Terraforming is not feasible

Or is it?

from GalCiv2 Forums
I am an avid watcher of the Science Channel, and love doing casual research into all kinds of science (mostly computer and space-centric topics) and have come to the conclusion that Mars will not be terraformed for centuries, more likely millenia. Of course, I'm hardly qualified to make such a decision, so I've come here for all of your opinions. Not that you'll change my mind, just that it'd be an interesting discussion ;)

There are no less than four (maybe five) attributes that any world must have to be brought to an Earth-like state.

1. An Earth-like Atmosphere: This is of course the most obvious of them all. Without a proper atmosphere a colony is restricted to heavily shielded installations to protect from the harsh environment, be that the existing atmosphere, the lack there-of, or cosmic radiation that is not being stopped by the (non)atmosphere.

We can cultivate an atmosphere through various means, but they almost all depend on existing sources of water. Which is yet another requirement that we can't count on even on Mars, even though Scientists are farely certain there is water somewhere under the surface.

2. A Strong Magnetic Field/Iron/Nickel Core: The planet in question must have an Iron and Nickel Core in order to maintain a powerfull magnetic field, or energetic particles emitted by the sun will burn away the atmosphere that we so lovingly cultivated. This magnetic field also influences our weather, somehow, by-proxy, I think... If this can be verified/debunked that would be great. At any rate, that magnetic field is essential to protect the new atmosphere.

3. The planet must be Near 1G: Meaning that it must have a level of surface gravity very near that of Earth. To much and our bodies cannot handle it, to little and we start to fall appart, not to mention that the atmosphere will slowly leak away.

4. Lastly, it must have A Satellite: By that I mean a Moon. The Moon does a wealth of good to the Earth. It stabilizes Earth's orbit, giving us predictable seasons and stable weather (compared to the rest of our star system). It also creates the tides, which are important to alot of Earth based life forms. Not to mention the huge number of impacts the Moon takes for us. I think there is more, but the stability of the planet's rotation is so important that nothing else matters.

I also believe that active plate tectonics are essential, but I don't remember why I came up with that, so I didn't include it in my list.

Here are the ways these problems can be addressed, granted most of these solutions will not use current technology, because current technology will not suffice.

1. Atmosphere: Assuming there is frozen water, you introduce large amounts of carbon dioxide into the atmosphere to increase the planet-wide temperature enough to melt the ice. This would release more CO2 and continue to warm the planet, as well as introduce water vapor into the new atmosphere. After a certain point algae is introduced (most likely geneticaly engineered for the task) to increase nitrogen levels. When nitrogen levels are high enough, and enough water is available, higher level plants (more evolved) are introduced to increase oxygen levels. In the case of Mars there are huge levels of Oxygen tied up in Iron Oxide all over the planet (that is why Mars is a rusty red color) which can be released when a great deal of energy is applied. In this method you could create an Earth-like atmosphere in a few centuries, if we started next week  ;p 

2. Magnetic Field/Iron Core: This one is simple, tractor beam (or attach a rocket to) a big hunk of iron, or lots of pieces of iron, and smash it into the planet. If your lucky the impact will melt a large portion of the surface and cause the heavier-than-rock iron to sink to the core of the planet, thus supplanting the normally rock core with an iron one. The impact will have to be sufficiently large to melt enough of the rock to get all the way to the bottom or the magnetic field will be off-center at best, and not work at the worst. You also don't want to blast the whole planet apart, unless your trying to make a moon ;) Obviously this step will have to be done before the formation of the atmosphere.

3. Earth-like Gravity: Basically this will be done in the same step as the construction of the iron core. By introducing heavier elements at various levels, or by sending other other large mass objects (perhaps from the asteroid belt) to the planet a higher level of gravity could be achieved.

4. Natural Satellite(Moon): Either piece one together from asteroids and meteors to achieve the right size at the right distance or do it the way the Earth got its moon. The first method is more likely to happen soon... well sooner.

By gathering together many large objects, again from the asteroid belt, you could eventually form a moon. At first you may need to maintain their relative position to eachother and the planet. Eventually their mutual gravity would draw them together, and after a great deal of time the increasing gravity of the object would cause it to become more cohesive, eventually becomeing a sphere. This process could be sped up if the initial objects are of a super heavy element, such as Uranium, but an inert element/substance would probably be a better choice.

