165 réponses à ce sujet

[Dean_the_Young]

tractrpl wrote...

The Reapers make a disturbingly effecient solution to the Fermi paradox. The Fermi paradox was positid by Henrico Fermi to his colleagues while on a lunch break while working on the Mahattan Project.  He came to the conclusion that it should take any spacefaring civilization at most a few million years to colonize the entire galaxy, even assuming ponderously slower than light travel. This is a blink of an eye in galactic time scales. Therefore, either advanced civilization don't exist, or something else might happen.

Several solutions to the Fermi paradox include:
1) The rarity of Earth. Either habitable worlds are very rare,we may be the only civilization
2) A star like the sun is unlikely to produce life, so most civilizations ingnore our star.  
3) It's rare for civilizations to survive past a certain technological level
4) Advanced civilizations evolve away from biological level, don't require habitable planets, and so ignore us
5) They have a non-intervention policy, note that this one is very implausible because if a civilization exists, the likelihood that some of its members decide to "break ranks" and make contact, for ill or for good, is overwhelming
6) There's only one advanced civilization in existence and it destroys all other civilizations it encounters.  This one is deemed probable by no one other than Stephen Hawking.

If number 6 is true, then basically we're all toast. The only way we could defeat such a civilization is through sheer luck, up to including their architect giving up and saying "I'm tired of winning all the time".  

Alternatively, Fermi could have had a poor grasp of the scale of the space involved, and what that means as a barrier to decision-making and organization. Slower than light transportation doesn't simply mean it takes a long time to get from a to b: it also means that it has a very, very high economic and political cost, and for few practical results.

In terms of resources, ease of capability, and practical returns, it's far more feasible and desirable to colonize your deserts and/or oceans rather than another solar system: not only is it cheaper to do, you can get a return on your investment.

[The Protheans]

Navasha wrote...

Honestly, I would imagine its a combination of many different reasons that end up being the "truth" of the matter.

For instance, while its nice to dream about an advanced future for humanity... its not actually very probable. The time we are living in right now could very well be the apex of human technology. Theres a pretty good chance that things will start to decline for humanity pretty rapidly.

The fact that we have pretty much abandoned our attempts to expand into space and begin to focus on rising domestic issues for which there is no real solution seems to indicate that we have reached our golden age of humanity and beginning to decline. Growing population, dwindling food and resources. Its hard to push for space exploration when people are hungry in the streets.

As resources and food become scarce, more wars and violence will escalate, which again will shift resources away from "dreaming".

Expanding into space requires an immense amount of initial investment of resources for a civilization, and I imagine most civilizations, including ours, are going to be unwilling to make that initial investment during that small window of opportunity of time when resources still are in abundance. Our window is rapidly closing. Our population explosion will quickly hit the limit of our resources in the near future.

Russia and China are planning to develop a more space friendly culture.
Food isn't scare is misused and is not efficently used, look at how much food the west dumps.
That's capitalism, it is a barrier to space exploration and human development.
Greedy people would rather make a profit dumping toxics rather than cleaning them up.

Modifié par The Protheans, 21 avril 2012 - 12:30 .

[Lonsecia]

tractrpl wrote...

The Reapers make a disturbingly effecient solution to the Fermi paradox. The Fermi paradox was positid by Henrico Fermi to his colleagues while on a lunch break while working on the Mahattan Project.  He came to the conclusion that it should take any spacefaring civilization at most a few million years to colonize the entire galaxy, even assuming ponderously slower than light travel. This is a blink of an eye in galactic time scales. Therefore, either advanced civilization don't exist, or something else might happen.

Several solutions to the Fermi paradox include:
1) The rarity of Earth. Either habitable worlds are very rare,we may be the only civilization
2) A star like the sun is unlikely to produce life, so most civilizations ingnore our star.  
3) It's rare for civilizations to survive past a certain technological level
4) Advanced civilizations evolve away from biological level, don't require habitable planets, and so ignore us
5) They have a non-intervention policy, note that this one is very implausible because if a civilization exists, the likelihood that some of its members decide to "break ranks" and make contact, for ill or for good, is overwhelming
6) There's only one advanced civilization in existence and it destroys all other civilizations it encounters.  This one is deemed probable by no one other than Stephen Hawking.

