Terraforming Mars
Some time ago, an article in Nature discussed methods for making Mars habitable. Authors McKay, Toon and Kasting noted that, to raise the average surface temperature of the red planet above the freezing point, an absorber has to be active over the entire thermal infrared spectrum. An absorber active over only part of the spectrum would raise Martian temperatures no higher than 260 degrees Kelvin i.e. below freezing (273K). In contrast, a full-spectrum absorber would cause temperatures to shoot up rapidly to about 300 K--quite Earthlike. Somehow, terraformers will have to greatly lower the albedo of Mars, in effect transforming it from the Red Planet to the Black one.
The authors also noted that, given a denser atmosphere with a substantial greenhouse effect, the polar caps of Mars are certain to disappear via sublimation. That would greatly increase the density of the Martian atmosphere, especially in light of the big reservoir of CO2 at its south pole. But studies also indicate a new Martian atmosphere would only be in equilibrium if its pressure were 800 millibars and its average temperature 250 K. An average temperature below freezing may rule out most vegetation except in the lower latitudes.
posted by starman at 3:33 AM
3 Comments:
Mars seems to be the only planet that humans could possibly colonize in this solar system. Modifying Venus or Mercury for colonization is apparently out of the question. Planets beyond Mars (i.e. Jupiter, Saturn, etc.) in this solar system are also apparently not candidates for making settlements. I personally think that Mars should seriously be considered for atmospheric modification and eventual colonization.
Neal
This is very interesting, but I would NOT even try to terraform Mars or any other planet. But I DO STRONGLY believe in colonizing the whole Solar System, and look forward to the day when many hundreds of millions of people will be living comfortably and prosperously on Mars, Mercury, and even Venus, Jupiter, the asteroids, Saturn, the large moons like Titan, and beyond! The solution is NOT terraforming!!! The solution is glass domes, to cover limited areas, or in many cases glass sheets or tarps, e.g., on asteroids, where there is no natural atmosphere. For example, on Mars, I would build maybe ten cities, of ten square miles each, with a population density of 1-3 million per square mile, which is like 8 to 25 square feet per person, which, if the buildings average 30 stories tall, is like 240 to 750 square feet of living space per person; the buildings could be 40-60 stories tall and cover 1/2 to 3/4 of the city's area, leaving 1/4 to 1/2 of the city's area for farms and parks and recreation space.
Now, I have to admit that I am not an engineer and I do not know how thick the glass city-dome would have to be or how much steel may be needed to reinforce it; perhaps some other material, preferably clear, like maybe Lucite, should be used, but I do strongly believe that--maybe with a lot of further research--materials could be developed that would serve the purpose. Silica, anyhow, seems to be abundant in the Solar System, so that should be no problem. Anyhow, every day, millions of people could don space suits and leave the cities to explore the fabulous, exotic Martian environment, from the great volcanoes to the great canyon. It would be fun to design the kinds of vehicles they might use to travel over Mars' surface; naturally, there would be great challenges, the extreme cold, the airlessness, etc; but these are the sorts of problems that hundreds of thousands of engineeers could solve.
I would also build sprawling suburbs, of homes spaced widely apart on winding roads, across tens of thousands of square miles, with a population density of 100-1000/sq. mi., this would be pleasantly roomy. Again, thick glass domes would serve, in this case for individual homes, although again, I imagine these homes as most likely being not very large; but their beauty is that they would be bases for individual families to roam widely across Mars' fascinating surface.
In this way, maybe only a few hundred thousand sq mi of Mars' surface would be covered over with protective material, glass or whatever--less than say 2% of Mars' surface--leaving 98% of it pristine wilderness, for the tens of millions of people who would enjoy exploring it every day--billions over the course of a lifetime.
One key is that agriculture --plants-- is very efficient and productive per unit area when properly farmed. Meat, of course, is far less efficient, yet with enough energy--abundantly available even if we only use solar energy--there could still be lots of meat to eat.
Each world would present different yet related engineering problems, Venus would seem to be the most difficult, along with the moon Io--in both cases because of their extreme surface temperatures, yet I am certain that scientists and engineers could develop solutions that would make living on these worlds comfortable as well as exciting.
So forget terraforming, work on glass and/or other materials and do lots of research and development, to open up the entire Solar Sysytem to all humanity!
Roger
Fascinating Roger, but I can't believe 10-30 million people could be fed with only 2.5-5 square miles of land under cultivation. I suggest 10 square mile, domed towns with 500-1,000 colonists would be more practical.
Post a Comment
<< Home