Terraforming of Mars
4923933
226099170
2008-07-16T20:38:08Z
Rachkovsky
3709560
/* Background */
{{Refimprove|date=March 2008}}
[[Image:MarsTransitionV.jpg|thumb|200px|right|Artist's conception of the process of terraforming Mars; the final appearance of the planet is based on data from the [[Mars Global Surveyor]].]]
The '''terraforming of Mars''' is the hypothetical process by which the [[Climate of Mars|climate]], surface and known properties of [[Mars]] would be deliberately changed with the goal of making it [[planetary habitability|habitable by humans]] and other terrestrial [[life]]; and thus providing the possibility of safe and sustainable [[Colonization of Mars|colonization]] of the large areas of the [[planet]].
Based on experiences with Earth, the environment of a planet can be altered deliberately; however the feasibility of creating an unconstrained planetary [[biosphere]] is undetermined. Several of the methods described below may fall within humanity's technological capabilities, but at present the economic resources required to execute such methods are far beyond that which any government or society is willing to [[NASA Budget|allocate]] to such a purpose.
==Why terraform?==
In the not-too distant future, population growth and demand for resources may create pressure for humans to colonize new habitats such as the surface of the Earth's oceans, the sea floor, near-Earth orbital space, the moon and nearby planets, as well as mine the solar system for energy and materials .<ref>[http://www.amazon.com/Millennial-Project-Colonizing-Galaxy-Eight/dp/0316771635| Savage, Marshall T., ''The Millennial Project: Colonizing the Galaxy in Eight Easy Steps'' (Little Brown and Company, 1994)] </ref> Thinking far into the future (in the order of hundreds of millions of years), some scientists point out that the [[Sun]] will eventually grow too hot for [[Earth]] to sustain [[life]], even before it becomes a [[red giant]] star, because all [[main sequence]] stars brighten slowly throughout their lifetimes. When this happens, it will become imperative for humans to migrate away to areas farther from the sun if they have any hope of surviving. Through terraforming, humans could make Mars habitable long before this 'deadline'. Mars could then be in the [[habitable zone]] for a while, giving humanity some thousand additional years to develop further [[space technology]] to settle on the outer rim of the [[solar system]], before Mars becomes uninhabitable due to the sun's increasing heat.
On the other hand there are some disadvantages. If Mars was to be terraformed, significantly less [[sunlight]] would reach the surface.
==Background==
{{Seealso|Atmosphere of Mars}}
Mars consists of much of the soil minerals needed to terraform, but a significant challenge is that [[water]] is present in trace amounts, and only in the [[Atmosphere of Mars|atmosphere]]. As the polar [[carbon dioxide]] ice (CO<sub>2</sub>) sublimes back into the atmosphere during the martian summer, it leaves a small amounts of water residue, which fast winds sweep off the poles at speeds approaching 250 mph (400 km/h). These seasonal actions transport large amounts of dust and water vapor giving rise to Earth-like cirrus clouds.
[[Oxygen]] is present in the atmosphere only at trace amounts but it is found in large amounts bound to the highly oxidized [[iron oxide|metal-oxide]]s on the Martian surface; some oxygen is also found in locked in the soil in the form of [[nitrate|per-nitrates]].<ref name=Lovelock>Lovelock, James and Allaby, Michael ''The Greening of Mars''</ref>
It is generally thought that Mars could once have had an environment relatively similar to today's Earth, during an early stage in its development. This similarity is predominantly associated with the thickness of the atmosphere and the past presence of water, both considered to have been lost over the course of hundreds of millions of years. The exact mechanisms which resulted in this change are still unclear, though several mechanisms have been proposed. For instance, the gravity of Mars today indicates that lighter gases in the upper atmosphere would have contributed to this loss, with the excess atoms dissipating into space. The lack of [[plate tectonics]] on Mars today and in the past, indicated by the thorough examination of its surface features is another plausible factor, since this would cause the recycling of gases locked up in sediments back into the atmosphere to occur at a slowed rate. The lack of [[magnetic field]] and geologic activity may both be a result of Mars' smaller size, which allows its interior to cool more quickly than Earth's, though the details of such processes are still not precisely clear. However, none of these processes are likely to be significant over the typical lifespan of most animal species, or even on the timescale of human civilization, and the slow loss of atmosphere could possibly be counteracted with ongoing low-level artificial maintenance activities.
