OT: Carbon Dioxide races -> known vs unknown -> terraforming mars -> is or is not

[Jack Simth]

Originally posted by Imperator Fyron:
Any statements about it beyond the basics of what antimatter is (according to theory, I do not know if any has yet been made in labs) would be pure speculation.

Yes, they do make antimatter in labs - often accidentally; when two sufficiently high-energy photons collide, they produce a particle and its matching antiparticle. However, it's made in single particle quantities with the standard Version right next to it, and so (with modern methods), antimatter is both difficult to capture and nearly impossible to produce in any meaningful quantity.

[Taera]

Jack - this fact is what had allowed you to post in this forum meaning, for all of us to exist untill now you never, though, know what they can come up with in the labs...

edit: realized its a complete pointless post... ohwell, ill let it live

[ July 16, 2003, 10:20: Message edited by: Taera ]

[henk brouwer]

Originally posted by Imperator Fyron:
The problem is that there are no other substances that can perform all of the roles of oxygen in complex organisms. All organisms on Earth that are more than a simple cell rely on oxygen for all parts of energy generation (not necessarily storage, as for plants, but the molecules they store it in still rely on oxygen). This is because oxygen is a very unique substance that has just the right combination of electronegativity, molecular mass, size, charge, ionization, etc. to work as it does in organisms. Complex alien organisms that do not rely on oxygen could not rely on a single gas; they would have to use several things to fulfill all of the roles of oxygen. And yes, they all need to be fulfilled, because they are too fundamental to be ignored (all relating to energy transmission within the organism and releasing the energy to be used).

Earth life is so dependant on oxygen that some scientists say, as Fyron mentions, that oxygen is the only substance with just the right characteristics for (complex) life. The question is whether this is realy the case or caused by the fact that life has adapted during millions of years of evolution in such a way that it perfectly exploits the characteristics of oxygen, which may make it seem perfect.

If not oxygen but another molecule, that can generate sufficient amounts of energy in biological processes, was used in evolution, then life would have adapted to this situation, and proteins and other processes would have developed that would exploit this resource, making this molecule look "just perfect". Maybe then we would have laughed at the thought of oxygen-dependent life.

[ July 16, 2003, 11:33: Message edited by: henk brouwer ]

[Jack Simth]

Originally posted by Imperator Fyron:
Complex alien organisms that do not rely on oxygen could not rely on a single gas; they would have to use several things to fulfill all of the roles of oxygen.

And the problem with relying on multiple things is what, exactly?

[dogscoff]

If realy, how can you know we wont find some unique element even deep in mars, in the asteroid belt or on Pluton?

Because there are no more elements to be discovered (none that would be useful for this thread, anyway), and we know there can't be.

Here's how:
An element is a "type" of atom. All atoms are made up of neutrons, protons and electrons.

The thing that makes one element (say, hydrogen) different to another (say, helium) is the number of protons they contain. For example, a hydrogen atom has one proton. To put it another way, any atom with only one proton is Hydrogen. Any atom with 2 protons is helium, any atom with 3 protons is {insert element name here}, and so on up to >200 protons. There might be a few more up the top there yet to be discovered, but they can't exist in nature- they could only be made in labs and would self-destruct almost immediately after creation. This makes them pretty much useless when you're considering things like natural biology.

The point is, you can't have 1.5 protons, it's either 1 or 2. You can't have 2.4 protons, it's either 2 or it's 3, and so on. This means that just about every atom in the entire universe is of a type we have already discovered.

By the time you eliminate the ones that can only exist in a proton accelerator/ the centre of a star/ supernova/ black hole etc, you find that there are only about 100 or so elements actually available to Mother Nature for making life. We know the properties of all of those elements, and so we can make some pretty good assumptions about what aliens will be made of.

===============

Disclaimer: I'm no scientist, aIdpooTV. Doubtless there are loads of glaring errors in the above, but I'm pretty sure it's getting the right general message across.

[dogscoff]

Sorry to double post, but I have a mostly on-topic question for my own sci-fi writing purposes, and this post has nothing to do with my Last.

I know Mars has a thin CO2 atmosphere. If we were to build a domed ecosystem on Mars, I imagine we could use photosynthesis or some chemical process to extract all the oxygen we needed from this CO2.

However, as has already been stated in this thread, our own atmosphere is mostly nitrogen, and that is also important to us. (Nitrates in the soil for plants etc)

Does anyone know if there is any useful amount of nitrogen present in the martian atmosphere, or is it all CO2? If there is none, would we be able to extract the required nitrogen from other nearby resources (rocks, asteroids etc)?

Finally, would an artificial atmosphere made up in this way (say ~75% nitrogen, ~15% oxygen, ~10% CO2) be viable for a human ecosystem, or would we need to import/ locally source all the other trace elements in our own atmosphere?

