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  #51  
Old 07-12-2016, 04:06 PM
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Originally Posted by msmith537 View Post
"Energy based beings" are a staple of sci-fi, but what does that even mean?
The meaning is perfectly clear, even if the physics is totally speculative. One can easily imagine a self-sustaining "living" reaction in a complex of magnetic and electric fields. Self-focusing impulses of light actually do exist; a whole blort-load of these, interacting with each other, might accumulate into a "photonic computer" of some sort, and thus generalizable to a "life form."

It's also perfectly legitimate for such a speculative notion to permit a substrate of matter; a glowing ball of plasma, maintained in a self-organizing manner, would be an "energy being" as much as a "matter being."

You're right that the idea cannot be precisely modeled...but, c'mon, we all know what it "means."
  #52  
Old 07-12-2016, 05:20 PM
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13.8 billion years sounds like a long time, but compared to how old the universe is going to get, it's still a baby. Assuming that until relatively recently the universe was a very dangerous place full of GRBs etc, it's possible Earth is among the early generation of worlds with technology. It's still an open question whether we'll ever leave our solar system much less colonize it. We haven't yet.

My personal favorite WAG is if there are spacefaring races they've probably spent so much time in interstellar space that's their preferred habitat and we may not find them until we ourselves wander out that far.

I'd be pissed if I found out they are out there watching and haven't popped by to give us some suggestions. What kind of jerk do you have to be to see an emerging species still suffering from war disease and famine and not help out? Dicks.
  #53  
Old 07-12-2016, 05:40 PM
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The thing I find ridiculous about the Fermi Paradox is that according to it, the human race doesn't exist. We haven't colonized the galaxy. I guess if someone on another planet comes up with their own version of the Fermi paradox, they'd conclude we don't exist. Also, it usually only takes into account the Milky Way and excludes the billions upon billions of other galaxies that may harbor planets and life. The distances are just too vast to say for certain that "Welp, because we haven't seen complete colonization of our lone Milky Way galaxy, life must not exist!" I think it's idiotic.
  #54  
Old 07-12-2016, 07:28 PM
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The thing I find ridiculous about the Fermi Paradox is that according to it, the human race doesn't exist. We haven't colonized the galaxy. I guess if someone on another planet comes up with their own version of the Fermi paradox, they'd conclude we don't exist. . . .
You're misreading the issue somewhat. The paradox doesn't conclude that other civilizations don't exist: it asks the question, "Why have we not seen evidence of them yet?"

Essentially, you're transposing an implication into its converse, which is bad logic.

"If other civilizations exist, we should have evidence of it."

This is very, very different from, "Because we have no evidence of other civilizations, they must not exist," something that no one has said, suggested, or claimed.

Last edited by Trinopus; 07-12-2016 at 07:28 PM.
  #55  
Old 07-12-2016, 10:04 PM
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The thing I find ridiculous about the Fermi Paradox is that according to it, the human race doesn't exist. We haven't colonized the galaxy. I guess if someone on another planet comes up with their own version of the Fermi paradox, they'd conclude we don't exist. Also, it usually only takes into account the Milky Way and excludes the billions upon billions of other galaxies that may harbor planets and life. The distances are just too vast to say for certain that "Welp, because we haven't seen complete colonization of our lone Milky Way galaxy, life must not exist!" I think it's idiotic.
None of that follows. There is nothing in the Fermi Paradox that requires us to have already colonized the galaxy. And I have no idea what you mean by saying, "it only takes into account the Milky Way."

The Fermi Paradox is simple: It says that if we are not unique, then there should be billions of other planets with life on them. And since we've come along many billions of years after life should have been possible (i.e. solar systems like our existed), there is no reason to believe that we should be the first ones to reach an advanced technological level of civilization. And given the rate at which our technology is advancing, it therefore stands to reason that there should be alien civilizations so powerful and capable of manipulating so much energy, and capable of sending self-replicating probes through the galaxy, that their presence should be visible to us.

The Von Neumann Probe issue is an important one. We are probably on a trajectory to have the ability to build such a probe within hundreds or maybe thousands of years. That's a blink of an eye in cosmic terms. And if we can do it, you'd think someone else would have already done it. And if they did, even if those probes only travel at a fraction of the speed of light the exponential nature of their replication means they should be swarming through the galaxy.

Unfortunately, the Fermi Paradox is called a paradox, and that's not accurate. It's more like food for thought. What don't we understand? Why are we not seeing this? What are we missing? Those are the questions the Fermi Paradox tells us to think about.
  #56  
Old 07-13-2016, 10:53 AM
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I'm not sure we should view Von Neumann probes as an inevitability, or put much significance in their apparent absence. We're a long way from building them and who knows what our views about them will be when we finally could build one. Human babies make good self-replicating probes too. Either way, your probes are phoning home and potentially telling the whole galaxy where you live, and we may decide that's not prudent.

When we say it would only take a million to 10 million years to colonize the galaxy, aren't we admitting we're a dangerous infection? How are infections generally treated?
  #57  
Old 07-13-2016, 11:50 AM
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I'm not sure we should view Von Neumann probes as an inevitability, or put much significance in their apparent absence. We're a long way from building them and who knows what our views about them will be when we finally could build one. Human babies make good self-replicating probes too. Either way, your probes are phoning home and potentially telling the whole galaxy where you live, and we may decide that's not prudent.

When we say it would only take a million to 10 million years to colonize the galaxy, aren't we admitting we're a dangerous infection? How are infections generally treated?
Well... the very first infection isn't treated. Put one bacterium in a pot of chicken broth and within hours, you have a pot full of bacteria. Now if you add a new bacterium, there is a conflict to see whether one wins or whether they reach an equilibrium, but the first one is going to colonize the whole pot in short time.

Intelligent species make the outcome a little less predictable. They could choose not to colonize the galaxy, but it still seems like a given to me that the first species that wants to colonize the galaxy will do so on a time frame that seems long to people, but is short on geologic/evolutionary scales.

Any species that wanted to stop this overrun would have to overrun it themselves, if only to monitor other species that might be more aggressive.
  #58  
Old 07-13-2016, 01:18 PM
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Doesn't matter how many Earth-like planets there are, or how many civilizations. They're just too far away to reach.
Even *if* we built a spaceship that flew at the speed of light (which is preposterous in and of itself), the overwhelming majority of space would still be much too far to reach in any practical way - by the time our brave pioneers made first contact, empires would have risen and fell down here, and once more before they make it back, rendering any contact irrelevant. The same naturally applies to the putative aliens.
  #59  
Old 07-13-2016, 01:29 PM
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Doesn't matter how many Earth-like planets there are, or how many civilizations. They're just too far away to reach.
Even *if* we built a spaceship that flew at the speed of light (which is preposterous in and of itself), the overwhelming majority of space would still be much too far to reach in any practical way - by the time our brave pioneers made first contact, empires would have risen and fell down here, and once more before they make it back, rendering any contact irrelevant. The same naturally applies to the putative aliens.
I'm not sure I agree with you about that.

First, if you had light-speed travel, the time dilation means that the trip would be near-instantaneous from the passenger's perspective. Kingdoms might fall back home, but for you and your family of colonists, it was a two-year trip to what might be a whole planet full of unclaimed land. Some people (perhaps crazy religious cults, unfortunately) would find that very attractive proposition no matter what happened back home. Here on Earth, plenty of groups have made what are essentially one-way moves to uncharted territories.

Second, a self-replicating probe would be a lot like the Voyager probes. There was a short-term goal, but they are still providing useful information decades later. We'd be looking at perhaps 100 years to get to the nearest stars (assuming 5-10% of light as a more realistic speed), but then it would produce data on a continuous basis forever.