The second would be to replicate the birth of our own moon. It is theorized that a large object, roughly the size of Mars, struck the early still-molten Earth. This impact threw off huge amounts of material into orbit. This material eventually coalesced into our moon. This method would make creating the Iron Core easier because it would most certainly melt the entire planet, allowing the iron to sink all the way to the bottom. However, it is extremely risky, because there is no way to be sure it will turn out properly. If to much is ejected than the mass of the planet may become to small, if to little than you just wasted your time and energy, and it takes alot of energy to move a planetoid! You also don't know if it will land in the right orbit (the correct distance). It gets even more complicated when you factor in that you need the distance to be just right for the ratio between planetary gravity and lunar gravity. This method is just too unpredictable.

Both methods could take centuries to create a moon.

As to my (almost) certainty that there must be active plate tectonics, well you'd introduce radioactive elements to the iron/nickel core when you insterted it, such as Uranium, Thorium, and Potassium. These elements exist at the center of the Earth, within the Iron/Nickel core, and create a kind of atomic engine that keeps the interior of the Earth very hot. Without it the Earth would have cooled after less than 100 million years after the formation of the moon, this would have eliminated plate tectonics, and thus made life impossible, for some reason I can't remember.

Okay, that is my rediculusly long post. Thoughts?
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Reply #1 from GalCiv2 Forums Top
2. A Strong Magnetic Field/Iron/Nickel Core: The planet in question must have an Iron and Nickel Core in order to maintain a powerfull magnetic field, or energetic particles emitted by the sun will burn away the atmosphere that we so lovingly cultivated. This magnetic field also influences our weather, somehow, by-proxy, I think... If this can be verified/debunked that would be great. At any rate, that magnetic field is essential to protect the new atmosphere.


Look at the Earth's magnetic field. There have been periods in the past where Earth had no magnetic field. Happens on average every 250000 years.

3. The planet must be Near 1G: Meaning that it must have a level of surface gravity very near that of Earth. To much and our bodies cannot handle it, to little and we start to fall appart, not to mention that the atmosphere will slowly leak away.


Genetic engineering can solve this problem. If we spread across multiple planets, the individual populations will diversify over time and eventually form distinct species. We can as well jumpstart the process by only sending specially crafted people to that planet.
Reply #2 from GalCiv2 Forums Top

Look at the Earth's magnetic field. There have been periods in the past where Earth had no magnetic field. Happens on average every 250000 years.


Cite a reputable source, then we'll talk about this.

Genetic engineering can solve this problem. If we spread across multiple planets, the individual populations will diversify over time and eventually form distinct species. We can as well jumpstart the process by only sending specially crafted people to that planet.


Genetic engineering is nowhere near precise enough for this. Besides, do you want to volunteer your children to the perfecting of this technology? Not many people do. Evolution only takes place if their are survivors, and evolution takes millions of years, even when jumpstarted. Humans in low to no gravity enviroments experience rapid bone decay and heart shrinkage, as well as a shutdown of the immune system.

Your method still takes centuries of advancement, and the points you do not contend take centuries as well. Even if we began next week, and we don't have the technology to do so, Mars would not be terraformed for atleast 700 years.
Sins of a Solar Empire II
Reply #3 from GalCiv2 Forums Top
The natural satalite requirement is not true, yes the moon does many of the thing you describe for the earth. But it's not the only way a planet can achieve a stable orbit and tides are not essential to support carbon based life. We would simpley have to manage a different ecology.

Oxygen/Nitrogen atmosphere would be needed as would a certain level of humidty for life as we know it.

A Magnetic Field is very useful for deflecting a lot of radiation, of course generating such a field artificially may one day be possible.

Anyway at our current level of technology and logistic capability terraforming Mars is indeed impossible.

But bare in mind that in 1908 even sending a probe to Mars, (or indeed into space) was impossible.

