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

[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?

[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:

---

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.

---

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 ?

[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).

[oleg]

Originally posted by 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?

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.