Third, humans have a relatively short life span. There's no reason an alien species couldn't live 10,000 years and have a very different perspective on what "too long" means.

Fourth, by the time a race gets to Dyson-sphere technology, they can't live entirely on their planet anymore. That much energy would fry the planet. So they probably live on space stations of some sort. Once you're used to living on a space station, it's not such a stretch to put engines on it and send it off to some other star. Even if you know it will be your grandkids who arrive, the impact on your personal life is pretty small because you were always going to be living on that space station. Only the view out the windows has changed.

So on a scale of millions of years, galactic colonization is just not that big of a hurdle. It's certainly appears to be easier than getting intelligent life in the first place.
  #60  
Old 07-13-2016, 09:34 PM
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Perhaps the universe is teaming with super-intelligent civilizations capable of FTL travel. If they exist, they'd realize they weren't the only super-intelligent civilization in town and they'd take measures to assure they aren't easily detected by any super-duper-intelligent civilization capable of knocking them out, like Mike Tyson against a 5 year old kid. I'm pretty sure such civilizations would operate in stealth mode (i.e. no leaky signals of any type traversing time and space announcing their whereabouts).

We, on the other hand, have not evolved to the point of realizing we're playing with fire transmitting episodes of I Love Lucy out to the Great Beyond. We're like fattened beefsteak prancing around singing, “dinner's ready, come and get us.” I have no doubt there's at least a few squadrons of interstellar spaceships manned by super-duper intelligent space-crew closing in on our solar system right now, wielding knives and forks...and bottles of A-1 sauce.

IOW: If advanced civilizations exist beyond our solar system, they'd probably want to detect us before we detect them and they most likely have the wherewithal to assure that happens. Let's hope they prefer pork.
  #61  
Old 07-13-2016, 09:57 PM
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Well, if they're looking for life, Earth has been farting suspicious amounts of oxygen for a couple billion years. Waiting for TV signals seems stupid. It could take a thousands of years for the signal to get anywhere and many many thousands of years for them to get here and who knows what's waiting for them when they get here? I'm guessing in thousands of years we'll be capable of defending ourselves, if that's the sort of galaxy we live in.
  #62  
Old 07-13-2016, 11:02 PM
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Well, if they're looking for life, Earth has been farting suspicious amounts of oxygen for a couple billion years. Waiting for TV signals seems stupid. It could take a thousands of years for the signal to get anywhere and many many thousands of years for them to get here and who knows what's waiting for them when they get here? I'm guessing in thousands of years we'll be capable of defending ourselves, if that's the sort of galaxy we live in.
Against an antagonist who is a thousand years more advanced than us and populates multiple planets? Seems about as likely as a 10th century Eskimo village defending themselves from a 2016 US army battalion.
  #63  
Old 07-14-2016, 01:09 AM
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The thing I find ridiculous about the Fermi Paradox is that according to it, the human race doesn't exist. We haven't colonized the galaxy. I guess if someone on another planet comes up with their own version of the Fermi paradox, they'd conclude we don't exist. Also, it usually only takes into account the Milky Way and excludes the billions upon billions of other galaxies that may harbor planets and life. The distances are just too vast to say for certain that "Welp, because we haven't seen complete colonization of our lone Milky Way galaxy, life must not exist!" I think it's idiotic.
Fermi's Paradox does not apply to us because we have unambiguous evidence of our own existence. It only applies to beings whose existence is unsupported by any evidence, when evidence ought to be abundant.

As for the rest of your post you might be interested to know that the SETI Institute itself completely and vehemently disagrees with you:

Fermi Paradox: Could we be alone in our part of the galaxy, or more dramatic still, could we be the only technological society in the universe?


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Fermi realized that any civilization with a modest amount of rocket technology and an immodest amount of imperial incentive could rapidly colonize the entire Galaxy. Within ten million years, every star system could be brought under the wing of empire. Ten million years may sound long, but in fact it's quite short compared with the age of the Galaxy, which is roughly ten thousand million years. Colonization of the Milky Way should be a quick exercise.

So what Fermi immediately realized was that the aliens have had more than enough time to pepper the Galaxy with their presence. But looking around, he didn't see any clear indication that they're out and about. This prompted Fermi to ask what was (to him) an obvious question: "where is everybody?"...

A lot of folks have given this thought. The first thing they note is that the Fermi Paradox is a remarkably strong argument. You can quibble about the speed of alien spacecraft, and whether they can move at 1 percent of the speed of light or 10 percent of the speed of light. It doesn't matter. You can argue about how long it would take for a new star colony to spawn colonies of its own. It still doesn't matter. Any halfway reasonable assumption about how fast colonization could take place still ends up with time scales that are profoundly shorter than the age of the Galaxy...

Consequently, scientists in and out of the SETI community have conjured up other arguments to deal with the conflict between the idea that aliens should be everywhere and our failure (so far) to find them. In the 1980s, dozens of papers were published to address the Fermi Paradox. They considered technical and sociological arguments for why the aliens weren't hanging out nearby. Some even insisted that there was no paradox at all: the reason we don't see evidence of extraterrestrials is because there aren't any
.
So: professional SETI specialists take Fermi seriously, but have apparently put no dent worth mentioning in his argument. If they can't do it then you would do well to give up and try your luck against some other titan of the history of science, because Fermi has you soundly beaten.
  #64  
Old 07-14-2016, 01:50 AM
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I'm not sure I agree with you about that.

First, if you had light-speed travel, the time dilation means that the trip would be near-instantaneous from the passenger's perspective.
If you had light-speed travel, you would turn into light. Which is gonna be a job to clean up, I can tell you that It's just not feasible on any practical level.
Even 5% of the speed of light would be a mind boggling achievement to reach, one that would require levels of magitek, magic materials and energy generation schemes we can't even fathom.

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Second, a self-replicating probe would be a lot like the Voyager probes. There was a short-term goal, but they are still providing useful information decades later. We'd be looking at perhaps 100 years to get to the nearest stars (assuming 5-10% of light as a more realistic speed), but then it would produce data on a continuous basis forever.
And that data would come back home 10 years later, and no concrete action could be taken upon that data for at least another 100. Garbage. We can't plan that far ahead. Hell, we can't plan 5 years from now.

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Third, humans have a relatively short life span. There's no reason an alien species couldn't live 10,000 years and have a very different perspective on what "too long" means.
Fourth, by the time a race gets to Dyson-sphere technology, they can't live entirely on their planet anymore. That much energy would fry the planet. So they probably live on space stations of some sort. Once you're used to living on a space station, it's not such a stretch to put engines on it and send it off to some other star. Even if you know it will be your grandkids who arrive, the impact on your personal life is pretty small because you were always going to be living on that space station. Only the view out the windows has changed.
Sure, but at that point it becomes all pointless speculation. I was answering the question from our own point of view, and within a timeframe that can be measured in generations. It's quite possible there is a species out there that lives for untold aeons, lives on a migrant fleet and has already colonized or consumed hundreds of thousands of worlds we can't even see from here (Tyranids, anyone ?).

What difference does it make ?
  #65  
Old 07-14-2016, 03:19 AM
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It's quite possible there is a species out there that lives for untold aeons, lives on a migrant fleet and has already colonized or consumed hundreds of thousands of worlds we can't even see from here (Tyranids, anyone ?).

What difference does it make ?
If we are prepared to accept civilisations that have colonised hundreds of thousands of worlds, then we need to ba able to find reasons why this colonisation hav not extended to every system in the galaxy. There are lots of possible reasons why such an expansive civilisation might not expand to colonise every world, but we don't know which one is the real answer. And of course we don't even know if expansive civilisations exist in the first place.

