Why Habitable Exoplanets Are Bad News for Humanity’s Future

By Andrew Snyder-Beattie, University of Oxford | April 24, 2014 11:21 am

PIA10363 exoplanetThis article was originally published on The Conversation.

Last week, scientists announced the discovery of Kepler-186f, a planet 492 light years away in the Cygnus constellation. Kepler-186f is special because it marks the first planet almost exactly the same size as Earth orbiting in the “habitable zone” – the distance from a star in which we might expect liquid water, and perhaps life.

What did not make the news, however, is that this discovery also slightly increases how much credence we give to the possibility of near-term human extinction. This because of a concept known as the Great Filter.

The Great Filter is an argument that attempts to resolve the Fermi Paradox: why have we not found aliens, despite the existence of hundreds of billions of solar systems in our galactic neighborhood in which life might evolve? As the namesake physicist Enrico Fermi noted, it seems rather extraordinary that not a single extraterrestrial signal or engineering project has been detected (UFO conspiracy theorists notwithstanding).

This apparent absence of thriving extraterrestrial civilizations suggests that at least one of the steps from humble planet to interstellar civilization is exceedingly unlikely. The absence could be caused because either intelligent life is extremely rare or intelligent life has a tendency to go extinct. This bottleneck for the emergence of alien civilizations from any one of the many billions of planets is referred to as the Great Filter.

Are We Alone?

What exactly is causing this bottleneck has been the subject of debate for more than 50 years. Explanations could include a paucity of Earth-like planets or self-replicating molecules. Other possibilities could be an improbable jump from simple prokaryotic life (cells without specialized parts) to more complex eukaryotic life – after all, this transition took well over a billion years on Earth.

Proponents of this “Rare Earth” hypothesis also argue that the evolution of complex life requires an exceedingly large number of perfect conditions. In addition to Earth being in the habitable zone of the sun, our star must be far enough away from the galactic centre to avoid destructive radiation, our gas giants must be massive enough to sweep asteroids from Earth’s trajectory, and our unusually large moon stabilizes the axial tilt that gives us different seasons.

These are just a few prerequisites for complex life. The emergence of symbolic language, tools and intelligence could require other such “perfect conditions” as well.

Or Is the Filter Ahead of Us?

While emergence of intelligent life could be rare, the silence could also be the result of intelligent life emerging frequently but subsequently failing to survive for long. Might every sufficiently advanced civilization stumble across a suicidal technology or unsustainable trajectory? We know that a Great Filter prevents the emergence of prosperous interstellar civilizations, but we don’t know whether or not it lies in humanity’s past or awaits us in the future.

For 200,000 years humanity has survived supervolcanoes, asteroid impacts, and naturally occurring pandemics. But our track record of survival is limited to just a few decades in the presence of nuclear weaponry. And we have no track record at all of surviving many of the radically novel technologies that are likely to arrive this century.

Esteemed scientists such as Astronomer Royal Martin Rees at the Cambridge Center for the Study of Existential Risk point to advances in biotechnology as being potentially catastrophic. Others such as Stephen Hawking, Max Tegmark and Stuart Russell, also with the Cambridge Center, have expressed serious concern about the exotic but understudied possibility of machine superintelligence.

Let’s Hope Kepler-186f is Barren

When the Fermi Paradox was initially proposed, it was thought that planets themselves were rare. Since then, however, the tools of astronomy have revealed the existence of hundreds of exoplanets. That just seems to be the tip of the iceberg.

But each new discovery of an Earth-like planet in the habitable zone, such as Kepler-186f, makes it less plausible that there are simply no planets aside from Earth that might support life. The Great Filter is thus more likely to be lurking in the path between habitable planet and flourishing civilization.

If Kepler-186f is teeming with intelligent life, then that would be really bad news for humanity. For that fact would push back the Great Filter’s position further into the technological stages of a civilization’s development. We might then expect that catastrophe awaits both our extraterrestrial companions and ourselves.

In the case of Kepler-186f, we still have many reasons to think intelligent life might not emerge. The atmosphere might be too thin to prevent freezing, or the planet might be tidally locked, causing a relatively static environment. Discovery of these hostile conditions should be cause for celebration. As philosopher Nick Bostrom once said:

The silence of the night sky is golden … in the search for extraterrestrial life, no news is good news. It promises a potentially great future for humanity.