[DarkHorse]

Originally posted by General Woundwort:
Has anybody read the book Rare Earth? I think it bears directly on the discussion here re: the viability of non-oxygen based life-forms (and other conclusions even more depressing to avid sciffers).

This thread reminds me of a series I'm just about finished reading, concerning a large space based multi-species hospital called Sector General.

James White is the author; unfortunately many of them are out of print now, although there are two or three compendiums available that contain the earlier volumes, if anyone is interested.

[dogscoff]

It is mostly CO2 with some water vapor. N2 is not important for us to breath, Appolo astronauts used pure oxygen. Proved to be very dangerous though - Appolo 1.

Yeah, pure O2 would be a bad idea for several reasons. Nitrogen would be crucial if you planned to have any plant life (which you would need for food, oxygen, medication, fabrics and more) because it is required in the soil. I seem to remember from school something about a "nitrogen cycle", which involved nitrogen going from the air to the soil or something. I guess I ought to look it up.

I'm not so sure there's quite that much {Co2 on Mars}. And the thinness of the atmosphere is going to slow down the conVersion.

Well, I'm not talking about doming the entire planet, just a few limited domes. Also, the atmosphere doesn't have to be thin inside the dome- you can keep pumping CO2 in until you reach an Earth-like pressure, dump a load of plants and soil in there, then wait. Once the plants have done their job, you bottle the oxygen for use in inhabitted domes, lather, rinse and repeat.

A good source for terraforming Mars is one particular sci-fi series: Red Mars, Green Mars, Blue Mars.

Well, I've read "White Mars" by someone or other (it was terrible) and also an excellent book by Clarke about the possibilities for terraforming. Personally I think terraforming on Mars is a bad idea, unless you can do something to prevent the atmosphere being stripped away again by the solar winds. Mars is something of an obsession of mine.

On Earth it's about 70% N2, 22%O2, 4% Argon, and the remaining 4% everything else (very small amount of CO2). But it's not the percentage of Oxygen that's important, it's the amount of O2 molecules per Liter of 'air'. So at lower pressures it's important to have a greater percentage of O2 and at higher pressures it's not only important to have a lower percentage of O2, but also to have less N2 or no N2. A high enough pressures N2 will act as an intoxicant, so an inert gas, such as He (elemental Helium), is used.

Well for a permanent colony, I should think it would be important to have air pressure and content as close to Earth's as possible for morale and health reasons. However it seems as though O2 and N2 are the only important ones for humans, and CO2 will be required for any plant life. Maybe the pressure could be maintained at one earth atmosphere, with a mix of (say) 70% N2, ~26% O2, ~4% CO2. A balanced excess of CO2 could counter any ill-effects caused by the excess of oxygen. Maintaining that balance would be hard, what with all those life-forms on there respiring away, but there would be ways and means.

So my main question remains: Would nitrogen be available on Mars? If it's not iin the air, is it likely to be found in rocks, soil etc?

[geoschmo]

[quote]Originally posted by dogscoff:

So my main question remains: Would nitrogen be available on Mars? If it's not iin the air, is it likely to be found in rocks, soil etc?

Going strictly from my fractured memory, isn't Nitrogen supposed to be the second most abundant element in the universe after Hydrogen? I may be wrong about that, but if I am right then I think we ought to be able to find some significant quantaties in some form on Mars.

Geoschmo

EDIT: Nope, guess I was wrong. Looks like Nitrogen is fifth behind Hydrogen, Helium, Oxygen and Neon. Oh well. Guess I should look that stuff up before posting.

I did find an interesting and relevant link.
(click on the quote to go to the source)

Oddly enough, nitrogen is the limiting gas species for plant life on Mars. There is more than enough CO2 for photosynthesis, nearly enough oxygen for respiration and the atmospheric pressure is close to the lower limit. In fact in some regions, the atmospheric pressure reaches 9 or 10 millibars and some hardy terrestrial plants could be found to survive such conditions. However, there is too little N2 for nitrogen fixation for some plants by a factor of 5. Nitrogen must also be found in the soil for plants to thrive. Currently, the N2 levels in the Martian soil are unknown. If these are later found to be low, Robert Zubrin [Zubrin & Wagner, 1996] suggests we may be able to make fertilizer out of the atmosphere.

[ July 16, 2003, 16:41: Message edited by: geoschmo ]

[Suicide Junkie]

Maybe the pressure could be maintained at one earth atmosphere, with a mix of (say) 70% N2, ~26% O2, ~4% CO2.

That is dangerously close to a lethal atmosphere. Your colonists would suffer greatly, and casualties would be high.
Drop that CO2 concentration by at least an order or two of magnitude.