This is the heart of the paradox; the question can be stated simply, but we don't know which of a myriad answers is the correct one. Or even if there is only one answer. But if the reason they are not here turns out to be an existential threat to our own civilisation then it is worth considering.
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Old 07-14-2016, 08:58 AM
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The issue with the Fermi Paradox is that there's so many assumptions baked into it that it's impossible to even begin to know which one is incorrect and by how much ... [snip]
It is a fact that Carbon, Oxygen and Nitrogen are relatively common in our galaxy. These elements combined with the single most common element, Hydrogen, produce methane, water, and ammonia. It looks like the only critical factor is that this commonplace water needs to be in it's liquid state, then life will spring forth with near certainty.

Based on this assumption, and it is an assumption is every way, it would logically follow that we should be finding life out there. The basic building blocks are common, we have time in great abundance, a sun that is average in every way, there's no reason we shouldn't find life thriving everyplace we look.

Thus the Fermi Paradox, "Where is everybody?"

Of course, there may well be other critical factors required and we'll not even begin to understand what they are until we actually do find life out there. The search continues ...
  #67  
Old 07-14-2016, 09:59 AM
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Against an antagonist who is a thousand years more advanced than us and populates multiple planets? Seems about as likely as a 10th century Eskimo village defending themselves from a 2016 US army battalion.
Well, they could be 10k years more advanced, but assuming FTL is impossible for everybody, it could take 1,000s of years for them to spot our communications, and easily much more than that for them to send anything here. We could easily have reached our own "tech singularity" by that time so would they really be able to do anything to us at that point? Anyway, it just seems if their goal was to wipe out life, the Earth has been showing signs of life for a couple billion years so they must be waiting for signals and that seems wasteful. Sort of closing the barn doors after the horses have left (or developed their own hyper-level of tech).
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Old 07-14-2016, 02:49 PM
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Nelson Pike: Cool quotes from SETI! Thanks!

Alas, I would have to disagree (mildly) with one thing in that quote: yes, ten million years is a very short time in the history of the galaxy...but it is a very long time in the history of individual species. Humanity has not existed for a tenth that time, and rocketry-competent humanity not for one one-hundred-thousandth of that time.

The longevity of civilizations is one of the scariest terms in the Drake Equation. We have no way to know if a technological/industrial civilization is actually sustainable or not. There are reasons to hope it is, but it is far from certain.

Entire civilizations might rise...and vanish...in the short time it takes our rocket to make the journey to the nearest extra-solar life-sustaining planets.
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Old 07-14-2016, 03:07 PM
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And that data would come back home 10 years later, and no concrete action could be taken upon that data for at least another 100. Garbage. We can't plan that far ahead. Hell, we can't plan 5 years from now.
Isn't that a lot like asking why we are sending probes to Pluto when no concrete action can be taken on that data? Or probes sent to Mars looking for life that may be a billion years extinct?

Any information about an extra-solar system would be of enormous theoretical value. There's only so many planet-formation or life-origination simulations you can run against our sample size of 1. Having even three or four detailed extra-solar surveys would be pure gold to certain scientists.

You can argue that there's not much practical application for theories of solar system formation and I wouldn't disagree. It's hardly useful for building the better mouse trap, but we're still spending a lot of time and money studying that issue. Humans are just incurably curious, and I think a similar level of curiosity would drive most intelligent species.
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Old 07-14-2016, 04:34 PM
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Well, if they're looking for life, Earth has been farting suspicious amounts of oxygen for a couple billion years. Waiting for TV signals seems stupid. It could take a thousands of years for the signal to get anywhere and many many thousands of years for them to get here and who knows what's waiting for them when they get here? I'm guessing in thousands of years we'll be capable of defending ourselves, if that's the sort of galaxy we live in.
Suspicious amounts of oxygen may correlate to a high probability of life, but it doesn't necessarily correlate to a high probability of intelligent life. If the aliens got a load of Fred Mertz however, and figured a significant % of Earthlings looked and acted (“aw, shuddup, Ethel!”) like him, they may be motivated to exterminate us as gesture of kindness to the universe to prevent Mertz's from spreading out and populating the galaxy and beyond.

Apparently, our early radio signals have traveled ~200 light years from earth thus far. According to this link, ~250,000 stars reside within 250 light years of us. There well could be a super-intelligent civilization or two lurking within earshot of our signals. And, if as I posited earlier, an advanced civilization may want to, and be capable of, cloaking it's existence to prying eyes/ears, we'd be oblivious to them. A ~200+ light year alien drone sortie could be a Sunday drive in the park for a super-intelligent civilization. Who knows?

Do I think this is a likely scenario? No. But, it's possible. The inverse square law degrades signal strength and despite wishful dreaming of FTL travel via wormholes and whatnot, I don't believe anything approaching c is possible for any type of non-light matter. But, maybe ~50% c is achievable—and that could potentially put us at risk.

Solution: we need to start broadcasting photos of me (wearing my form-fitting boxer-briefs) into outer space. I'll sacrifice myself to the wanton desires of alien space-chicks in order to protect mankind from planetary annihilation. You're welcome.

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Against an antagonist who is a thousand years more advanced than us and populates multiple planets? Seems about as likely as a 10th century Eskimo village defending themselves from a 2016 US army battalion.
The Eskimos would no doubt recruit polar bears and use their 100+ types of snow to level the playing field against the U.S. battalion.
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Old 07-14-2016, 05:28 PM
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Nelson Pike: Cool quotes from SETI! Thanks!

Alas, I would have to disagree (mildly) with one thing in that quote: yes, ten million years is a very short time in the history of the galaxy...but it is a very long time in the history of individual species. Humanity has not existed for a tenth that time, and rocketry-competent humanity not for one one-hundred-thousandth of that time.

The longevity of civilizations is one of the scariest terms in the Drake Equation. We have no way to know if a technological/industrial civilization is actually sustainable or not. There are reasons to hope it is, but it is far from certain.

Entire civilizations might rise...and vanish...in the short time it takes our rocket to make the journey to the nearest extra-solar life-sustaining planets.
YVW- glad you are enjoying the site.

Wiki indicates that before the impact of humans the average mammal species life expectancy was about 1 million years. (The longest species survival lifetime is thought to be some plankton species which lasted 13 million years)

However, IMO it is reasonable to suppose that our phenomenal intelligence may allow us to overcome even such imposing challenges as our homicidal mass psychology, and our Y chromosone degradation, thus sustaining the h. sapiens lifetime indefinitely.

As for the Drake equation it and not Fermi is the one I have trouble with, mainly because of the number of variables whose value we cannot in principle know of without a sample size of God knows what, randomly dawn from the galaxy, about ?half? of which is ?permanently? blocked from our view by the galactic center.
  #72  
Old 07-14-2016, 05:30 PM
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'Beings composed of pure energy' is a popular and fun SF trope, but has anyone ever come up with a remotely plausible framework for how that would work?

Energy doesn't tend to interact with other energy directly, and energy doesn't tend to stay in one place without dissipating or dispersing.

Never mind a sentient being. How can you make any complex system out of pure energy?
Your comments are correct. Your question's answer is No.

It may be good to distinguish original life, and life-like organisms developed by such life, e.g. robots. One might be able to imagine the latter based on photon beams are something, but original life — life that evolves from the primordial non-life — almost certainly derives from specific complex molecules, e.g. DNA.

This fact was made clear to me by Erwin Schrödinger's What is Life? (Re-reading that short book just now, I can't really recommend it however — it may be tedious and obvious.)
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Old 07-14-2016, 06:10 PM
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Suspicious amounts of oxygen may correlate to a high probability of life, but it doesn't necessarily correlate to a high probability of intelligent life.
True, but for them to wait until they find a radio signal doesn't seem like a good idea if they're afraid of other intelligent life. By the time they detect it, it could take them many thousands of years to get here and do anything about us. Our AIs and other technologies could be godlike by then. Just seems like waiting until you detect the signals it could well be too late if we do turn out to be aggressively expansive.