Who knows what another century of advancement will allow, if people continue to strive, dream and work hard.
Reply #4 from GalCiv2 Forums Top
700 years? I don't know... tech has progressed much faster over the last 2 centuries for some reason. Just over 100 years ago, flying was a ridiculous dream, and space travel even more. Cars were some sort of gimmick, and electricity was a new concept. Who knows how things will be in, say, 2118? Or 2225?

In fact, until the last ~12000 years, I don't suppose we've made much progress at all(for nearly 2000000 preceding years).

I'm not quite convinced, however, if we'll be able to go faster than light as early as 2178, though. Or if we'll get anti-gravity and artificial gravity so soon. Things like efficient & cheap fusion power, artificial gravity, genetic engineering, some way to create a huge artificial magnetic field, weather control, etc. would make colonization possible. Until then, we're stuck on this pale blue dot.


Look at the Earth's magnetic field. There have been periods in the past where Earth had no magnetic field. Happens on average every 250000 years.


250000 years is quite a short time. Considering humanity has existed for 2 million years, suffering these 'no-magnetic-field' periods 8 times.
Reply #5 from GalCiv2 Forums Top
Weaver, you are correct of course... we also have the added problem of how long this planet is going to be able to sustain life, with the way we have been going at it, we probably have 50, 60 years tops... nowhere near the time it would take to make a new planet or reach another one by conventional means... is there anything that you would propose to prevent this from happening?

Reply #6 from GalCiv2 Forums Top
Without a magnetic field there would be no protection from solar radiation and that nuclear radiation is extremely hostile to life as we know it. The magnetic field does occasionally reverse - most recently the Brunhes-Matuyama reversal is believed to have occurred roughly 750,000 years ago.

In classical theory (i.e. Einstein) the speed of light is a property of space and there is no way around it. That hasn't stopped science fiction authors (and game designers) from providing the technology needed to make their stories work but these are based on wishful thinking - not physics. Superstring theories, on the other hand, require at least 10 spacetime dimensions. When we learn more about them, these may have some clauses in fine print that modify Einstein's law. If so the theoretical basis of a faster than light drive will likely be found this century though it may take the engineers another century to figure out how to use the theory.

One of the more interesting fields in biochemistry is mirror image or Chiral molecules. Fundamental building blocks of life like sugars and amino acids can be left handed or right handed. On Earth all sugars are right handed and all amino acids are left handed but there is no obvious reason why that has to be so - other evolutions may have used left hand sugars, right hand amino acids or both. The key is that we can't digest left hand sugars or right hand amino acids so, that paradise planet you found - so much like Earth it could be it's twin - there is a 75% chance you'll starve because you can't digest the food.

I suspect the person who got it right was Gerard O'Neill who postulated massive massive orbiting cylinders - essentially inside out planets with gravity simulated by centrifugal force - as colonies. Positioned close to resources like asteroid belts or the Jovian moons. The ultimate evolution of this concept is the Dyson sphere with something like Larry Niven's Ringworld as a more realistic waystation.



Reply #7 from GalCiv2 Forums Top
I also believe that active plate tectonics are essential, but I don't remember why I came up with that, so I didn't include it in my list.


Lack of plate tectonics would generally indicate that there's poor/no circulation in the planet's interior (and thus likely a weak or no magnetic field as is the case with Mars), or that the pressure within the interior will slowly build until a total resurfacing event occurs, as is theorized has happened on Venus (not likely to happen in human civilization time frames, but definitely a very bad thing if it did).
Reply #8 from GalCiv2 Forums Top
Is that the only reason we want plate tectonics Kryo? Even so, that atomic engine at the planet's core will still be necessary.

A reversal of the magnetic field's polarity is not the same as not having one. I still want to see some kind of reference to the loss of a field every 1/4 million years.

How else would you create a stable orbit? Besides a natural satellite? And artificially creating a magnetic field would require more energy than we can supply anytime soon.

The whole point of this post was to point out the fact that terraforming a planet (and Mars in perticular) is not feasible, and will not be for a long time, due to several key factors that must exist in order for a planet to be terraformed (made Earth-like).

Bioengineering people and other life forms to suit the new planet doesn't count as terraforming, the whole point is to make it like Earth so you don't have to adapt.

