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MajorRawne

Life on other worlds

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A question. EDIT: Followed by loads of questions.

Why do scientists believe that life can only exist on worlds like Earth? Isn't that like a Scottish person believing that men from other countries can only have ginger hair?

Ok, sorry for the analogy :P

What happened to diversity? Why can't they seem to accept life-forms could be made of gas or silicon or some kind of substance we've never encountered? Why would the rules that apply in our corner of the galaxy apply to a galaxy ten billion light-years away? How do they explain that at least one galaxy we've observed is too big to exist according to our current understanding of physics?

Doesn't anyone else love the way our scientists look at what's in their immediate reach and declare that is all there is? I'm sure the first humans said something similar when they reached the shore and looked out across the ocean.

Here's a rather awesome (but timelineable) link as you ponder these questions:

http://htwins.net/scale2/

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MajorRawne said:

Why do scientists believe that life can only exist on worlds like Earth? Isn't that like a Scottish person believing that men from other countries can only have ginger hair?

Are you sure they even do? There's the notion of the "Goldilocks zone" but that seems to be as much about finding planets that humans might one day be able to inhabit, as it does finding other forms of life.

It seems obvious enough that life on this planet is adapted to this planet, and that if life existed on other planets it will be adapted to those planets, and potentially very different.

I guess at the very least you could argue that we only have one data point (our own planet). So while life might or might not be able to develop in different conditions, it definitely can develop in conditions that are similar to our own, and planets which have similar conditions are therefore worth investigating.

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First, scientists need to come up with a theory proving -at least on paper- that other kinds of lifeforms are possible/plausible under specific circumstances. Then they must also provide proof of said life's existence, if they want to shut the skeptics up. The problem is that in this field, the skeptics are usually religious and political figures, not fellow scientists, so formal proofs (or even an actual specimen) might still not be enough.

The first part can be justified on paper by proving how a hypothetical life form would fullfill the usual four criteria for classifying something as a life form -the one necessary condition being the ability to reproduce, as moving, reacting and feeding can also be fulfilled by machines, while reproduction implies the other three, to some degree. I would add that the ability to manipulate the physical world is necessary, otherwise even computer virii could be considered life forms. Even real virii are considered a borderline case in this respect -they are more like nanomachines than life forms.

In any case, the first part is only a pretty weak assumption/postulate ("A life form with characteristics X, Y and Z could exist through mechanisms A, B, and C"), and thus only necessitates a weak proof.

So e.g. if they prove on paper how a silicon-based crystal being might at least gather energy and resources to reproduce itself while staying intact inside the liquefied crust of the earth, then that would be a plausible mechanism for life. Even if such a life form doesn't exist (yet).

The second part however is the hardest: providing actual proof that such a life form actually DOES exist. Being theoretically possible doesn't mean it actually does exist anywhere. E.g. there's no debate that carbon-based life forms on Earth-type planets are possible, because we have plenty of tangible proof. Or that even sulphur-based life under more extreme conditions is possible, again because we have tangible proof of that. A strong claim ("Life form X EXISTS" requiring a pretty strong proof (a specimen).

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I saw - a few years ago - a program by Stephen Hawking on this subject. It's been a while, I'll see if I can find a link..but I recall suggestions that Jupiter could be inhabited by creatures made of gas, and a yak-like thing on Pluto with extremely thick fur.

EDIT: It's not great, but here's the gas creatures..

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Why do scientists believe that life can only exist on worlds like Earth?

Probably few scientists hold such an absolute position. Rather, many scientists would consider Earth-like worlds more likely to harbor life than Earth-unlike worlds for the simple reason that we know one example of an Earth-like world with life and don't currently know any example of an Earth-unlike world with life.

