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Old Jul 24th 2016, 10:10 AM
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Default Extraterrestrial Life

A friend and I were talking about science fiction, the future of space exploration and the possible future human colonization of the universe.

Being the cynic that I am, I suggested that the most likely way for life on earth to colonize the universe would be when our sun eventually goes supernova and explodes, which would blast our little earth to itty-bitty pieces. Those little pieces of earth would then become a bunch of meteorites and asteroids spreading through space - some of which could/would carry little bits of frozen bacteria from earth. When those asteroids or meteorites impact another body in space, if conditions are ripe for it, bacterial life from earth could act like a seedling to pollinate life on that planetary body. Exploding earth would probably make many millions of such asteroids and meteroites so the odds are that at least some of those asteroids and meteorites would eventually collide with some other planets.

And that concept got me thinking that the whole universe could thus be envisioned or imagined as an eco-system in itself, with life spreading and propagating itself from planet to planet via exploding planets when stars go supernova. Such a system of fertilization/pollinization would be not unlike how wild grass spreads and pollinates via the wind here on earth (albeit at a bit slower pace).

If this is so, it would therefore be reasonable or probable to expect that the universe would be filled with a vast and almost infinite variety of life-forms and ecological life-cycles on countless planets, even if [figuratively] 99% of all planets are barren of all life-forms.

Just some food for thought on a Sunday morning. Consider this an open thread for discussing all things sci-fi-ish, spacey or futuristic.
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Old Jul 24th 2016, 10:41 AM
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Default Re: Extraterrestrial Life

I believe there must be other sentient civilizations out there. It is too improbably that we are the only ones and that Earth is the only planet, out of billions, that can sustain life. There must be others.
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Old Jul 24th 2016, 01:51 PM
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Default Re: Extraterrestrial Life

I read an interesting short story recently which was premised on two things:
1. through biological science human beings had ended aging and developed quick cloning
2. through engineering science human beings had developed an implant that connected everyone's consciousness to an internet like network across space. one could even download one's consciousness to the network and then transfer it to another cloned body on another planet, leaving your other body in storage while you explore.

Basically, space exploration in this setting either happened in non-relativistic speeds because, hey, everyone lives forever so who cares how fast you get there, or happened by people shipping a cloning vat and network to another world and then people downloading themselves there.

Overall I found it to be a really intriguing way to get around the whole "faster than the speed of light by altering the laws or physics or magic space rocks" trope that most Science Fiction has.
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Old Jul 24th 2016, 06:42 PM
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Default Re: Extraterrestrial Life

Quote:
Originally Posted by Michael View Post
A friend and I were talking about science fiction, the future of space exploration and the possible future human colonization of the universe.

Being the cynic that I am, I suggested that the most likely way for life on earth to colonize the universe would be when our sun eventually goes supernova and explodes, which would blast our little earth to itty-bitty pieces. Those little pieces of earth would then become a bunch of meteorites and asteroids spreading through space - some of which could/would carry little bits of frozen bacteria from earth. When those asteroids or meteorites impact another body in space, if conditions are ripe for it, bacterial life from earth could act like a seedling to pollinate life on that planetary body. Exploding earth would probably make many millions of such asteroids and meteroites so the odds are that at least some of those asteroids and meteorites would eventually collide with some other planets.

And that concept got me thinking that the whole universe could thus be envisioned or imagined as an eco-system in itself, with life spreading and propagating itself from planet to planet via exploding planets when stars go supernova. Such a system of fertilization/pollinization would be not unlike how wild grass spreads and pollinates via the wind here on earth (albeit at a bit slower pace).

If this is so, it would therefore be reasonable or probable to expect that the universe would be filled with a vast and almost infinite variety of life-forms and ecological life-cycles on countless planets, even if [figuratively] 99% of all planets are barren of all life-forms.

