Thanks,
but I also wanted to know connor's line of thinking on this, otherwise I'd just report.

Edit; And as I realize I haven't put 2 and 2 together while participating in his ban discussion, I should also note that I may not get a reply.

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Numbers are not case sensitive. (me)

No. Someones got to try and argue it: I think we'll find a lot of strange and beautiful things out there (and already have), I think we'll learn and change in ways we can't imagine now because of it.

I think its possible we'll never find anything we can easily recognize as 'life'. Our definition of life is too narrow (and too vague) to easily satisfy the majority ofpeople, and so whatever wonders the universe holds we may never cross the point where we can say 'We've found life'. Of course I may very well be wrong...

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I'M WRITING UP MY THESIS AND BECOMING A DAD SOON. I'LL BE BACK IN SUMMER TO AUTUMN 2010.

For me it's enough for the garden to be beautifull; why do so many want to see fairies at the bottom?

"Many of those people are not getting four when adding two and two; many of them aren't even getting five or twenty-two. They're getting potato."
Gillianren

I find it funny how we can continue a meaningful conversation and topic, even AFTER the original poster is banned.

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I don't think it was a permanent banning, but only through the election.

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I say there is an invisible elf in my backyard. How do you prove that I am wrong?

Disclaimer: Avatar is not an official NASA image and does not imply any specific interplanetary or interstellar capability.

The Leif Ericson Cruiser

Other Lifeforms Out There? Yes or No?

Yes

If so, why has there been no direct contact?

They all are still at unicellular stage.

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Fiction has to be plausible. Reality is under no such constraint.

Not to single you out, as many make this or similar statements regarding our inability to recognize alien life. The definition we have for life is the only one that is meaningful for us. There must be some bounds on what constitutes life, otherwise, why not say rocks are living or whole planets? Pretty soon everything is alive and then the discussion becomes pointless.

Our narrow definition is perfectly conducive to establish "life" as a rare and marvelous treasure; one worthy to seek out.

A constraint may be the ability to cooperate in the management of resources. Without said cooperation progress would be difficult if not impossible. The world that the life arose on would need to allow such cooperation.

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(By the way, I hate it that so many papers in the areas of planetary science and geology are not easily available to the dreaded "non-subscribers". It is like they are screaming at me: "YOU CAN'T HANDLE THE TRUTH". Good, I feel better now.)

"Quaerendo inventis"

I wouldn't be offended if you did single me out as this a tune that I sing a lot!

I don't disagree that we should have a definition to go looking with, but I have issues with the way life is defined: whatever definition you have in mind as being meaningfull to us I bet there are at least a few things that are commonly considered not alive that fit it, or a few things that are blatantly alive that don't, and that makes me uncomfortable.

And I seriously think it is possible that there is nothing alive out there, at least within the places we will likely explore in my lifetime.

I also think that if the rest of the universe is barren it doesn't make the chemistry of titans lakes less fascinating, or the great red spot less remarkable, or the history of phobos less mysterious, or the hexagon around saturns pole less stunning, or the power of the sun less awe inspiring.....all these beautifull and complex things are no less compelling to learn about if we don't find life.

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I'M WRITING UP MY THESIS AND BECOMING A DAD SOON. I'LL BE BACK IN SUMMER TO AUTUMN 2010.

For me it's enough for the garden to be beautifull; why do so many want to see fairies at the bottom?

"Many of those people are not getting four when adding two and two; many of them aren't even getting five or twenty-two. They're getting potato."
Gillianren

Rocks and planets do not decrease entropy.

My favorite definition of life is "something that uses energy to increase complexity", i.e. locally decreases entropy. This includes viruses and even computer viruses, but does not include rocks, planets, fire, or even computer hardware.

A stable self-replicating magnetic structure in Sun's corona would match this definition. But we would not recognize it even if we were looking straight at it.

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Fiction has to be plausible. Reality is under no such constraint.

(my emphasis)

Whould Would this definition include crystals?

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I may have many faults, but being wrong ain't one of them. -- Jimmy Hoffa

No. It may not look like that, but crystals are in a higher entropy state than solution they precipitated from. Notice I wrote "uses energy to increase complexity". Crystal growth is an exothermic reaction. It stops when solution is exhausted, and there is no way to increase the complexity by adding more energy to the structure.

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Fiction has to be plausible. Reality is under no such constraint.

I like that definition. How 'mainstream'/accepted is it?

From what I had seen, it is fairly common, but not universally accepted. OTOH, there is NO universally accepted definition of 'life"! I first saw this definition in a book published in 1980 (forgot the name, unfortunately), which was emphatically about "life as we don't know it". Each chapter covered a hypothetical planet (or star, or interstellar gas cloud) with life based on something other than carbon/water combination. Ammonia-based and hydrocarbon-based life each had a chapter, but as far as the author was concerned, those were mundane ones-- still chemistry-based. Really strange ones were life based on interacting magnetic fields, or on spin states of atoms in solid hydrogen.

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Fiction has to be plausible. Reality is under no such constraint.