If number 6 is true, then basically we're all toast. The only way we could defeat such a civilization is through sheer luck, up to including their architect giving up and saying "I'm tired of winning all the time".  

If I were to hazard a guess, I would assume Hawking is referring to humans.

Personally, I'd think that if there are other lifeforms out there, then the fact it'd take so long just to reach other systems would mean ships themselves would have to support not only the current population of them, but also those that -have- to be born on the ship to then continue the journey if it's anything more than a a lifetime away.
I kinda picture ships like this being so vast that it would almost be worth just maintining the ship rather than trying to land on other planets and hope they're habitable. Not to mention that they'd have a similar issue as the Quarians in that their immune system would be compromised. I would also suspect that being stuck on a ship for generations would affect the races psyche and their appearance in some ways, as in light sensitivity, skin colouring and so on. Their psyche I would guess at changing due to the lack of contact with new people. Ideals and opinions would likely end up less disparate.
This in turn, to me, would make entirely possible that the ships could simply fail beyond a few centuries in space - if they lasted even that long. I mean by that the simply fact that you'd need to train engineers, doctors, police, teachers, farmers (for all those crops you need to grow onboard), etc and that as time goes on, the lack of diversity on the ship could lead to there being no one remotely capable of doing any of these jobs. I would guess that if the population as a whole were naturally inclined to act as engineers, then it might be less of an issue, but that wouldn't help with people who need medical attention, or keeping the colony educated in their history... Which would end up as irrelevent anyway due to the fact that upon leaving their solar system, they essentially are no longer part of that civilisation, and their knowledge of what has happened will cease as soon as they're out of range of their homeworld.
Stasis is one way to get around some of it, but you'd need some general safeguards to make sure the crew don't just die, or that the ship can sustain itself for long enough. After all, a space ship leaving its planet to travel to other galaxies is pretty much instantly obsolete. I say this because if they're travelling at speeds we know are attainable, then by the time they reach somewhere, at least decades will have passed. If they've managed to make one ship space worthy, they will manage again with massive improvements.
In theory, each ship would then not only make their predecessor obsolete, but also affect the way the crews evolve. I'd not be surprised if we did see an alien lifeform, that it'd almost be exclusively unique to its own ship due to some of what I've said above. Certainly I can't imagine any of the ships would have the same idealogy as their homeworld, which would have evolved along a path they can't know about, and in a different environment.

Basically I think that a major issue is that scientists on Earth can only think like, well, scientists on Earth. I know there's a calculation that supposedly can determine the likelihood of life on other planets, taking into account distance from their sun, atmosphere of the planet and so on. The issue with it is that any variable that is zero means the answer is too. The other issue with it, at least from a lay persons viewpoint, is that it seemingly favours not only disproving life on other planets, but also is obviously bias to the only life we actually know. A lot of people appear to believe that not only are we unique, but we're the only viable type of life in the universe, that everything was 'just right' to allow life.

But yeah, it's all speculation.

[ImmovableMover]

I'm pretty sure that its not "Probable" at all, possible sure but far, far from probable.

I would posit that the most logical reason that we have not encountered other civilisations, even given that other, more advanced civilisations exist, is that space is ****ING HUGE.

People just don't grasp how much empty space there is versus planets and stars and just how far apart they are, a species would need to break the speed limit of the universe just to make Space travel sensible.

IMO the "Reaper" hypothesis is the least likely as it follows zero logic nor precedence.

[Biotic_Warlock]

Erm i believe i have read articles saying scientists are finding that going faster then the speed of light is possible; but i forgot what anything said.

