Will Mars and Venus support life soon?

Question

Are we looking at planets capable of supporting life in their earliest stages? Even if they won't evolve on their own if we put plants on there and leave it will a whole new lifeform(s) develop on there? The reason for my question is in this extract from BBC Bitesize revision:

The early atmosphere was probably mostly carbon dioxide, with little or no oxygen. There were smaller proportions of water vapour, ammonia and methane. As the Earth cooled down, most of the water vapour condensed and formed the oceans.

It is thought that the atmospheres of Mars and Venus today, which contain mostly carbon dioxide, are similar to the early atmosphere of the Earth.

Changes in the atmosphere:
So how did the proportion of carbon dioxide in the atmosphere go down, and the proportion of oxygen go up?

• The proportion of oxygen went up because of photosynthesis by plants.

Ran out of characters - page here: http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/oils/changesrev8.shtml

Answer 1

Neither Mars or Venus resemble the early Earth; and they are not "young". Life may have existed on these planets earlier in the history of our solar system, but for reasons which can only be speculated (at this stage) their environments have moved away from expected tolerable limits for the maintenance of life - although extremophiles may still exist on these planets.

If you do some internet searches you can find exactly what we believe the early atmosphere was made up of. The oceans actually leached out of the Earth (rather than condensed out of the atmosphere).

Liquid water seems to be a prerequistit for the development of life. Mars and possibly Venus early in their history had water on their surfaces. Due to the proximity of Venus with the sun a run away greenhouse effect has turned that planet into a acid drenched inferno. Conditions for life may exit in the upper atmosphere and strategies for teraforming Venus include introducing bacteria in the high atmoshere to slowly change the atmospheric composition thereby allowing a reduction in pressure, temperature and acidity.

Mars has the opposite problem - its way too cold. It had an atmosphere once which probably was like the early earth but due to Mars's smaller mass and lack of plate techtonics the atmosphere gradually escaped reducing the atmospheric pressure to the triple point of water where it stabilised. The triple point of water is a region of pressure and temperature where all three phases of water can exist simultaeously (ice, water and steam). Once the pressure reached this critical point the oceans started to evaporate and Mars eventually lost its surface waters completely. This is what the Nasa Mars explorer robots have discovered during their mission. Is is estimated that it might have taken a billion years or more to lose these surface waters which, based on our own plantetary fossil record is plenty time enough for life to have got going. It is in my opinion highly likely that there are microfossils waiting to be discovered on Mars if not large eco systems still intact (although now either dormant or alive but under the martian surface).

Oxygen is a characteristic chemical signal that life exists on this planet. If there was no life the oxygen would rapidly bind / react with other chemicals and disappear. Plants excrete the O2 gas and remove CO2 through photosynthesis. The high oxygen content in our own atmosphere and the low CO2 levels can be regarded as the first massive instance of pollution that the earths atmosphere experienced.

This is a fascinating subject and I would stongly recommend internet searches or even contacting NASA and ESA on guidence for further reading.

Good luck.

LT

Answer 2

Mars may have been able to support life as we know it long ago when its atmosphere was much thicker; today it has lost much of its atmosphere to space, and the surface temperature and pressure are far too low to support life as we know it here on earth. Also absent is the presence of large amounts of liquid water. While Mars has shown some signs of water flows in the near past, there is not a significant amount available on the surface to sustain life as we know it. This does not mean that it can't support some other kind of life, but as of yet we have not found any.
Venus, on the other hand, is the exact opposite. The air pressure and temperature on the surface are far too high to support life as we know it. The atmospheric pressure is about 90 times greater than earth's, and the temperature averages around 800 degrees F (400 C). There is no liquid water on the surface of Venus at all, and the major constituents of the lower atmosphere are Carbon Dioxide, Hydrogen Sulfide, and Sulphuric Acid, making the surface of Venus one of the most inhospitable places in the solar system for Humanity.
In summary, while the atmospheres of these two planets may have the right chemistry for life, the physical conditions of these worlds make it nearly impossible for life as we know it to take root and flourish. Mars would need to increase its atmospheric pressure by about 1000 fold, while Venus would need to lose about 90% of its atmosphere. In addition, both planets would also need large amounts of water to become hospitable to life.

Answer 3

terraforming the planets Venus and Mars theorectically not possible. however it would take thousands of years with our present technologies.
a tremendous huge solar shade would have to be contructed for venus for starters to assist in further terraforming of the planet.

a hugh solar mirror would have to be constructed for Mars to melt and relise carbondioxde and water into the atmosphere.
no mere feats of engineering.

mars would be the easiest of the two, but their would be some large problems to be solve, ie. the reason that Mars lost most of it atmosphere in the first place was because of it's weak gravity. the atmosphere literally escape into space.

and then another 500 to a 1000 years before you could even introduce the simplist forms of life to start relising oxygen.

so will Mars and Venus support life soon? the answer is no not in our lifetime or the next 10 to 15 generations.
but on the cosmic time scale the answer is yes very soon.

what i do see in our lifetime though is the colonisation of our oceans undersea cities and factories. aswell as larger space stations and possible settlements for mining on the moon. these would be the first steps towards terraforming the planets.

there is another possibility which is constrovestial, genetic engineering, if we can't adapt the planets to suit us maybe we should adapt ourselves to suit them.

Answer 4

Maybe for mars, but Venus is too close to the sun. Unless they work out some way of cooling Venus down there is now way.

Mars is a good bet as you would need global warming on mars to make in inhabitable

Answer 5

What are you blabbering on about ,how can Venus support life ,2 Minuit's exposed and you turn in to brown toast,
Venus is not a option to close to the sun (a none runner)for a start, as for Mars ,1000 years if you think that's soon,

Answer 6

The question of whether Mars had once had water states that Mars had already supported life. I believe that the lifeform that once habitated Mars sucked up all its resources and left it for dead. Earth is next.

As for Venus, if you're thinking "soon" in a galactical time frame, then yes, Venus will "soon" support life.
In our time frame, however, that will be 5 billion years.

Better pack a lunch.

**

Answer 7

veanus is probably les likaly ofthe 2 becouse it is the hotest planet but ive herd that we will be trying to make mars a breathable atmophear so that when the sun expands and mercary and veanusd are fried and earth is burnt we can go out to mars and live ther for a while then we wil move to titan a moon of jupiter that buy then will be entirely water then out of the solar system for good

Answer 8

Wow!! short question, long detail.

I should say....Venus and Mars will maybe support life soon...

Answer 9

Mars yes, Venus , no.

Answer 10

atm venus is too hot and mars is too cold