Just some food for thought on a Sunday morning. Consider this an open thread for discussing all things sci-fi-ish, spacey or futuristic.
Couple of issues with your scenario.
First is that our Sun cannot go supernova. It's not massive enough for that. A star needs to be above the Chandrasekhar limit for that which is at 1.44 solar masses. Our precious Sun will go red giant and eventually become a white dwarf. The explanation on Wiki is pretty good.

Secondly, a supernova is an event which is very hard to describe. When it happens a single star can outshine an entire galaxy. The amount of energy released is just beyond description. It's an incorrect analogy but think of it as an atom bomb the size of a star. Nothing in such a system beyond single ions survives that. So for the propagation of existing life forms it's the worst method imaginable.

But ironically, supernovas are actually the mechanism by which heavier elements, which are only produced in stars, are spread throughout galaxies. And those elements are indispensable for life forms, at least any we know or can conceive of. So supernovas do participate in a life cycle but only at the most fundamental level and never in the propagation of actual species. That's quite impossible.
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Old Jul 24th 2016, 06:55 PM
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Default Re: Extraterrestrial Life

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[snip]
2. through engineering science human beings had developed an implant that connected everyone's consciousness to an internet like network across space. one could even download one's consciousness to the network and then transfer it to another cloned body on another planet, leaving your other body in storage while you explore.
Howard Philips Lovecraft used that idea in The Shadow out of Time (1936!).
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Old Jul 24th 2016, 07:57 PM
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I believe there must be other sentient civilizations out there. It is too improbably that we are the only ones and that Earth is the only planet, out of billions, that can sustain life. There must be others.
Yes, but there is an ever increasing problem with that which is expressed in Fermi's Paradox. Simply put: if that is correct, then where is everybody?

This is a bigger problem than one would think at first sight. We can say that we've been listening to what's out there for some 50 years with no results. Most people will understand that this means that in a sphere with a 50 light year radius, centered on Sol, no indication of intelligent communication is present. But it's actually worse than that. It actually means that in the entire past light cone of that sphere no indication of intelligent communication has taken place. For instance, we should also detect such a communication if it originated from a source e.g. 5000 light years away 4950 to 5000 years ago or from a source 24120 light years away 24070 to 24120 years ago. That narrow band of potential sources where a range of 50 years is observed in a 13.5 billion year old universe is of course very narrow but at the same time it does stretch in all directions and makes a pretty good random sample. Now, while there are certainly a number of reasons why such communications wouldn't have reached us (signal not energetic enough, redshift, interstellar dust, the supermassive black hole in the center of the Milky Way, etc, etc), the fact remains that we have heard and hear nothing. If our galaxy is teeming with life, it's very silent life.

The longer it takes to at least hear something rather than nothing the lower the probability of extraterrestrial life, at least life which uses technology.

That concept of technology leads to another paradox which only adds to the former one. The thing is that any life we know, and one can easily argue that this is a necessary aspect of life of any kind, is that it grows exponentially when given the opportunity. Now imagine that at some point in our past, a civilization anywhere in our galaxy reached the point where it could colonize other systems than its own. Even if it started slow with e.g. one colony a century, at some point the first colonies would start sending their colonies and start the typical exponential growth curve. I'd have to do the maths but I estimate that as little as 10 million years would be plenty to colonize all colonizable star systems in the entire galaxy. Since that hasn't happened we are forced to conclude that no civilization has ever achieved this point in our galaxy.

If one wants to see or meet aliens, the prospect is actually looking grim. The longer the galactic silence lasts, the more Ockham's razor suggests that either interstellar travel is impossible regardless of technological level and/or technological civilizations don't last long enough to really spread. My money is on both these possibilities actually. The first because science and the second, well, just look at what homo sapiens sapiens is doing with its technology.
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Old Jul 24th 2016, 08:58 PM
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Default Re: Extraterrestrial Life

While Dominick's technical analysis is on point, this is funnily similar to how Star Trek (unecessarily in my opinion) tried to explain why we magically run into humanoids everywhere we go.
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Old Jul 26th 2016, 06:46 PM
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Default Re: Extraterrestrial Life

