Which Shall We Terraform First: Mars, or Venus?

[Chronomar]

Your opinions, preferably backed up with arguments, over which is most terraformable. You could also suggest an alternative...or deny that we should/could terraform anything at all (which I would then love to attempt to prove you wrong).

For background: (with the caveat that I may not know what I'm talking about 100%)

Problems with Terraforming Venus:

-lack of magnetic field (hence no protective shield against stuff flung out of the sun)...its core (thought to be similar to Earth's) is not liquid, so does not produce a magnetic field.

-too much CO2 in atmosphere

-too little O2 (and I would assume, O3) in atmosphere

-too much sulfuric acid in atmosphere (although, this could be neutralized with simple baking powder--it would react and produce water and a salt)

-not enough water

-closer to the sun, so the temperatures at the poles (assuming an earth-like atmosphere) would be tolerable, but not anywhere else

Problems with Terraforming Mars

-does not hold atmosphere very well

-verrrry thin atmosphere

-not enough water (liquid, anyway)

-extreme temperatures

**Keep in mind, you can use living organisms that have been genetically altered as a method of atmosphere alteration...I think it's a good idea anyway.

 

[Cognisant]

Terraforming is incredibly impractical, Venus is simply too hostile for anything but a post-singularity society to tackle and Mars is too small to hold an Earth like atmosphere, at best Mars will be partially teraformed and permeant residents will undergo modifications to survive in its thin atmosphere.

Transhumanism is so much easier and cheaper than planetary teraforming.

Edit: If we do anything with Venus it'll probably be strip-mining for the sake of constructing a Dyson's sphere bubble or some other large scaled project.

 

[Darby]

Problems with Terraforming Venus:
-too much sulfuric acid in atmosphere (although, this could be neutralized with simple baking powder--it would react and produce water and a salt)

-not enough water

Well to me it looked like you just solved your lack of water problem, just pour baking powder on it! You'll even have salty oceans like on earth!

For O2, I was going to say something stupid about cutting the cheery out of cheerios and mating them, but my brain screamed "malfunction!" so i'll shut up now.

 

[Kuu]

Terraforming is incredibly impractical, Venus is simply too hostile for anything but a post-singularity society to tackle and Mars is too small to hold an Earth like atmosphere, at best Mars will be partially teraformed and permeant residents will undergo modifications to survive in its thin atmosphere.

Transhumanism is so much easier and cheaper than planetary teraforming.

My thoughts exactly Altering an entire planet, and keeping it that way vs altering/augmenting the human body. No contest.

 

[Decaf]

Neither Venus nor Mars exist in the habitable zone. Mars is closer to the edge of the zone, so its my preference, but I think real terraforming will have to breach our solar system to be truly productive.

Anyone know what the closest Earth-like planet we've discovered is? Adaire?

 

[Cognisant]

Okay now there's two ways of crossing the interstellar expanse, one would be the agonizing slower-than-light method and the other would be bending space/time (the Event Horizon method).

By comparison living on a non-Earth-like planet is easy.

 

[Latro]

The amount of alkaline substance you would need to neutralize Venus' atmosphere would be astronomical, and it would also need to be in the vapor phase, which has other problems. You would also then generate extremely hot steam, which is actually a very powerful greenhouse gas (multiple times stronger than CO2), not salty water, and the salt that would result would be considerably different from ordinary NaCl. (On Earth the greenhouse gas effect of water vapor is dissipated by the way that the rain process works. With atmospheric temperatures WAY above the boiling point of water, the steam would just sit there and heat the planet even more.) Also, it's probably not feasible to try to dissipate the sheer amount of CO2 that is in Venus' atmosphere, which brings the planet pretty much surface-wide up to 900 F.

Neither Venus nor Mars exist in the habitable zone. Mars is closer to the edge of the zone, so its my preference, but I think real terraforming will have to breach our solar system to be truly productive.

Anyone know what the closest Earth-like planet we've discovered is? Adaire?