==Changes required==
Terraforming Mars would entail two major interlaced changes: building up the atmosphere and keeping it warm. The atmosphere of Mars is relatively thin and thus has a very low surface pressure of 0.6 kPa, compared to Earth's 101.3 kPa. The atmosphere on Mars consists of 95% [[carbon dioxide]] (CO<sub>2</sub>), 3% [[nitrogen]], 1.6% [[argon]], and contains only traces of [[oxygen]], [[water]], and [[methane]]. Since its atmosphere consists mainly of CO<sub>2</sub>, a known [[greenhouse gas]], once the planet begins to heat, more CO<sub>2</sub> enters the atmosphere from the frozen reserves on the poles, adding to the greenhouse effect. This means that the two processes of building the atmosphere and heating it would augment one another, favoring terraforming. However, on a large scale, controlled application of certain techniques (''explained below'') over enough time to achieve sustainable changes, would be required to make this theory a reality.
===Building the atmosphere===
[[Image:TerraformedMarsTharsis.jpg|thumb|right|250px|Artist's conception of a terraformed Mars centered on the Tharsis region.]]
[[Chlorofluorocarbon]]s (or CFCs) are the most likely candidates for artificial insertion into the Martian atmosphere because of their strong effect as a greenhouse gas. This can conceivably be done relatively cheaply by sending rockets with a payload of compressed CFCs on a collision course with Mars.<ref name=Lovelock/> When the rocket crashes onto the surface it releases its payload into the atmosphere. A steady barrage of these "CFC rockets" would need to be sustained for a little more than a decade while the planet changes chemically and becomes warmer.
As the planet becomes warmer, the CO<sub>2</sub> on the polar caps [[sublimation|sublimes]] into the atmosphere and contributes to the warming effect. The tremendous air currents generated by the moving gasses would create large, sustained dust storms, which would also contribute to the warming of the planet by directly heating (through absorbing solar radiation) the molecules in the atmosphere. Eventually Mars would be warm enough that CO<sub>2</sub> could not solidify on the poles, but liquid water would still not develop because the pressure would be too low.
After the heavy dust-storms subside, the warmer planet could conceivably be habitable to some forms of terrestrial [[life]]. Certain forms of [[algae]] and [[bacteria]] that are able to live in the [[Antarctic]] would be prime candidates. By filling a few rockets with algae [[spores]] and crashing them in the polar areas where there would still be water-ice, they could not only grow but even thrive in the no-competition, high-radiation, high CO<sub>2</sub> environment.
If the algae are successful in propagating themselves around parts of the planet, this would have the effect of darkening the surface and reducing the [[albedo]] of the planet. By absorbing more sunlight, the ground will warm the atmosphere even more, and the atmosphere will have a new small [[oxygen]] contribution from the algae. This is still not enough oxygen for humans to breathe, but it's a step in the right direction. If the atmosphere grows denser, the atmospheric surface pressure may raise and aproximate that of Earth. At first, until there is enough oxygen in the atmosphere, humans will probably need nothing more than a breathing mask and a small tank of oxygen that they carry around with them. To contribute to the oxygen content of the air, factories could be produced that [[Redox|reduce]] the metals in the soil, effectively resulting in desired crude metals and oxygen as a byproduct. Also, by bringing [[plant]]s with them (along with the microbial life inherent in fertile topsoil), humans could propagate plant life on Mars, which would create a sustainable oxygen supply to the atmosphere.