So, I'm not too worried about what they're up to because they've had a couple billion years to find us and wipe us out and they haven't, and I'm not that worried about them picking up our radio signals because that doesn't seem like a good strategy if you have ill intent.
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Old 07-14-2016, 08:39 PM
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. . . However, IMO it is reasonable to suppose that our phenomenal intelligence may allow us to overcome even such imposing challenges as our homicidal mass psychology, and our Y chromosone degradation, thus sustaining the h. sapiens lifetime indefinitely.
I'd never heard of Y chromosome degradation. As a male, I find the concept worrying! What's happening to us?

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As for the Drake equation it and not Fermi is the one I have trouble with, mainly because of the number of variables whose value we cannot in principle know of without a sample size of God knows what, randomly dawn from the galaxy, about ?half? of which is ?permanently? blocked from our view by the galactic center.
I like the Drake Equation, but, yeah, a lot of the terms are unknown. To my mind, the D.E. is tautological: it's self-evidently true. It's just vague, because of the unknown terms.

It's sort of like saying F = ma, where we know m, but don't have a clue what a is. The equation is true...it just doesn't help us a whole lot!
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Old 07-14-2016, 08:58 PM
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The concept of Y chromosome degradation is not universally accepted:

https://en.wikipedia.org/wiki/Y_chromosome#Degeneration
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Old 07-14-2016, 09:13 PM
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I admire the man as much as the next Chicagoan, but could Fermi simply be wrong?

Not that I think he is. I just think we are thinking on time scales that are simply too small. But why assume he is right?
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Old 07-14-2016, 09:39 PM
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He wasn't right or wrong, because he wasn't making a factual claim. He was simply asking a question to stimulate our thinking about the subject. There are many potential answers tomthe Fermi Paradox.
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Old 07-15-2016, 12:04 AM
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I admire the man as much as the next Chicagoan, but could Fermi simply be wrong?

Not that I think he is. I just think we are thinking on time scales that are simply too small. But why assume he is right?
Many contributors to this thread have tried to go beyond mere assumption.

Expert astrophysical consensus, including that of SETI proponent researchers, appears to be that Fermi's argument is a good one.

See quotation and link in reply #63.
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Old 07-15-2016, 12:34 AM
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The concept of Y chromosome degradation is not universally accepted:

https://en.wikipedia.org/wiki/Y_chromosome#Degeneration
My information came from the book Adam's Curse by Oxford geneticist Bryan Sykes. I have not read the relevant chapters for a while, I'll take another look.

Wiki is often very helpful, and I have enjoyed it on a near-daily basis ever since I got wired years ago. However, sometimes it prints nonsense, and the first sentence of its section on Y chromosone degeneration is really off the deep end:

By one estimate, the human Y chromosome has lost 1,393 of its 1,438 original genes over the course of its existence, and linear extrapolation of this 1,393-gene loss over 300 million years gives a rate of genetic loss of 4.6 genes per million years.

The human Y-chromosone is not any 300 million years old, (the human species in less than 300 thousand years old, isn't it?) and when one's introduction is that badly falsified then everything that follows should be rewritten, preferably by different author.
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Old 07-15-2016, 12:52 AM
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Now MIT I'll pay attention to:

THEORY OF THE "ROTTING" Y CHROMOSOME DEALT A FATAL BLOW

...even if they repeat the part about the 300-million year old Y-chromosone, which they need to explain a lot better than they do. I caught that 300 mya was the time of the first appearance of the Y-chromosone, any Y chromosone, presumably ancestral to all species' Y chromosones, but to allude to it as the human Y chromosone must involve some kind of abstruseness of technical expression.

It's 150am here, and I am not up to a careful reading. Will get to it later.
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Old 07-15-2016, 01:02 AM
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Isn't that a lot like asking why we are sending probes to Pluto when no concrete action can be taken on that data? Or probes sent to Mars looking for life that may be a billion years extinct?
Not really. The people who sent these probes are going to get results within their lifetimes, answers to questions they're asking. Sending a probe that only your great-great-great-grandkids are going to be able to hear is a different kind of crazy. It's not everyday we send a Voyager out.

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Any information about an extra-solar system would be of enormous theoretical value. There's only so many planet-formation or life-origination simulations you can run against our sample size of 1. Having even three or four detailed extra-solar surveys would be pure gold to certain scientists.

You can argue that there's not much practical application for theories of solar system formation and I wouldn't disagree. It's hardly useful for building the better mouse trap, but we're still spending a lot of time and money studying that issue. Humans are just incurably curious
Excellent point.

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, and I think a similar level of curiosity would drive most intelligent species.
*needle scratching record* but.. why ? We only know one kind of intelligence, which is our own (there may or may not be some more on our planet that we haven't or can't grok, like whales, insect colonies...). It's quite a jump to extrapolate from one of our traits to a universal one. Especially considering it's not really one of our traits. Yes, some of us are driven by an insatiable need to figure out how everything works or where we come from. The overwhelming majority just want to eat, fuck and maybe get another beer before watching the game. Which is why SETI is such a fringe side-show

I would also add that it's one thing to send probes to poke at the fiddly bits of the Universe ; and another to actually sustain thousands of years of ongoing semi-aggressive galactic colonization. Science-fiction is full of stories of space colonists completely forgetting why they were sent out and where from, either during their trip or during the time-frame it would take for a seed of a few hundred folks to the kind of thriving planetary economy and population it would take for these colonists to build another outer-space colonization expedition. And for the home civilization, considering the time lag in such colonization, it's essentially a big money & resource drain for little benefit.

It's not even that huge of a stretch of the imagination. Most people can't read things that have been written a mere thousand years ago in their own language, the language itself having evolved too much since then. There are other human languages and writing systems that are simply opaque to even experts on them. A human Ark, trying to make a trip from here to wherever and hoping the descendants of the descendants (etc...) of the hopeful few who signed up are going to begin again in the Off-World Colonies (hi, Deckard !) is hardly likely to have anything left of their homeworld by the time they make it to Planet X - no commonality of culture or experience or language, nevermind politics or shared goals. Possibly not even basic biology, depending on the length of the trip.

Given that, why assume that there's a species out there for which this is not only not true, but not true enough that they'd keep on doing it over and over without a hitch ? Fermi's paradox sort of handwaves this away, assuming that it doesn't matter how long the interplanetary trip is, at some point the colony will itself send seeds further into space, and on and on. But that's hardly a given. Hell, it's hardly a given *we* are ever getting off the blue dot.
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Old 07-15-2016, 02:08 AM
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Kobal2 I generally agree with your points, but I'd like to make a few counter-counter-arguments.

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Science-fiction is full of stories of space colonists completely forgetting why they were sent out and where from, either during their trip or during the time-frame it would take for a seed of a few hundred folks to the kind of thriving planetary economy and population it would take for these colonists to build another outer-space colonization expedition.
Sure, this is a factor for humans as we know them, and a generation starship.
Humans in stasis, or self-repairing AI, or some kind of super, GE human not so much.
Plus it's not really a solution to the paradox. If the Flobbians get here and can't remember why they came, so what?

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but.. why ? We only know one kind of intelligence, which is our own (there may or may not be some more on our planet that we haven't or can't grok, like whales, insect colonies...). It's quite a jump to extrapolate from one of our traits to a universal one. Especially considering it's not really one of our traits. Yes, some of us are driven by an insatiable need to figure out how everything works or where we come from. The overwhelming majority just want to eat, fuck and maybe get another beer before watching the game.
I think this is backwards. It's not that we're assuming all species would have curiosity.
It's that we'd need to assume no species (other than us) has it to solve the paradox. And that's one hell of a leap.

