Re: Atmospheres
 

<font size="2" face="Verdana, Helvetica, sans-serif">Hey Cheeze, why are Pirates so cool?

Because they just AAAAAAAAAAAAAAAAARRRRRRRRR.

http://forum.shrapnelgames.com/images/icons/icon10.gif

Slick.

Re: Atmospheres
 

<font size="2" face="Verdana, Helvetica, sans-serif">Hey Cheeze, why are Pirates so cool?

Because they just AAAAAAAAAAAAAAAAARRRRRRRRR.

http://forum.shrapnelgames.com/images/icons/icon10.gif

Slick.</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Did you see the previews to the movie about the Pirates?

It's rated AAARRR. http://forum.shrapnelgames.com/images/icons/icon10.gif

Re: Atmospheres
 

Slick:

While anti-matter (and even dark matter) races would be cool, they can not really be modeled in se4. http://forum.shrapnelgames.com/images/icons/icon7.gif

Couslee:

There are only so many ways elements can form compounds (all based off of the types of elements you are dealing with). Life on other planets would have to evolve in a similar way as to on earth (in the very beginning stages), or it would not evolve. The evolution of life from primordial oozes is an extremely rare occurence that requires a very specific set of circumstances (noone is fully aware of them all). Only a very small fraction of other planets in the universe could possibly have any form of life evolve on them. Even without knowing all of the factors that contributed to the evolution of life on earth, we can see that there is a very narrow range of conditions in which life can evolve (speaking on a planetary scale, taking other stellar bodies into account and all, not talking about specific climatic regions on the planet and all that). So, any planet that has life evolve on it is going to be fairly similar to earth in many ways.

I have a question for the lot of you:

What other compounds besides O2 do you think could serve the same role that O2 serves for earth-based macroscopic organisms? Why?

Re: Atmospheres
 

<font size="2" face="Verdana, Helvetica, sans-serif">First, I agree that the game can't model antimatter as it works in a physics book, but this game is not about physics, it is about fun, use some artistic license! SE4 already fractures known physics, but who cares, it is one of the best games I have ever played.

As for the other compounds, let's put it this way. We don't know what alien life might be like. There is a famous equation called the Drake Equation which mathematically sets the probability of life in the universe. You can look it up for further reading. It basically comes out to a mathematical certainty because of the sheer number of stars that we can see that there is life out there somewhere. The real question is what is it like. We only have the earth as an example. We know that life can exist on planets like the earth, but how different can it be and still support life? There is a vast range of types of life on earth - plants, animals, people, viruses, bacteria, etc. Even on earth, we have microbes that exist in the polar ice caps and others in the sulfur vents of volcanoes, neither of which use oxygen and both conditions are deadly to humans. We like to say oxygen is necessary because that is what we see and we project that to say we couldn't have evolved without O2. Yes, humans couldn't have evolved without O2, but we would have evolved differently in another atmosphere. Therefore on earth, only O2 makes sense for humans as we know them. The reason we see light in the wavelengths that we do is that we evolved on a planet whose atmosphere lets in those wavelengths. We would have different "eyes" if we were on a different planet. It is clear that a living being must make energy in some fashion, with at least part in a chemical reaction. The energy, if for no other use would be required for growth & reproduction, which are requirements to be defined as "life". Humans use aerobic respiration and a cycle of adenosine triphosphate to generate energy. Plants use sunlight, CO2 and water. Microbes use other exotic chemical reactions. So there are lots of examples here on earth. I would submit that other "atmospheres" would not be found out of complex molecules or of rare gasses because these are not observed in the universe on scales large enough to make an entire atmosphere.

In addition to what is already in SE4, "believable" (at least to me) atmospheres would be Ammonia, Methane and Sulfur Dioxide (found on IO, moon of Jupiter). As to "why", these are simple molecules, containing common elements which are reactive enough to possibly be used in a biological energy-producing reaction.

You may now return to your regularly scheduled programming.

Slick.

edit: typos

[ February 20, 2003, 02:55: Message edited by: Slick ]

Re: Atmospheres
 

There have been many experiments carried out simulating conditions prebiotic Earth. The test atmospheres usually contain mixtures of NH3, CH4, H2, and H2O and a spark generator to simulate lightning. Lots of carboxylic acids, amino acids, nucleic acid bases (like those of DNA, RNA, and ATP), and even pentose and hexose sugars have been observed to form under these conditions. Adding inorganic ions like Cu2+, Ni2+, Zn2+, etc, help to increase the polymerization of these components, not to mention other factors like UV radiation, heat, and things like that. Interesting stuff.