A more technical argument is that any form of life must depend on chemistry (or plasma gas dynamics or whatever) that is complex (and stable) enough to sustain it. According to our current understanding of chemistry, carbon is by far the most versatile element when it comes to forming complex, stable molecules, and it does so under conditions that occur on Earth's surface (with liquid water, etc.). This makes Earth-like carbon-based life the most plausible candidate for life elsewhere in the universe. Other forms of life can by no means be ruled out entirely, but until we are able to actually observe them, or create them ourselves in the laboratory, it's just speculation.

Why would the rules that apply in our corner of the galaxy apply to a galaxy ten billion light-years away? How do they explain that at least one galaxy we've observed is too big to exist according to our current understanding of physics?

I don't know anything about the particular observation you're referring to, but yes, there are several unresolved problems in astrophysics (and other branches of physics, for that matter). The best answer is probably "they're working on it" or "they don't yet have enough data to come up with a satisfactory theory".

We can't know for sure that the laws of physics that we observe here on Earth are valid everywhere in the universe. We do have a lot of confidence in the current fundamental theories because they have withstood an enormous amount of experimental testing, across scales varying by many orders of magnitude. Supplanting them will require very good evidence.

Moreover, a good reason to believe that the rules are the same is that we can observe galaxies (or the cosmic background radiation) and find that they look more or less the same in all directions. Even if our understanding of physics at large scales needs revision, there's no reason to expect that the universe should behave differently far away if viewed locally, zoomed in just a bit further than what we can currently do. We can always speculate, but without evidence, Occam gets to work his razor.

Doesn't anyone else love the way our scientists look at what's in their immediate reach and declare that is all there is?

Strawman scientists perhaps. Few people are as eager as actual scientists to look beyond what we already know. It's true that scientists mostly look at what's in their immediate reach, but that's unavoidable. Most scientific progress happens in very small increments, not because scientists don't have greater ambitions, but because research is hard. There are many more possible scientific theories than there are correct ones, and the only reliable way to expand our knowledge one small piece at a time.

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Wow, excellent replies gents, thanks :)

Fraggle: Excellent points, and I was kidding about the Scottish :P

Maes: While the basic diagnostic criteria work fine with humanity's current experience, I have a couple of questions. When/if we create artificial intelligence which is self-aware, is capable of thinking for itself and has the same or higher IQ than a genius-level human, would they then be considered alive - or would they never be considered alive as they are not biological and/or were not "made by God" or do not have "souls"?

If such beings were restricted so they couldn't reproduce themselves, but regarded themselves as alive, what would be the difference between them and us? Can we measure the "spark of life", and can we say that machines don't have souls when we can't prove we have them?

By reproducing, wouldn't that simply mean building another machine? We are provided the natural tools to create new human lives, I suppose the difference is machines would have to make the tools themselves - it would be artificial conception. If we gave them those tools, would we be God?

This is just one aspect of a super-science that we don't need yet -- I just wonder what will happen to contemporary science if the universe does provide us with something new. (There are other complications too. What if a machine knowingly sacrificed itself to save a human, or dedicated itself to exploring the mysteries of the universe to try to find God, or loved the philosophy of meaning, or wanted to become a doctor but lacked the software/hardware...)

Eris: Nice, thanks. Imagine if something like this was discovered in our lifetime. I sometimes wonder if life on earth will grind to a halt for a couple of weeks when/if we discover alien life - then after those weeks, life would go back to normal, the papers would be full of sleazy celebrities and scandalous politicians again and basically nobody would care. Humanity's "who cares if it doesn't directly affect me" attitude would come to the rescue.

Enjay: That was very relevant. Does anyone else wonder at the accuracy of these equations? They seem to be based on finding life like ours on worlds like ours. I have heard lots of theories about black holes and supervoids leading to different dimensions or realities. Wonder what would happen with the equation if they could take that lot into account. Just think, in at least one reality, humanity never went through the dark ages and we probably sent our first manned ship outside the solar system.

Fredrik: I can't find the reference either, I read it on the net so it probably isn't canon. I suppose my view of scientists is tainted; I love sci-fi and watch a lot of documentaries about weird and wonderful things, and no reputable scientist will come on the shows except to debunk things. It's a bit of "don't mess with the fantasy" I think.