One thing to remember is that we are talking a scale in the billions of tons of material and light minutes in distances. Even with a dream drive, within reason, it would take 6 months to get a ship from Earth to Mars. Longer if they stop on their way through the asteroid belt to grab some material for the planned moon and/or core. We can't even get people to Mars for an exploratory mission yet, much less create a massive industrial complex to terraform the planet.
Reply #9 from GalCiv2 Forums Top
I also believe that active plate tectonics are essential, but I don't remember why I came up with that, so I didn't include it in my list


to circulate soil and mineral nutrients, among other things. plate tectonics are a part of having a hot core. mars has a metal core, but it's gone cold, ergo no magnetosphere.

not sure i agree about having a moon, though. several of the things you specify are totally true, but i'm not sure what you mean about orbit... AFAIK the bigger effect is on the earth's rotation, not revolution (its spin and wobble, or lack of wobble, rather than its orbit around the sun).

this reminds me of my 'bussard ramjet' thread...

i agree that terraforming isn't feasible, but not because of specific reasons. because of scale. it's a simple question of economics: is it cheapter to terraform a planet, or is it cheaper to live in domes, orbital stations, and other environmentally controlled enclosures?
Reply #10 from GalCiv2 Forums Top
I misspoke(typed) when I said Orbit, I should have said rotation. The moon is essential in stabilizing the Earth's rotation. Without it the poles would be all over the place (not because of a shifting magnetic field, but because the planet is tipping over like a college chick at Mardi Gras), and the levels of exposure to the sun that are quite predictable now would vary wildly.

What I'm trying to say is that if an existing planet does not have each of these attributes, the missing ones will have to be artificially inserted in the terraforming process.

I was unaware of the existence of Mars' metallic core. So the atomic engine is ABSOLUTELY necessary because it is essential to a magnetic field, which is essential to the terraforming process.

I forgot to mention that one of the problems with counting on adaptation is that humans have essentially stopped evolving. People don't generally factor in genetics when they choose who they have children with (if they really make the choice at all). I understand fully the massive timescale evolution requires, but our society spends vast resources on saving the lives, and correcting the defects, that evolution would rather toss out. These corrected defects don't alter our genes. Someone who wears glasses or gets lasic still has genes for bad eyesight, these will be passed on.

I don't think I, or anyone now alive, would like to create and live in a society where people aren't alowed to have children because they are in the bottom 60% of the fitness rankings (as an example). Such a mentality can only lead to ruin, and Nazis. And we don't want either :P

I agree dystopic, the major reason is the scale. But the scale is a problem because of how much must be done to create an Earth-like world.
Reply #11 from GalCiv2 Forums Top
Something that I haven't seen mentioned but that I think would be kinda important would be flora and fauna. Let's assume you do get a magnetic field for protection, and find water, and "make" a moon, and inject metal into the core to get the correct gravity, and so on and so...then what? There's entire food chains that would be missing.

1. I think trees and plants and green things are important to the atmosphere because of that whole photosynthesis thing and exchanging CO2 for O2, right? You would need the correct soil to grow plants, but those plants wouldn't get the same amount of sun as they do on Earth. And the seasons would be totally different, anyhow. Where would get the plants? Ship over a lot of seeds and throw them on the ground? Would they even grow?

2. Would we all be vegetarian? Because we would have to import a lot of chickens, cows, etc. since they don't happen to live there already. And I think seafood would be tough to replicate. Even if you "made" an ocean, I wouldn't even begin to imagine trying to replicate the oceans here, with shrimp/fish/predators/filter feeders/etc. I know we could have farms where you raise things like that, but even livestock have to eat. Where would we get the food to feed them? It has to come from somewhere. Shipping it from Earth seems like not such a good idea.

Just a few other questions to throw on the fire of discussion...
Reply #12 from GalCiv2 Forums Top
[...]
In classical theory (i.e. Einstein) the speed of light is a property of space and there is no way around it. That hasn't stopped science fiction authors (and game designers) from providing the technology needed to make their stories work but these are based on wishful thinking - not physics. Superstring theories, on the other hand, require at least 10 spacetime dimensions. When we learn more about them, these may have some clauses in fine print that modify Einstein's law. If so the theoretical basis of a faster than light drive will likely be found this century though it may take the engineers another century to figure out how to use the theory.

