Why do we all think that aliens are carbon based? Can't they be Silicon based, or even compuond based. Conditions would exist on their planet to permit existence of such life-forms.
Anythings possible. We shouldn't be baised towards carbon.
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Why do we all think that aliens are carbon based? Can't they be Silicon based, or even compuond based. Conditions would exist on their planet to permit existence of such life-forms.
Anythings possible. We shouldn't be baised towards carbon.
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Physics, chemistry, and biology favor carbon based life. We have no reason to believe that any other combination of elements not centered on carbon can achieve spontaneous generation and evolve to sentient complexity. In competition with carbon based critters each will lose to the greater stability of the carbon based critters.
Our bias is reasonable.
On Titan,there's a lot of nitrogen and ammonium...so don't you think there would be nitrogen- or ammonium-based life there?
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Nope. More complex molecules are needed.On Titan,there's a lot of nitrogen and ammonium...so don't you think there would be nitrogen- or ammonium-based life there?
Geez, Gourdy! Earthly DNA consisted of A G C and T. It was that simple. Don't you think that in another environmnet with different conditions from our own, that life may just yet be possible in some other different manner?Nope. More complex molecules are needed.
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Yes, but carbon based. Maybe different at the amino acid and protein level, different chirality but equivalent complexity (RNA,DNA, etc.,) and carbon based.Don't you think that in another environmnet with different conditions from our own, that life may just yet be possible in some other different manner?
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The reason we are carbon based and that biologists feel it is the best, if not the only, method of creating complex biological life is because carbon can have up to four other atoms form molcules with a single carbon atom. Carbon has four empty slots in it outer electron shell that can be filled and this allows for some very complex chemistry to occur. Some have speculated that since silicon also has four open slots in its outer electron shell that maybe it could also from a basis for complex biological life, but we've found no examples of it, or any possible precursor chemicals such as silcon based amino acid type compounds that could form the basis of such a life form.
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Most likely we are unique, and if any other life forms can exist elsewhere in the Universe, it will be us.
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What if silicon based life can exist elsewhere because the conditions are just right for silicon to form long-lasting polymers ? You know, on our planet, the conditions are also just right.
It's possible.
I think It's already happenning...Computers.
What if silicon based life can exist elsewhere because the conditions are just right for silicon to form long-lasting polymers ? You know, on our planet, the conditions are also just right.
It's possible.h34r:
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Yes, but computers are not spontaneous life. We are searching for life which has evolved on its own, not with help from other life.
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In one of Isaac Asimov´s books he tells how an alien civilization discovers the archaeological remains of an even earlier galactic civilization that had disappeared thousands of years earlier. In their investigations one particular archaeologist - who´s considered an outcast even in their society - discovers a planet of robots who were left more or less to their own devices as a sociological experiment by the super advanced but extinct civilization. This planet of robots had been forgotten for millions of years but this archaeologist discovers its whereabouts & makes a couple of trips there. The end of the story comes when he is discovered & his (forbidden) activities are questioned & he defends himself by saying that his activities had been discovered by the robots & that they had the right to live & they had in fact dismantled his own spacecraft & had discovered FTL & were about to leave their solar system & explore the galaxy. We then discover on the last page of the book that the planet of robots was in fact the Earth & the "Robots" were humans!! :P
So who knows if we appeared without outside intervention!!!! :P
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I liked that story. But our biologists are sure that we came into existence spontaneously. I, too belive it, because we have created amino acids in the lab by simulating conditions on the early earth.
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Carbon is usually the best because it's electron field is perfectly half full. (4 out of 8 electrons) Because of that, it bonds readily with itself. Some of the strongest materials on the planet, such as diamonds, and corundum are based from carbon.
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Corundum isn't a carbon-based mineral.
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It isn't? Oops..sorry. I know coal, graphite, and diamonds are though. Coal can be turned into graphite, and graphite into diamond (by metamorphism-intense heat and pressure)
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Corundum is aluminum oxide.Originally posted by abyssalroamer@Jun 1 2004, 05:47 PM
Corundum isn't a carbon-based mineral.
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Jeez man, have you like memorized all the main minerals and their components or something?
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I Googled the word and it came up. Google can tell you anything! B) Ask it "How many grains in an ounce?" and it will come up with the conversion factor. It'll do all sorts of things if you just ask it.Originally posted by Deep_Eye@Jun 2 2004, 11:06 AM
Jeez man, have you like memorized all the main minerals and their components or something?
And I don't work for them.
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Originally posted by Spacemad@May 30 2004, 11:49 AM
We then discover on the last page of the book that the planet of robots was in fact the Earth & the "Robots" were humans!! :P
So who knows if we appeared without outside intervention!!!! :P
Thats what I think we are. An experement. They took neanderthals, and geneticly mutated them, and created us, and then put us here to see what we'd do, and how we'd flourish in our surroundings. I bet they also have this synthesised in a lab of some sort, and we destroyed ourself and the planet.
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We could just have evolved from them you know? I don't think that we were the results of an experiment.