HP Lovecraft takes a refreshing approach. He wondered what would happen if the rules of physics etc only applied here, in a limited region of the universe. The creatures of his mythos are beings who belong to the "true" universe. Their magic is actually the galaxy's underlying science. It seems nightmarish and chaotic to humans as our brains are evolved to work here, not out there, and we cannot interpret or safely use mythos science. That explains why some of our weapons and technology won't work against some of them: it's designed to work against us, and we're fundamentally different. The only way to defend ourselves is to hide from the universe or turn mythos technology against its creators, sacrificing our sanity and physical health in the process.

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On Earth we've already discovered things such as waterbears, which can live in/survive practically everything and things like non-carbon-based life aren't being dismissed out of hand, just presumed highly unlikely. So, in theory, there could be things out there beyond our imagination. Humanity just won't find them in our life time.

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I'm of the belief that when (not if) we discover that we're not alone in the universe, a lot of people are going to be disappointed by the initial finds: microorganisms.

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DoomUK said:

I'm of the belief that when (not if) we discover that we're not alone in the universe, a lot of people are going to be disappointed by the initial finds: microorganisms.

That depends. What if the microorganisms can produce oil?

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Fredrik said:

That depends. What if the microorganisms can produce oil?

Great for us all if we can harvest it and transport it back to earth. Still a disappointment for people expecting something we can converse with.

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DoomUK said:

I'm of the belief that when (not if) we discover that we're not alone in the universe, a lot of people are going to be disappointed by the initial finds: microorganisms.

Well, I'd be thrilled imagining and hoping that those micro-organisms might have a chance of being the cures to diabetes and cancer that we've been seeking for so many centuries.
So yeah, there's always an advantage to counter a disadvantage, and there's always a disadvantage to counter an adventage. It's a two-faced universe. ;)

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MajorRawne said:

Maes:While the basic diagnostic criteria work fine with humanity's current experience, I have a couple of questions. When/if we create artificial intelligence which is self-aware, is capable of thinking for itself and has the same or higher IQ than a genius-level human, would they then be considered alive - or would they never be considered alive as they are not biological and/or were not "made by God" or do not have "souls"?

This is a very subjective question. Considering there's no evidence of a "soul" so to speak (rather, your personality is dynamically created within your brain) I'm of the opinion that humans and, say, computers aren't really different at all. Sure, we're a lot more sophisticated than any machine we could currently make, but we're still a form of programming language in its own right (DNA) and capable of self-modification (evolution). We're just computerized robots that uses carbon builds to transport ourselves and find our own power supplies instead of being fed power directly (via a wall outlet, for example.)

DoomUK said:

I'm of the belief that when (not if) we discover that we're not alone in the universe, a lot of people are going to be disappointed by the initial finds: microorganisms.


Honestly, I hope we find evidence of microbes all over our solar system--because I'm fairly confident that life is incredibly widespread like that when considering the diversity of our own local Earth life. Anyone who is disappointed with the first sightings being microorganisms is just ignorant of how important such a discovery is.

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188DarkRevived said:

I never deny the possibility of there being cybernetic lifeforms who are capable of functioning without oxygen. It's always cool to imagine with an open mind.

I'm pessimistic about the chances of humans ever leaving our solar system. I suspect that if anything ever travels to other star systems, it will be artificial intelligences of our creation, which will be able to better survive the harsh environment and long timescales needed to make such a journey.

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eargosedown said:

I'm of the opinion that humans and, say, computers aren't really different at all. Sure, we're a lot more sophisticated than any machine we could currently make, but we're still a form of programming language in its own right (DNA) and capable of self-modification (evolution). We're just computerized robots that uses carbon builds to transport ourselves and find our own power supplies instead of being fed power directly (via a wall outlet, for example.)

