene.com DT Krippene

    An interesting concept, but I’m thinking proximity to the sun with extensive bombardment by solar flares makes even the fiction of this option unrealistic. Landing, maybe creating a research post in a location with the least exposure, possible viable.

  • Dan

    Like you I have always had a soft spot for our little hot headed sister Venus. My interest in terraforming Venus encouraged me to do rough calculations to estimate the amount of energy required to do it. Energy to remove essentially all of Venus’ atmosphere is 2.5*10^28 joules.
    Energy to give Venus a 24 hour day is 2*10^29 joules. Obviously there are huge values and probably only available to a civilization between Type I and II on the Kardashev scale(No cheating allowed! We’re Type 0!:). But a terraformed Venus doesn’t have to be exactly like earth. I came up with a compromise energy requirement of 2.2*10^28 joules to remove 90% of the air and to spin up Venus to a 72 hour day. If handled right (expel the air horizontally at escape velocity at the equator) both tasks can use the same energy. A “two for one” approach. I postulated a 100% efficient solar cell 5 times the diameter of Venus for energy to complete the project in 100 years. How to apply the energy becomes the issue. In my story ‘The Planet Brokers’ I suggest spinning the air away by turning Venus into a homopolar motor with a magnastar magnetic field and a an asteroid sized ion cannon. Whether we can generate a big enough magnetic field without an available magnestar is an open question. Maybe someone has an idea.:)

  • Gabriel

    Geoffrey A. Landis conceived that since Earth’s breathable air is less dense than Venusian one, a compartmentalized flotation bubble filled with air would serve both as a flotation balloon and a habitation area. The so-called “floating cities” making use of this principle are real and feasible, for a floating outpost, at-least.
    Taking this further, those balloons can reach high enough where atmosphere is cool and its pressure is just one atmosphere, making heavy shielding completely unnecessary. Then, we can build a floating factory, which will sequester carbon from the atmosphere, use it to produce graphene nano-tubes or carbon fibers, used to build more such airships. One may fiddle with the idea and conceive a credible process for his story to show how this can be done with minimal external assistance.

    Non-habitable balloons can be used to float high in the atmosphere at such great numbers as to partially shield and reflect sunlight.

    • http://www.scifiideas.com admin

      Ooh, now there’s an interesting idea, and quite a bizarre mental image.

    • Thomas Thorne

      Also, due to the super-rotation of the atmosphere, the day-night cycle on such a colony would be only four Earth days long. That’s way better than the sluggish rotation on the surface, which would likely ruin even the most carefully terraformed ecosystem. How can you maintain liquid water–even after you’ve removed the dense Co2 atmosphere–when an ocean faces the sun for a hundred and seventeen days? Combined with a closer distance to the sun this makes terraforming doubtful indeed.

  • Peterh

    Cool Venus enough and CO2 will start reacting with surface rocks. This will be accelerated by addition of liquid water. Uncertain is whether exposed rock is enough. Erosion by the introduced water cycle should sequester most of the CO2 in carbonate rock given enough time, but how long is that?

    On the matter of planetary rotation, control of cometary impactors should give some spin, but is it enough?

    A 600km hunk of ice sounds like something we might find in the Kuiper belt.

  • http://physics.stackexchange.com/users/1255/alanse AlanSE

    There’s a persistent problem with the arguments involving water. For instance, it’s just not thinkable that algae could produce water on Venus. This isn’t just because the atmosphere is dry, but it’s because there’s not enough Hydrogen. It doesn’t matter how you spin it, you obviously can’t make water without Hydrogen.

    Several valid approaches to terraforming do exist, but to have a proposal seriously considered, it should be clarified how it satisfies the mass balance. In other words, Venus should start with the same elements it ends with unless you introduce more material. Doing the job with only domestic materials would be difficult due to the purities needed. You’ll need to sequester the Carbon while not capturing much Oxygen, Hydrogen, or Nitrogen along with it. Because of that, it’s likely that scooping dirt from the surface will help. That will introduce new elements that can engage in chemical reactions with the atmospheric gases. Sequestration is totally possible, it’s just not easy. Because of that, I imagine the process as more of a serial industrial process than clean self-replicating bacteria or Von Neumann bots. In other words, the feel would be much more steam punk.

  • Joshua

    Now Alan, there is rather abundant hydrogen on Venus still, in the sulfuric acid cloud cover. We already have extremophiles here on earth that can handily tolerate sulfuric acid. Find a way to free the hydrogen and excrete the sulfur, combine with oxygen that is a byproduct of any photosynthesis, and water can be made locally.

    • Thomas Thorne

      The sulfuric acid is actually more rare than it’s made out to be, and it gets all its hydrogen from the water vapor already present on Venus. Most of the sulfur is present in sulfur dioxide. Hydrogen is extremely scarce on Venus. Less than thirty parts per million, including both molecular hydrogen and hydrogen in other chemical compounds.

  • http://physics.stackexchange.com/users/1255/alanse AlanSE

    Oh dear, I didn’t realize Sulfuric Acid had an OH on it. Of course, this would naturally be a Hydrogen source. It’s many times more abundant than water itself, so this is quite relevant. There’s still not enough Hydrogen to pair frequently with Carbon, but that’s probably obvious to most people.

    • Thomas Thorne

      Most of the sulfur compounds in the atmosphere of Venus are sulfur dioxide, the sulfuric acid forming via solar radiation interacting with carbon dioxide, sulfur dioxide and the trace amounts of water vapor present on Venus. This is where the hydrogen comes from. Hydrogen truly is scarce over there. Here’s the stats on the composition of Venus’ atmosphere: ( http://upload.wikimedia.org/wikipedia/commons/6/6c/Atmosphere_of_venus.png )

      Argon is actually three times as common as water vapor. Woof. That’s brutal.

  • Dan

    Venus is pretty dry. If you could cool Venus down to room temperature the total water would not even condense out of the air. All the water on earth would make up a sphere approx 1300 km (860 miles in diameter). So where to get more water for Venus once the temperature is cooled off? I once suggested pulling Saturn’s moon Phoebe(200 km dia.-50% water ice) out of orbit with a huge solar sail. But that would only make a flat layer 15 feet deep and would likely end up as chemically locked into the dry subsurface rock. Better choices are Saturn’s moon Iapetus which is 1400 km(890 mi) diameter and almost all water ice or a trans-neptunian dwarf planet like Makemake or Sedna. But getting them to Venus safely would be a massive engineering challenge. Also I don’t know how much frozen CO2 these bodies contain. That’s something you definitely don’t want to bring to Venus.

  • Jason B

    What about introducing sodium hydroxide? Once mixed with sulfuric acid the byproducts are water and salt. Considering the temp of Venus is reduced enough to allow water to form, aerosoling sodium hydroxide (lye) would also scrub co2 from the atmosphere.

  • http://theoconsequentialism.com RDSouth

    Replace the clouds with a substance that’s reflective in light but clear when dark, like those sunglasses. When it gets cold enough the C02 starts raining down, making bodies of liquid on the surface. At a temerature of 40 below (parka) and a pressure of 8 atmospheres(scuba) you could walk around. The atmosphere would be 3 parts nitrogen and 5 parts CO2. Use geothermal and wind to keep dwellings warm. The long day would be equivalent to seasons, with autumn (evening) rains followed by lower pressures and temperatures, then a spring (morning) dry season, with rising pressures and temperatures. That’s not really “terraformed” but it makes a Venus that is a plausible setting, with all kinds of problems that are interesting in themselves.