Mass relays would be flipping awesome.
Especially so i don't have to use the extortionate UK public transport

[tractrpl]

The Protheans wrote...

tractrpl wrote...



Ok, I guess I need to go into more detail.

1. Just google rare earth hypothesis. It's not a matter of opinion, it's a matter of lack of observational evidence. It's truth or non-truth is independant of anyone's opinions.  Earth-like planets may be rare or non-rare, we just don't have enough data yet. Part of this goes into possibility 2. The sun is not a very common star, like was previously assumed. Most stars like the sun are part of binary systems, and such systems make planetary orbits very unstable.  As far as yellow dwarf stars that are not binary, our sun is very interesting. Just a tiny fraction more mass, like 10% more mass, our sun would have a lifespan of 4 billion years. Complex life didn't evolve until the sun was about 4 billion years old, meaning such a sun is unlikely to produce a space-faring civilization.  Finally, we have night and day thanks to our huge moon, and the unusual circumstances under which it was formed (giant impact theory).  An earthlike planet orbiting around any star like ours is likely to have an unstable axis and it's days would be so long that one side would scorch, the other freeze. Plate techtonics would stop working, and it would lose its magnetic field within a billion years. All of this makes it unlikely that any earth-like planet in the habitable zone circling around a sun-like star would harbor any life without something like our moon, and the probability of something like our moon be created around an earthlike planet is unknown, but we can probably safely bet that such circumstances should be very, very rare.

Its all a matter of opinion and no human really knows the truth behind it so it probably if you say it is one thing the opposite is true and vice versa.

2. This one is tied to 1 because, like I said, an earth-like planet with something like our moon revolving around something like our sun is probably rediculously rare. However, it might be more common that life revolves around red dwarfs.  Red dwarfs are the most common type of star in our galaxy, but an earthlike planet revolving around such a star would be tidally locked, with one side always facing its sun.  Perhaps a large moon could be created around such a planet from a giant impact, giving the planet spin.  It's more likely that a gas giant could settle in the habitable zone around such a star and one of its large moons could harbor life. Living moons might be more common in the universe than earth-like planets.  Therefore, civilization that arise would look for life within red dwarf stars containing gas giants in the habitable zones.  Most civilizations might ignore sunlike stars because, as I've already mentioned, such stars are unlikely to harbor life, but red dwarfs might be more likely to harbor life.

This one is tied to #1

3. As for this one, all we have is human nature. However, scientists have used the notion that we're nothing special and usually have been proven right. More than likely, a civilized species would evolve from a predatory species because predators must be smarter than their prey. Likely they will also have territorial instincts as well.  A species with predatory instincts is far more likely to be hostile than a non-predatory species, but non-predatory species are not likely to become sentient.

One example doesn't justify it to used in every encounter.

4. Says our own dependance on technology. Eventually we get implants to make us stronger. Perhaps a little genetic engineering.  We start replacing more and more of our bodies with tech until we replace our own brains with tech. Eventually we BECOME tech.  Instead of the sci-fi notion that synthetics wipe out organics, it's more that we become synthetics.  As synthetics, we'd have no need of earthlike planets at all, because as synthetics, we don't need to eat biological food. Instead we just get energy directly from solar radiation and all the resources we need from mining asteroids and such.

What if a group of people don't want to get a implant that makes them more synthetic than organic

5. See explanation number 3

6. See explanation number 3. If humans have a tendancy to be selfish @ssholes, what makes you think that other civilizations would NOT be selfish @ssholes?

See previous points

1) Opinion implies that there is no truth, or that truth is relative. In this case there is an absolute truth, but the truth is unknown. Being unknown does not make it a matter of opinion, the facts are merely unknown. We can debate the evidence, but one or both of us will be definitely wrong.

3)  This is why there are multiple possibilities. This particular possibility is countered by other examples that I have listed.

[tractrpl]

Dean_the_Young wrote...

Alternatively, Fermi could have had a poor grasp of the scale of the space involved, and what that means as a barrier to decision-making and organization. Slower than light transportation doesn't simply mean it takes a long time to get from a to b: it also means that it has a very, very high economic and political cost, and for few practical results.

