|
Helps explain the reason the atmosphere is so thin nowadays. OK, first thing to make clear, all planets have atmospheres that leak out, slowly, into space. The rate of losing such atmosphere depends on 4 things, first, how geologically active the planet is, second, how reactive the gasses in the atmosphere react with other substances to form liquids and solids, third, how strong the gravitational pull is on those gasses, and fourth, the ambient tempurature of the planet's surface.
Now, I'll go into detail as to how this relates to Mars, the first, geologic processes, namely volcanoes, contribute greatly to not only the composition of atmospheres, but there overall thickness as well. On Earth, we have many eruptions per year, and that contributes, quite a bit, to keeping the Earth's atmosphere stable in regards to thickness, composition is more complex, but mostly the only reason Earth is habitable to humans at all is because of photosynthesis. Now, onto Mars, basically its a situation of the larger the object, the more heat it can retain, this is also related to how many radioactive elements are present in said planet, but a molten ACTIVE core is necessary, outside of tidal effects, to keep the interior of a planet warm enough for active geology. Mars lacks that, as is noticed by the lack of a magnetosphere, meaning the core isn't spinning rapidly, also, being half the size of the Earth, it lost a lot more heat over the years than the Earth. While Mars is home to the largest volcanoes in the Solar System, none of them have erupted in at least a billion years, according to most theories. This leads to a gradual thinning of the atmosphere, if Mars had a biosphere based on photosynthetic life, they would eventually die out, lowering the oxygen content, NOTE: much of Mars surface is Iron Oxide, rust, and without a sustainable biosphere, that oxygen becomes locked up into molecules with iron. Now, the atmosphere, by this time, would be quite thin, being thin, it doesn't retain enough heat necessary to keep surface tempuratures high enough to prevent, at the south pole at least, from carbon dioxide from freezing into dry ice thinning the atmosphere even further.
Now, during this time, the water present in both atmosphere and surface becomes locked up in the north pole or vaporizes out of Mars atmosphere entirely, water locked up already in subsurface aquifiers wouldn't vaporize, they would be plugged, by either rock or ice, and its possible that it is JUST warm enough down there for water to remain in a liquid form, hence possibility for life to survive. What water is left becomes permafrost or frozen ice at the north pole, but NOT in liquid form anywhere on the surface. That is the situation today, what used to be a warm, somewhat wet planet, with rivers and oceans, is now a planet in a frozen deathtrap, where the atmosphere now contains 95% carbon dioxide, is 1/100th the pressure of the atmosphere of Earth, and dotted with extinct volcanoes.
So, what could humans do to thicken the atmosphere, you ask, first things first, it would take a while, decades at least, possibily centuries, though not necessarily. One method mention is to darken the poles with what amounts to soot, that is too heavy to be moved by the thin winds, but basically will absorb more heat from the Sun than white ices would. Another method involves placing orbital mirrors over the poles, that increase the amount of solar radiation that reaches them. A combination of these two methods could greatly increase the amount of energy hitting the poles, and, because CO2 has a MUCH lower melting point than water means that the south pole will vaporize first, and there MAY be enough CO2 present to thicken the atmosphere enough to have almost three quarters the pressure of Earth's atmosphere at sea level, about the same pressure as many human habitations at high altitudes here on Earth. Now, this is enough atmospheric pressure to allow the North Pole to melt and have liquid water form on the surface of the planet. Not to mention that since the composition of the planet will not change much, if at all, more water vapor, to be sure, but mostly a CO2 atmosphere, the greenhouse effect then kicks in, warming the planet even futher.
Once that is done, a few things could then happen, one is that with oceans, you can have algae on the surface of the planet, so we could "seed" Mars with photosynthesizing organisms that can tolerate high radiations along with low oxygen enviroments. In addition to that, we could then process the dust of the planet, using robotic, factories, or possibly organics, like bacteria that would utilize solar power to break apart the chemical bonds between the oxygen and iron, giving us a large iron resource on the planet and freed oxygen in the atmosphere. With freed oxygen, an ozone layer could form naturally with the oxygen reacting with cosmic radiation in the high atmosphere. Once that is done then we would have a planet that is fully habitable by humans and any other organisms we wish to bring with us. Plus the biosphere would last, with little maintainence, for thousands of years. However, one thing to make clear, while Mars would be habitable, leaving it to its own devices, it would again revert to the way it was before terraforming, unless maintained. Granted, energy and man-hours wise, its probably more efficient than let's say, space stations or habitats, at least after the initial hard work in warming it is done but it would most likely still be worth the costs. The best part would be that it could be done remotely, with no humans ever having to actually set foot on the planet, nor risk going there at all.
One thing I think people don't realize is that this is actually much cheaper than it sounds, and slightly easier than it sounds. While its easy to destroy, its a bit harder to create, as we find out on Earth. There are a couple of things that would be expensive, no getting around it either, the first would be constructing the Mirrors necessary to increase the solar radiation. They don't have to be all one piece, but rather could be thousands of individual pieces orbiting in sync with the poles. To be honest, we had the technology to do this about 30 years ago, give or take, we were capable of sending probes to Mars, that could operate somewhat independently. Back then, the biggest stumbling blocks were lack of computing power, and lack of experience. Nowadays, we have enough experience in exploration, though its still a crapshoot, just like everything else in life, but even then, we have robotic probes that OUTPERFORM their initial design, that's actually heartening.
While we have the technology, nothing science fiction about robots in space that operate semi-independently, we do lack experience in space construction. While we can jam Earth constructed pieces of space station together in orbit with few problems, thank Russian experience for that. It still requires direct human intervention to fit those pieces together. In order to make this economical at all, we would actually have to have experience in constructing useful objects in space from basic raw materials ALREADY present in space, using robotic fabrication facilities in various orbits. An idea would be to either tear apart either Phobos or Deimos to build the mirrors I mentioned, then using the remaining regolith to darken the poles.
Now the real question is why would we do this in the first place? Depending on the person it could be just to explore, in other cases call it insurance, in still others, simply expansion. From an economical only standpoint, we would be making an enormous investment, but at the same time, we would double the amount of real estate that humanity can occupy. That is one thing that people may not realize, on Earth, we are running out of space, and we are running out of energy, in addition to a host of other problems related to human activity, most related to human overpopulation. With the loss of various biospheres and species on this planet, we are running the risk of having a homogenized planet. Given that diversity in species and between them ensures longterm survival, we would have to face choices that would be untenable to many. Not to mention the risks associated with having all of humanity, and various host species, all on one planet, that we finally realized after Shoemaker-Levy, is actually vulnerable to utter destruction. It would most likely be in our best interest to expand in space, both for humanitarian and economical reasons.
|
Printer-friendly format
Email this thread to a friend
Bookmark this thread
(1000+ posts)
Send PM |
Profile |
Ignore