[...]
I'm not going to add to the discussion too much, I just wanted to point this out; the underlined part is wrong. The "folding" of space is indeed possible. The problem is the requirements in power and distribution. You would need (supposedly) the power of an entire star to create enough "folded space" (i.e. "warp") to make it usable in any way.

Regardless, it is a reality, and I have no doubt that "we" will one day do it on a massive industrial scale. But the way towards that is indeed very long. So it's not impossible. Just very, very improbable. Right now.
Reply #13 from GalCiv2 Forums Top
It's really amazing all the things that came together just right for life to flourish on Earth. There are so many chance factors like the presence of the moon, the magnetosphere, the ozone layer, the temperature, the abundant water. Mars just doesn't have any of that. Though, it's probably the most hospitable planet in the solar system next to Earth. One of the big obstacles, assuming an oxygen rich atmosphere can be created in the first place, is that Mars lower gravity allows it to more easily escape into space. The lack of a magnetosphere allows radiation to affect air molecules, further assisting their escape into space. Also, consider it took Earth almost 4 billion years of prolific photosynthesis to reach the oxygen levels we have today. Terraforming Mars involves some very large obstacles. I can't imagine it's anything that could be done in the next few hundred years. If man can remain technologically successful for the next few thousand, it might happen. It would be quite a thing to see. In any case, I would imagine more of bio-dome approach. That's something feasable with technologies of the near future.

Reply #14 from GalCiv2 Forums Top
Getting Mars to an earth-like state would be a massive task. Personally, I'd settle for just getting temperature and pressure to a tolerable level (melting the icecaps might achieve both). If people can walk around with just a breath mask and some heavy sunblock, that would certainly be a big help toward further development. :)
Reply #15 from GalCiv2 Forums Top
I'll add some comments myself.

I forgot to mention that one of the problems with counting on adaptation is that humans have essentially stopped evolving. People don't generally factor in genetics when they choose who they have children with (if they really make the choice at all). I understand fully the massive timescale evolution requires, but our society spends vast resources on saving the lives, and correcting the defects, that evolution would rather toss out. These corrected defects don't alter our genes. Someone who wears glasses or gets lasic still has genes for bad eyesight, these will be passed on.


Have we really stopped evolving? Last time I checked, the ability and knowledge required to correct our vision was once beyond us. Sure that it doesn't prevent bad genetics from being passed on, but genetics are starting to take a back seat to our ingenuity. I recall reading (or hearing) a while ago that some success has been made in a special chip that if properly installed in a blind person's eyes, that it would allow them to see in the colour yellow. I need to check up on the details though.

In any case, does the lack of improvements in our genetics makeup prevent us from evolving?

By the way, here is a video about the progress in prosthetics about 2 years back.
WWW Link

Genetic engineering is nowhere near precise enough for this. Besides, do you want to volunteer your children to the perfecting of this technology? Not many people do. Evolution only takes place if their are survivors, and evolution takes millions of years, even when jumpstarted. Humans in low to no gravity enviroments experience rapid bone decay and heart shrinkage, as well as a shutdown of the immune system.


Why genetic engineering? How about other technologies such as nanites? With nanites, we could have them to reverse such problems. They could rebuild bones, give the heart a work out, and if need be, replace the immune system. The best part is, it could in theory be added to any living human being. Early experiments could be performed on the dying (and maybe the dead) as an effort to save their lives.

Alternatively, they could grow a suit of armour for the host, that not only produces a force on the body, and resist movement to simulate a stronger gravitational force, but also serve as a protective suit of armour to allow the host to better survive other enviroments besides earth. Terraforming a planet might be quite dangerous, expecially if it hasn't been done before, so stuff to protect early colonists would be helpful.

Please note, I'm saying that this will work, I'm only giving a possible solution that some creative people might come up with.
Reply #16 from GalCiv2 Forums Top
Getting Mars to an earth-like state would be a massive task. Personally, I'd settle for just getting temperature and pressure to a tolerable level (melting the icecaps might achieve both). If people can walk around with just a breath mask and some heavy sunblock, that would certainly be a big help toward further development.