The Conversation

Image courtesy NASA

CATEGORIZED UNDER: Space & Physics, Top Posts
MORE ABOUT: exoplanets
  • smerge

    There could be any number of alien civilizations lurking in space. They may have already visited earth and dismissed it as too primitive or undesirable. We cannot fear that life does not exist elsewhere just because it hasn’t made itself apparent in an age where humanity could understand what it was looking at. We may have missed our chance to experience alien life because they arrived just a few hundred or a thousand years ago and they aren’t broadcasting in near space using radio waves.

    • SixSixSix

      I think they were highly attracted at first, but found our women way too pushy. Just saying..

  • http://blogs.discovermagazine.com Marshall Gatten

    So pessimistic. I’ll admit the Great Filter is a sobering hypothesis. But there’s another explanation: Perhaps technologies like a working Alcubierre Drive are truly impossible. If we really can’t find a way around the cosmic speed limit, then the distances are simply too vast. We aren’t seeing aliens because they are too far away. We have yet to build an instrument that could detect life on an exoplanet (though at least two are currently in the works), so we can’t see it in situ. And they are too far away to come here, so we can’t see them here. And we’re too far from them to go there, so we can’t see them there. The universe could be teeming with life, but we’re as yet too blind to see it. But the blinders will come off soon. There may be other civilizations with amazing technology, currently watching our dinosaurs, and once we can see them, we’ll watch their dinosaurs for a while. We’ll wonder what they’re up to today. We’ll ponder about whether or not they’ve developed intelligence from the humble beginnings we get to witness. In the meantime, they’ll look back on our own beginnings and wonder the same thing. And we’ll remain forever isolated, but knowing for the first time that we are not alone in our isolation.

    • Lot Saucedo

      Excellent post ! Another thing that has always caused me to think that our scientists are thinking only in a small box, is that they are always looking for life such OUR type of life. How can we ever be sure that life in the HUGE universe is ONLY in the form we see on Earth ??? Water, oxygen … those elements are needed for OUR type of life … what if there’s life capable of no breathing anything at all ? Or, breathing sulfuric acid ? ( there is a type of bacteria or organisms here on Earth, under deep water, that breathe that around the volcanic fumes ) …. if we just look outside for life like ours, we are limiting ourselves …

      • RMR

        You are so right Lot Saucedo, we need to stop assuming that we are so superior that our likenesses are the only form in the universe, therefore, no other life forms evolve without oxygen, Sunlight, red blood cells, water, and so forth. If we are the only living life form throughout millions and billions of galaxies, then this will make us the last life forms left after others died out, therefore, extinct, or the first life forms to evolved, but either way this is too scary to comprehend on every level of thinking.

        • SixSixSix

          You also need to stop using biological models. Once an intelligence reaches even our pathetic level, yes there are conflicting reports of intelligent life on the third rock from the sun, then the deployment of far more effective physical mechanisms becomes possible. Good luck finding any biological life form that operates in the gigahertz range like the cell phone in your pocket.

      • Grey

        I agree that we are “thinking only in a small box”, but I also believe that we know life is capable with the available resources and circumstances here on earth, and we should focus our efforts to looking for life like us.

        Until we have the capability to search every planet and every solar system, I think we should look where we might expect life, and not where we don’t expect life. I can only hope that we will have the resources at some point to send probes to each and every planet.

    • SixSixSix

      Given the age of the universe, a distance of 500 light years is a trifling. Aliens with a one billion year lead might just have found a way to get around, one would thing.

      • disqus_atlq8Zmtsd

        Assuming that the speed of light can’t be overtaken by any level of technology, 500 light years is still a phenomenally long distance to travel. If Isaac Newton had set out at the speed of light on the day of his birth, he still wouldn’t be there for about 125 years.

        The light reaching that planet right now would be from the year 1514, so certainly there would not be any radio signals to receive even if they had sufficiently powerful sensors to detect our unbelievably faint signal.

        Simply put, it sure looks like there are some absolute limits on what technology can achieve regardless of how advanced. That being the case, the age of the civilization simply may not matter.

        • SixSixSix

          OK, but you assume that we reached the same level of maturity at the same time. But we are late starters. Our star system is only some four or five billion years old and made out of stuff that was already old when it began to form. So one would think their would be civilization far, far ahead of us and there would be many of them if the emergence of life and sentient beings is not a fluke. As for dealing with the time scale, there are life forms on Earth over 2,000 years old. Surely elsewhere there must be life on time scales at least as long as our and much longer too. The silence is a puzzle, especially after years of SETI. Not a final answer, but legitimately can be called a puzzle at this stage.