In terms of resources, ease of capability, and practical returns, it's far more feasible and desirable to colonize your deserts and/or oceans rather than another solar system: not only is it cheaper to do, you can get a return on your investment.

Fermi? Have a poor grasp of the scale of space involved? Please, human, not an undergraduate.

Fermi had a far better grasp of the scales involved than I think you do. His PhD in physics and Nobel Prize, in fact, gives me conclusive evidence that he's far better informed than you are. During his day, Faster Than Light travel was considered impossible and he knew with pretty good accuracy how big the galaxy was.  In fact, he assumed that the average distance between stars is even greater than we now know them to be, because we know that the galaxy is 70% more populated with stars than even Fermi was aware. All of his calculations were conducted using slower than light travel, and with stars spaced apart as sparsly as he knew, which as I mentioned is far more sparse than we now know it to be.

Imagine how much society has advanced in the last 2000 years. Now imagine how far we will advance in another 2000, now in another 50000. Now realize that those timescales are barely noticeable compared to the timescale of the universe.  In 50,000 years, we could easily have colonized nearby stars systems. Add a few million years, and we'll have colonized the entire galaxy. A few million years is still a blink of an eye compared to the age of a galaxy. Even if it took a billion years, that's basically a short amount of time compared to the age of the cosmos. If this is true, and most deem it unlikely that we're the first civilization, then why haven't we encountered other civilizations already? This is the Fermi Paradox.

[Jamie9]

It's just a matter of time until we discover something about physics that fundamentally changes the laws of everything. Look back in history, every few hundred years a MAJOR discovery seemingly makes most past discoveries irrelevant, or slightly off the mark.

The next one could be FTL, or a deeper understanding of matter, considering the Hadron Collider.

[Dean_the_Young]

If PhD's and Nobel's made people excellent in all forms of knowledge, the natural order of things would be an aristocracy of science. Being incredibly smart in some things, however, in no way applies excellence in other fields.

As you yourself are making an excellent if inadvertent example of, misreading patterns can lead to misleading conclusions. Knowledge hasn't grown exponentially over the last 2000 years: it hasn't even grown linearly. The sustained exponential growth of science is actually a recent development tied with the development of the transistor and computer, and this is a field where we are well aware that constant improvement will not continue indefinitely.

Fermi's calculations are simple and mathematical... and as many simple mathematical formulas for complex things are, they rely a lot on unsupported assumptions. An assumption of a drive for constant intersteallar expansion, for example.

This is a really, really fundamental question that needs to be answered before we can have an expectation of what 'should' be. Why should expansion across the galaxy be expected, when our own best case study (the many places of Earth) refuse to colonize two thirds of the planet we do have? Concentration, not dispersion, is our model for growth. Political decision making is our system for capital-intensive expansions of capabilities.


The weakness of scale I refer to isn't simply the scale of distances: it's the scale of decisionmaking needed to justify making those distances.

[tractrpl]

Dean_the_Young wrote...

If PhD's and Nobel's made people excellent in all forms of knowledge, the natural order of things would be an aristocracy of science. Being incredibly smart in some things, however, in no way applies excellence in other fields.

As you yourself are making an excellent if inadvertent example of, misreading patterns can lead to misleading conclusions. Knowledge hasn't grown exponentially over the last 2000 years: it hasn't even grown linearly. The sustained exponential growth of science is actually a recent development tied with the development of the transistor and computer, and this is a field where we are well aware that constant improvement will not continue indefinitely.

Fermi's calculations are simple and mathematical... and as many simple mathematical formulas for complex things are, they rely a lot on unsupported assumptions. An assumption of a drive for constant intersteallar expansion, for example.

This is a really, really fundamental question that needs to be answered before we can have an expectation of what 'should' be. Why should expansion across the galaxy be expected, when our own best case study (the many places of Earth) refuse to colonize two thirds of the planet we do have? Concentration, not dispersion, is our model for growth. Political decision making is our system for capital-intensive expansions of capabilities.


