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mercury
2004-Sep-14, 10:21 AM
We are very curious to know if life exists in outer space. But have we really ever considered how life must have come into existence? Perhaps the life in other parts of the universe do not the same basic necessities as we do that is- food, water, air. Or may be the life forms there are not even made of the same elements and compounds as we are that is- carbon, hydrogen, oxygen etc.(these aliens may have complete metal bodies and an unknown intelligence) Who knows- there is a probability that there are completely different elements in far away parts of the universe. As an example if we consider how life originated on Earth, we do not even know the full truth yet because life can grow or multiply itself(make more matter than what is given) while the elements and compounds(like amino acids, water, carbon, etc.) it is made up of cannot do so. So my hypothesis is that aliens may be completely different than us in the above respects (that is if aliens at all exist). Please give your valuable suggestions on this topic.

GOURDHEAD
2004-Sep-14, 01:03 PM
Carbon in water has such an advantage over other combinations that other forms of biological life are hardly worth considering as survivors of the early stages of self organization. Some of these carbon based critters somewhere in the universe may have developed AI and housed it in metal casings capable of self reproduction. They may have discovered ways to make non-carbon based biology to work and have developed it to explore regions of high temperature and pressure like that found in gas giant planets. If they did, let's hope they kept it on a short lease and also kept control of the off switch.


Who knows- there is a probability that there are completely different elements in far away parts of the universe.

Compounds maybe; elements no; chirality of complex compounds maybe; levels of polymerization highly probable; multiply neucleated cells possibly.

abyssalroamer
2004-Sep-14, 06:06 PM
People have been wondering obviously longer than I have. My interest started in 1966, when i was still in high school and my mentor suggested looking into cosmology for the answers to origins and evolution of life. When he suggested that, far less was known of interstellar molecules and organic strands than is known today, but he had some ideas that the process started with the Big Bang.

The basis for limiting our search to carbon-based molecules is that so many of the interstellar molecules are, in fact, carbon based. These molecules, floating around a good part of the universe, are capable of taking us to the brink of creation. Finding the right electrochemical environment can allow the threshold to be crossed. Staying in a favorable one could allow for the evolution into more complex life. That evolution doesn't have to follow anything we can conceive. The key to accepting the ubiquitousness (ubiquity?) of carbon is the acceptance of the validity of the remote sensing of those molecules.

Bases other than carbon are being, and have been, considered at places like NASA/Ames. Likewise, the role of water. We assume that water is a necessary ingredient in life processes. At this point, we can rely only on earth-based examples. Hence, almost all work has been done in an aqueous environment. To consider reactions and formations in other environments, maybe all that is needed is H and O in some molecule in the series of half reactions that can enter into formation. Conditions might occur where, in the formation of another molecule, water can form as a product. If it stays in the chemical soup long enough, it might be utilized in the formation, sustainment, and replication of that life in ways that we have not seen on earth.

At any rate, at this time I don't see a need to look beyond carbon or to consider that p-chem laws, other than what we have in play now, need to uncovered to explain any other part of the universe. What can happen to carbon within those laws is a whole different thing. We need only look at some of the creatures that evolved on earth see that

StarLab
2004-Sep-14, 06:14 PM
What about silicon-based life?

abyssalroamer
2004-Sep-14, 06:25 PM
Thomas Gold believed that silicon-based life may be found below the deepest part of the known biosphere. He has been an icon to me and I use his model(s) in alot of things. I wanted to have him speak at the Dec. AGU meeting in San Francisco. His death has taken away the greatest bridge from what we know to what seems likely to be. It is in that repsect that I would pause to consider silicon-based lfe.

What about it?

GOURDHEAD
2004-Sep-19, 01:28 AM
Thomas Gold believed that silicon-based life may be found below the deepest part of the known biosphere. He has been an icon to me and I use his model(s) in alot of things. I wanted to have him speak at the Dec. AGU meeting in San Francisco. His death has taken away the greatest bridge from what we know to what seems likely to be. It is in that repsect that I would pause to consider silicon-based lfe.