Another, more intricate method, uses [[ammonia]] as a powerful [[greenhouse gas]] (as it is possible that nature has stockpiled large amounts of it in frozen form on asteroidal objects orbiting in the outer solar system), it may be possible to move these (for example, by using very large [[nuclear bomb]]s to blast them in the right direction) and send them into Mars's atmosphere. Since ammonia is high in [[nitrogen]] (NH<sub>3</sub>) it might also take care of the problem of needing a [[buffer gas]] in the atmosphere. Sustained smaller impacts will also contribute to increases in the temperature and mass of the atmosphere.
The need for a [[buffer gas]] is a challenge that will face any potential atmosphere builders. On [[Earth]], [[nitrogen]] is the primary atmospheric component making up 77% of the atmosphere. Mars would require a similar buffer gas component although not necessarily as much. Still, obtaining significant quantities of nitrogen, [[argon]] or some other comparatively inert gas could prove difficult.
[[Hydrogen]] importation could also be done for atmospheric and [[hydrosphere|hydrospheric]] engineering. Depending on the level of carbon dioxide in the atmosphere, importation and reaction of hydrogen would produce heat, water and graphite via the [[Bosch reaction]].{{Fact|date=February 2007}} Adding water and heat to the environment will be key to making the dry, cold world suitable for [[life]]. Alternatively, reacting [[hydrogen]] with the carbon dioxide atmosphere via the [[Sabatier reaction]] would yield [[methane]] and water.{{Fact|date=February 2007}} The methane could be vented into the atmosphere where it would act to compound the greenhouse effect.
[[Image:TerraformedMarsGlobeRealistic.jpg|thumb|right|275px|Artist's conception of a terraformed Mars. This realistic portrayal is approximately centered on the prime meridian and 30 degrees north latitude, and a hypothesized ocean with a sea level at approximately two kilometers below average surface elevation. The ocean submerges what are now [[Vastitas Borealis]], [[Acidalia Planitia]], [[Chryse Planitia]], and [[Xanthe Terra]]; the visible landmasses are [[Tempe Terra]] at left, [[Aonia Terra]] at bottom, [[Terra Meridiani]] at lower right, and [[Arabia Terra]] at upper right. Rivers that feed the ocean at lower right occupy what are now [[Valles Marineris]] and [[Ares Vallis]], while the large lake at lower right occupies what is now [[Aram Chaos]].]]
===Adding heat===
Adding heat and conserving heat present is a particularly important stage of this process, as heat from the [[Sun]] is the primary driver of planetary climate. Mirrors made of thin aluminized [[PET film (biaxially oriented)|PET film]] could be placed in orbit around Mars to increase the total [[insolation]] it receives.<ref>{{cite web|url=http://www.users.globalnet.co.uk/~mfogg/zubrin.htm|title=Technological Requirements for Terraforming Mars|author=Robert M. Zubrin (Pioneer Astronautics), Christopher P. McKay. [[NASA Ames Research Center]]|year=1993?}}</ref> This would direct the sunlight onto the surface and could increase the planet's surface temperature directly. The mirror could be positioned as a [[statite]], using its effectiveness as a [[solar sail]] to orbit in a stationary position relative to Mars, near the poles, to sublimate the CO<sub>2</sub> ice sheet and contribute to the warming greenhouse effect.