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Given that, why assume that there's a species out there for which this is not only not true, but not true enough that they'd keep on doing it over and over without a hitch ? Fermi's paradox sort of handwaves this away, assuming that it doesn't matter how long the interplanetary trip is, at some point the colony will itself send seeds further into space, and on and on. But that's hardly a given. Hell, it's hardly a given *we* are ever getting off the blue dot.
It doesn't make such an assumption. One species slowly making their way around the galaxy is just one scenario, and is just mentioned as one somewhat plausible way that ETs could make it to earth. And note that even in the single "magellan" species scenario, we *don't* have to say they get everywhere without a hitch or always want to move on immediately. We could say that only N% of communities eventually decide to explore the stars and K% of those successfully get to another planet after spending J years at one planet. Even conservative values of N, K and J would lead to in many cases a lot of exploration for one species relative to the age of the universe.

And once again, fermi's paradox asserts nothing about the existence or non-existence of life. It asks the question why do we not see evidence of ET life yet?

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  #83  
Old 07-15-2016, 02:39 AM
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Sure, this is a factor for humans as we know them, and a generation starship.
Humans in stasis, or self-repairing AI, or some kind of super, GE human not so much.
Plus it's not really a solution to the paradox. If the Flobbians get here and can't remember why they came, so what?
So why launch the expedition in the first place ? If it's not cost-efficient, if there's no point beyond "because we can", it the home planet gets nothing whatsoever out of the deal, why spend the money on some silly Ark project instead of a cure for space-cancer or (more likely) a brand new three-dimensional jetpack football sphere ? You could posit a "get off before it's too late" scenario where the last remnants of a proud race jet off into the unknown seconds before Krypton's sun flickers out, but that adds quite a bit of time to the equation.

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I think this is backwards. It's not that we're assuming all species would have curiosity.
It's that we'd need to assume no species (other than us) has it to solve the paradox. And that's one hell of a leap.
Not necessarily no species. But if, say, only 50% of sentient civilizations ever get curious enough and driven enough and so on enough to make with the spacefaring, that cuts down mightily on the odds of one making it to precisely this boring corner of the Universe. It's perfectly imaginable for a species, even a smart and savvy species, or millions upon millions of them to never get off their rock. For us to hear about one that did would require that A) said species exists and has the drive B) their planet has enough resources and energy to tap for them to reach the tech stage needed for outer-world explorations, C) they do so within the tiny corner of the Universe we can watch and have been watching for a hundred years at best. And not even that closely, either.

To my mind, the Fermi paradox is "solved" by realizing that the Universe is really, really, *really* big and we have been here for a really, really, *really* short time.
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Old 07-15-2016, 02:41 AM
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(Oh, and humans in stasis would still face that problem. Thomas Jefferson wouldn't want anything to do with you )
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Old 07-15-2016, 03:22 AM
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This may be true of intelligent species which closely resemble humans in development, but if life turns out to be very diverse in our universe, we can't assume that their civilisation would follow a similar path. What crises would be faced by a civilisation made up of intelligent sea-snakes, or slime-molds, or bacterial mats? What climate changes would occur on a planet with supercritical water for an atmosphere? What weapons would a race of intelligent computers be vulnerable to?
Missed this earlier. Anyway obviously any argument about a hypothetical advanced alien species is speculative but let's try to think about why humanity faces existential threats today. A large part of the answer is that our instincts evolved in a completely different world than that which our technology has created. We evolved in small packs of hunter-gatherers and today we have to deal with nuclear weapons that can destroy the world. Secondly and closely related, the sheer scale of our industrial civilization threatens the natural environment on which we depend. Again we find it difficult to deal with this because it's so different from the problems which our hunter-gatherer ancestors faced.

I suspect these are general problems for a wide range of potential alien species. Remember in the context of the Fermi paradox we are talking about species which have the capacity to travel and communicate through space. No species would start off with this technology. Like us they would probably have evolved in primitive environments and only much later developed advanced technology. Like us, their "natures" shaped by evolution would struggle to cope with that advanced technology.
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Old 07-15-2016, 03:27 AM
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One assumption that people often make when considering the expansion of a civilised species in the Galaxy is that each colony acts in isolation, sending out new colonisation craft at random. This is the basis of Geoffrey Landis' influential 'Percolation Hypothesis'
http://www.geoffreylandis.com/percolation.htp
If each colony acts as an independent unit, deciding whether or not to continue expansion independently, then the colonisation becomes patch and partial, with large areas and individual stars remaining uncolonised even if colonisation spreads widely across the galaxy.

This model may explain why certain colonisation models do not cover every star, but it doesn't explain why other, different colonisation models could not be more efficient. In particular it seems to assume that all the colonies never speak to one another - if all, or many, of the colonies regularly contact each other, then the expansive ones can maintain a catalog of uncolonised stars and target them deliberately.
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Old 07-15-2016, 03:40 AM
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A large part of the answer is that our instincts evolved in a completely different world than that which our technology has created. We evolved in small packs of hunter-gatherers and today we have to deal with nuclear weapons that can destroy the world. Secondly and closely related, the sheer scale of our industrial civilization threatens the natural environment on which we depend. Again we find it difficult to deal with this because it's so different from the problems which our hunter-gatherer ancestors faced.

I suspect these are general problems for a wide range of potential alien species. Remember in the context of the Fermi paradox we are talking about species which have the capacity to travel and communicate through space. No species would start off with this technology. Like us they would probably have evolved in primitive environments and only much later developed advanced technology. Like us, their "natures" shaped by evolution would struggle to cope with that advanced technology.
This is a very real possibility. However nuclear weapons are at the bottom end of the sort of weapons an interstellar species might possess. To get from star to star needs very powerful spacecraft, capable of travelling at significant fractions of the speed of light; whatever powers those spacecraft would be comparable to nuclear weapons, be it controlled fusion or antimatter annihilation. An interstellar spacecraft firing its motors above a city would be very destructive. Even worse, such spacecraft would make very good kinetic weapons.

Another possibility is that the spacecraft are propelled passively by laser beam or particle beam (such methods are attractively efficient); any civilisation equipped with very large beam guns could use these in warfare. These are existential threats very few people have considered, except maybe SF nuts and gamers, but they may be a significant contributory factor to our quiet skies.
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Old 07-15-2016, 03:41 AM
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So why launch the expedition in the first place? If it's not cost-efficient, if there's no point beyond "because we can", it the home planet gets nothing whatsoever out of the deal, why spend the money on some silly Ark project instead of a cure for space-cancer or (more likely) a brand new three-dimensional jetpack football sphere ? You could posit a "get off before it's too late" scenario where the last remnants of a proud race jet off into the unknown seconds before Krypton's sun flickers out, but that adds quite a bit of time to the equation.
Why not?

Space to us still seems extraordinarily costly, but then we're very new to this. There are plenty of people alive that can remember the first space flights.

Very soon space may start to become profitable, as asteroids are immensely rich in precious metals for example. And beyond that just about every raw resource in scales that would dwarf the earth. Why would a species capable of space travel necessarily stick to the grain of dust they started out on?

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Not necessarily no species. But if, say, only 50% of sentient civilizations ever get curious enough and driven enough and so on enough to make with the spacefaring, that cuts down mightily on the odds of one making it to precisely this boring corner of the Universe.
Throwing in a 50% does little to change the scale of the numbers. We're talking hundreds of billions of galaxies containing hundreds of billions of stars. Now maybe there are great filters that mean basically no species become interstellar.

But just saying "Maybe half aren't curious enough" is an irrelevance.