What about it?

Is this the Gould that regularly contributed articles to Natural History ? In spite of the great respect due him, I think he guessed wrong on this one. Once carbon based life self organizes, it rips apart all competitors until it develops species with enough technology to design non-carbon based forms for specific tasks. Due to the prevalence of the CHON elements over S and Si and other suspects, carbon based life has too large an advantage due to the charge based affinities amongst the CHON elements. Whether evolution can incorporate enough Si and other elements into the carbon based forms to confuse taxonomists prior to technology development is another question. With the right but highly improbable environmental changes such hybrid forms may morph to non-carbon based ones.

StarLab
2004-Sep-19, 03:06 AM
I dunno. :blink: Maybe computers can be consider silicon-based life?

abyssalroamer
2004-Sep-19, 03:24 AM
Thomas Gold was an astrophysicist at Cornell and had been correct in many of his observations and conclusions in many areas. He added considerable support to plate tectonics theory in the earliest 60's, well ahead of the explosion to follow. He has proven correct, I think, in most aspects of the nature of the deep biosphere. Over the years in the oil industry, I corroborated most of his ideas. By using his model of the deep biosphere and some of the essentials of the Panspermia concept I was asked to consider a Fellowship at NASA/Ames last year to set up a system of carbon-based reactions and the energies and stabilities, within various geologic systems and a wide range of P-T conditions.

Because of my regard for Gold, I am willing to consider, or keep in the back of my mind, the (bio)chemistry of Si and the possibility of it's equivalent role to C in the life systems. Other than that, I have no real reason or need to invoke Si-based life forms. Carbon has been at the heart of almost all of my research and work since the late 60's. At the same time, since my work has also been with rock-forming minerals, I have looked at the structural chemistry of Si and understand it fairly well. I am currently looking at carbon cycle in the gigayear cycle as well as the shorter one(s) and the role of the deep carbon in earth systems. I also did some work in evolution at the base of the tree/web/net/circle of life, when we lucked into some astounding microbiotic and molecular paleontological data in the Santa Barbara (CA) Channel.

As I said before, the presence of C-based molecules throughout the universe is a compelling basis for searching only for C-based life forms. If life did evolve elsewhere, it doesn't have to be like anything we might even be able to imagine and molecular signatures--if that is all that is left-- might even be missed initially.

I think it is unfair to say he guessed, wrongly or rightly on any of his work. He may have concluded incorrectly, but unlike what goes on at our level alot, I dont think it was guessing or hoping.

GOURDHEAD
2004-Sep-19, 12:18 PM
I think it is unfair to say he guessed, wrongly or rightly on any of his work. He may have concluded incorrectly, but unlike what goes on at our level a lot, I dont think it was guessing or hoping.

Oops! my error and my apologies. Obviously I was thinking of Gould not Gold with whom I am unfamiliar. Theories are born of speculation which is born of guessing. It was not my intent to denigrate his position by referring to it as a guess. I was pointing out that my guessing lies in a different direction supported by my strong bias towards carbon based life coupled with the tendency of life to modify its environment to suit itself (and usually become less suitable for other forms).

Are there artifacts supporting Gold's position or was he "reading between the rocks"?

StarLab
2004-Sep-19, 03:55 PM
So, are archaebacter considered C-based?

abyssalroamer
2004-Sep-19, 08:27 PM
Archeobacter are C-based.

eburacum45
2004-Sep-21, 07:50 PM
I wrote this essay based on Dr Gold's ideas of deep silicon life;
http://www.orionsarm.com/xenos/Rheolithoids.html
although I have studied geology (long ago), I have no idea if such a thing is possible.

Probably not on this planet. But perhaps somewhere among the billions of rocky planets with diverse chemistries that must exist, something quickens.

mercury
2005-Jan-21, 09:57 AM
I've got these weird ideas about how aliens could be like. Suppose an alien has the power to convert total kinetic energy into potential energy. If he moves himself forward, all this kinetic energy will be converted into potential energy enough to move himself the same distance ahead. Is this possible?