An ICAN EduToSpace Pioneer Initiative
What is Terraforming?
Terraforming is changing a planet that we cannot live on at present. The idea is to change it so some life from Earth could exist there. It would need a suitable atmosphere (air), heat, and water.
Some think it is possible to terraform Mars, our Moon, Titan, Callisto and Mercury.
It is arguable that we have already succeeded in terraforming right here on Earth. Thanks to modern technology, humans can now thrive in places that should be impossible to live in such as deserts and the Arctic.
Reasons For Terraforming
Mars is the most earthlike of all the other planets in our Solar System. It is also believed that Mars once had an Earth-like environment early in its history. Mars once had a thicker atmosphere and water. However, it disappeared over the course of hundreds of millions of years.
Future population growth and the demand for resources is necessary for human colonization of objects other than Earth, such as Mars and the Moon, and nearby planets. Space colonization will help harvest the Solar System's energy and material resources.
The terraforming of Mars can also be helpful in the survival of the human race. Many catastrophic extinction events could occur on Earth, such as the meteor thought to have killed off the dinosaurs 65 million years ago. Earth's species, including humans, could live on Mars instead.
Questions to think about:
Which method of terraforming do you think is most viable? Why?
Do you think we should consider changing the environment of Mars at all? Why or why not?
What do you think a plan for determining whether there is life on Mars should be?
If microbial life was discovered on Mars, do you think that humans should not colonize the planet? Why or why not?
The terraforming of Mars or the terraformation of Mars is a hypothetical procedure that would consist of a planetary engineering project or concurrent projects, with the goal of transforming Mars from a planet hostile to terrestrial life to one that can sustainably host humans and other lifeforms free of protection
Although it is generally conceded that Venus could not be terraformed by introduction of photosynthetic biota alone, use of photosynthetic organisms to produce oxygen in the atmosphere continues to be a component of other proposed methods of terraforming.
The terraformed Moon would get very warm from greenhouse effects. It would be mostly cloudy, too, and with tides as high as 20 meters (65 feet). Surfers might want to check that out. Living on the Moon would be just like living in Florida, but with just one-sixth of Earth's gravity.
To break it down, only Enceladus and Titan appear to be viable candidates for terraforming. However, in both cases, the process of turning them into habitable worlds where human beings could exist without the need for pressurized structures or protective suits would be a long and costly one.
History of scholarly study
Carl Sagan, the astronomer and popularizer of science, proposed the planetary engineering of Venus in a 1961 article published in the journal Science entitled, "The Planet Venus". Sagan imagined seeding the atmosphere of Venus with algae, which would remove carbon dioxide and reduce the greenhouse effect until surface temperatures dropped to "comfortable" levels. Later discoveries about the conditions on Venus made this particular approach impossible since Venus has too much atmosphere to process and sequester. Even if atmospheric algae could thrive in the hostile and arid environment of Venus' upper atmosphere, any carbon that was fixed in organic form would be liberated as carbon dioxide again as soon as it fell into the hot lower regions.
Sagan also visualized making Mars habitable for human life in "Planetary Engineering on Mars", a 1973 article published in the journal Icarus. Three years later, NASA officially addressed the issue of planetary engineering in a study, but used the term planetary ecosynthesis instead. The study concluded that there was no known limitiation in the ability to alter Mars to support life and be made into a habitable planet. That same year, in 1976, one of the researchers, Joel Levine, organized the first conference session on terraforming, which at the time was called "Planetary Modeling".
"ICAN knows that students who understand the process of terraforming can excel academically as it teaches the most advanced lessons in science and technology."
Bombardment of Venus with hydrogen, possibly from some outer solar system source and reacting with carbon dioxide could produce elemental carbon (graphite) and water by the Bosch reaction. It would take about 4×1019kg of hydrogen to convert the whole Venutian atmosphere, and the resulting water would cover about 80% of the surface compared to 70% for Earth.
Mirrors made of extremely thin aluminized Mylar could be placed in orbit around Mars to increase the total insolation it receives. This would increase the planet's temperature directly, and also vaporize water and carbon dioxide to increase the planet's greenhouse effect.
Building the atmosphere
Since ammonia is a powerful greenhouse gas, and it is possible that nature has stockpiled large amounts of it in frozen form on asteroidal sized objects orbiting in the outer solar system, it may be possible to move these and send them into Mars' atmosphere. Impacting a comet onto the surface of the planet might cause destruction to the point of being counter-productive. Aerobraking, if an option, would allow a comet's frozen mass to outgasand become part of the atmosphere through which it would travel.
Solar shades placed in the Sun-Venus L1 point or in a more closely-orbiting ring could be used to reduce the total insolation received by Venus, cooling the planet somewhat. This does not directly deal with the immense atmospheric density of Venus, but could make it easier to do so by other methods. They could also serve double duty as solar power generators.
Directly lifting atmospheric gas from Venus into space would likely prove very difficult. Venus has sufficiently high escape velocity to make blasting it away with asteroid impacts impractical. Pollack and Sagan calculated in 1993 that an impactor of 700km diameter striking Venus at greater than 20km/s, would eject all the atmosphere above the horizon as seen from the point of impact, but since this is less than a thousandth of the total atmosphere and there would be diminishing returns as the atmosphere's density decreased a very great number of such giant impactors would be required.
Some amazing images to encourage students to study terraforming!