The weakness of scale I refer to isn't simply the scale of distances: it's the scale of decisionmaking needed to justify making those distances.

It should be noted that Fermi accounted for all of this in his calculations.  He was very, very pessimistic in how long it would take a civilization to start leaving its homeworld. It's very difficult to predict how far we would advance in 50,000 years, but seeing as even as NASA's funding is being cut, we have private companies already planning to make profits from space, including mining asteroids. Governments could completely abandon space at this point and we could still end up colonizing space. We have limited resources here. It's very rational to assume we'll look towards space to acquire more of those resources, and we're finding better and more efficient ways of propulsion to make spaceflight cheaper, easier, and more accessible. 

[tractrpl]

Joccaren wrote...

Ummm. No.
Not probable. Possible? Sure. Probable? No.

I agree, but I wanted a more eye catching thread topic. So sue me. 

[NoSpin]

It saddens me to think that the ending controversy has taken our focus off threads like this one, what a great topic!

All of those are very possible, my only problem is #1. Of course habitable worlds are rare in the universe, but that doesn't put an ounce of doubt in my mind that there are TONS of worlds out there with some form of intelligent life.

What sucks is, by the time we finally get our heads out of you know where, give space travel the attention it deserves and actually DO find somebody else out there.....we will all be LOOOOONG dead.

[General User]

We've learned much since Fermi's day, namely just how lucky we've been.

After all, what are the chances that a given galaxy will have a low enough radiation background that life as we know it could even develop in the first place?

Similarly, what are the chances that a star will be neither so hot that it simply fries any planets that might form around it, or conversely leaves them bitter-cold?

What are the chances that a planet will form at the proper distance from the right type of star to make possible for that planet to have liquid water on it's surface? And what are the chances that such a planet will have the atmosphere that allows it retain liquid water for extended periods of time?

And even if a planet with that temperature range happened to form, what are the chances that such a planet will have or (even more remarkably) be able to acquire the water, carbon, oxygen, etc., etc., to make life possible?

And, perhaps most unlikely of all, what are the chances that a terrestrial planet, with abundant water and everything chemistry of life needs to take place, will have the tremendous good fortune to experience the exact right type of impact early in it's history to ensure that the planet has a single, large, rotation/climate stabilizing moon?

And that's just out planet. We've also bee incredibly fortunate to be located in a relatively stable solar system, with gas giants that have settled into stable orbits that help shield the rocky inner planets from comet/meteor impacts rather than simply migrate sunward, swallowing the smaller planets whole or knocking them out of the solar system entirely.

And still that's just setting up the stage! There's no reason for even a planet as blessed with fortune as our has been to EVER give rise to sapient life. Life on Earth existed for almost 3.8 billion years, but creatures that could master fire (let alone try their hand at space flight) have only existed in the last 2 million or so.

The Earth and the Human race have been the beneficiaries of so many strokes of out outrageously good fortune that the odds against any similar chain of events happening elsewhere in the entire universe are simply... astronomical (pun intended).

Why have we never met any aliens? Most likely, because there are none. Or so few, and so distant that we'll likely never meet.

[tractrpl]

NoSpin wrote...

It saddens me to think that the ending controversy has taken our focus off threads like this one, what a great topic!

All of those are very possible, my only problem is #1. Of course habitable worlds are rare in the universe, but that doesn't put an ounce of doubt in my mind that there are TONS of worlds out there with some form of intelligent life.

What sucks is, by the time we finally get our heads out of you know where, give space travel the attention it deserves and actually DO find somebody else out there.....we will all be LOOOOONG dead.

