Define Life

NASA is having trouble with the definition of life. If they are to explore other planets in a search for life they need to have a good definition. The only life we are familiar with is found on earth. Life forms on other planets may be unrecognizable to us, so they need to be able to recognize it when and if they find it. Can a forest fire be considered life? It breathes, feeds, reproduces and grows all of these things suggest that its alive.


How do you define life?

Jupiter's moon Europa, one of the most likely homes for extraterrestrial life in our Solar System, was named earlier this month as a priority for exploration by the US National Research Council. But NASA's working definition of life, "a self-sustained chemical system capable of undergoing Darwinian evolution", is far from ideal. It risks excluding some novel life forms that could exist, such as ones that replicate so haphazardly that natural selection is not an option. And there's a practical problem - just how long are you going to hang around on Europa to see whether potential life forms are evolving?

Instead, the search will have to rely on a list of expected characteristics, such as the presence of complex organic molecules, or entities with a morphology that can't be explained by chemistry alone.

www.newscientist.com...



[Edited on 30-4-2004 by kinglizard]

That is rockingly awesome.

I'm willing to bet we'll have a lot more luck finding life once we know what we're looking for- good for NASA to get the ball rolling before they've mucked up the Europa missions.

You're right with the example of the forest fire, and it also includes one of the characteristics of life: it dies eventually.

But now, life is also supposed to include this other one characteristic as well, and I don't think a fire does that, not as such: elimination of waste.

Maybe that life could be defined as and entity capable of breathing (even like breathing water such as a fish), feeding, reproducing, growing/developing, being born/dying and eliminating waste.

And indeed, the "self-sustained chemical system" is not a right definition: all life forms, I think, need material from outside (like air, food etc.), and therefore it is not self-sustained.

Self-animation

If it can move on its own, it's alive.

Originally posted by Protector
Self-animation

If it can move on its own, it's alive.

That means trees and plants aren't alive ?

life - an organized collection of biological material who's main objective is to survive in a competitive world.

Pisky - trees and plants do move, just exceptionally slow.

Over the course of its life, a tree could move as much as 20 meters any direction through the ground, generally it will do so selectively. If it has something it can 'grip' nearby, then it will slowly edge and grow towards it.

There's actually been a surprising amount of research done into the possibility that plants are fully conscious beings that live active lives and engage in some sort of ESP. It's quite interesting, and amazing. I'm not sure where you can do more research, but I'm sure you can somewhere, I watched it on a documentary..

I think some bacteria and viruses don't move. They're barely transported by their surroundings...

Is that moving? Hey, by the way, the air is moving!?!

Life: There are three rules for life I made up
1 It must consume somekind of energy directly or indirectly
2 It must expend the energy it consumes
3 It must be able to reproduce in someway

So how are my rules

here something i found on the internet www.junkerhq.net... it's the ending analysis of metal gear solid 2. it explains the process of evolution of human and machines. the basic message is how do we classyfi life. can a self-concious electrical signal that exist in the computer be consider life? it doesn't reproduce, it doesn't eat or excreat. it certainly doesn't need food as we know it, it doesn't need oxygen and water. but can it still be consider life?

if we find a realm of pure spirit in some other distant planet, can we say that's life? it in no way fit our conventional description of life...

so here's my answer.....there is no answer. there is no answer for our current understanding of knowledge and wisdom. but the closest thing we have is this "life is something that contain self-conciousness or it can evolve either in biological way or idea evolution. you can find what is "idea evolution" if you read my link above.

You're right with the example of the forest fire, and it also includes one of the characteristics of life: it dies eventually.

But now, life is also supposed to include this other one characteristic as well, and I don't think a fire does that, not as such: elimination of waste.

Maybe that life could be defined as and entity capable of breathing (even like breathing water such as a fish), feeding, reproducing, growing/developing, being born/dying and eliminating waste.

And indeed, the "self-sustained chemical system" is not a right definition: all life forms, I think, need material from outside (like air, food etc.), and therefore it is not self-sustained.