I saw a talk by someone in the physics and astronomy dept at my university whose focus is in astrobiology. The "habitable zone" theory is no longer generally accepted in the astrobiology community, according to him. A pity I forgot his name. =/

 

[Decaf]

The concept of a habitable zone is criticized by Ian Stewart and Jack Cohen in their book Evolving the Alien, for two reasons: the first is that the hypothesis assumes alien life has the same requirements as terrestrial life; the second is that, even assuming this, other circumstances may result in suitable planets outside the "habitable zone". For instance, Jupiter's moon Europa is thought to have a subsurface ocean with an environment similar to the deep oceans of Earth. The existence of extremophiles (such as the tardigrades) on Earth makes life on Europa seem more plausible, despite the fact that Europa is not in the presumed CHZ. Astronomer Carl Sagan believed that life was also possible on the gas giants, such as Jupiter itself; Iain M. Banks's novel The Algebraist is based on the same idea. A discovery of any form of life in such an environment would expose these hypothetical restrictions as too conservative. Life can evolve to tolerate extreme conditions when the relevant selection pressures dictate, and thus it is not necessary for them to be "just right".

I agree that the habitable zone is too restrictive for determining the possibility of alien life, but that doesn't mean we can terraform those planets.

terraform: To transform the atmosphere (or biosphere) of another planet into one having the characteristics of Earth

The HZ concept might be outdated for life in general, but I believe it still holds very true with regard to the potential for supporting human life.

 

[Reverse Transcriptase]

I'm all for settling Mars, but terraforming will be difficult.

Here are some bonuses to settling Mars before you terraform it:

• You only need an oxygen mask to breath. Seriously! You will be just fine on the surface otherwise, except for dust.
• Despite what hollywood would have you believe, the winds are no real pushing power. The winds DO get up to really fast speeds, hundreds of miles per hour, but the atmosphere is so thin that the wind can't knock you over.
• Plants inside a (sealed, atmosphere'd) greenhouse could feasibly grow (slower than on earth) just from sunlight.

 

[Chronomar]

I'd go for Mars too (especially considering the problems brought up by Latro...good point). But, I suppose by "terraform" I meant changing the planet entirely, which, upon second consideration, is not as feasible as simply making a series of "bases" to live in.

I suppose also, with the parallel advents of both synthetic biology (genetic engineering) and high-power computing...perhaps changing the humans themselves would be better. But the problem with that is creating a separate class of humans before we are even able to control ourselves with our present limited means. At the same time, I would support transhumanism...just with very very very (repeat very) careful foreplanning.

Maybe it comes down to watching to much sci-fi...or reading too many of Shakespeare's plays, for that matter...but from what I know of human nature it would be a neat trick to pull a transhumanistic revolution off. Of course, stranger things have happened.

 

[Decaf]

I suppose also, with the parallel advents of both synthetic biology (genetic engineering) and high-power computing...perhaps changing the humans themselves would be better.

I figure we'll eventually invent self repairing robots and artificial intelligence first. Then we combine the two and send them up to Mars. Wait a couple hundred years and then send a political delegation to iron our the terms of our peace treaty with our new neighbors.

 

[FusionKnight]

This (http://en.wikipedia.org/wiki/GJ_1214_b) is a good candidate for a habitable ocean planet. Pretty wild.

Remember that Mars also does not have a magnetic field, although it appears to have had an internal dynamo much like Earth sometime in the past.

 

[Latro]

This (http://en.wikipedia.org/wiki/GJ_1214_b) is a good candidate for a habitable ocean planet. Pretty wild.

Remember that Mars also does not have a magnetic field, although it appears to have had an internal dynamo much like Earth sometime in the past.

40 ly out...ugh. .1c is about as fast as we can expect to be able to get even with thermonuclear propulsion (look up Project Orion for more on this), unless we have FTL or a source of energy like starlight that we can absorb in large amounts in space. (And in the latter case acceleration would almost certainly be very very slow.) At .1c it'd take 400 years to go 40 ly.