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To my mind, the Fermi paradox is "solved" by realizing that the Universe is really, really, *really* big and we have been here for a really, really, *really* short time.
But remember we're not talking about ET visiting earth for a long weekend or something. If they put a probe around our world then that's evidence that would hang around for millions or billions of years and how brief our civilization has been doesn't matter.
Or any evidence of any large-scale project that would affect the light we receive from stars. We would see this in any nearby galaxy and would likely persist indefinitely.
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Old 07-15-2016, 03:46 AM
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One assumption that people often make when considering the expansion of a civilised species in the Galaxy is that each colony acts in isolation, sending out new colonisation craft at random. This is the basis of Geoffrey Landis' influential 'Percolation Hypothesis'
http://www.geoffreylandis.com/percolation.htp
If each colony acts as an independent unit, deciding whether or not to continue expansion independently, then the colonisation becomes patch and partial, with large areas and individual stars remaining uncolonised even if colonisation spreads widely across the galaxy.

This model may explain why certain colonisation models do not cover every star, but it doesn't explain why other, different colonisation models could not be more efficient. In particular it seems to assume that all the colonies never speak to one another - if all, or many, of the colonies regularly contact each other, then the expansive ones can maintain a catalog of uncolonised stars and target them deliberately.
But that's my issue with Fermi's assertion that it would only require time for a campaign of deliberate conquest to succeed ; with the travel times involved being a mere delay. Except that presumes a level of socio-political stability that's hard to imagine. It also presumes that once a planet is "flipped" by this putative conquering empire, it stays flipped for ever, for thousands if not tens of thousands of years, all or most of the planets working together in happy harmony with a singular goal of expansion into the empty.

Considering the fate of our empires, that seems difficult to support however. Especially if the conquering species is especially warlike or resource-hungry - sure, that would give it the drive to go out and flip planets. But thenthe people or robots on those planets would also get the drive to try and conquer the known Imperial space right back (it's much faster that way, all the infrastructure is already built and all the population already born), slowing down any further expansion. Ask the Romans, they know. Logistics and personal ambitions get in the way of getting anything done .
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Old 07-15-2016, 03:54 AM
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But remember we're not talking about ET visiting earth for a long weekend or something. If they put a probe around our world then that's evidence that would hang around for millions or billions of years and how brief our civilization has been doesn't matter.
Or any evidence of any large-scale project that would affect the light we receive from stars. We would see this in any nearby galaxy and would likely persist indefinitely.
Again, we haven't been watching all that long nor all that closely. Maybe there's a silent, long-dead alien probe the like of Voyager hanging around the asteroid belt - would we really know ? Similarly, if the light of a star was affected by something that's been there as long as we've been watching, would we notice at all ? Wouldn't we just assume there's something wonky in the way, or put it down to dark matter, or assume it's closer/farther than it really is just because that's how it looks etc... ?

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Old 07-15-2016, 03:56 AM
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I believe simple life may be relatively common throughout the Universe; multi-cellular life an order of magnitude less common; intelligent life an order of magnitude less than that and super-intelligent life capable of interstellar travel or intergalactic communication an order of magnitude less than that.

Given an infinite or near-infinite universe one could say the universe is teaming with super-intelligent life, yet average only one or a couple examples every galactic cluster or so. If that's the case, what are the odds that we will ever be visited by, or even detect the presence of their existence? Fair to middling at best is my guess.

I think we have to accept the premise that the vast majority of the Universe for any civilization, no matter how advanced, is forever closed off to us/them with regard to exploration or communication. I believe there are absolute limits to how far any life-form can reach, even by signal. If most of the Universe is expanding away from us faster than the speed of light and no matter or signal can exceed the speed of light, then most of the Universe is essentially dead to us and them.

At best, I believe we have only the Milky Way's local galaxy cluster (~54 galaxies) in which we have any chance of detecting intelligent life (galaxy clusters within Super-clusters aren't bound by gravity and are expanding away from each other due to Hubble Flow). However, there's a lot of stars in our local cluster, so I support SETI-type exploration. But, if we don't find extra-terrestrial intelligent life, it doesn't mean it's not out there...somewhere.
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Old 07-15-2016, 11:23 AM
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As for the rest of your post you might be interested to know that the SETI Institute itself completely and vehemently disagrees with you:

Fermi Paradox: Could we be alone in our part of the galaxy, or more dramatic still, could we be the only technological society in the universe?
That's not the best FP article I've ever read. From the link:
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Fermi realized that any civilization with a modest amount of rocket technology and an immodest amount of imperial incentive could rapidly colonize the entire Galaxy. Within ten million years, every star system could be brought under the wing of empire. Ten million years may sound long, but in fact it's quite short compared with the age of the Galaxy, which is roughly ten thousand million years. Colonization of the Milky Way should be a quick exercise.
I don't see any kind of empire lasting long enough or being in any way able to convince its colonizers to stay in the empire. Sure, people may spread out and eventually colonize a lot of systems, but as part of a huge empire? No way. How could an empire ever convince its colonies 100s of lys away to remain loyal and share its imperial goals?

I can imagine a time 50 million years from now two space faring species encountering each other for the first time on the far side of the galaxy and having no memory of where they came from or that the two species may have had a common ancestor, or where that common ancestor may have come from. Might make a fun sci fi story.
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Old 07-15-2016, 12:19 PM
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I can imagine a time 50 million years from now two space faring species encountering each other for the first time on the far side of the galaxy and having no memory of where they came from or that the two species may have had a common ancestor, or where that common ancestor may have come from. Might make a fun sci fi story.
There's something akin to that in the fluff of the Galactic Civilizations series of video games. After going into space and meeting a number of freakishly weird alien species, the Terran Federation (i.e. us) encounter the Altarians : an alien species that is incredibly similar to humans - one head, two arms, two legs etc... and is even 100% compatible with humans wrt reproduction.

Neither species know why and both are very freaked out by this, especially since the Altarians had a small space empire going long before humanity ever evolved but they have no records of ever having gone anywhere near Earth. There may or may not be time travel fuckery involved, or possibly intelligent design, or both - the games do not provide any actual explanation, only cryptic hints.
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Old 07-15-2016, 01:06 PM
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That's not the best FP article I've ever read. From the link:



I don't see any kind of empire lasting long enough or being in any way able to convince its colonizers to stay in the empire. Sure, people may spread out and eventually colonize a lot of systems, but as part of a huge empire? No way. How could an empire ever convince its colonies 100s of lys away to remain loyal and share its imperial goals?



I can imagine a time 50 million years from now two space faring species encountering each other for the first time on the far side of the galaxy and having no memory of where they came from or that the two species may have had a common ancestor, or where that common ancestor may have come from. Might make a fun sci fi story.

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Old 07-15-2016, 01:10 PM
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*needle scratching record* but.. why ? We only know one kind of intelligence, which is our own (there may or may not be some more on our planet that we haven't or can't grok, like whales, insect colonies...). It's quite a jump to extrapolate from one of our traits to a universal one. Especially considering it's not really one of our traits. Yes, some of us are driven by an insatiable need to figure out how everything works or where we come from. The overwhelming majority just want to eat, fuck and maybe get another beer before watching the game. Which is why SETI is such a fringe side-show
Can we agree that natural selection is going to be a universal feature of life? It applies to any self-replicating system in which there is competition for resources. Random mutation and natural selection produce a lot of weird combinations but every viable combination must have the ability to compete for resources and reproduce.

From there, we have to just observe trends on earth. The smartest species are mobile, social and curious, and that's true even when they're as different from each other as an octopus, a raven and a chimpanzee. Intelligence follows certain convergent pathways just like eyes do. Applying this to non-Earth life is no guarantee, but if we're plugging assumptions into the Drake equation, my money says interstellar explorers are mobile, social and curious.