There are molecules that can replace O2, but some organisms on Earth can use H2, H2S, S, HNO3, H2SO4, and CO2 in lieu of O2. But as I've said before, they just don't make enough energy to be useful for anything more than a bacteria, and in that case, it has to have little or no competition!

[ February 20, 2003, 03:28: Message edited by: Captain Kwok ]

Re: Atmospheres
 

<font size="2" face="Verdana, Helvetica, sans-serif">Yes, and it attempts to determine the relative number of life-supporting planets in the universe. So what? It has nothing to do with atmospheres that do or do not support life, or with gases that can be used for energy purposes in organisms.

<font size="2" face="Verdana, Helvetica, sans-serif"> <font size="2" face="Verdana, Helvetica, sans-serif">This is why I have been careful to always say "complex organisms" instead of just "organisms". http://forum.shrapnelgames.com/images/icons/icon7.gif

<font size="2" face="Verdana, Helvetica, sans-serif">Assuming that is actually possible in the first place.

<font size="2" face="Verdana, Helvetica, sans-serif">Yes, examples of simplistic organisms that do not need very much energy to survive. All complex earth-based organisms use O2 to get energy. Even plants use O2 to break down the glucose they make to get energy. They just make a lot more glucose than they use, which is why they put out a lot more O2 than they do CO2.

How exactly would Ammonia, Methane or Sulfur Dioxide be used to get energy for complex organisms (not monerans, not protista, not any other forms of microscopic life)?

[ February 20, 2003, 05:57: Message edited by: Imperator Fyron ]

Re: Atmospheres
 

<font size="2" face="Verdana, Helvetica, sans-serif">They would generally replace O2 in some sort of Version of the electron transport chain, which drives the production of ATP, the major energy carrier in the cell. Instead of O2 being the final electron acceptor to make H2O, one of the other compounds like SO4- (to H2SO4) would be. I suppose if there was lots and lots of the substance available in the alien cell, it might be able to produce enough energy. The problem is that the reduction potential is less than most of the energy carriers in the cell, so it needs to use more energy to get things started.

Some of the substances mentioned before work better as electron donors than acceptors, like ammonium, NH4+. For example, we use H2O as our electron donor for ATP synth, but on a planet with abundant NH4+, it might be possible for more complex organisms to use it the same way that nitrifying bateria do on Earth, but that still requires moderate levels of O2. However, it's just not energetic enough to be effective. But... H2 as an electron donor is fairly energy rich and might be able to form some sort of pathway, but I'm not so sure about the plausability of that.

[ February 20, 2003, 05:43: Message edited by: Captain Kwok ]

Re: Atmospheres
 

<font size="2" face="Verdana, Helvetica, sans-serif">Several months ago I read "Rare Earth" by Peter Ward and Donald Brownlee (a paleontologist and an astronomer IIRC).
The rare earth theory is that though bacterial life may be common in the universe, intelligent life - in the form of terrestrial animals and plants - is unique.
Their modifications to the Drake Equation are quite interesting. I do not know enough about the the topics they raised tp prove them right or wrong. Anyway, it's a book well written and full of ideas new to me. I never would have thought of plate tectonics as crucial for evolution on Earth.

Re: Atmospheres
 

<font size="2" face="Verdana, Helvetica, sans-serif">I only just started hearing about that one myself. Often people claim some robust life would live on Mars or Venus. But without plate tectonics, atmospheric gases on Mars just get locked up.

Venus, the Last I heard, has a different problem. The most recent radar mapping of it's surface seems to imply that the entire surface is no more than 100 million years old -- all of it, the same age. I wouldn't want to be there when the entire planets surface decides to "recycle"

For SE4, as it's been said already, I would like it if there was more variety to the planets -- some that were just about useless for colonization.

But the AI needs some work to be able to make good decisions about these. Recently I went MEE, so I started using the planet conditions bomb. After all, I have all the planets I need. This seriously crippled the AI -- it saw the empty planets and colonized them -- and couldn't really thrive with 25 deadly planets.

[ February 20, 2003, 13:47: Message edited by: Arkcon ]

Re: Atmospheres
 

Plate tectonics - yes, Everyone ought to have to take Physical Geology in college. Plate tectonics and the sun drive and define our environment, which in turn defines the life-forms on the planet. I am still not convinced that you could not have life on a "non-tectonic" planet, but its development would be far different and more sedate.

And, I still want a "build queue finished message" and a main screen components readout by right-clicking on an enemy ship :-)

[ February 20, 2003, 15:09: Message edited by: solops ]