When the topic of terraforming is discussed, the planets that make for the best opportunities with current technology make Venus or Mars the best targets. Although humanity could land on the surface of Mars, the time it would take to terraform the planet would be immense, on the scale of 900 to 100,000 years and be a complex process. Nevertheless, the argument for terraforming Venus instead has gained traction in the scientific community. over the past few years.
Although there are challenges to terraforming Venus in addition to the terraforming methods, the benefits of terraforming Venus include 30-50% closer than Mars, .9 G gravity as compared to Earth, and a thicker atmosphere with Venus so travelers would receive less radiation,.
Humanity might never be able to terraform the surface of Venus, but the benefit of a shorter trip and closer gravity to Earth would provide a plethora of benefits to human health. Cloud cities in Venus would be an attractive option, and maybe a potential option within technology. That said, here are a few options that could be done to terraform the planet.
Eliminating the dense carbon dioxide atmosphere is required because of the very thick carbon dioxide atmosphere, which makes the ground level pressure of Venus being measured at 1,330 psi. This makes the greenhouse effect increase the temperature on the surface to be several hundred degrees too warm for any currently known lifeforms, which requires all terraforming methods to include some form of removing practically all the carbon dioxide in the atmosphere. This had led to several interesting proposals, which include:
- Biological approaches have been considered for many years by scientists, but it has been determined that this method might not be successful.
- Capture In Carbonates would focus on capturing and removing carbon dioxide through chemical reaction trapping and carbonate minerals stabilization.
- Injection Into Volcanic Basalt Rock would work by removing carbon in the atmosphere by method of high-pressure injection into subsurface porous basalt formations, where carbon dioxide is rapidly transformed into solid inert minerals.
- Introducing Hydrogen into the atmosphere of Venus would cause the carbon dioxide to react could produce elemental carbon in the form of graphite and water through the Bosch reaction.
Direct removal of the atmosphere has been proposed by many scientists using methods such as a large asteroid impact or through direct methods. But these have been seen to be ineffective.
Cooling Planet By Solar Shades could involve reducing the insolation at Venus’ surface to prevent the planet from heating up again. There are some differing ways to do this, but they all have varying levels of success.
Artificial Mountains have been proposed as an alternative approach to terraforming that does not require changing the atmosphere of Venus. If built on the surface of Venus and reaching up to 50 kilometers, 31 miles, the the atmosphere would get to the point at which the temperature and pressure conditions are similar to Earth. At which point, a colony could be built on the peak of this artificial mountain, but there are many considerations including how to build the mountain to handle the pressure of the surface and how much material would be required.
Since Venus only has a fraction of the water on earth (less than half the earth’s water content in the atmosphere, and none on the surface), water would have to be introduced from an external source.
Although Venus does have the slowest rotation period of any known object in the Solar System, there is much debate over whether this is good or bad for the environment in terms of terraforming. There are a few proposed methods to change the potential problems this would cause, but there is not enough research on the subject.
Venus presently lacks an intrinsic magnetic field, therefore creating an artificial planetary magnetic field is needed to form a magnetosphere via its interaction with the Solar Wind. To avoid the loss of hydrogen, Venus would require an artificial magnetosphere, which could be possible with current technologies.
References And Further Reading
Fogg, Martyn J. (1995). Terraforming: Engineering Planetary Environments. SAE International, Warrendale, PA. ISBN 978-1-56091-609-3.
Landis, Geoffrey (2011). “Terraforming Venus: A Challenging Project for Future Colonization” (PDF). AIAA SPACE 2011 Conference & Exposition. doi:10.2514/6.2011-7215. ISBN 978-1-60086-953-2. Paper AIAA-2011-7215, AIAA Space 2011 Conference & Exposition, Long Beach CA, Sept. 26–29, 2011.
Landis, Geoffrey A., “Terraforming: Engineering Planetary Environments (review)” (also available here) (accessed 25 Dec, 2016).