Thats interesting, I had never considered elimination of waste. A fire does eliminate waste in the form of smoke and ash though.
Trees and plants eliminate waste as well in the form of carbon dioxide,dead leaves,bark,?

What will our conscious minds accept? The scientists say there are parrallel universes and other deminsions right next to us right now. But "our" consicous minds won't "let" us see them or experience them. What if one of these "Alien" life forms stood before you, could your concisous mind accept that form without some point of reference, or would you just die on the spot from fear? What I am trying to say is that this is a fulid thing. What we know today is changed be what we learn tomorrow. LET THE DEFINATION BREATHE!!!

[Edited on 30-4-2004 by nojoy]

Originally posted by 2009
there is no answer for our current understanding of knowledge and wisdom.

Well that�s the whole problem. NASA needs a loosely defined set of rules for the definition of life. They need to recognize it to be able to search for it. What properties are present in all life forms? What do we consider to be alive?

I would say that:
1. It takes in substances for energy to stay alive.
2. It expells waste after using the "food".
3. It reproduces AT WILL to preseve the species.
All the above actions are done deliberately, not randomly.

Originally posted by nojoy
What will our conscious minds accept? The scientists say there are parrallel universes and other deminsions right next to us right now. But "our" consicous minds won't "let" us see them or experience them. What if one of these "Alien" life forms stood before you, could your concisous mind accept that form without some point of reference, or would you just die on the spot from fear? What I am trying to say is that this is a fulid thing. What we know today is changed be what we learn tomorrow. LET THE DEFINATION BREATHE!!!

[Edited on 30-4-2004 by nojoy]

That is a profound thing to say, I remember seeing a documentary on the perception of time. Because trees and plants move slow and thier sense of time different, are they aware of us? Our time perception is different than an insect and we are unable to see some insects unless they are still. Are other life forms moving at a faster rate than us so that we are unaware of them? I suppose relativity is a factor. I mean a microscopic bug cannot concieve of us, as we are unable to concieve of the Universe and the the truth about it, just theories we have and hypothesis.

[Edited on 2-5-2004 by Narnia]

To me everything has a life. There is a begining and a end.

reply to post by Imzadi


but a mule is a live isn't it? yet a mule doesn't cannot reproduce. The only way to make a mule is to cross-breed a horse and a donkey.

Also, bananas do not reproduce.

And about elimination of waste, a comment made by someone else, isn't that...essentially, self sustaining? to keep the system running. in ordder to stay "alive" or continue operating, waste must be eliminated.

i think there's a parralell universe in your head, there is only life here to deal with for you and I, if there was life on another planet, it would be extremely similar to the life on this planet, not so different that the beings would posses exeeding great knowledge which would dwarf mankinds awareness of his surroundings in that they would have the power to locate other worlds and even infiltrate the life on that planet to the degree that that life would be in immediate danger of being destroyed without any chance of living, and also be able to take in the intellegent beings of their conquest planet (that being the earth for that) hold them hostage sneek them unto their ship, take them unto another planet!, what a bunch of crap!, planets have a common denominator, they never contain actual life!, but this one is the property of the living God who sent his only begotten son, that who so ever bellieves in him will not perish but have everlasting life!, he cares so much and is so merciful that their is no life on other planets, at least that the life of either or would unholily commungicate with one another!?!?

i think there's a parralell universe in your head, there is only life here to deal with for you and I, if there was life on another planet, it would be extremely similar to the life on this planet, not so different that the beings would posses exeeding great knowledge which would dwarf mankinds awareness of his surroundings in that they would have the power to locate other worlds and even infiltrate the life on that planet to the degree that that life would be in immediate danger of being destroyed without any chance of living, and also be able to take in the intellegent beings of their conquest planet (that being the earth for that) hold them hostage sneek them unto their ship, take them unto another planet!, what a bunch of crap!, planets have a common denominator, they never contain actual life!, but this one is the property of the living God who sent his only begotten son, that who so ever bellieves in him will not perish but have everlasting life!, he cares so much and is so merciful that their is no life on other planets, at least that the life of either or would unholily commungicate with one another!?!?