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

[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.

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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?

[geoschmo]

[quote]Originally posted by dogscoff:

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.

Well dang. That makes a lot of sense teh way you put it there, but it's kind of depressing. It makes it seem like we are closer to the end of knowing pretty much everything then to the begining.

[oleg]

[quote]Originally posted by geoschmo:

quote:

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Originally posted by dogscoff:

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.

Well dang. That makes a lot of sense teh way you put it there, but it's kind of depressing. It makes it seem like we are closer to the end of knowing pretty much everything then to the begining.

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Not really. For example the known matter makes only 10% or even less of Universe. The rest is "dark matter". Or how about cosmological constant ? It is not proven yet but it appears to be not zero. But what is its nature ?