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Life

Started by ToohrVyk Jul 19, 2003 at 4:25 AM 0 replies 250+ views

Original Post

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Jul 19, 2003 at 4:25 AM

This thread concerning a new extrasolar planet has brought up (amongst many religion vs science and creationism vs big bang flamestuff) problems about the current definition of life. How is life defined? How do we know if something is alive? How should it be defined? Arion answered (along with some other ideas):

quote:
Original post by Arion However I believe that a more abstract definition of life may be in order. The only life we know and derive a definition for is that of the life found on earth. I believe that there could be life in the universe the defies our present definition of it.

This is so very true. But most important, there may even be life on our own planet that does not take the "natural", known shape of living beings with DNA and proteins and cells. Wouldn''t it sound counter-intuitive if the new definition stated that, for instance, crystals are living being, and that my engagement ring is as alive as my pet is? Waverider replied:

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Original post by Waverider I think it''s safe to say that what it takes to make a solar system''s formation successful, and what it takes to make a single cell have the capability to survive on its own, are two very different dynamics. The universe is full of matter and gravitational forces and chemical reactions that would cause the formation of solar systems eventually. Many fail, but some succeed. Gravity and chemical reactions cause the attempts to occur over and over again, as physical systems try to reach an equilibrium. However, on a single planet, how many drafts of a living form must be tried and fail before it gets it right? And what is the motivation for getting it right? I don''t believe that life represents a system trying to reach an equilibrium. Something very different is going on.

You are correct in saying that, given the time and matter, the process that turns nebulae into stars is unavoidable, while the creation of life (which, by the way, we are not trying to talk about) is more a question of probability. But life appeared, some way or another, on at least one planet in the universe. Yes, life is not an equilibrium. It''s unstable. The whole point is not reaching this equilibrium or not: it''s about following the rules. When you create a physics engine using euler approximation, you create a set of rules. Objects in there can reach an equilibrium, or become unstable and oscillate out of the system. Same with our on universe : a system can stay unstable for a long time (our planet, for instance). ToohrVyk

Arion

Jul 19, 2003 at 12:57 PM

The complexity of drawing a conclusion to the definition of life can be overwhelming. Since we have not yet seen life any place else than here on earth, there is no proof that present day definitions are wrong. However, I believe life is plentiful in the universe, especially on the discovery of such an old planet. But I also think it would be foolish to think that life in the universe abides by our definitions.

With no proof of bizarre life forms else where, we can only imagine a condition in which a vastly different kind of life form may exist from a total different set of circumstances. But true definitions can only be based on present day knowledge and imagination serves no purpose in advancing this definition. So we are stuck with our vastly limited knowledge and extremely narrow perceptions.

It would be difficult to draw even a basic line to separate the living and no-living. But a total inert system I believe would be a starting point in defining what is not alive.

There was a discussion among scientists on how small a living thing could be and still be alive. A minimum number of molecules was required to make life in a materialistic way fall under our definitions. If we stick to this then size may be a factor in the definition of life unless we find evidence to the contrary. Now we have the possibility of life in an active system of a size greater then the minimum for life to exist. Also there must be some kind of organized reactions in the system. The simple evaporation of water does show signs of life. There must also be some kind of independence and uniqueness to separate it from non-living things. We must not also confuse the potential for life with the definition of life itself.

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