Self-modification is not evolution. Robots would reproduce neither sexually, asexually or even with virus-like replication. A robot could built a replica of itself, but it could just as easily build anything else or...nothing at all. Robots have no agency and even if they did, they have no motivation to do anything really. Certainly not moved by hunger, avoidance of pain, seeking of saftey and shelter or reproduction.

I find the notion of a robot with honest intelligence and maybe even self-realization and free-will to be rather silly tbh.

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188DarkRevived said:

Well, I'd be thrilled imagining and hoping that those micro-organisms might have a chance of being the cures to diabetes and cancer that we've been seeking for so many centuries.
So yeah, there's always an advantage to counter a disadvantage, and there's always a disadvantage to counter an adventage. It's a two-faced universe. ;)

eargosedown said:

Honestly, I hope we find evidence of microbes all over our solar system--because I'm fairly confident that life is incredibly widespread like that when considering the diversity of our own local Earth life. Anyone who is disappointed with the first sightings being microorganisms is just ignorant of how important such a discovery is.

You're both completely right of course.

But admit it, there's something about the possibility of another sentient species of creature in the (perhaps unreachable) depths of space that puts a smile on your face and ignites the imagination, in a way that neither philanthropic thoughts or "smaller" scientific discoveries just can't compete with.

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Not enough futurists around here. Everybody's looking for us to die out as a species without space travel, strong AI, etc. Blah :P

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Quasar said:

Not enough futurists around here. Everybody's looking for us to die out as a species without space travel, strong AI, etc. Blah :P

Yeah, sometimes I feel as if people are just wishing to tie me and burn me up like some kind of warlock. LOL
Anyways, there's bound to be some kind of Elfish/Vulcan/Romulan type of race similar to our homosapien kind somewhere out there. There's definitely bound to be. I only doubt that I'll see them up close and personal within my ticking lifetime, as I already stated in another thread similar to this one. If I do live up to that moment then it'll be a dream come true, of course.

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188DarkRevived said:

Well, I'd be thrilled imagining and hoping that those micro-organisms might have a chance of being the cures to diabetes and cancer that we've been seeking for so many centuries.

I'll be less than thrilled if those micro-organisms get loose and discover we're delicious. :(

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GreyGhost said:

I'll be less than thrilled if those micro-organisms get loose and discover we're delicious. :(

If that becomes the unfortunate case then eventually there's bound to be antidotes/antibodies of some kind for fighting the invading microscopic pests. But it would be a question of time, and several lives could be lost by the end of the search. :/ I really don't like thinking of the worst-case scenarios. Too unpleasant to do.

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Quast said:

Self-modification is not evolution. Robots would reproduce neither sexually, asexually or even with virus-like replication. A robot could built a replica of itself, but it could just as easily build anything else or...nothing at all. Robots have no agency and even if they did, they have no motivation to do anything really. Certainly not moved by hunger, avoidance of pain, seeking of saftey and shelter or reproduction.

I find the notion of a robot with honest intelligence and maybe even self-realization and free-will to be rather silly tbh.


Sure it is self modification. aspects of organisms constantly mutate, and ones that work in the organisms favor will continue on. It's almost like a brute-force method of becoming a better organism. Our form of sexuality is, in a sense, encouraging a set of carbon blueprints to form while feeding the new organism the energy it needs to construct itself.

They're not constructed with the same drives of life, of course, but there's no reason such couldn't be developed. For example, humans have already programmed simple robots that avoid things (hell, even those little vaccuum things that slide around using sensors to avoid walls and stuff) so it's not a far stretch to assume that the innate programming in life couldn't be extended to a mechanical orgasm.

It's a broad common theme between the two. I'm in no way saying that we'll be able to ever make robots that are as self aware or advanced as humans or some such thing, but moreso that the difference between life and an the computers and machines we produce to solve tasks are very similar in their overarching design. To assume that humans or any other creature has some innate special attribute ("soul") that makes it life is an abstract line to draw, especially when keeping an open mind to our sample size of life is just one.