I've suggested elsewhere, in a fictional context, that the early universe contained lifeforms, even a civilisation, based on strings and other topological defects. The first few fractions of a second in our universe's hstory included a lot of very complex events, wich happened very rapidly indeed; everything that has happened since is an epilogue.

Do I believe it? No; but it is at least as bizarre as lifeforms in stars.

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New Orion's Arm Site . The Starlark . Against a Diamond Sky (OA Novella Collection) . OA Flickr set

And looking from the other end of time, long after proton decay plus expansion of the universe reduced all matter to electron-positron plasma, it is possible to imagine "matter" and, conceivably, living creatures, made out of electron-positron pairs. IIRC, each such electron-positron "atom" (also known as positronium) would be larger than current visible universe, and would complete one revolution in 10¹¹⁴ years. From the viewpoint of such positronium beings the entire era of stars, planets, and black holes[1] is just a detail of Big Bang -- an unimaginably short burst of complexity among exotic ephemeral particles.

[1] Since all black holes, even galaxy-mass ones, will evaporate via Hawking radiation in far less time than one revolution of a positronium atom

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Fiction has to be plausible. Reality is under no such constraint.

I like that one to, but which side of the line does a hurricane fall? It's a stable structure, that uses heat energy drawn from the the ocean to create and maintain itself. It doesn't reproduce but as it grows and it's structure becomes better defined it is certainly increasing in order and complexity.

It might be argued that a hurricane is a structure that results from the flow of energy from the sea to the air, but that seems to me like a chicken and egg argument. Besides, can anyone show that life is a decrease in entropy that uses the flow of energy, rather than one that results from a flow or imbalance of energy that was there anyway? It doesn't seem like a clear cut thing to me.

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I'M WRITING UP MY THESIS AND BECOMING A DAD SOON. I'LL BE BACK IN SUMMER TO AUTUMN 2010.

For me it's enough for the garden to be beautifull; why do so many want to see fairies at the bottom?

"Many of those people are not getting four when adding two and two; many of them aren't even getting five or twenty-two. They're getting potato."
Gillianren

Here is a nifty discussion on the related topic on Peter Watts (biologist and SF writer) blog: The Living Dead (Candidatus Desulforudis audaxviator)

[Edit] Warning: Peter Watts and his commenters use a lot of not-family-friendly words

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Fiction has to be plausible. Reality is under no such constraint.

Love this paragraph:

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Fiction has to be plausible. Reality is under no such constraint.

Good question. The plot thickens. This article here, gets around this by saying:(my highlights) In other words, hurricanes can be defined away

And from the wiki page a more modern take:
Ilya good link/article. Thanks. But what's with the all black backgrounds?

You're welcome. And yes, I find black background annoying. Apparently some people complained, so Peter Watts took a poll of his regular commenters -- and most of them preferred it that way! So he kept the black background. Go figure.

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Fiction has to be plausible. Reality is under no such constraint.

I like Ilya's decreasing entrope definition, but also feel that reproduction is essential to the definition of life and so the collective entity should outlive the individuals from which it is comprised.

The positronium universe is an interesting idea.
One caveat; I don't think proton decay is currently mainstream physics;
http://en.wikipedia.org/wiki/Proton_decay

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New Orion's Arm Site . The Starlark . Against a Diamond Sky (OA Novella Collection) . OA Flickr set

On jupiter storms persist and maintain their structure for centuries, thats pretty long term! ( Menacingly storms on jupiter also consume smaller storms, apparently to sustain themselves).

Large storm systems also tick another box on the GCSE biology list of whats alive: many large storm systems seem to maintain a degree of homeostasis, on earth hurricanes within their eye , on jupiter the interior of the great red spot is actually a pretty placid place.
From that article: .

The reason there is more bubblegum on the pavement than dust or cigarrette butts is that nature selects bubblegum to stay because its sticky and plastic so it forms a low profile. These properties are determined by bubble gums chemical makeup, which is a form of information, so the information content of the pavement has been altered by natural selection but bubblegum is not alive!

I suppose the point I'm trying to make was best put by Veeger earlier: Having thought about it i'm of the opinion that it may be pointless, and that the universe may be of such complexity and diversity in the kinds of systems and phenomena it gives rise to that trying to put a hard limit on whats life is doomed to failiure.

He is kinda blue isnt he! Good link, despite what i've put above I could easily imagine such a creature surviving beneath the surface of mars today.

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I'M WRITING UP MY THESIS AND BECOMING A DAD SOON. I'LL BE BACK IN SUMMER TO AUTUMN 2010.

For me it's enough for the garden to be beautifull; why do so many want to see fairies at the bottom?

"Many of those people are not getting four when adding two and two; many of them aren't even getting five or twenty-two. They're getting potato."
Gillianren

No, he is white on black.

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Fiction has to be plausible. Reality is under no such constraint.

Is there life out there? Probably. Why hasn't it come here (during the short time we've been around and/or actively looking)? Why would it? And how do we know it hasn't, and we simply didn't know enough at the time to recognize it?

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"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
"The Mayan symbol for "book" looks a lot like a triple hamburger, but I've never seen them claiming it as proof the Mayans had Big Macs." - KaiYeves
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort