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Space Science

Aliens and the Fermi Paradox 686

First time accepted submitter sayhem (1842674) writes Various explanations for why we don't see aliens have been proposed—perhaps interstellar travel is impossible or maybe civilizations are always self-destructive. But with every new discovery of a potentially habitable planet, the Fermi Paradox becomes increasingly mysterious. There could be hundreds of millions of potentially habitable worlds in the Milky Way alone. This impression is only reinforced by the recent discovery of a "Mega-Earth," a rocky planet 17 times more massive than the Earth but with only a thin atmosphere. Previously, it was thought that worlds this large would hold onto an atmosphere so thick that their surfaces would experience uninhabitable temperatures and pressures. But if this isn't true, there is a whole new category of potentially habitable real estate in the cosmos.
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Aliens and the Fermi Paradox

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  • by Anonymous Coward on Wednesday June 11, 2014 @08:01PM (#47218213)

    At a certain point that starts looking like an attractive option. If NASA announced that they've managed to create a warp bubble, no matter how small, then I'd say the low hanging fruit is that aliens are in contact with certain elements of humanity and that this isn't widely known because a huge percentage of the world would freak the fuck out.

    At Los Alamos, right around the time of the Fermi Paradox, everyone was agog at the green fireball phenomenon. One of the greatest collections of scientists ever assembled were pretty evenly split on the subject. Some though the the green balls of fire flying through the sky and changing direction as if being intelligently guided were some kind of secret earthly craft, while many other were certain they were extraterrestrial in origin. No one doubted they were real, however, and no one thought they were natural.

    You don't really hear about this, but it's part of what started Fermi along the way towards his paradox.

    As for the usual "OMG, nobody could keep that secret!" meme. Even if someone had 100% proof of alien encounters, the signal to noise ratio is assumed to be no signal and all noise. Someone could have been shouting the truth from the rooftops for forty years and nobody would care because they'd be lost in the din of people seeing little green men and anal probes.

    Between "every civilization eventually kills itself" and a high level conspiracy to keep the world from shitting their pants at alien life, I'll pick the conspiracy. The fact that half of humanity isn't really ready to stop killing one another over five thousand year old superhero stories is kind of telling. Hell, half of humanity is confused by shoes.

  • Re:Progenitors? (Score:5, Interesting)

    by Electricity Likes Me ( 1098643 ) on Wednesday June 11, 2014 @08:20PM (#47218319)

    We can't be.

    We weren't the first complicated life here. It took several mass extinctions, but then humanity as we know it took around 300,000 years to evolve from the ancestor primates, give or take a few million to get from the single-cell stage.

    So sans a few mass extinctions, someone would've been here are a lot sooner - and the Earth is 4 billion years old and we know planet formation doesn't seem to take that long.

    So given the size of the universe, we know from just here that there's definitely been life and intelligent life favorable conditions elsewhere just from the limited sample set we've collected. What we don't know is what happens to it - what's the "main sequence" behavior of technological civilizations like ours? What do they become?

    Of course, it's also entirely possible we actually are in particularly well governed galaxy and everyone is staying out of our way till we reach out and make first contact. Then we'll find out that Galactic Resolution 8A prohibited the international broadcasting of luminal RF in our direction or something.

  • Re:Progenitors? (Score:5, Interesting)

    by Firethorn ( 177587 ) on Wednesday June 11, 2014 @08:21PM (#47218323) Homepage Journal

    It may also be possible that we are part of a nature preserve, or that there are more than enough planets with similar conditions to inhabit, to not have to displace or destroy an entire culture.

    I've been told off for proposing the nature preserve idea. Various arguments were that the aliens would need a 'huge fleet' to stop colonization efforts from reaching our system, that we'd notice our neighboring systems are inhabited, etc...

    They didn't have a good response to my point that our radio reception efforts have been primitive enough that in order to 'hear' Alpha Centari the aliens would need to deliberately transmit an easy to intercept radio signal at us using several GW of power using the best dish technology we have.

    The Earth, at it's loudest(digital technology is actually making us 'quieter' on the interstellar scene), wouldn't be 'heard' by the Arecibo Observatory at distances over a light year.

    In short, I don't see an alien civilization beaming GW level signals at prospective systems more or less continously for millions of years in the vague hope that we'll notice and answer back. Meanwhile, we've been able to 'listen' for the equivalent of not even an eyeblink.

    Eh, whatever. My other pet theories are that by the time a civilization is capable of colonizing other solar systems it's either become too insular to want to bother(you give up a LOT going to another solar system), or so adopted to space that colonizing planets is no longer a thing. Which makes 'nature preserve' for potentially life-bearing planets, cradles for new civilizations, not an expensive strategy at all.

  • Re:Progenitors? (Score:4, Interesting)

    by Anonymous Coward on Wednesday June 11, 2014 @08:25PM (#47218349)

    There is so much a water and other elements key to life as we know it that have been floating around for billion of years.

    Unlikely? How can you know that?

    What's the probability of life beginning in the first place?

    What's the probability of life becoming complex?

    What's the probability of sentience evolving?

    There's no reasonable way to know what those probabilities really are. The only way to even get to the question is for all of them to have happened.

    And the fact that it took about 1/2 the lifetime of our Sun for them to happen could very well be an indicator that all three aren't very likely at all to happen before the sun's life runs its course for any other habitable planet.

  • Re:Progenitors? (Score:5, Interesting)

    by Anonymous Coward on Wednesday June 11, 2014 @08:42PM (#47218481)

    All stars and stellar generations are not the same. As the Universe ages, every generation of supernovae introduces more metals (which in astro means 'anything except hydrogen and helium') into the galactic medium. Stars significantly older than our sun are unlikely to have had enough metals to form lots of rocky planets. Or if they did, any intelligent life there would find many of the metals that we consider fairly rare to be virtually nonexistent.

    Conversely, in the far future when a large fraction of the ISM is heavier elements, the freak exception will the formation of rocky worlds small enough that the inhabitants on their surface can escape into space at all...

  • by WrongMonkey ( 1027334 ) on Wednesday June 11, 2014 @08:46PM (#47218509)
    The Rare Earth Hypothesis is still the strongest contender for the solution to the Fermi Paradox. Suppose that there are a hundred different conditions necessary for intelligent life to evolve. These could include basic requirements (like liquid water and protection from ionization radiation), up to more subtle components (like a moon that massive enough to cause tides or an axial tilt to create seasons). Until we have another data point for reference, any condition on Earth might be considered a necessary condition. If each of these conditions has an independent probability of 1 out 10 or less, then it very well could be that Earth is unique in the galaxy, possibly the the universe. The universe is big, but it is not 10^100 planets big.
  • Re:Progenitors? (Score:5, Interesting)

    by Sibko ( 1036168 ) on Wednesday June 11, 2014 @08:55PM (#47218581)
    Or maybe the universe is so competitive that anyone who announces their presence eats the bad end of a relativistic weapon.

    Who knows - maybe one's already headed for Earth. It's not like we have been hiding our radio transmissions or anything. Sure would be naive of us to assume aliens are all sunshine and rainbows and want nothing more than to love and hug us. Now granted, I think if relativistic weapons flying about were a real issue, we'd probably have seen evidence for it in the universe by now, but anyone who ascribes benevolence to aliens is just a fool ignoring every lesson nature has taught us on this planet.

    Personally, I'm against alien contact unless it's US doing the contacting. The kind of power-play dynamic where we're met by aliens only puts us at a serious disadvantage. We're basically blind right now. We need to stay silent, open our eyes and ears, and see what happens around us a little before we go shouting to the galaxy at large "Hey! Over here!"

    I think the only comforting fact about it all is that our biodiversity is probably the rarest thing about our planet - so if there is any value in that, any conquerors will at least leave our biosphere intact.
  • Re:Progenitors? (Score:5, Interesting)

    by Immerman ( 2627577 ) on Wednesday June 11, 2014 @09:07PM (#47218661)

    Well, it's been less than a century since we started broadcasting our existence as a technological species to the cosmos, the signals have only had a chance to reach a few hundred other planets so far. And through an accident of evolution our atmosphere was flooded with toxic oxygen early on. It's quite possible that any alien astronomers would have glanced at our world and thought "Whoa - an oxygen atmosphere, that's weird. What sort of hellish fire-stormed world do you imagine *that* would make for? Well, we're not going to find any life there, make a note in the logs and lets keep looking for more promising candidates."

    Not to mention the fact that even if we had an identical twin Earth around Alpha Centauri, one of our nearest neighbors, it's unlikely that we could detect their transmissions with our current radio telescopes - they would be lost in the much louder radio noise of their star. So I think it's still a little premature to assume there's any paradox at all. Technological civilizations could be orbiting practically every star in the galaxy, and unless one of them when out of their way to contact us (or someone else in the same line of transmission) we would have no idea they were there. Hell, we're barely beginning to reach the point where we could detect massive engineering projects like a Ringworld around even the nearest star

  • Re:Progenitors? (Score:5, Interesting)

    by tysonedwards ( 969693 ) on Wednesday June 11, 2014 @10:22PM (#47219055)
    Really, most of our broadcasts are now directed back towards earth via satellites, and any signals sent to space are of such a low intensity and so absurdly directional that the odds of it being detected are minuscule at best even with extremely sophisticated equipment sitting on the moon.

    That isn't to say that we can't *also* talk into space, but we have gone to highly directional, low powered communications systems as our primary means of communications as a species. Even AM, FM, VHF, UHF, and various Cellular transmissions are now directional and positioned in a longitudinal configuration to reduce power waste by broadcasting where people won't be (strait up).

    During the 50's and 60's, sure... we were broadcasting some very powerful signals into space simply because we as a civilization were trying to be as loud as possible to hit every inch of our planet. During that point in time, there is a chance that another culture, if they were of sufficient technological advancement (about where we are today or ahead of it) that they *could* have seen us if they were specifically surveying our star and it's planets.

    The bottom line is that like everything, intensity of any signal falls off at the square of the distance, and we are taking some major distances here. While those signals would be severely disrupted by the Oort Cloud, one would still see a deviation from the Cosmic Microwave Background Radiation as well as that of our star.

    And we didn't give a species like us much time to find us.
    And as long as we are talking like that, is it reasonable to also make a logical jump that a species that would have developed technologies necessary to detect us would have also implemented similar efficient means of communications for their species, as a result making them "less detectable" in a similarly short window?
  • Re:Progenitors? (Score:2, Interesting)

    by mestar ( 121800 ) on Wednesday June 11, 2014 @11:40PM (#47219399)

    That is a very simple and probably the most important explanation.

    Life does not need intelligence. In fact intelligence itself is a handicap, and a product of sexual selection and its handicap principle. (Same with elks' antlers and peacocks' tails.)

    We don't know how long do intelligent species exist. By using one smoothing technique, one can say that they live for average of 200k years.

    It's worse for nuclear civilisations. A guess by the same rule would say that they live for around 100 or so years.

  • by Adeptus_Luminati ( 634274 ) on Thursday June 12, 2014 @12:24AM (#47219591)

    1) 2011 "Out of the Blue" - Best researched UFO documentary: []
    2) 2001 Disclosure Project - Dozens of high ranking goverment+military officials testify publicly of aliens+UFOs: []
    3) 2013 Citizen's Hearing - 40 researchers and military/agency/political witnesses testify for 30 hours before 6 former congress members: [] (part 1)
    4) Bob Lazar Area51/S4 whistleblower - 10.5 hours of testimony : []
    5) Ex CIA death bed confession on reality of aliens/ufos - []
    6) List of countries that have disclosed UFO files: (loooong list) - http://www.disclosureproject.o... []

    I could go on, but there's already week's worth of material here alone.

  • Re: Progenitors? (Score:5, Interesting)

    by O('_')O_Bush ( 1162487 ) on Thursday June 12, 2014 @12:58AM (#47219683)
    Well, as has been pointed out before, just because life appears to stem from one thing, doesn't mean there wasn't a "Second Genesis" (or multitudes of them, even happening today). However, those other lifeforms have to compete for the same resources as better adapted ones (per natural selection). And then there are things that are "arguably life" that seem awfully close to life and awfully orthogonal to the existing tree, like viruses.

    But besides that, what amazes me is that we are not only the most intelligent life on earth (for some values of intelligence), but as far as we can tell, the most intelligent life to have ever developed on earth.

    This seems odd, given that there are so many other intelligent life (but nowhere near our level) like cetaceans, some birds (which are descended from Dinos, which had a longer time to evolve in interesting forms- not like early, ratlike mammals, to boot), other primates, some species of octopuses, and I am sure I can think of more examples.

    Maybe the trick is having a big brain and a body plan that is flexible enough to do many things, starting with a high metabolism. I would think that a therapod with human intelligence levels would have an awfully hard time building spaceships.

    And the brain consumes a lot of energy, which is why human muscles are relatively weak and energy efficient (also for endurance).

    In that sense, it is my opinion that life is probably common, but intelligent life is rare, maybe even extraordinary, and probably not inevitable for a planet or system.
  • Re:Progenitors? (Score:5, Interesting)

    by GigsVT ( 208848 ) on Thursday June 12, 2014 @01:04AM (#47219707) Journal

    Directionality is a mostly irrelevant consideration.

    The fact that an antenna is 9db or 30db higher in one direction quickly becomes irrelevant with the vast distances of space. Antennas don't work like flashlights. They are more like a light bulb with a two-way mirror on one side that reflects 50% of the light and lets 50% of it through out the back. At VHF and above, things like mountains act like mirrors that reflect signals straight up (among other directions), as well.

    You are somewhat wrong about AM... at least broadcast band AM is mostly only directional in the sense that there's dead zones straight off the ends of the dipole. They are shooting quite a bit of signal upward. Our ionosphere does strongly reflect and attenuate what would make it out to space in those bands though.

    This goes toward your comment about the 50s and 60s... we have far more powerful transmitters in operation now (some VHF TV the better part of 1 megawatt!), and in bands that aren't reflected by the ionosphere. If anything we are getting louder and louder.

    Unfortunately the first thing they might see of humanity is free-to-air broadcast TV, and just assume that we are all complete idiots.

  • Re:Progenitors? (Score:5, Interesting)

    by presidenteloco ( 659168 ) on Thursday June 12, 2014 @01:05AM (#47219711)

    You are right. We don't know for sure.
    But a large variety of elements with fundamentally different properties (different masses, different chemical bonding properties) yields a large vocabulary of different molecules with widely differing properties. This large vocabulary of structure allows for a large vocabulary of function, increasing the number of ways in which self-sustaining reaction groups (and eventually life) could occur.

  • by aepervius ( 535155 ) on Thursday June 12, 2014 @02:37AM (#47219975)

    The problem is that the power of the signal very rapidly went down (in 1/R^2) so even when we were broadcasting in the 50ies-60ies, our best signal did not even go beyond 1 light year before being indistinguishable from noise , in the best case scenario (actually probably much less depending on the signal). There are only 2 signals which went beyond the 1 or 2 LY, and those were intentional "we are here" signal, sent toward M10 i think (or was it M52?) and those signals were maybe a few dozen minutes all combined together.

    We would not be able to detect ourselves if we were located on our direct neighbor, 4 LY away, alpha centauri. By that point even our most powerful unintentional signal is beyond the noise floor (again except those few dozen minutes TOTAl over all our whole civilization time).

  • by zentext ( 1470769 ) on Thursday June 12, 2014 @02:50AM (#47220009)

    There are no old, space faring civilizations, for one inescapable reason. Technology is incompatible with species. No ifs or buts.

    Brief explanation: Life of any kind, in any environment must always evolve as species - defined as multiple beings sharing a common 'genetic code base' - regardless of how the information is encoded. In our case it's DNA. In all species the individuals serve as reproductive vectors for the code they carry, and individual survival of the fittest is required for any species to evolve and adapt to its environment. This implies that individuals also die - this is necessary, otherwise natural selection cannot operate, hence no evolution.

    Life is likely quite common in the Universe. Even if intelligence is statistically a rare development, there still should be countless instances, including plenty long ago, where 'long' means more than one star lifetime. So if intelligence results in technological cultures, including any kind of major engineering or space travel, where are they all? Even if such civilizations choose not to say hello to us, we should still see evidence of their works.
    But we don't. There's apparently nothing. Just elusive local UFO sightings, of unknown reliability. Certainly no daylight landings in city park, so to speak. That was just to restate the Fermi Paradox. Where is everyone? We exist, so there should be other civilizations like us, but much older and more technologically advanced.

    The logical error here, is to assume that technology is a continuum; that a society develops technology and then just continues to progress as a society - a cooperating population of individuals with a common genetic heritage, hence species.

    But this NEVER happens. Can never, will never, never does. Here's the inescapable reason.
    As a species develops technology, they inevitably discover the nature of the physical encoding scheme of their own biology. They develop the means to manipulate that coding scheme. Our fledgling genetic engineering is an example of how that starts. Quite rapidly the science of engineering their own coding will advance, since after all it's just a messy 'wet' version of computing science, and you can't have high tech without already being well advanced in computing technology.

    Somewhere in the process of unraveling their genetic coding, an intelligent species will also develop a science of consciousness - what we presently think of as AI, but which is ultimately about minds in general and how they work, including our own.

    As these two science threads advance, genetics and mind-science, it is 100% totally inevitable, that at some point individuals will gain the technological capability to begin modifying their own nature. We already do this - for instance using altered viruses to perform corrective edits of faulty DNA, eg the Cystic Fibrosis cure.
    But that is primitive stuff. Ultimately, gene engineering and AI technology provide individuals with the means to 'transcend' - to embark on total self re-engineering.

    At this point in the analysis, most people become incapable of logically carrying through. It seems there's another strong cognitive bias or two, not listed in the Wiki. One is that most people seem incapable of thinking impartially about the probability of termination of their own species. Another is a mental block against thinking logically about the likely motivations of entities that do not share the species-centric world-view of us genetic humans.

    Here's an idea: try thinking about an intelligent entity, that does NOT share any of our reproduction-motivated species-protective instincts. Nor any of the many cognitive biases in the Wiki list.
    Because that's what you get eventually, after any species-based individual achieves self-engineering capability, then immortality, an ability to deliberately optimize and enhance it's own mental capabilities, weed out instincts no longer appropriate to it's new existence as an immortal space-traveling entity.

    Anyway, the point is that 'technological speci

  • Re: Progenitors? (Score:5, Interesting)

    by sFurbo ( 1361249 ) on Thursday June 12, 2014 @07:26AM (#47220691)
    Out to the geostationary orbit? Not in the last 3.9 billion years. That is 350 times farther out than the limit of space. Anything that removed everything in that bubble would have killed all life on earth. The only event of that magnitude that we have evidence of created the moon.

"The one charm of marriage is that it makes a life of deception a neccessity." - Oscar Wilde