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"Anything" is not possible. Only those things permitted by the laws of physics are possible, the only caveat being that we have an incomplete knowledge of what those laws are. Life, as we understand it, is not posible based on silicon.Originally posted by rahuldandekar@May 25 2004, 06:22 AM
Why do we all think that aliens are carbon based? Can't they be Silicon based, or even compound based? Conditions would exist on their planet to permit existence of such life-forms. Anything's possible. We shouldn't be baised towards carbon.
The reason for this is that, while silicon (Si) has 4 bonding electrons available, like carbon ( C ), Si is a bigger atom; it makes longer & weaker bonds. One result of this is that Si only makes single bonds, while C will double bond. So, for instance CO2 is a closed shell molecule, because the C has double bonded to each of the O, whereas SiO2 has only two single Si-O bonds, and still has two electrons available to bond. So the Si electrons aren't used up until you get SiO4, but since the bonds are single, SiO4 has 4 loose electrons looking for bonds, one for each O atom. The bottom line is that Si forms crystals with O and does nothing greatly interesting with H. On the other hand, C forms a gas with O (CO or CO2), and creates a suite of noncrystalline molecules that are the basis of organic chemistry. If you create a definition of "life" that is sufficiently non-commital as to exactly what "life" is, then perhaps you can claim that Si based life can exist ("living crystals" that transmit information by moving crystal defects). But that is not "life as we know it".
And here's another point. Look at the relative abundances of the elements (the plot is probably representative of the abundances in the present universe). Aside from the obvious H and He, the next most abundant elements in the universe are, in order, O, C & N (it might be easier to look at the table). We already know that "CHON" is the basis for organic chemistry, and it's no coincidence that "CHON" are also the most abundant elements in the universe. The Si relative abundance is only about 1/10 that of C. So Si is both underabundant, and deficient in double bonds. It just does not work for "life as we know it".
We should be biased towards what we know. That is not to say that imaginative ideas are not welcome, but we learn best, I think, by extrapolating (even if by a long reach), from what we know. A simplistic look at Si, seeing that it has 4 loose electrons, animates that idea of Si based life. But we should not stop there and just say "anything's possible". We should look more closely and see what really is possible, and what that means.
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Carbon may be more common in the universe than silicon, but on Earth silicon is actually more abundant.
Having said that the form of life which has evolved on this planet is carbon based not silicon based, so obviously silicon based life has associated dificulties. Which if you compare carbon based organic chemistry with silicone chemistry, the advantages are obvious. For a start the oxide of carbon is a gas, the oxide of silicon is a rock.
Nevertheless I have imagined two fairly far-fetched types of silicon based life; one is a collection of self-organised rheolithic crystals in lavatube conditions; the other is descended from ancient self-evolving Von Neumann machines sent out millions of years ago by a possibly extinct alien race...
science fiction of course, but perhaps possible somwhere in the infinite universe...
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CARBON IS UNVERSAL WASTE?
sunil deshpande
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With so many extreme conditions existing on earth, if life were to have originated in any other form we surely would have found it. Other places in the universe studied so far are less hospitable. It's a wonder, too, why all life on this planet is traceable to one original DNA molecule. If anything else got a start, it didn't survive long enough to leave a mark.
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Other places in the universe studied so far are less hospitable.
However true that may be, we have not studied any place other than earth with sufficient thoroughness to really know. Although "far less hospitable" several places in the solar system besides the large moons of the gas giants are not necessarily prohibitively hospitable. Both Mercury and the moon could be hosting microscopic life miles below their surfaces where acquifers may exist. Although less likely, Venus and the gas giants may harbor life in their atmospheres. We don't have enough data yet to really know. It's not the sort of thing you'd want to bet the lunch money on.
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I thought I heard something about them finding evidence of non carbon based life near geo thermal vents deep deep below the ocean, but I can't Google anything up. Maybe it was wishful thinking.
I don't know all the science but I would like to think that 'Our current understanding' is that it is not possible, but in an infinite universe with plenty still to learn... who knows!
Call me a dreamer if you like. :P
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Weaselbunny! Where You Been?
I did a google search using "tube worms geothermal vents and a bunch of stuff came up, including this at the top:Ocean Floor:Hot Springs...
The tube worms do not rely upon photosynthesis for energy, but rather chemosynthesis (chemicals). This one article I looked at did not contain any reference to carbon in the list of chemicals that the tubeworms and their bateria buddies depend on, so until someone finds a different article, you could be correct. :unsure:
Order of Kilopi
No, these are ordinary carbon based lifeforms; they have the same type of body chemistry as the rest of life on Earth.
These deep sea organisms which cluster around 'black smoker' vents gain their energy from the internal heat of the Earth; chemoautotrophic bacteria use the chemical enrgy of the vents to support a food chain which is independent of the Sun's radiation. Such chemoautotrophy might be common on other planets in the universe; we just don't know.
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Hey Tom, been busy, but I've still been looking in on the threads from time to time.
I read the article, it could be what I was thinking about, but I seem to remember these odd creatures were surviving in a radioactive environment or something similar... again, maybe it was a vivid dream I had or maybe I picked it up somewhere but got my facts skewy, cos let's face it, if there was non-carbon based life on the planet, surely there'd be something on the net about it.
How's your space ship going Tom, still up for a race! :P
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