Sand wrote:
One of the basic misconceptions is that the enterprise of terraforming a hostile environment involves huge clunky machines and robots roiling the landscape and puffing out water and oxygen to permit the human pioneers to stop cowering in their bubble enclosures and walk freely on the planet. What is obviously needed are machines that live off the environment and reproduce themselves indefinitely and change the environment to something more welcome. Plants did this for oxygen breathing animals on Eath and this is what will probably happen on another planet to be made fit for Earth life. The "machines" will be biological creatures that change things by their dynamic physiology. It might take centuries but that's the way it will happen - if it does. The science fiction concept of alien invaders come to take over Earth with heat rays and waving tentacles is nonsense. The first wave will be strange alien microbes that change the atmosphere suitable to aliens and then alien plants that push that further along. Then will come the monsters.
Re-establishing life on Mars by biological means is a daunting task. Consider the following:
1. The magnetic field of Mars is long gone, perhaps a billion years.
2. The gravity of Mars is so weak it cannot retain a thick atmosphere.
3. Mars is blasted by solar radiation and since there is no magnetosphere to divert charged solar particles any life on the planet would be thoroughly cooked.
The only way for living things to survive on Mars is to live underground, shielded from the solar radiation and solar wind.
Combine this with the scarcity (if not complete absence) of water and you have a less than promising scene for establishing earth-compatible flora on Mars.
However, compared to Venus, Mars is downright comfortable.
ruveyn
21 Apr 2009, 10:28 am