And despite your example of how humans aren't curious about other star systems, the fact remains that we're still very curious critters. Is that edible? Can I fuck her? Should buy those shoes? Will Trump win the election?

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I would also add that it's one thing to send probes to poke at the fiddly bits of the Universe ; and another to actually sustain thousands of years of ongoing semi-aggressive galactic colonization. Science-fiction is full of stories of space colonists completely forgetting why they were sent out and where from, either during their trip or during the time-frame it would take for a seed of a few hundred folks to the kind of thriving planetary economy and population it would take for these colonists to build another outer-space colonization expedition. And for the home civilization, considering the time lag in such colonization, it's essentially a big money & resource drain for little benefit.
If you blow on a dandelion, the seeds spread out and they make more dandelions. Is this is a sustained plan of continental domination, or is it just how a self-replicating device functions?

I make no assumptions about galactic domination. I make no assumption that aliens themselves travel anywhere. All I assume is that the aliens look at space and say "I wonder what's going on up there? Let's shoot off a probe to tell us." I'm not even presuming that the probe has any more intelligence than is required to reproduce itself and send signals back home.

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Hell, it's hardly a given *we* are ever getting off the blue dot.
Humans have already launched a probe into interstellar space. In 10,000 years, we went from the discovery of agriculture to the start of interstellar travel.

Now, it may well be that no flesh and blood homo sapiens ever visits another star system. It might even be that Skynet takes over and we die off. Even so, we are already on a path that will litter our corner of the galaxy with probes by the end of the next 10,000 years, and if any self-replicating devices are sent into the galaxy, trying to stop all of them will be like keeping the dandelions off your lawn.
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Old 07-15-2016, 01:32 PM
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That's not the best FP article I've ever read. From the link:

I don't see any kind of empire lasting long enough or being in any way able to convince its colonizers to stay in the empire. Sure, people may spread out and eventually colonize a lot of systems, but as part of a huge empire? No way. How could an empire ever convince its colonies 100s of lys away to remain loyal and share its imperial goals?

I can imagine a time 50 million years from now two space faring species encountering each other for the first time on the far side of the galaxy and having no memory of where they came from or that the two species may have had a common ancestor, or where that common ancestor may have come from. Might make a fun sci fi story.
I cited SETI because they are Fermi's natural adversaries, and if they take him seriously then others should too.

I doubt Fermi stipulated that any alien contacts need be part of an empire. Indeed, the distances involved would mitigate against any galactic central organization. I expect the sited SETI author threw out the image of an "empire" off-the-cuff and non-seriously, maybe just as a sort of literary flourish.

Certainly aliens advanced enough to show up in our space would have to be advanced enough to be independent of authority and support many light years distant.
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Old 07-16-2016, 10:33 AM
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Can we agree that natural selection is going to be a universal feature of life? It applies to any self-replicating system in which there is competition for resources. Random mutation and natural selection produce a lot of weird combinations but every viable combination must have the ability to compete for resources and reproduce.
Maybe, or maybe not. The universe may have figured out alternate pathways. The case for selection is strong, but I don't think it necessarily has to depend on competition for limited resources—at least not Earth-type aggressive competition, pitting one life-form against another.

Earth's particular pathway to intelligence could be exceedingly rare in our universe. Let's face it, our genetic code is not exactly the most elegant means for evolving into complex lifeforms. DNA-based evolution is rather haphazard and dirty, dependent on mutations, a tremendously branching tree of life, aggressive competition for limited resources and eating one another.

Surely, the universe can allow more elegant pathways toward organic complexity resulting in high intelligence. Less branching speciation and a more homeostatic relationship with the environment may be the norm. Chemosynthesis as a “food” source, on a planet rich in the necessary inorganic chemicals should evolve less competitive (and less aggressive) species. What would drive life toward intelligence on such a planet? Perhaps the answer is simply that more complex, intelligent organisms obtain more chemosynthetic nourishment and have more offspring. Some type of mutation process needs to take place, I'm sure, but there should be more efficient methods than that which our DNA uses (lot's of non-vital detritus hanging around). Population could be in homeostatic balance with their environment and they could be happy with that arrangement, with no desire to kill less advanced species or spread their seed outward into space. They would be very nice and content aliens—the kind I'd like to befriend.

I do believe curiosity is an important requisite for intelligent life, but alien curiosity could be fully focused inward toward their own environment and not out toward other star systems. Maybe entirely aquatic planets harboring life are the norm in the universe. Put, let's say, octopuses on a fully aquatic planet and give them millions of years to evolve super-intelligence. They'd no doubt learn to build complex technology to master their environment, but I doubt they'd have the resources to develop rocketry or any other means of leaving their planet. With no means for space travel, it's doubtful they'd expend resources even signaling into outer space. “We're here, if you like octopus sushi, come and get us.”

Maybe planets harboring life living under a mile of ice are most common. They could be quite intelligent, yet ignorant that outer space even exists.

Life on Earth came about via a very specific and circuitous set of unlikely circumstances (from carbon dioxide-rich to oxygen-rich, part land/part water, tidal forces, etc.). Our pathway to intelligent life may be so rare as to be virtually non-existent elsewhere in our part of the universe. Our local cluster of galaxies could be peppered with intelligent life evolved via very different pathways, but we could be the only ones with the means and/or inclination to reach out to the stars.

Alternately, perhaps there are other civilizations within the Milky Way that have mastered inter-stellar travel and focused signaling, but choose to do so between a group of stars in close proximity to them (beyond our earshot). I mean, how much space and how many planets does any civilization need to be satisfied (assuming they're not greedy, war-mongering bastards)? Surely, even a super-intelligent species would weigh risk/benefit and the further they travel, the more risk and cost is involved. They could populate enough planets and space-station colonies within a sphere of limited light-years to suit their needs for billions of years. Why go further than you have to? If I want a Big Mac, I'm going to drive to the McDonald's closest to home.

If not for empire-building expansion, what else would motivate a civilization to explore ultra-far reaches? Curiosity? What could they possibly expect to discover on the opposite side of the galaxy that they can't find on their own side? I believe there's enough homogeneity built into the universe to preclude them from finding anything new and exciting thousands of light years away.

Anyway, the Perseus-Pisces Super-cluster is where the action is. I've heard the guys in that party-cluster are zipping around all over the place, getting into all sorts of sordid trouble.
  #98  
Old 07-16-2016, 07:56 PM
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Originally Posted by Tibby or Not Tibby View Post
Surely, the universe can allow more elegant pathways toward organic complexity resulting in high intelligence. Less branching speciation and a more homeostatic relationship with the environment may be the norm.
By definition, it can't really. Life is an energy store. If you aren't storing energy, you aren't alive. As such it's impossible for anything alive to be in a " homeostatic relationship with the environment ".

Quote:
Chemosynthesis as a “food” source, on a planet rich in the necessary inorganic chemicals should evolve less competitive (and less aggressive) species.
I can't see how that would make any difference at all. You've just described life on Earth as it is now, but without any ability to use light as an energy source. If anything that would competition even more fierce.

Quote:
What would drive life toward intelligence on such a planet? Perhaps the answer is simply that more complex, intelligent organisms obtain more chemosynthetic nourishment and have more offspring.
But that is competition. The organism producing more offspring is out competing the less intelligent lifeforms. That's exactly what happens here on Earth, only with a more fierce competition for energy sources.

Quote:
Population could be in homeostatic balance with their environment and they could be happy with that arrangement, with no desire to kill less advanced species or spread their seed outward into space. They would be very nice and content aliens—the kind I'd like to befriend.
Either all organisms are in homeostatic balance with their environment, or some are obtaining more chemosynthetic nourishment and having more offspring. Those two conditions are mutually exclusive.