I might have to specify what "rare" means. Rare would mean that in the entire galaxy, comprising approximately half a trillion stars, there may only be only 1 or 2 planets capable of supporting the evolution of complex lifeforms. Even if there are as many as 50 that would still fit the definition of "rare", but rare earth hypothesizers estimate have used some slick calculations to estimate the probablility of an earth-like world, with all the things necessary for that definition (rapidly spinning globe, moon needed for tidal interactions which also maintains plate techtonics and maintains our magnetic field around a sun-like yellow dwarf capable of remaining main sequence for 8+ billion years) to be somewhere on the order of about 0.5. There is at least one earth in the galaxy, obviously, so this makes the likelihood of another earth-like planet to exist in the entire galaxy approximately 25%.

[tractrpl]

General User wrote...

Why have we never met any aliens? Most likely, because there are none. Or so few, and so distant that we'll likely never meet.

The Fermi paradox states that if any other alien civilization exists, there's a 50% chance they're more advanced than we are. If true, they should be more advance by millions, if not a billion years or more than us, and we should have definitely contacted them by now.

Another interesting thing about the rare earth hypothesis is that a galaxy like ours seems even less likely to produce an earth-like planet, even if it contains more stars. Most rare earth hypothesis subscribers believe a galaxy like the Large and small magellenic cloud is likely to contain several earth like planets.

[General User]

tractrpl wrote...

General User wrote...

Why have we never met any aliens? Most likely, because there are none. Or so few, and so distant that we'll likely never meet.

The Fermi paradox states that if any other alien civilization exists, there's a 50% chance they're more advanced than we are. If true, they should be more advance by millions, if not a billion years or more than us, and we should have definitely contacted them by now.

Another interesting thing about the rare earth hypothesis is that a galaxy like ours seems even less likely to produce an earth-like planet, even if it contains more stars. Most rare earth hypothesis subscribers believe a galaxy like the Large and small magellenic cloud is likely to contain several earth like planets.

The thing that gets me is that even if you do find an earth-like planet, the chances are overwhelmingly against it having been the home to an alien "civilzation."  Of all the remarkable, incredible chances and coincidences that gave rise to our Earth, an equal, if not greater, number went into our evolution as a sapient race.

When you look at all those strokes of good fortune in our astronomical, geological, and biological history, the "we are alone" option looks better and better.

[Drummernate]

Stephen Hawking is creating the Geth.

Sorry Quarians. You are obsolete.

[tractrpl]

General User wrote...

tractrpl wrote...

General User wrote...

Why have we never met any aliens? Most likely, because there are none. Or so few, and so distant that we'll likely never meet.

The Fermi paradox states that if any other alien civilization exists, there's a 50% chance they're more advanced than we are. If true, they should be more advance by millions, if not a billion years or more than us, and we should have definitely contacted them by now.

Another interesting thing about the rare earth hypothesis is that a galaxy like ours seems even less likely to produce an earth-like planet, even if it contains more stars. Most rare earth hypothesis subscribers believe a galaxy like the Large and small magellenic cloud is likely to contain several earth like planets.

The thing that gets me is that even if you do find an earth-like planet, the chances are overwhelmingly against it having been the home to an alien "civilzation."  Of all the remarkable, incredible chances and coincidences that gave rise to our Earth, an equal, if not greater, number went into our evolution as a sapient race.

When you look at all those strokes of good fortune in our astronomical, geological, and biological history, the "we are alone" option looks better and better.

Many scientists disagree.  It may have taken about 4 billion years for a civilization to evolve on our planet, but that was because complex life wasn't able to evolve until about 500 million years ago. Complex life wasn't able to evolve because there was too much iron in our oceans, which prevented oxygen from accumulating in the atmosphere and oceans. Bacteria and other prokaryotes had to clense the iron from the oceans. Once this was accomplished, complex life evolved at a dizzying rate. It appears the only reason civilizations didn't evolve sooner was because as soon as life got suffieciently complex, a mass extinction would occur. In other words, if the dinosaurs weren't wiped out, it's very likely that there'd be an intelligent dinosaur species civilization flourishing on our planet and beyond, and would have been flourishing for millions of years already by now.