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eargosedown said:

I'm in no way saying that we'll be able to ever make robots that are as self aware or advanced as humans or some such thing

When my car's petrol tank is running low, a little warning light comes on on the dashboard. My phone and my PC and various other devices around the house also have some rudimentary "knowledge" of themselves to maintain normal operation, even if they rely on me to fix them when something goes wrong.

Simplistic examples, but self-aware machines are kind of already with us. If you throw the whole "soul" idea out of the window, what human beings amount to are no more than rather complicated machines, which have to be instructed at an early age about who we are, how to avoid danger etc. Is it completely inconceivable that the level of introspection that we have couldn't at least be mimicked in something else to a shocking degree of accuracy?

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MajorRawne said:
http://htwins.net/scale2/

This was quite nice presentation of how small we really are, and the opportunities in the universe. :)

Not enough futurists around here. Everybody's looking for us to die out as a species without space travel, strong AI, etc. Blah :P

I highly doubt that we can really traverse in space, between the systems or even galaxies, not even in millenium, if this current rate keeps going.
Would be milestone, if human lands to Mars in this century, if I dare to say so.

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DoomUK said:

Is it completely inconceivable that the level of introspection that we have couldn't at least be mimicked in something else to a shocking degree of accuracy?


In general? Not at all. I'm sure if life is as common as I expert it to turn out to be, humans will just be another run of the mill sentient species in the universe. For us to make robots that can compete in all levels of introspection and sophisticated contemplation of the world, though, would be akin to us making an artificial human brain--something that I am not certain we'll be able to achieve to the same complexity, at least not in the near future for sure.

The alternative in our immediate realm for us to encounter non-DNA based sophisticated organisms would be through producing something "artificial" that has the basic concepts of drives that life has--a drive to find energy sources so it can reproduce and multiply. In other words, make something and give it a chance to evolve. The problem with that approach to "playing god" is that if evolution of the new organism started takes as long as it did for life on Earth, it'd be a very long time and a lot of chance-work that it'd ever achieve a similar sentience to humans. It'd be a very cool experiment though.

CorSair said:

I highly doubt that we can really traverse in space, between the systems or even galaxies, not even in millenium, if this current rate keeps going.
Would be milestone, if human lands to Mars in this century, if I dare to say so.


I concur. I am of the opinion that without a major readjustment to our scientific knowledge of physics, we'll never reach efficient stellar or intergalactic travel. The human species may be forced to expand via slow-travel.

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I agree microorganisms will likely be the first life forms found elsewhere. This is mostly why life on earth will return to normal just a few days after the discovery is announced - unless of course the governments decide to cover it up for some reason. I also believe things will return to normal quickly if we discover advanced life and they are either neutral towards us, or friendly but unable or unwilling to come to us.

Of course, if we discover the Klingons or the Tyranids, everyone on the planet would need to join the armed forces or become scientific researchers to have a hope of defending our world.

I believe that aliens do not necessarily have the aggressive tendencies we do - since few or no other animals on earth behave as violently and murderously as we do - and I don't think many out there would want to start a fight. Why would they come here for resources when we would fear them, probably hate them and possibly end up nuking ourselves to deny them our planet? They could just go somewhere else.

Besides, the "space brothers" (Pleiadeans - and I spelled that right first time, hooray!) reported in the 60s and 70s were reportedly coming here to warn us about ourselves, so if this is even remotely true, not everyone in space is a dickhead.

There are a few doom-and-gloomers who believe we won't leave our solar system, just as cavemen believed they would never leave the grassy plains next to their caves, and the first fishermen never thought we would cross the sea. I tend to put this type of thinking in the "we'll never cure schizophrenia, we'll never cure the cold, we'll never learn to live in space" category of nay-saying.

Thinking from our limited success in all of these fields, of course it's hard to imagine doing these things, but those who say it can't be done are simply getting in the way of those who are going out every day to do it.