Since long term climate stability would be required for sustaining a human population, the use of especially powerful greenhouse gases possibly including halocarbons such as [[CFCs]] and [[Perfluorocarbon|PFCs]]. A proposal to mine fluorine-containing minerals as a source of these gases is supported by the belief that since the quantities present are expected to be at least as common on Mars as on Earth, this process could sustain the production of sufficient quantities of optimal greenhouse compounds (CF<sub>3</sub>SCF<sub>3</sub>, CF<sub>3</sub>OCF<sub>2</sub>OCF<sub>3</sub>, CF<sub>3</sub>SCF<sub>2</sub>SCF<sub>3</sub>, CF<sub>3</sub>OCF<sub>2</sub>NFCF<sub>3</sub>) to maintain Mars at 'comfortable' temperatures, as a method of maintaining an Earth-like atmosphere produced previously by some other means.<ref>{{cite web|url=http://www.pnas.org/cgi/content/full/98/5/2154|title=Keeping Mars warm with new super greenhouse gases}}</ref>
Changing the [[albedo]] of the Martian surface would also make more efficient use of incoming sunlight.<ref>{{cite web| url=http://www.nexialquest.com/The%20Terraformation%20of%20Worlds.pdf| title=The Terraformation of Worlds| author=Peter Ahrens| publisher= Nexial Quest| format=PDF| access date=2007-10-18}}</ref> Altering the color of the surface with dark dust and [[soot]] (likely from both of Mars' moons, [[Phobos]] and [[Deimos]], because they are dark in color and could be ground into dust while in space and then somewhat uniformly distributed across the Martian surface by "dropping" it onto Mars), dark microbial life forms such as [[lichens]] would transfer a larger amount of incoming solar radiation to the surface as heat before it is reflected off into space again. Using [[life|life forms]] is particularly attractive since they could propagate themselves.
Another way to increase the temperature could be to direct small cosmic bodies ([[asteroids]]) onto the Martian surface; the impact energy would be released as heat and could evaporate Martian water ice to steam, which too is a greenhouse gas.
==Dealing with solar radiation==
It is believed by some that Mars would be uninhabitable to most life-forms due to higher [[solar radiation]] levels. Without a [[magnetosphere]], the sun is thought to have thinned the Martian atmosphere to its current state; the [[solar wind]] adding a significant amount of energy to the atmosphere's top layers which enables the atmospheric particles to reach [[escape velocity]] and leave Mars (effectively boiling off the atmosphere). Indeed, this effect has even been detected by Mars-orbiting probes. [[Venus]], however, shows that the lack of a magnetosphere does not preclude a dense atmosphere. A thick atmosphere could also provide solar radiation protection to the surface, as it does at Earth's polar regions where [[Aurora (phenomenon)|aurorae]] form, so the lack of a magnetosphere probably would not seriously impact the habitability of a terraformed Mars. In the past, Earth has regularly had periods where the magnetosphere changed direction and collapsed for some time.{{Fact|date=July 2008}} Some scientists believe that in the [[ionosphere]] a magnetic shielding was created almost instantly after the [[magnetosphere]] collapsed, a principle that applies to [[Venus]] as well and may also be the case in every other planet or moon with a large enough atmosphere.
==See also==
* [[Colonization of Mars]]
* [[Terraforming of Venus]]
* ''[[Total Recall]]'', an American [[science fiction]] film from 1990; an example of popular culture speculation regarding the terraforming of Mars.
* [[Mars trilogy]], a science fiction trilogy of novels by [[Kim Stanley Robinson]] which goes into great depth about possible terraforming techniques and the consequences resulting.
==References==
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==External links==
*[http://aerospacescholars.jsc.nasa.gov/HAS/cirr/em/10/10.cfm NASA - Aerospace Scholars: Terraforming Mars]
*[http://www.spectrum.ieee.org/oct07/5584 Recent Arthur C Clarke interview mentions terraforming]
*[http://www.redcolony.com/ Red Colony]
*[http://society.terraformers.ca/ Terraformers Society of Canada]
*[http://www.users.globalnet.co.uk/~mfogg/zubrin.htm Research Paper: Technological Requirements for Terraforming Mars]
*[http://www.nexialquest.com/The%20Terraformation%20of%20Worlds.pdf Peter Ahrens The Terraformation of Worlds]
*[http://www.marsdrive.com/ MARSDRIVE: Colonizing Mars]. Red Colony parent organization planning the future exploration and colonization of planet Mars.
*[http://www.worlddreambank.org/M/MRZ.HTM Mars Reborn], a portrait of a possible Mars one thousand years from now, by [[Chris Wayan]], 2003
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