So, in short, all we need to find is a planet that has had enough time for its microorganisms to cleanse its oceans of iron. On such a planet, we should find complex life, and likely, civilization.

Modifié par tractrpl, 21 avril 2012 - 09:06 .

[tractrpl]

Drummernate wrote...

Stephen Hawking is creating the Geth.

Sorry Quarians. You are obsolete.

That would be humans which are obsolete. If Hawking could create synthetic life, he'd do so, and tranfer his mind into that mechanical construct. I'm sure he's sick of being confined to that wheelchair by now.

[PillarBiter]

tractrpl wrote...

1) The rarity of Earth. Either habitable worlds are very rare,we may be the only civilization
2) A star like the sun is unlikely to produce life, so most civilizations ingnore our star.  
3) It's rare for civilizations to survive past a certain technological level
4) Advanced civilizations evolve away from biological level, don't require habitable planets, and so ignore us
5) They have a non-intervention policy, note that this one is very implausible because if a civilization exists, the likelihood that some of its members decide to "break ranks" and make contact, for ill or for good, is overwhelming
6) There's only one advanced civilization in existence and it destroys all other civilizations it encounters.  This one is deemed probable by no one other than Stephen Hawking.

A fun paradox indeed to think through. A couple of my thoughts:

1) To me there are only 2 possibilities, either we're alone, or there is a LOT of life. The first one actually raises way too many philosophical questions, so I prefer to believe number 2. It makes more logical sense. But I don't exclude
2) This i find a stupid answer. If an alien race is advanced enough and willing to search for life other then their own, they would be remiss to skip even a star with the ever so slightest ability to produce life.
3) Most likely, in my humble opinion. I am pretty confident that the human race will wipe itself out before we reach other habitable places.
4) Possible, but then, they'd still go through an expansion and exploration phase (though not necessairily all civilisations) before reaching such a level, and we'd still be discovered.
5) actually possible, in my opinion. and to respond to the OP's thoughts on rank-breaking: You're applying human logic. There's no way to know if aliens think like us. Maybe they are hive-minded. Maybe they actually have other's best interests at heart. You don't know.
6) Well humans would do it.. So I don't see why other species wouldn't. But don't worry, if I've learned anything from stories, it's that the americans will save us. And. well, if they do wipe us all out, still a better ending then mass effect 3.

[General User]

tractrpl wrote...

General User wrote...

tractrpl wrote...

General User wrote...

Why have we never met any aliens? Most likely, because there are none. Or so few, and so distant that we'll likely never meet.

The Fermi paradox states that if any other alien civilization exists, there's a 50% chance they're more advanced than we are. If true, they should be more advance by millions, if not a billion years or more than us, and we should have definitely contacted them by now.

Another interesting thing about the rare earth hypothesis is that a galaxy like ours seems even less likely to produce an earth-like planet, even if it contains more stars. Most rare earth hypothesis subscribers believe a galaxy like the Large and small magellenic cloud is likely to contain several earth like planets.

The thing that gets me is that even if you do find an earth-like planet, the chances are overwhelmingly against it having been the home to an alien "civilzation."  Of all the remarkable, incredible chances and coincidences that gave rise to our Earth, an equal, if not greater, number went into our evolution as a sapient race.

When you look at all those strokes of good fortune in our astronomical, geological, and biological history, the "we are alone" option looks better and better.

Many scientists disagree.  It may have taken about 4 billion years for a civilization to evolve on our planet, but that was because complex life wasn't able to evolve until about 500 million years ago. Complex life wasn't able to evolve because there was too much iron in our oceans, which prevented oxygen from accumulating in the atmosphere and oceans. Bacteria and other prokaryotes had to clense the iron from the oceans. Once this was accomplished, complex life evolved at a dizzying rate. It appears the only reason civilizations didn't evolve sooner was because as soon as life got suffieciently complex, a mass extinction would occur. In other words, if the dinosaurs weren't wiped out, it's very likely that there'd be an intelligent dinosaur species civilization flourishing on our planet and beyond, and would have been flourishing for millions of years already by now.