 

[Chronomar]

Best bet for that then is sending a ship built to sustain a population through many multiple generations...perhaps combined with live-lengthening technology/medical advances. This would be rather expensive, I think. Yet, I think it's worth it if possible.

 

[Latro]

Best bet for that then is sending a ship built to sustain a population through many multiple generations...perhaps combined with live-lengthening technology/medical advances. This would be rather expensive, I think. Yet, I think it's worth it if possible.

An issue with that is gravity. Look how much larger that planet is than Earth. That size brings with it a bunch of gravity, which our generation ship-riding descendants won't be able to handle without a RIDICULOUS amount of preparation.

 

[fullerene]

Nah... more things than just radius go into a planet's gravitational field. Wikipedia said that the surface gravity was .91g, so its actually a bit weaker than we experience it.

 

[Latro]

Nah... more things than just radius go into a planet's gravitational field. Wikipedia said that the surface gravity was .91g, so its actually a bit weaker than we experience it.

I knew that, but I had assumed it would be around the density of Earth, if it was otherwise Earthlike. Evidently I was wrong and it is considerably less dense than Earth. Interesting.

Gravity's still a problem when you're in zero g for 400 years, though.

 

[Decaf]

Gravity's still a problem when you're in zero g for 400 years, though.

Haven't you ever seen the Matrix

http://en.wikipedia.org/wiki/Electrical_muscle_stimulation

In order to "fill in the gaps" for realistic muscle development you would spin part of the ship. The angular momentum of the occupants will create the necessary gravitational approximation.

 

[FusionKnight]

I still think we'd be better off waiting to develop FTL before sending generation ships. Say it takes 10,000 years to get to a star with your ship. In the mean-time, the human race has had 10,000 years to develop its technology. It seems a case of diminishing returns.

 

[Latro]

Haven't you ever seen the Matrix

http://en.wikipedia.org/wiki/Electrical_muscle_stimulation

In order to "fill in the gaps" for realistic muscle development you would spin part of the ship. The angular momentum of the occupants will create the necessary gravitational approximation.

And how much rotation would you need to do that? Seems like it would be a rather large amount of necessary energy to get it to rotate that fast.

 

[Decaf]

And how much rotation would you need to do that? Seems like it would be a rather large amount of necessary energy to get it to rotate that fast.

http://en.wikipedia.org/wiki/Artificial_gravity

 

[fullerene]

you can figure that out rather easily, actually. Suppose that the area of the ship where people live is a cylindrical room.

m=mass off spaceship
r1=inner radius of cylindrical room
r2=outer radius of cylindrical room
v=linear speed of the object (undergoing circular motion)
w=angular velocity
a=the acceleration we want, namely, something close to 10 m/s (like earth's)
I=moment of inertia

I = .5*m*(r1**2 + r2**2) (taken from wikipedia. We're neglecting the endpoints, but they won't change the answer very much if a relatively small proportion of the mass is contained in them). Centripetal acceleration for the passengers is v^2/r1, with v=w*r1... so a=r1*w**2, which we want to be somewhere around g, or .9g, or whatever. So w**2= 10/r1

Rotational kinetic energy is .5*I*w**2, or .25*m*(r1**2 + r2**2)*(10/r1)

= 2.5*(m/r1)*(r1^2 + r2^2) joules of energy into that sucker to make the gravity that you want.