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While Dominick's technical analysis is on point, this is funnily similar to how Star Trek (unecessarily in my opinion) tried to explain why we magically run into humanoids everywhere we go.
As far as I'm concerned, Star Trek's most egregarious error was the way they beemed down (the captain and top officers of the crew) onto every single planet they came across. No protections, no space suits, no oxygen masks, nothing. That is so far from any kind of realism that it made me laugh when I was a kid. That always struck me as even more fantasy-fake than the magic gravity machine that everyone had on every ship.
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Old Jul 26th 2016, 10:08 PM
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Default Re: Extraterrestrial Life

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As far as I'm concerned, Star Trek's most egregarious error was the way they beemed down (the captain and top officers of the crew) onto every single planet they came across. No protections, no space suits, no oxygen masks, nothing. That is so far from any kind of realism that it made me laugh when I was a kid. That always struck me as even more fantasy-fake than the magic gravity machine that everyone had on every ship.
Oh the "transporter" was totally ridiculous in any number of ways. Among other things, it should have been the ultimate weapon system. Why would anyone ever fire a "photon torpedo" when you could just "beam" the warhead directly into the enemy ship (or at least beam it right next to their shields).

But the truly silly part has to do with what you're talking about: beaming people from one place to another. Truth be told, if you can actually perfectly re-assemble a specific person at some remote location, you might as well try it first without worrying about protective gear. If it goes badly, so what? As long as you kept a copy of the pattern and have the material to spare, you should always be able to assemble another one...or another thousand, for that matter.
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Old Aug 30th 2016, 06:51 PM
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Default Re: Extraterrestrial Life

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Originally Posted by Dominick View Post
Yes, but there is an ever increasing problem with that which is expressed in Fermi's Paradox. Simply put: if that is correct, then where is everybody?

This is a bigger problem than one would think at first sight. We can say that we've been listening to what's out there for some 50 years with no results. Most people will understand that this means that in a sphere with a 50 light year radius, centered on Sol, no indication of intelligent communication is present. But it's actually worse than that. It actually means that in the entire past light cone of that sphere no indication of intelligent communication has taken place. For instance, we should also detect such a communication if it originated from a source e.g. 5000 light years away 4950 to 5000 years ago or from a source 24120 light years away 24070 to 24120 years ago. That narrow band of potential sources where a range of 50 years is observed in a 13.5 billion year old universe is of course very narrow but at the same time it does stretch in all directions and makes a pretty good random sample. Now, while there are certainly a number of reasons why such communications wouldn't have reached us (signal not energetic enough, redshift, interstellar dust, the supermassive black hole in the center of the Milky Way, etc, etc), the fact remains that we have heard and hear nothing. If our galaxy is teeming with life, it's very silent life.

The longer it takes to at least hear something rather than nothing the lower the probability of extraterrestrial life, at least life which uses technology.

That concept of technology leads to another paradox which only adds to the former one. The thing is that any life we know, and one can easily argue that this is a necessary aspect of life of any kind, is that it grows exponentially when given the opportunity. Now imagine that at some point in our past, a civilization anywhere in our galaxy reached the point where it could colonize other systems than its own. Even if it started slow with e.g. one colony a century, at some point the first colonies would start sending their colonies and start the typical exponential growth curve. I'd have to do the maths but I estimate that as little as 10 million years would be plenty to colonize all colonizable star systems in the entire galaxy. Since that hasn't happened we are forced to conclude that no civilization has ever achieved this point in our galaxy.

If one wants to see or meet aliens, the prospect is actually looking grim. The longer the galactic silence lasts, the more Ockham's razor suggests that either interstellar travel is impossible regardless of technological level and/or technological civilizations don't last long enough to really spread. My money is on both these possibilities actually. The first because science and the second, well, just look at what homo sapiens sapiens is doing with its technology.
Maybe they found us.

http://www.npr.org/sections/thetwo-w...nal-from-space
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