          • disqus_atlq8Zmtsd

            Is it silence, or are we too far away to hear? If they aren’t specifically trying to communicate with us (why would they? They would not have received a signal from us yet), then I wouldn’t expect any signal to be detectable.

          • SixSixSix

            If they have been bleeding indiscriminately all over the electromagnetic spectrum like we do, but for the last billion years, I think the signal would be here by now.

          • Steve Marethyu

            Um, the edge of the observable universe is 13 billion, give or take, light years from us. A billion years of sending out a signal, which in and of itself would be a feat to imagine a society sending out signals for a billion years, would still have only reached 1/13 of the way, and in terms of the distance left to travel would actually be much larger of an unreached area (or volume assuming the universe is spread out in all directions.) I think if in a billion years we haven’t heard a signal, we still wouldn’t be able to rule out other life on distant planets. There are so many factors that could limit the ability for us to receive such a message.

          • Steve Marethyu

            SixSixSix- We’re late starters, but how do you reach high levels of civilization without the higher elements required by the death of earlier generations of stars? Doesn’t it stand to reason that intelligent life and the civilization required to send out signals that could be received by another planet, presupposes that the planet have those higher elements, and that life have time to evolve? It seems to me that a late start is almost a prerequisite.

        • Steve Marethyu

          Well said disqus. It’s what I’ve been thinking about this, but you put it more succintly.

    • Arborine

      Aye – the Fermi paradox as it stands at the moment says more about the limitations of our measurements than it does about the fate of the cosmos. If the, well, Fermi calculations (as in estimation) I’m doing right now are anything to go by, Alpha Centauri could be swarming with antimatter torch rockets and we wouldn’t be able to see them with our current measurements – what’s some more gamma rays when you’re looking at the neighborhood of a yellow star?
      Even then, it’s all based in a lot of very confidently-made assumptions about “the sort of civilization we expect our descendents to build,” that we’re making on limited data and some very biased extrapolation about culture,values and people being people, to say nothing of Zarminans being Zarminans (just to pull an exoplanet out of the hat at random).

    • OregonIan

      I agree. This article is really pessimistic and arrogant. One other possible reason for not finding alien life forms is that they are hiding. It seems reasonable to assume that any species advanced to the point of interstellar travel also would have camouflage or some technology allowing it to evade detection.

      • humble_pedantic

        yeah, people seem to forget that if a civ develops working FTL they could literally out run their radio signals with a ship and generate an inverse to cancel them out thus stopping the propagation .

    • JVM

      I’ve wondered if its all just simple and not so complex, and I will add pessimistic after this article… Just a Novice here, I am right in assumption we can’t see so well to the opposing spiral arm of our galaxy? That being said the fact that there is an opposing spiral arm, says the odds of a Earth like of incredible likeness is there, then it would follow with teaming life. The only unfortunate fact might BE without a asteroid or comet impact that teaming life might be Reptilian, and with a nasty disposition towards You Know Who? Us!

      • denni

        or maybe a civilization though it best to be little house on the prairie ish..simple

  • Carlos José

    I guess Enrico Fermi drove the conclusion to a narrow two apocalyptic views because he lived in a different era. He is considered one of the fathers of the atomic bomb, he may tend to have a apocalyptic view derived from the world he lived on. Three things in his paradox may be not right.
    First, that travel faster or at light speed is possible, since the interstellar travel at lower speeds may exceeds a lifespan of most life forms in the universe.
    Second, more important than have the technology the civilization need first a motivation to go to other stellar systems. Considering the vast amount of space one might need to travel and the efforts involved, the real question, rather than simple mathematics extrapolation may need to consider the motivation. Our species certainly has a curiosity spirit, but we can’t assume that this “need for discovery” is present on other civilizations around the universe.
    And the third problem is that the paradox assumes that the planet never had a visitor from out of space, but we are here for just 200 000 years, and we are tracking history more or less for a few thousand years. So maybe we already had visitors in the past. There is a lot of things to consider.
    A million year civilization may be so evolved that they simply don’t care about the infant species like us. The same way that we let those isolated tribes in Amazon living as they want to.
    To preserve them we need to let they think they are alone in the world rather then go there and pay a visit. Maybe we are just a isolated tribe on our universal neighborhood.

    • Dennis

      I think the isolated tribe is a great consideration. Lack of curiosity is another great consideration. On earth, there are cultures that for thousands of years, were equally intellectual, but had different priorities as far as technology and civilization. Native Americans were more about harmony (and their laws were many of the key laws adopted by the constitution) and while aborigines in Australia didn’t pursue technology, they do have a verbal history that dates back 8000 years. Those cultures colliding with Europeans through global exploration is really the only thing that seemed to push those cultures into a technological society. So maybe the technological intelligent species are the rarity. And, of course, the time between apocalyptic meteors could also narrow the number of species that are allowed to evolve that far. If a mass extinction event that devastatingly changes climate and spawns oppressive religions occurs every 100,000 years or more, that could throw civilization back into tribal societies for decades or centuries every time it happens. And that could lead to extinction, which might take another billion years to restart. The dinosaurs certainly didn’t just spark back up again a couple millenium later.

      For that matter, maybe we haven’t been wiped out by a meteor only because we have some cousin species that has technology set up to steer massive meteors away from earth, without us even knowing about it, and if we start heading down the wrong path, that technology gets switched off. lol

  • http://www.rawinfopages.com/tips/ Roland Waddilove

    The planet is 500 light years away, so if they had radio transmissions and if we could pick them up, they would have had to transmit them 500 years ago. But if they were looking at us, they would see us as we were 500 years ago when we had no radio. They might therefore assume there was no intelligent life here and not send any signal to us.

    • dave birney

      yea they would have seen we were only at the printing press stage. bah, amateurs!

      • Goldpenny’s Graffix

        500 light years away, we weren’t at the printing press. Humans didn’t even exist for a planet looking at us 500 light years away. Smh you amateur.

    • Goldpenny’s Graffix

      You all seem a little confused as to what a light year is. It’s the distance light travels in the space of a year. At 186,000 miles per second 1 light year is a lot longer than 500 years. Now you have 500 light years? A planet 500 light years away wouldn’t see us in 1514 you nitwits they would see dinosaurs roaming the earth.

      • Boxman

        You’re absolutely wrong but yet so arrogantly certain of yourself… How embarrassing for you.

        Light does indeed travel 500 light years in a span of 500 years; that’s why they call it a “light year”, genius. So yes, beings on a planet 500ly away would right now be observing earth as it was in 1514.

        • Goldpenny’s Graffix

          You need to learn how to read. And maybe get a life, you’re trolling comments that are months and years old. My post seemed to confused you despite it being as simple as I could put it. So I’ll get rid of it and I’ll try again. If a habitable planet was 500 light years away WE COULD NOT GET THERE. A light year is around 63k au, and an astronomical unit (au) is 93 million miles. At that distance, no matter what we saw we could not get there by conventional means. So, if an astronomer looking at us saw dinosaurs, by the time they got to earth (provided they were immortal) they would find us, humanity. In all its stupidity.

          • Boxman

            And yet you felt compelled to delete your original comment, the one that I replied to. Hmmm…

            Look we all make mistakes. Whether intentional or not, your comment definitely made it sound like you were asserting that light would take thousands of years to traverse the 500ly distance between Earth and Kepler-186f. Maybe that’s not what you meant, but anyone reading your post would have drawn that conclusion.

            I didn’t want to feed any misconceptions people already have about light and light years. Surprisingly, a lot of people don’t really understand how they work. Sorry for being snarky about it.

            And by the way, your statement that if a planet is 500ly away, we absolutely “cannot get there” is technically inaccurate. We could definitely “get there”, even with current technology, using an unmanned vessel. For example see Project Orion (a nuclear pulse propulsion spacecraft capable of 10% lightspeed that could be built even with current technology, albeit at a ridiculous cost). I would imagine in a few hundred years, building something like Project Orion would be very affordable, with sophisticated AI and robotics doing the exploring once it got there. No warp drive or hyperspace required.

            Of course, what’s more likely is we’ll limit ourselves to exploring solar systems within 10-20 light years (there are hundreds of systems even within that relatively short distance, enough to keep humanity quite busy for centuries). No warp drive or hyperspace required; even slow sublight travel (10-20% lightspeed) is sufficient.

            Of course, this all assumes humanity doesn’t wipe itself out in the next few hundred years; with religion, nationalism and general stupidity still reigning supreme even in the year 2015, it’s looking increasingly likely we won’t survive the coming age of nanotechnology, so all this space talk is probably wishful thinking.

  • Fang Queen

    If that technology could check far galaxies you just can’t say that there is no really extra terrestrials. Remember we got billions of stars and galaxies and we are inside of inside of galaxy and star. I agree with other’s comment that they already visited the earth in century, of cause they are “Ancient Aliens on History” connects so many things. And one not got yet idea I have. If you can’t really find outside, they are now living with us, they invade some people, how can I say? Just look at the unbelievable inventions, those super smart people can do so many things, U.S.A. got the top secret why did just hide news when it comes sightings of UFO and the UFO sightings happened a years ago and no one sighting for now because THEY LIVE WITH US NOW.

    • 18235

      its racist to imagine that some superior white aliens from outer space responsible for ancient technology, especially among dark skinned Egyptians and native americans.

      it’s always superior white or green men who come to earth, from all the humans who claim alien abduction.

      • Fang Queen

        I’m Asian actually.nIt’s not racist they have the “capability” the Money, Knowledge and Power. Most of all they are “Interested” to Show to people what they Learn, Study and Understand. Then you call them a racist.

        • 18235

          like many a recent scientist or sociologist have stated, if some superior aliens from outer space would come to earth, they would treat humans the way old world europeans treated native new world indians—as inferiors to be killed or enslaved.

    • Jim

      And you are one of them.

  • 18235

    Giordano Bruno—-burned at the stake, by the Vatican, in 1600, for suggesting that there was life on other planets.

    • Fang Queen

      I am Roman Catholic I believe that was a long time ago and we do not burn who believes in ET now when in fact scientist keep searching for it. He burned because the teachings of church will be question. Because there’s no saying Alien created on this day but the other parts of the “Bible” saying God used to create peopl that don’t see, we are not really alone despite our endless universe.

      • http://blogs.discovermagazine.com John Shuey

        The only reason the HRCC is no longer burning heretics is that it no longer has the power to do so. When it had such power, it did.

        • Fang Queen

          I know that, why did just people bring back the burning stake just to show the ones who believes are CRAZY. That man believe that there is more planet than Earth but no strong evidence and the church don’t believe that, because people will questions what they had teach, until time come scientist prove that we have more planets somehow they trying to find LIFE on other planets. We have different perceptions if you don’t believe fine. Just don’t ruined what we believe.

      • alanpeart

        You could have just stopped at “I am Roman Catholic”. All the rest of your statements can be derived from our knowledge of that institution, including the spelling and grammar.

  • Jeffrey Coley

    Strictly in terms of probability, although intelligent life is virtually certain the odds of finding it are very, very slim indeed. Not only would it have to exist, but it would have to be during the same time period and develop technology compatible with our own.

  • Michael W. Gray

    The further from the source radio waves travel the weaker the signal, unless an alien civilization was *very* close (in cosmic terms) they couldn’t hear us nor we them. If there is some brilliant way of engaging in interstellar communication we haven’t discovered it yet, which means aliens possessing such theoretical tech wouldn’t be able to communicate with us anymore than we could with them. As for interstellar travel, if there is a way around the cosmic speed limit (which call me an optimist, but I’m sure there is), the VASTNESS of the cosmos would act to hide our currently “quiet” planet from star faring civilizations.

    • Kesh Meshi

      The galaxy is so incredibly vast, the fact that we haven’t found anything yet means very little in my opinion. The odds are also stacked against life developing on any individual planet. Mars could have had the conditions for life, but fate (so to speak) had other ideas.

      I do agree with the Fermi paradox just to the extent that our own species is doing an awfully efficient job destroying our environment and depleting our resources (particularly any resources that would enable us to explore space). Who’s to say other species haven’t made/aren’t currently making the same mistakes?

  • Stephen Cunningham

    If we can assume that a more advanced species is capable of faster than light travel, we must also assume that they would have developed a communication system that is faster than light. Why bother to call someone, if you can get to their house faster than a telephone call could reach them? And if they have such communication capabilities, we don’t have the technology yet to intercept and interpret their communications.

    • SixSixSix

      Hot damn, is that what lives under my bed at night? And here I thought I was paranoid but it is just the faster than light, you can’t seem them, aliens.

    • Goldpenny’s Graffix

      That’s ummm, that’s really dumb. The two things are not intertwined. Why would we have to assume that because they can travel faster than light that they have found a way to communicate faster than light? Or even at the speed of? I mean sure, give the mail man a letter, he jumps in his ftl (faster than light) mail truck and delivers it. But it doesn’t mean we could figure out a way to make telecommunications to travel just as fast. And besides, if my friend is in Japan it’s still gonna be cheaper to give him a call then the thousands of dollars it would coast to travel there at ftl speed. Also, if I’m lying in bed I’d rather not get up, get dressed, take a piss, grab my keys, let my dog out, bring my dog back in, lock the garbage up so the dog doesn’t get into it, make sure my front and side doors are locked, wait another 15 min for my fiance to get ready, go out to my car, wait for my fiance to run back in the house because she forgot her sun glasses, start the car and arrive at his/her house. No. Ftl travel isn’t necessarily faster than calling someone old school.

  • http://www.kosmostudio.com/ KOSMO

    The Great Filter is not a scientific theory.

  • Mike Lausier

    This is like me saying “jobs must not exist because my daughter hasn’t found one and none have tried to contact her.” She is three. By the same token, we are infants on the cosmic scale. We have only been looking for a few years (so intelligence would need to be within that many light years) and even then, our search was with simple equiptment. Our technology is growing, our ability to detect weak signals is growing. Time, give it time.

  • Randy McDonald

    Do we actually have evidence that there is a real Great Filter? Or could it just be we lack the observational capabilities at present to discern the civilizations out there?

    • http://pfoct.blogspot.com/ James Knauer

      None whatsoever. Space is much bigger than humans can generally conceive. Aligning things in space and time — including contact between any two independent civilizations — over the age of the universe is getting into lottery winnings in probabilities.

      • Randy McDonald

        Is there any way we can be sure that there aren’t any civilizations active right now? As far as I know, we’re only reasonably certain that there are no civilizations actively communicating at the radio wavelengths predicted by SETI enthusiasts in our observed spaces, and that there are no visible megastructures like Dyson spheres in our stellar neighbourhood. That’s it.

        • http://pfoct.blogspot.com/ James Knauer

          Even if there were only one civilization per galaxy, that adds up to hundreds of billions of them. Maybe more. But the distances in time and space mean its very unlikely they would ever encounter one another. Their remains is another matter entirely. There is no reason not to conduct detailed archaeology right here in the solar system. Very wet here aboots. Good oasis in an otherwise back corner of the galaxy.

  • John Majkrzak

    The field of science makes a few people so overly self important that they cannot chance diminishing their subject authority by acknowledging the possible. Live Shuttle feeds have accidentally shown them and former Astronauts have talked about them yet mention in this Discovery article with regard to possible extraterrestrial life goes, “UFO conspiracy theorists notwithstanding.” Sad.

  • RMR

    Marshall Fatten, you are right about the distance and speed in which traveling throughout space would require the tools and specific technology to do so. I guess whichever generation would have to wait for a particular genius to born, in order to put this plan in motion. But for now we have a long way to go to reach this goal. Also, we are thinking that other life forms must need oxygen, Sunlight, water, etc, etc to strive and live the way humans do. But what if other life forms evolved and adapt differently throughout their evolution due to lack of sunlight, oxygen, etc, ? On our planet Earth, we have humans, as well as other creatures that evolved differently according to adaptation and environment. So wouldn’t it be the same for other planets with life forms? Again, we need to stop thinking and assume like humans when we speculate about the vast universe we are a part of.

  • Nathan Willmore

    Why are we all assuming that they even use radio waves? LOL. This is silly.
    Other life exists out there. Anyone who says it doesn’t is either scared or too ignorant to even care. Humanity will survive and one day join the billions of life forms out there that have existed for “billions” of years.
    And let’s be realistic, other life forms out there don’t need to send out radio waves or any other form of communication; they have been visiting this planet for millions of years already.

  • disqus_atlq8Zmtsd

    We haven’t met them. They would have to be within 100ish light years to have any radio output from Earth to detect.

    We haven’t heard them. Inverse square law.

    Haven’t seen engineering feats. WE CAN BARELY DETECT PLANETS!

    No interstellar civilization. We haven’t even gotten to Mars.

    Assuming we are talking about relatively human-like civilizations with technology that developed along the same lines as ours, it would be rather more staggering if we did stumble across another civilization by now than if we didn’t.

    It is fun to speculate on, but the fact of the matter is that we have confirmed life on one habitable planet and no other relevant data points. There are entirely too many variables that we simply have no knowledge of for us to begin to pretend we have any idea of the likelihood that there is more life in the galaxy.

  • Future Legend

    The Great Filter could just be the intersection of technology and relativity. If there is no way around the lightspeed barrier, interstellar travel becomes a very difficult proposition on any kind of grand scale. Who wants to seal themselves into a tin can for 50 years just to get to the nearest habitable planet? Nobody, that’s who, even if they can afford it.

    Advanced technology might also make it possible to observe other worlds remotely and then simulate them perfectly back at home. So why go to the trouble of sending yourself 100 light years away to visit Earth? At most aliens might send a probe the size of a sand grain – a device we’d never even notice – and then simulate Earth in the comfort of their own living rooms.

    Let’s face it, if you could perfectly simulate some remote vacation destination like Fiji without leaving home, would you bother traveling there physically? I wouldn’t. Flying is a pain in the butt.

    And of course they wouldn’t be limited to simulating one world – they could “visit” hundreds or even thousands of worlds all without leaving home.

    • disqus_atlq8Zmtsd

      I found the sequels to Ender’s Game to paint a pretty good picture of what an interstellar empire would look like and why it may be so onerous as to prevent the enterprise from ever gaining traction.

      The travel times would be obscene. The colonies would be almost completely isolated. Communication would be completely impractical, and if you set out as a young man to meet someone, you would not reach them before they died of old age.

      Never mind the inherent difficulties of long term space flight at relativistic speeds. We’ll assume those engineering hurtles are manageable enough that it makes intersystem space flight possible even if it isn’t practical.

      The fact of the matter is that in the absence of superluminal fight, it probably isn’t going to happen.

  • SixSixSix

    As a variation on the Fermi Paradox, I suggest the entropy principle of civilized destruction. Basically civilization is a giant indulgence in the advancement of entropy. Technology destroys, literally. Look at the pristine condition of the earth pre-civilization and see now the destruction in its wake. The older the area, the worse the destruction. Advanced technology just churns out entropy at an accelerating rate. In short our kind of civilization is clearly not sustainable over any long period of time (even 10,000 years) with or without big weapons to hurry the process along. In fact a nuclear war might help prolong the process before final collapse. Do not get Gaea really angry. Oh my, in a dire mode tonight.

  • Arun Prabhu

    Well, the time we think is time is not the same for others out of earth! And anything which is not captured by our six dull senses does not mean things do not exist! doh! intelligent is a word to boast the human ego and even the animals in our own planet has super natural powers (as per humans tiny understanding abilities) which we are still discovering and having a hard time understanding! We as a race need to grow up!! Bitches got too much venom to go sneak another place in the universe and suck the joy out of it!!

  • Arthur Smith

    I posted yesterday. Where did it go? I spent over half an hour writing it…

  • DesertSun59

    Given the trajectory of our species, it stands to reason that at least one of the reasons for the Fermi Paradox is that a sufficiently intelligent species can and WILL self-destruct.

    Our current level of civilzation, where we have mass communication, massive quantities of food, health care, and the ability to send probes into space as well as detect the universe around us with sensors, is nearly 100% dependent on fossil fuels. If our species continues on the same path we’re on where we burn all of our fossil fuels, raise the atmospheric temp, then our sea level, we will effectively destroy the civilization we have.

    Fossil fuels are finite energy inputs. We’re on a well-documented unsustainable course. Our current civilization WILL come to a screeching halt unless that dependency is eradicated. It won’t be, and you all know this.

    So, stop dreaming that everything is all hunky-dory and that only pessimists believe we’re about to discover the ‘Big Surprise’. It’s inevitable that this will happen. Greed will show us the way to our demise as sure as the sun will rise tomorrow.

