Terraforming Planets

Which, if any, Planets in our Solar System could be Terraformed? This includes Moons, and even Asteroids if possible. Also, how long would it take to do a Terraform?

The wiki article would suggest Mars, Venus, and Europa. Though I’m unconvinced that it is possible within our realm of technological imagination. A quick browse of a few articles suggests it would take a few hundred years of intense human activity to produce something in the range of 3000 years of “terraformed” planet. It seems to be a very non-permanent endeavour.

There are still quite a few unknowns.

Some people believe that an Earthlike environment requires an unusually large moon to stabilize the axis tilt. If so, Mars an Venus are both out. (Mars’ moons are tiny compared to Earth’s.

Some people believe that you need a strong magnetosphere. Short-term, it protects the inhabitants against solar flares. Long-term, it keeps the solar wind from stripping away the atmosphere. Mars has very little magnetosphere.

The current best bet is Mars and really only because the incident light is strong enough for farming, the place has water as well as carbon, nitrates etc. and it may be possible to tip it into a warmer climate state depending on how much carbon dioxide there is in the regolith and how quickly it out gases. Anything else is even more fanciful given that we can barely keep contained open loop systems going (e.g. ISS) and terraforming really deals with uncontained close loop systems like the Earth.

A good resource is Terraforming - Engineering Planetary Environments by Martyn J. Fogg.

This is all science fiction with no way to answer your question. We cant even terraform a small desert into a rain forest, let alone a planet.

But if you’re looking for science fiction on the subject, try The Sky So Big and Black by John Barnes.

Would it be feasible to bioengineer a prolific plant or algae that could thrive in the Martian atmosphere; converting CO on O2?

IANAphycologist so I can’t say whether this is actually possible or not, but the main problem here is that even if you could, the atmosphere of Mars is only about 1% the pressure of the atmosphere of Earth, with a total mass of less than half a percent of Earth’s. If you wanted to support human life off that, there just simply isn’t enough of it.

Other problems I can’t comment on re: not being a botanist/phycologist (that’s the word, right?) would be the temperature, harmful radiation concerns, and possible lack of nutrients available for such a species to thrive.

Would be pretty dang neat, though.

There is a good bit of frozen water and CO2 on mars, mostly at the poles.

Mars terraforming plans typically include some way of getting all that frozen stuff unfrozen, creating a decently thick atmosphere.

And while it is true that a lack of magnetosphere, and mars being just a bit too small will result in the eventual loss of the atmosphere, thats something that would happen (in my understanding) over hundreds of thousands of years or even a bit longer. It won’t last in geologic terms, but in terms of civilizations it would be pretty damn long.

I’ve heard good things about this series, but haven’t read it myself: http://en.wikipedia.org/wiki/Red_Mars

Terraforming Europa would be a bad idea, for several reasons: First, it’s darned cold, even more so than Mars. Second, it’s far less massive, so it’d retain atmosphere even less readily than Mars would. Third, and most important - we’ve been warned, quite sternly, against attempting any landing on Europa.

How do you expect to create an atmosphere of the correct composition at the correct pressure without the correct gravity?

Therefore, of our solar system, the only planet remotely capable of being “Terraformed” is Venus. Simply drop a few trillion tons of sulfuric acid eating algae that produce gasous oxygen and liquid water as waste products (and solid sulfer) onto the planet and a few eons later you have a planet suitible for Earth’s lifeforms. You’d have to update the algae composition to deal with the climate as it changes, of course. A rather simple solution, really.

How to sell an idea that will cost trillions of dollars and not gain results for many generations - that’s the problem.


My understanding is “short term” mars is about as “doable” atmosphere wise.

And some of the really big moons (and mercury?) might be if you use REALLY high molecular weight gases. Whether there is enough mineable Xenon in the solar system to do that is a whole nother issue.

Loss of a gas due to a weak gravitation field is a function of at least three things, how hot the atmosphere is, the gravitational field of the planetary body, and the molecular wieght of the gas.

Which also makes Venus require high maintenance to keep the water in the atmosphere as Hydrogen tends to get swept away from solar wind. Not to mention the air conditioning requirements with the nearly year long days.

Mars is not, by any means, Terraformable. It’s simply impossible to maintain oxygen at the surface at sufficient density to support a human breathing. Heavier non-reactive gases would increase the pressure, but push the oxygen higher into the sky - no where near where we’d need it to breathe.

It’d be like a helium breathing life form trying to breathe on Earth’s surface.

IANAPlanetologist (real thing?) but how is it Venus has 82% of the mass of the Earth and yet 93x the atmospheric density?

Seems you are saying being smaller perforce means less pressure but clearly that is not true.

Gasses don’t work that way (mostly).

And there is terraformed and terraformed.

There is walk around in shorts enjoying the fresh air, and there is it aint so cold the “air” is turning liquid and you can breath fine with just a simple no pressure oxygen mask like moutaineers or hospital patients wear.

Its always been my impression that at the least the latter is physically possible for Mars. Whether we are ever economically wealthy enough to do that to mars is a whole nother can o worms.

What do we mean by terraforming here? The OP muddied the waters by including asteroids and we’ve got people saying Venus would be a better candidate than Mars.

Let us define Terraforming as the alteration of a planetary environment such that not only is it capable of sustaining life in a close cycle without externally imposed controls; it is also capable of sustaining humans. With that definition the answer is simple – there are no bodies in the solar system capable of being terraformed.

The obvious question coming out of all the replies is - for how long? You could dump a few ice-steroids on Mars and up the water content; perhaps some form of atmospheric dissociation to split that water vapour into oxygen and hydrogen, and let the hydrogen get blown off faster by the solar wind.

However, the atmosphere would probably bleed off until the partial pressure of oxygen was too low to support life- the question is - in 100 years or 100,000 years? If 100,000 then probably we could live with the temporary nature of the result. Recorded history is only about 6000 to 10000 years; geological time scales are not the same as historical. (if a fault-line creeps a few inches a year - how far will things be out of whack in a century? A millenia? In 1 million years?). What air pressure is acceptable - seal level? 5,000 ft? 10,000ft? 18,000 ft (1/2 atm.?)

Ditto for Venus or Europa - what mechanism would you use to make up for the disparity in sunlight needed to keep a decent temperature? Reflective clouds on Venus? Giant solar mirrors around Europa? Jupiter is 5 times as far, gets 1/25 the solar heating; Saturn, 10 times as far, gets 1/100 the solar heating. Also adding ice/water/gas is a lot more stable process than needing a million square miles of orbiting mirror to stay in place for eons.

Unfortunately, the Galilean satellites -the big moons of Jupiter - are embedded in Jupiter’s immense magnetic field and get radiation so hard that it would probably be fatal to space travellers and also likely to someone on the surface without a huge thick insulating atmosphere. We’ll need the same magical technology that enables terraforming in the first place.

What mechanism would your venusian sulphur-eating bacteria use to ensure that the acid clouds did not simply become acid oceans? Details, details…

Seems to me if you could terraform Mars in the first place then it would be trivial to continue the process intermittently (or even in an ongoing, low-level basis) to replace what is lost over time.

I don’t have a cite, but I did take classes that touched on this stuff.

My impression/recollection is that for LARGE bodies that werent quite large enough, or just a bit too hot, or the gasses were just a bit too light, it was for all practical purposes an eternity compared to human history. Again, the losses were only quick on geological time scale.