Quote:
Put, let's say, octopuses on a fully aquatic planet and give them millions of years to evolve super-intelligence. They'd no doubt learn to build complex technology to master their environment, but I doubt they'd have the resources to develop rocketry or any other means of leaving their planet.
The first thing that any complex technology requires is a means to directly harness chemical energy. How that is done is unimportant, it may be through exothermic chemical reactions as on Earth, or through bio-engineering to harness enzyme systems, but without that ability to directly harness chemical energy, technology can't advance beyond horse and cart or wind power. So, if our octopods have an advanced technology then they have the resources to develop rocketry. Whether they choose to do so is another question, but they must have the resources in order to be an advanced technology.

Quote:
Maybe planets harboring life living under a mile of ice are most common. They could be quite intelligent, yet ignorant that outer space even exists.
That seems more plausible, though it still has problems.

Quote:
Alternately, perhaps there are other civilizations within the Milky Way that have mastered inter-stellar travel and focused signaling, but choose to do so between a group of stars in close proximity to them (beyond our earshot). I mean, how much space and how many planets does any civilization need to be satisfied (assuming they're not greedy, war-mongering bastards)? Surely, even a super-intelligent species would weigh risk/benefit and the further they travel, the more risk and cost is involved. They could populate enough planets and space-station colonies within a sphere of limited light-years to suit their needs for billions of years. Why go further than you have to? If I want a Big Mac, I'm going to drive to the McDonald's closest to home.
That has always been the important one for me.

The amount of energy needed to propel a spacecraft to light speed is infinite. I read somewhere that it would take more time, energy and engineering to propel a New York sized spaceship 5% of the way across the galaxy than it would to move Venus into an inhabitable orbit. To me that suggests that any civilisation capable of a space empire would just terraform the planets of the closest solar systems rather than colonising huge swathes of the galaxy. If each new planet takes a billion years to terraform and lasts 10 billion years, it's going to take a long time for anybody from the other side of the galaxy to start encroaching on us.
  #99  
Old 07-17-2016, 02:26 PM
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Originally Posted by Blake View Post
By definition, it can't really. Life is an energy store. If you aren't storing energy, you aren't alive. As such it's impossible for anything alive to be in a " homeostatic relationship with the environment ".
Why? Competition between individuals or other species may be the population homeostasis mechanism most common on Earth, but it's not the only possibility, and it may not be the most common mechanism on alien planets. My guess is that intelligences equal to or greater than ours would willingly regulate their population to suit their environment, without having to out-compete others. Choosing comfort and stability over an overarching drive to fill (/overfill) every available niche seems the smart move to me.

Quote:
I can't see how that would make any difference at all. You've just described life on Earth as it is now, but without any ability to use light as an energy source. If anything that would competition even more fierce.
Why? If a planet is populated with organisms that rely only on inorganic chemicals for food/energy and the planet has enough of those chemicals to adequately sustain the growing population, where does “more fierce” competition come in? And, a planetary population in self-regulated population balance that doesn't require organic matter to live should negate the competitive predator/prey model, I'd think. Admittedly, that model had much to do with evolving to intelligence on Earth, but, we're kicking around alternate methods that alien environments may employ.

We can include photosynthesis in the mix...but those pushy plants can be pretty competitive vying for sunlight.

Quote:
But that is competition. The organism producing more offspring is out competing the less intelligent lifeforms. That's exactly what happens here on Earth, only with a more fierce competition for energy sources.
Yes, that is exactly what happens on Earth, but I question whether it has to work that way on all alien planets given a different set of physical circumstances and alternate modes of evolution.

Quote:
Either all organisms are in homeostatic balance with their environment, or some are obtaining more chemosynthetic nourishment and having more offspring. Those two conditions are mutually exclusive.
Again, I'm assuming a planet with enough food/energy to feed all. Larger/more complex/more intelligent species may eat more and have more offspring, but not necessarily at the expense of other species. Each species could reach it's homeostatic population balance independent of other species, with little or no extinction taking place in the process (it would be nice to see your entire family tree, back to seedling).

A newly evolved species could have more offspring to start, to the point of comfortably filling its niche, then convert to replacement fertility level naturally, or with conscious intent. Admittedly, this is a bit far-fetched and would, at some point, require expansion beyond the confines of their home planet for the continuously speciating population. This may just be an extreme hypothetical, but something less extreme could be the norm. We see plenty of species on Earth, living in close proximity, that don't compete against each other. Plenty of symbiotic examples of various types, too. I'm simply expanding on that model as possibilities for alien environments.

Quote:
The first thing that any complex technology requires is a means to directly harness chemical energy. How that is done is unimportant, it may be through exothermic chemical reactions as on Earth, or through bio-engineering to harness enzyme systems, but without that ability to directly harness chemical energy, technology can't advance beyond horse and cart or wind power. So, if our octopods have an advanced technology then they have the resources to develop rocketry. Whether they choose to do so is another question, but they must have the resources in order to be an advanced technology.
I get your point, but I don't know if it's an absolute. However, the thought of an octopus riding a horse and cart is amusing (maybe a seahorse).

Given the resources available in a likely aquatic environment, isn't it possible, or even probable, our octopods could harness exothermic chemical reactions, and find the building blocks to build smart phones and whatnot, but still be unable to build and launch a rocket into outer space? I'm guessing they would first have to build a missile-launching submarine to launch the rocket and why would a race of octopus people bother to build a missile-launching submarine, if not to launch a rocket to a place they have no desire to explore? (At least I hope that's the case...because I have no desire to meet them, they could slap us around pretty good with those 8 arms).

This brings up an interesting side question, however: could a species evolve cognitively and be considered super-intelligent, yet not have the ability to build advanced technology?

Imagine an Earth where man destroys himself and bottle-nosed porpoises take center-stage in the brain department. Give them millions of years to evolve, with dominating their environment via advanced predation techniques (math skills could be involved), communication, socialization, etc. being the selection filter. But, they never acquire anything beyond flippers and mouths with which to manipulate their surroundings, so they can't build anything very complex, no less inter-planetary rocketry or communication. I'd consider them an advanced civilization (not technologically advanced, just cognitively advanced) with no chance of contacting us. Maybe those type of beings are common in the universe.

Quote:
That seems more plausible, though it still has problems.
A closed environment, opaque to the universe, rich enough in resources to evolve intelligence, but not enough to drill through a mile of ice. What are the problems?

Quote:
That has always been the important one for me.

The amount of energy needed to propel a spacecraft to light speed is infinite. I read somewhere that it would take more time, energy and engineering to propel a New York sized spaceship 5% of the way across the galaxy than it would to move Venus into an inhabitable orbit. To me that suggests that any civilisation capable of a space empire would just terraform the planets of the closest solar systems rather than colonising huge swathes of the galaxy. If each new planet takes a billion years to terraform and lasts 10 billion years, it's going to take a long time for anybody from the other side of the galaxy to start encroaching on us.
Anyway, the first few points of in my post #97 have little to do with the Fermi Paradox, they were just to offer a counter to dracoi's first point in #95.

I believe we agree on what's perhaps the most plausible reason we have not made contact with alien civilizations. It's not that they're not out there, it's that they don't have the need or means to get here.
  #100  
Old 07-17-2016, 03:45 PM
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Originally Posted by Nelson Pike View Post
Many contributors to this thread have tried to go beyond mere assumption.

Expert astrophysical consensus, including that of SETI proponent researchers, appears to be that Fermi's argument is a good one.

See quotation and link in reply #63.
Yes, and I agree with the idea, but for all the talk about aliens watching I Love Lucy we have only been broadcasting on the FM band (AM bounces off the ionosphere) since 1933 and, thanks to the inverse-square law, it's unlikely anyone has noticed us. Give it time.
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