could we make mars get an atmosphere , then bring life to it?

Sure it's called Terraforming and there are lots of idea's how we could do that to mars.

Mars is considered by many to be the most likely candidate for terraformation. Much study has been done concerning the possibility of heating the planet and altering its atmosphere, and NASA has even hosted debates on the subject. However, a multitude of obstacles stand between the present and an active terraforming effort on Mars or any other world. The long timescales and practicality of terraforming are the subject of debate.

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 (CO2), 3% nitrogen, 1.6% argon, and contains only traces of oxygen, water, and methane. Since its atmosphere consists mainly of CO2, a known greenhouse gas, once the planet begins to heat, more CO2 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

Chlorofluorocarbons (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. 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 CO2 on the polar caps 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 CO2 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 CO2 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 reduce the metals in the soil, effectively resulting in desired crude metals and oxygen as a byproduct. Also, by bringing plants 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 bombs to blast them in the right direction) and send them into Mars's atmosphere. Since ammonia is high in nitrogen (NH3) 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 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. 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. The methane could be vented into the atmosphere where it would act to compound the greenhouse effect.

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 could be placed in orbit around Mars to increase the total insolation it receives. 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 CO2 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 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 (CF3SCF3, CF3OCF2OCF3, CF3SCF2SCF3, CF3OCF2NFCF3) to maintain Mars at 'comfortable' temperatures, as a method of maintaining an Earth-like atmosphere produced previously by some other means.

Changing the albedo of the Martian surface would also make more efficient use of incoming sunlight. 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 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 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. 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.

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Hey Paul B, no one should keep all their eggs in one basket. ;)

No. If we got there tomorrow and started Terra forming mars it would take way longer than 40 years. It would take longer than 100 years. Unless we find some new technology that could speed up the process unlikely, it will take a long time to Terra form mars. and what ever life is there it would have been brought from earth. Now if you asking could we have colonies on mars that live in dome shaped habitats than yes by 2050 there could be a couple hundred people on mars but you would have to wear a space suit to go outside.

"Not realistically -- Mars doesn't have enough gravity to keep a good atmosphere."

well you're partly right.... mars indeed does lack a naturally occuring force to hold in an atmosphere.... but it's not gravity.... mars' core is thought to be cooled and solidified... which creates the shielding nessicary to keep solar winds and radiation from blowing the atmosphere away.

but no it's not realisitc.... it's possible, but without that sheilding, the atmosphere would just be blown away AND we wouldn't be shielded from the solar radiation either... which would fry us in a matter of minutes, if not seconds.

since reigniting a core is pretty much just as unrealistic, the only REALISTIC (but not logical) alternative would be to create domes on mars' surface (like in the sixth day)

but that in and of itsself would require phenomenal resources... then we still have to generate the atmosphere within the domes before it could become habitable.....

The terraforming of Mars is the hypothetical process by which the climate, surface and known properties of Mars would be deliberately changed with the goal of making it habitable by humans and other terrestrial life; and thus providing the possibility of safe and sustainable colonization of the large areas of the planet.

Humans currently do not possess the technological or economic means to terraform another planet or moon. Since space exploration is primitive, terraforming techniques remain speculative at best. Based on experiences with Earth, the environment of a planet can be altered deliberately; however the feasibility of creating an unconstrained planetary biosphere has yet to be attempted.

Movie guy is right. But I just don't understand why anyone wants to terraform Mars when we can live in much greater comfort in Antarctica.

Not realistically -- Mars doesn't have enough gravity to keep a good atmosphere.

The only is to get plants to grow there ,but it is so very cold there.Most plants will not grow...