The Earth's characteristics protect us from *a lot* of solar radiation. Even with normal atmospheric pressure, I don't think you could ever just walk around Mars without some sort of radiation suit. But even in a full space suit, that would be an incredibly awesome experience.

Reply #17 from GalCiv2 Forums Top
Have we really stopped evolving? Last time I checked, the ability and knowledge required to correct our vision was once beyond us. Sure that it doesn't prevent bad genetics from being passed on, but genetics are starting to take a back seat to our ingenuity. I recall reading (or hearing) a while ago that some success has been made in a special chip that if properly installed in a blind person's eyes, that it would allow them to see in the colour yellow. I need to check up on the details though.


Its all a matter of what you want to define evolution as. If you mean evolution by means of natural selection, like what Darwin was meaning, then yes, in a way as he described it, we have stop evolving. IE. We don't "weed" out through death, the handicap and infirm. But if you include technology advances, etc. (which arent really natural), then no we havent stopped evolving. Of course, thats if you believe in evolution at all, which is an entirely different matter altogether (and thread).

The Earth's characteristics protect us from *a lot* of solar radiation. Even with normal atmospheric pressure, I don't think you could ever just walk around Mars without some sort of radiation suit. But even in a full space suit, that would be an incredibly awesome experience.


Until one of the Transformers steps on you! I saw it in a movie it must be real!

Reply #18 from GalCiv2 Forums Top
In current technological state, we could achieve mars terraforming. However, our infrastructure just cannot support such a venture. It would take several centuries to achieve the massive amount of resources needed to do it. By that time, technology would have changed so drastically, we might have the ability to simply create artificial gravity, build machines which can artifically create magnetic field (the primary problem with the likelihood of that is energy requirements. Fusion or something similar in output would be needed), and perhaps (if we get really, REALLY sophisticated) even change the chemical composition of the atmosphere however we want by changing the atomic structure on a massive scale (adimittedly, that's pretty far fetched).

Also, by that time, FTL could have been mastered in some form or another (either by the very possible "warp tehnology" of space bending (which is once more very exepnsive in energy terms), by using another "dimension" for lack of a better word, or by simply existing in one place, then existing in two places, then existing in the second place, thus going a tremendous distance without even "moving" at all). Going by simple math, we would definately find another earth-like planet.

But these are just my thoughts. By the way, another possibility which is undermentioned is Venus. If a way to cool it down could be found (perhaps by building a massive orbital system of mirrors to reflect the sinlight away from the planet enough) it would have water, a fairly easily fixed atmosphere, and a size pretty comparable to earth. But that's just me, and I wouldn't put very much credence on my words.
Reply #19 from GalCiv2 Forums Top
Like Piznit said, I meant genetic evolution, and nanotechnology isn't even a viable technology yet.

This whole post was to point out that TERRAFORMING, makeing a planet EARTH-LIKE, will not be feasible, which is not to say impossible, for a long time. This post also says that even when it becomes feasible, it will take an extremely long time, on the order of centuries. Alot of, nearly all in-fact, of the objections i've heard are not even terraforming, they're practically cheating.

If Kryo agrees its enough for me. Getting pressure and temperature would be a far more reasonable task, a good step for us to learn the basics of terraforming.
Reply #20 from GalCiv2 Forums Top
You could theoretically overcome all the limitations with time and tech but those limitations certainly apply to any planet that would be logically terraformed by a civilization less than 3 on the K scale. A type 3 civilization could choose planets based on desired location and make it any way they wanted it, but why waste the energy, just move a more suitable planet where you want it to be. :) 

In the foreseeable future (probably thousands of years) the primary requirement for terraforming would be cultural stability since any meaningful changes would take centuries and as yet no human civilization has lasted long enough to complete a public works project of that magnitude. Current best estimates to make Mars atmosphere breathable are on the order of millenia. Raising the temp enough to allow for liquid water would take hundreds of years.
Reply #21 from GalCiv2 Forums Top

I forgot to mention that one of the problems with counting on adaptation is that humans have essentially stopped evolving.


True and untrue. True because due to the lack of 'natural selection', the only traits that will evolve will likely be subtle ones. A mutation that gave you green skin would pretty much blow your chances of procreation.

