What is the exact definition of life?

[Alberts]

We simply cannot deny that probability. Just as you now, people in ancient times did not believe the existence of bacteria and viruses. The Universe is infinite both in macro and micro perspective.

[JorgeLobo]

LOL - Try to understand - some of us are scientists. We don't engage in childish projections based on nothing but thin air and uninformed BS.

Give us even the slightest technical support for your foolish proposal - even the slightest.

[AstusAleator]

He called it an "imagination." I can't think of any great scientists that haven't had some sort of imagination.

I hope you've been warned for griefing.

[JorgeLobo]

No - he offered it as a probability that can't be denied - please read his post. He did NOT call it imagination.

[AstusAleator]

Ok, poor choice of words on his part when defending the magazine's hypothetical "imagination." Replace probability with possibility and there you have it, back to the realm of maybe/whatif.

Anyhow, I used to have the same sorts of thoughts when I was in middle/high school. In fact speculations like these were probably a large part of what drove me to learn more about physics, both atomic and astronomical. I don't see anything wrong with sharing thoughts like these - as long as one is not presenting them as fact from a supposed position of authority on the subject.

I'm not sure what you're looking for in your challenges and insults, but they don't seem to be accomplishing much.

If you're so concerned, really, then maybe give a brief synopsis (or long detailed if you prefer) of how the physical properties of atoms and galaxies differ - and why you think that the situation postulated by his magazine could not exist.

I'm just suggesting that it might be more constructive to inform than to ridicule.

[charles brough]

To have an effective definition of life does not require that it be "exact." Indeed, nothing is exact. We cannot even give an exact definition of a chair. A definition of life, it seems to me, must be what is subject to natural selection, has a life cycle and reproduces. If it does not do all three but only two out of three, perhaps it is "quasi-life." If only one, "pseudo-life."

[JorgeLobo]

LOL - I'll look for that in Websters.

[biohazard]

I have seen an interesting imagination from an magazine: There may exist a living form so small that they just live on the surface of electron; also there may exist a very large living form that our Galaxy just is an atom of their organism.

Etc.

I remember thinking the same at some stage. Apparently the universal tendency of things rounding other things becomes obvious to people at certain age, and then it's of course interesting to postulate that there could be universes in different "scales" because of this apparent logic: life on electron surface and stars being just electrons of larger systems.

Naturally when you then learn your physics bit more, the idea becomes a that bit naive. But what the hell, even if you are a hardcore scientist who only relies on solid reason, you should sometimes give your imagination a childish freedom. Who knows, maybe sometimes something more mature can be refined from those absurd ideas ;)

And of course, since you really cannot see what's inside a quark or a boson, who knows what small green men live there. You can freely call the idea stupid, childish, unrealistic or whatever, but you may still find yourself having a hard time disproving it!

[Alberts]

We have not discovered or could not made other forms of life ,such as extraterrestrial life, artificial life, life based on different matter, life on different scale (e.g. life on the surface of electron), not because they are not exist or are impossible to make, but just because our current technology of observing and making is extremely limited.
The probability of existence or making of those living forms raises a great challenge to the realm of theoretical biology and biophilosophy. Then defining life becomes more and more difficult.