Planets outside the Solar system
Even if we manage to prove a planet is within all the planetary habitability conditions that might support lives, it will be too far of a distance that we hardly can put it in real useful investment for any human being to travel to such a planet as a gamble of his future. Unless we have major breakthrough in interstellar journey, which makes such journey as short as intercontinental travel on Earth today's.
When searching exterrestrial habita in the Solar system, our choice seems to be on Mars, the red planet. But Mars is a small planet. Following conditions would rule out Mars as an ideal planet for human being to establish mass habitat of colonies.
1. Mars atmosphere is too thin to protect colonies residents from direct impact of mini asteroid, which would otherwise burn out in Earth atmosphere. Such thin air around the Mars would not protect lives from the high energy particles and high-energy galactic cosmic rays (GCRs) threat. There is no strong magnetic field on Mars similar to the Earth magnetic field.
2. Mars is too far from the Sun, which means the solar energy is too weak to support planetary scale of warming. We could create heat shelter to insulate colonies from heat lost.
3. Gravity of Mars is only 38% of Earth, it has long term damage to human's body if residents live too long on it without artificial gravity compensation. Any potential lives grown in such gravity environment will be different species from planet Earth.
How about Venus? It has very hot atmosphere, which is impossible to be transformed into habitable planet by today's technology. But in my opinion, if we cast our human history of a million years of natural evolution, we have to say thank you to the tribe that took their migration out of African jungle. What our ancestors did had impact to future generations that created civilization. Most significantly, our modern civilization started 250 years ago when engines were developed. We begin to use energy for many things our ancestors weren't be able to do.
Geo-engineering of environment so far is quite limited by human society but it is nonetheless happening, especially what we have been doing has long-term impact on our ecosystem. Planet Venus could be the potential second home for humanity if we have a plan for 10,000 years, which is only a blink of eyes for our universe. If we know how to transform Venus in the Solar system, we will be able to do the same in other star systems in the future.
Ideas that have been proposed
Can we cool down Venus atmosphere with outer space light weight shelter fully or partially surrounding the planet? There have been some speculative publications on such potential. On the Venus atmosphere, about 50 km of altitude, the temperature and pressure is just like planet Earth at sea level, which makes it the perfect environment for buoyancy floating colonies, which can be used as factories of photosynthesis, or hotels for space tourists. In the floating cities, we can create factory which use algae in special built photosynthesis tanks to absorb CO2. Algae can produce oxygen that can be used by human beings living in the floating colonies. We can then fabricate carbon fiber net using dry algae material to make light weight solar shelter material. It would take time to cover Venus outer space with such net to block Solar light, which will cool down Venus eventually.
Other solutions is to place such shield in Lagrangian point L1. This would require much larger area to achieve the same result when the shield is on the Venus atmosphere. But the solar blockage will be long term and permanent.
With buoyancy engine, geostationary colonies above Venus atmosphere don't have to be on Lagrangian point. It can be anywhere above any star or planet. Our second paper will discuss how powerful and important buoyancy engine could be in terraforming of a hostile planet into earth like home.
In order to have continuously algae based photosynthesis process on the upper Venus atmosphere, water is essential. Water can be found through comets by towing these comets from asteroid bell. So the algae photosynthesis in upper Venus will create carbon fiber net for shelter while O2 will be stored until Venus air temperature drop. In order to fast track the cooling, we can also consider removing gas from Venus into space using solar energy. Due to this is simple gravitational process, we can expect energy neutral. Gas, mainly CO2, can be contained by large pressurized cargo spaceship and accelerated to escaping velocity into vacuum space.
Our next blog will concentrate on the effect of buoyancy engine on Venus terraforming.
(To be continue)
* Fogg, Martin J. , Terraforming: Engineering Planetary Environments, SAE Press, 1995. ISBN 1560916095, ISBN 978-1560916093
* Jump up ^ Landis, Geoffrey A., "Terraforming Venus: A Challenging Project for Future Colonization," paper AIAA-2011-7215, AIAA Space 2011 Conference & Exposition, Long Beach CA, Sept. 26-29, 2011.
^Wikipedia: Discoveries of extrasolar planets