However it's untrue because, you're basing this on what? The last 1000 years? How about the last 10000 years? 10k years to make noticeable evolutionary advances is pretty quick in the big picture.
Reply #22 from GalCiv2 Forums Top
A reversal of the magnetic field's polarity is not the same as not having one. I still want to see some kind of reference to the loss of a field every 1/4 million years.


I've read the same thing, here's some sources:

Bentley, Molly "Earth loses Its Magnetism" BBC Online. 12-31-03
Hutton, William "Hutton Commentaries" 07-27-01

These also speak of the implications of such an event, Noting that the switching of poles is a very slow process (the event itself could take thousands of years), and noting that the times durring the shift seem to coincide with a large number of extinctions.

Considering humanity has existed for 2 million years, suffering these 'no-magnetic-field' periods 8 times.


Not really. The First Homo classes are 2-2.5 MYA. However, the "modern human" did not appear until less than 500,000 YA as a desendant of Homo Errectus.
Fagan "Ancient Lives" 2004
Reply #23 from GalCiv2 Forums Top
There are two main reasons why active plate tectonics is essential to having an earth-like planet.

Firstly, as has already been mentioned, it circulates materials that are important to life but aren't otherwise present in the crust. Potassium, for example, is critical to nerve and muscle function, but it settles deep in the mantle during planet formation. Plate tectonics is necessary to churn up the planetary interior and bring the potassium (and lots of other important elements) to the surface.

Secondly, plate tectonics drives the carbonate-silicate cycle, which regulates CO2 levels. CO2 dissolves in water to form carbonic acid, which reacts with silicate rock to cause erosion and form limestone. The CO2 is trapped in the limestone, which is then subducted into the mantle where it is broken back down into CO2 and silicates, and eventually returned to the surface. Since the rate of erosion rises with temperature, too much greenhouse warming will trigger more limestone formation and reduce CO2 levels until the planet cools. Too much cooling slows the process, allowing CO2 to build up until it gets warm again.

This whole process is dependent on plate tectonics to keep things moving. Without fresh silica and CO2 being brought to the surface, you'll eventually run out of one of them and trigger either runaway greenhouse warming or an eternal ice age.

Of course, plate tectonics requires oceans to work, as the water acts like a lubricant to keep the plates moving. And to have oceans, you need enough gravity to hold an atmosphere...
Reply #24 from GalCiv2 Forums Top
Here's some recommended reading, if anyone's interested, all fiction but by reasonably good (ie practical) authors:

Red/Green/Blue Mars by Kim Stanley Robinson

Based on the colonization and eventual partial terraforming of Mars. Interesting, but there's at least one glaring flaw: Mars is too light to hold an Earth temperature atmosphere for any apperciable length of time, especially without a magnetic field. I ran the math myself after I read the books; N2, O2, and water vapor are simply too light to stick around.

Destiny's Road by Larry Niven

Based on the colonization of a Earth-type planet in a nearby system by slowboat (colonists in cryogenic storage, only crew active). Planet ends up being nearly devoid of potassium due to relative lact of techtonics and mircobiota that have nearly depleted the ocean of potassium.

Ringworld by Larry Niven (all of his Known Space, really)

This was mentioned above as a possible build-your-own-planet idea. It provides an incredible setting, but fails the precticality test - the ringworld floor was built out of a material with a tensile strength nearly as strong as the Strong Nuclear Force. Needless to say, we don't even have a theory to make such a material.
Reply #25 from GalCiv2 Forums Top
Mars is too light to hold an Earth temperature atmosphere for any apperciable length of time


I don't doubt that you are correct, the problem is one of filling a leaking container. However, I read somewhere that if you could instantly pump the moon up to 1 eartn atmosphere, it would remain breathable for about 2000 years, (I didn't do the math). That's long enough to be useful in people years, but in cosmic terms it is a moment. I don't recall the number for Mars but I believe it was over 100,000 years.

If we are ever able to manipulate energy and mass on a large enough scale we will be able to do just about anything we choose to do, but most futurists believe there will be enough earth type planets to keep us busy without terraforming. I think it was the Hyperion trilogy that mentioned that Mars was half terraformed and basically a failure as a colony because FTL travel arrived and made it kind of pointless.