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188DarkRevived said:

there's bound to be some kind of Elfish/Vulcan/Romulan type of race similar to our homosapien kind somewhere out there. There's definitely bound to be. I only doubt that I'll see them up close and personal within my ticking lifetime

Or, for that matter, within humanity's lifetime. It's something that I feel is often overlooked in these discussions, that for the time the universe has been in operation humankind might come and go within the space of an additional hundred thousand years, or maybe less. Even granted a long and prosperous existence nearing five or six times that number (perhaps as another species evolved from this one, lest technology says otherwise), that still leaves a lot of lifeless period during which multiple civilizations might have come and gone.

So yeah, I think the likelihood of finding other intelligent life is as dependant on our coinciding with theirs as it is on their being within distance. Those two factors combined diminishes our chances somewhat... but I always love surprises!

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^Yes, that is all very true! And it crosses over into another somewhat related topic... That at some point in time the only way for our species to avoid extinction might be either to:

1.) reallocate ourselves to a different planet due to the fact that our Sun will eventually expand from a yellow-dwarf classification to some super-yellow-giant classification before eventually burning out;
-OR-
2.) artificially create a new yellow-dwarf Sun / learn how to reverse or slow down or otherwise control the aging process of our Sun;
-OR-
3.) genetically modify ourselves to prevent our tissue from being burned by our newly expanded super-giant Sun

Of course, it's hard to predict or say for certain when or whether our species will be lucky to achieve such solutions. And it's also unknown whether such solutions were already successfully carried out by other species somewhere within our astral neighborhood, but complete doubt isn't good to have either. :p

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eargosedown said:

Sure it is self modification. aspects of organisms constantly mutate, and ones that work in the organisms favor will continue on. It's almost like a brute-force method of becoming a better organism.

Semantics I suppose, but when you say 'self-modification' I picture an individual organism 'modifying' itself. Which of course isn't evolution. Populations evolve, not individuals.

They're not constructed with the same drives of life, of course, but there's no reason such couldn't be developed. For example, humans have already programmed simple robots that avoid things (hell, even those little vaccuum things that slide around using sensors to avoid walls and stuff) so it's not a far stretch to assume that the innate programming in life couldn't be extended to a mechanical orgasm.

Creatures that lack brains even are more complex than trying to compare what they do to a string of if/else statements let alone those that do have brains.

And putting aside that, how could one possibly give anything real agency? How do you give it the desire to reproduce? And by what mechanism? You can't possibly program those things. And these hypothetical robots would be dependent on us to do just that. A little robot vaccuum that turns 90 degrees when it bumps into wall does not and will not ever have the gumption to leave your house in the pursuit of its own life, liberty and happiness in whatever form that may take. Not to mention it can't open the front door or communicate to you its desires or even if it understood that you ought to be communicated to in the first place anyway...

but moreso that the difference between life and an the computers and machines we produce to solve tasks are very similar in their overarching design. To assume that humans or any other creature has some innate special attribute ("soul") that makes it life is an abstract line to draw, especially when keeping an open mind to

I would define life as anything that extracts nutriment from its environment of its own accord and has the capacity to reproduce wherein it passes on a slightly modified version of it genetic code. All life also has a role to play in its environment helping shape and make its biosphere what it is. Robots don't have an environment and they don't play a role, not predator, prey or parasite.

The supernatural is not needed here as well.

our sample size of life is just one.

While this is technically true, life on earth is varied enough in just about every aspect you might think to kind of disagree a little. Not all life, but in fact most life doesn't follow. Viruses in particular are quite exotic in that regard. But it stands to reason that life anywhere is probably going to follow some basic rules which involves having a food source it can exploit and the ability to reproduce and evolve. Everything else is fluff really. It doesn't matter how weird life might appear.

188DarkRevived said:

3.) genetically modify ourselves to prevent our tissue from being burned by our newly expanded super-giant Sun

The earth will be consumed by the upper atmosphere of the sun when this happens. 10s of millions of years beforehand however the earths atmosphere and oceans will have long since boiled away.

Sunburn will be the least of our worries I assure you.

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