So, in short, all we need to find is a planet that has had enough time for its microorganisms to cleanse its oceans of iron. On such a planet, we should find complex life, and likely, civilization.

And I (not surprisingly) disagree with those scientists. 

Largely because I know that there's no set course evolution is bound to take.  Early in Earth's history bacteria evolved in such a way that they ended up transforming the Earth into a more hospitable place.  But there's no reason this had to be so.  It was basically yet another stroke of outrageously good fortune that this occurred.

I also disagree that if/when sophisticated life does develop on a planet that there is any inherent reason it should tend towards intelligence.  The only reason it did on Earth was because of the relatively specific environmental and biological factors at work in Africa's Rift Valley.  Alter any of the circumstances our proto-hominid ancestors faced even a little and we could easily have "leveled off" in terms of intelligence much as our Great Ape relatives did.

And major extinction events are another whole enchilada all by themselves.  That the fates should align in just such a way that mass extinctions would "clear the way" for sapient life to develop without killing it off is once more an incredible stroke of good fortune.  AYYHS, we are still not entirely out of that particular killzone ourselves.

So not only does so very much have to go right for a civilization of sapients to come into being, but so very much has to not go wrong as well.  So very many chances and coincidences went into our and our planet's development that, even as vast as the Universe is, if it turned out that we really are alone (apart from bacteria and such), I would not be at all surprised.

Modifié par General User, 21 avril 2012 - 09:33 .

[Doomhams]

Or secret option number 7, his assumption is wrong.

Or secret option number 8, aliens have been here and they see no reason to deal with us in anyway. We have nothing to offer them so they ignore us, which is perfectly plausible. Do you go out of your way to deal with a group of people that you think has nothing to offer you once you find them?

[BeDotWe]

tractrpl wrote...

The Reapers make a disturbingly effecient solution to the Fermi paradox. The Fermi paradox was positid by Henrico Fermi to his colleagues while on a lunch break while working on the Mahattan Project.  He came to the conclusion that it should take any spacefaring civilization at most a few million years to colonize the entire galaxy, even assuming ponderously slower than light travel. This is a blink of an eye in galactic time scales. Therefore, either advanced civilization don't exist, or something else might happen.

Several solutions to the Fermi paradox include:
1) The rarity of Earth. Either habitable worlds are very rare,we may be the only civilization
2) A star like the sun is unlikely to produce life, so most civilizations ingnore our star.  
3) It's rare for civilizations to survive past a certain technological level
4) Advanced civilizations evolve away from biological level, don't require habitable planets, and so ignore us
5) They have a non-intervention policy, note that this one is very implausible because if a civilization exists, the likelihood that some of its members decide to "break ranks" and make contact, for ill or for good, is overwhelming
6) There's only one advanced civilization in existence and it destroys all other civilizations it encounters.  This one is deemed probable by no one other than Stephen Hawking.

If number 6 is true, then basically we're all toast. The only way we could defeat such a civilization is through sheer luck, up to including their architect giving up and saying "I'm tired of winning all the time".  

You should read the book called The Singularity is Near by Kurzweil. He imagines that the humans will become "Reaper"-like being a few decades into the future. I made a thread about it if you want to read (shameless advertisement) : 
http://social.biowar.../index/11252092 

[my Aim is True]

Also important to note is that civilizations that develop advanced space travel probably develop advanced AI around the same time. A synthetic is better suited to space travel and may become the dominant life form by eliminating organic life, or via organics voluntarily merging with synthetics to create Reaper like forms.

[Filanwizard]

When we stop watching reality TV, and stop education from being a for profit business maybe then we will crack the science needed for FTL travel.

I bet lots of good minds go to waste simply because of finances not being able to send them to the best engineering schools.*

*Note this mostly applies to here in the US where our education system can shut people out just due to wallet size and not knowing the right people.