Using Wikipedia as an estimate for the space shuttle mass 10,000 tons, or 9.1*10^6 kg. Ship diameter is 56m, so r2 = 28m. Allowing for 1m of wall (pretty arbitrarily picked--could be worked out knowing the strength of material and working with atmospheric pressure, but I'm too lazy), let's call r1=27m

so 2.5*((9.1*10^6)/27)*((27^2)+(28^2)) = 1.2*10^9 joules


This is a very high-end estimate, imo though, because you're spinning the whole ship. realistically, the astronauts don't need the entire thing to have earth-gravity, so you could easily get by with just spinning a fraction of it. (although, in that case, you would have to worry about friction--the spinning parts of the ship grating against the stationary ones)

Still, 1 kg of nuclear fuel releases 3.4*10^14 joules of energy by fission--way more than you would need to get it spinning fast enough to create earth-like gravity. Even if your efficiency sucks, or you're using something other than fission, it's not going to be *that* much different that it'll cripple your ability to hold that much extra stuff.

 

[FusionKnight]

This is a really cool tool for calculating artificial gravity: http://www.artificial-gravity.com/sw/SpinCalc/SpinCalc.htm. It also takes into account comfort factors based on the Coriolis force experienced by a spinning body.

As for energy requirements, many things can be done to minimize it. For one, spinning the entire vessel, rather than portions of it. Once you set it spinning, it should go on spinning at the same rate indefinitely (friction in interstellar space is virtually non-existent due to extremely good vacuum). A series of even smallish fission reactors could power such a ship for a very very long time. Of course is fusion were developed as a power source, or better yet matter-antimatter reactors, power would become a trivial concern.

Maintenance would be far more troublesome with limited matter with which to fashion spare parts, etc.

 

[The Frood]

In answer to the OP i think Mars would be better, Being Martian sounds quite a bit better than a Venusite or something. What would you call a being from venus? lol. Idk, The problems of terraforming just seem enormous. Especially with regards to magnetic shielding, and shipping in all the necessary chemicals. However in an article about terraforming saturn's moon Titan Ellis Miner of NASA said "In the case of Mars, relatively small changes to the
atmosphere could create a partial greenhouse effect on Mars, in part
because the temperatures at Mars are only slightly below those of Earth."
(full article here)
But, then again I haven't read much else on it lately. Does anyone know (or care to look up, i'm not feeling it right now) on whether or not we can (given infinite resources) terraform anything at our current tech level?



http://www.orbitalvector.com/Space%20Structures/Space%20Colonies/Space%20Colonies.htm

Link i found relevant, mostly for the artificial gravity thing. But the whole site is very interesting.

 

[Atriamax]

Terraforming seems more reasonable than transhumanism, you get the chemical reactions going and over some number of years the planet is sustainable. For mars vs venus, definitely mars. The four problems you described are all the same problem of little atmosphere. Also Theres no way we are going to travel out of the solar system in a space ship, wormholes are a much more reasonable method. Spacetime is more understood every year and once we have the technology to warp it, Im sure wormholes we be used.

 

[Latro]

Also Theres no way we are going to travel out of the solar system in a space ship, wormholes are a much more reasonable method. Spacetime is more understood every year and once we have the technology to warp it, Im sure wormholes we be used.

Possibility, much less feasibility, of FTL is still very much an open question. A ship that could cruise at .1c (about 67 million mph) like a Project Orion vessel (google it) could escape the solar system and go about 40 ly in about 400 years. A radius of 40 ly gives us a lot of possible planets, if we can overcome the gravity, food/water, and radiation issues and more importantly can find a suitable destination (arriving at a planet only to find it inhospitable would REALLY suck).

Hmm...I crunched some numbers on the food issue and got a best case scenario (for feeding 1000 people based on a 2000 Calorie diet) of about 10^15 J (100% efficiency in food production and digestion) and a worst case of 10^18 J (0.1% efficiency). Not TOO bad...

 

[Ogion]

I tihnk a reasonable alternative to terraforming (which takes huge amounts of ressources and time) could maybe be space stations, buildings on the moon..
I also think it might be very beneficial to human society to 'split up'. I mean to form lots and lots of small communities (ie spaceships/stations etc). Should bring an end to a lot of inter-factional conflicts.
Though, unfortunately, it could be that we are not built all that well for having a group of a few dozen/hundred people in a tin can of finite space...

Ogion