  • Humayoun Khan

    Speed of light may be an unbreakable limit. Also with advances in technology comes the ability to produce any kind of material so there is no need to go to other planets to bring back any exotic material. Population pressure and persecution was another reason to explore and that most likely does not exist for advanced civilizations. Extending life and producing less offspring is possibly a norm. Keeping the above factors in mind going on a one way trip would be impossible for an individual or a small group. For the same reason no government would waste resources on a futile exploration specially all that you need to flourish is readily available or can be easily manufactured. They possible have very powerful telescopes that would give them a good view of the surrounding cosmos. Their view may be as good as being there. They are watching us. Google Aliens in the Quran or check endphysics dot com.

  • Felipe

    Maybe there are wise and enlightened so they don’t need to communicate nor to conquer the universe. They just stay there rejoying with this marvelous universe.

  • Jim

    At 492 light years away communicating with intelligent life on Kepler-186f is impossible. They may have sent a message 492 years ago and we don’t have the technology to even receive it yet.
    Or it arrived during the time of the dinosaurs or the Roman Empire.

  • Jim

    And if superior life forms could travel faster than light we would possibly look like food to them. We eat cows, right?

  • Biswadip Saha

    Thing is our ultimate goal is to spread or expand our species, thats
    biological nature . thats how we came from deep sea to planet surface
    and we should not stop here. Long way to go .

  • Beast From the Past

    We Have To search for another Earth To live on … Earth Number Two then tree then four then five etc

    • jimbow

      Yeh we build big ships, blast the ones living there to nothing and take over, use up that planet then move on. Until some one stops us
      with a computer virus.

  • Beast From the Past

    We Do Not have To concern about extra terrestrial intelegent life form for our rival.. because if it was. then it will all ready happen by now….

  • Beast From the Past

    or before I presume

  • SayWhat?

    I would suspect that we are limiting ourselves in every way possible. Forms of life. The definition of life. Distance. Time. All these things are seen through our very limited view. For instance, as some posters have already suggested, we may be just one form of life, and another form of intelligent life might breathe sulfuric acid. Or perhaps our predecessors will be machines, super-intelligent androids, and that is the natural course of things. After all, to the universe, whether its biological life or mechanical life makes no difference. perhaps we are just one step in the evolutionary process that creates a mechanical race of beings that light speed and time matter nothing to.

    Another assumption we make is that our perception of time and distance is the only one there is. Well, to a sand fly we live an extraordinary long life, and to a house fly we move super slow. So maybe there is an intelligent life out there that a thousand year voyage to another star is just a day in the life. The “light speed barrier” to them is not an obstacle to overcome, but more like a far off limit that they don’t even need to consider since their life span is so great and they perceive life in a much slower time frame than we do.

    There are just so many possibilities out there we cannot even imagine. In defense of the article though, I guess, since we cannot imagine these things, we must start somewhere to look for life. And where better to start than the life we already know?

  • Serhan Ogan

    Finally, a sound comment about the century of long debate over extraterrestials.
    Ever aspect of the environment that we live in, is actually a prerequisite for our existance. Air, water, plants, insects, etc. Say we found a perfect replica of the planet earth, including the nature, we still need an astroid, or whatever it is to wipe out the dinasours. Unless you want to go all the way just to be a late supper for a group of young T-Rex’s. After all, even if life exist , it is more likely that it would be in the form, not much sophisticated than a colony of algea or mold. What we really have to work on, is to find ways to dodge astroids, predict supervolcanos and eventually to move Earth to a higher orbit around the sun or put giant screens in between to avoid the effects of our sun expanding and heating up as she ages.

  • Arthur Smith

    Looks like I have to write this again. I should start saving comments in MS Word… 1. It’s too early to say we’re alone in the universe. It’s too early to say there’s no sign of activity in our universe. For the entirety of human history we’ve been flying blind, and we still are today.
    2. For the last couple decades we’ve had new telescopes like Hubble that can show us distant stars, and a new telescope will show us even more distant stars, etc. But that’s about all we can see right now. Seeing anything else, like planets or anything smaller, is next to impossible. This is why I say we’re flying blind. Plus, we haven’t really been looking for anything besides star activity, and measuring larger-than-star activity, such as black holes.
    3. Our Galaxy is already pretty old. Over 70% of our suns are dwarfs. Considering the vast length of time that’s past, it’s very likely that advanced space-travelling civilizations have already come and gone. It’s also possible, if they’re anything like warring civilizations here on Earth, that they actively try to hide their space stations, craft, etc. In the emptiness of space, the ability to cloak your ships must be crucial in defense. Who knows, maybe all the “dark matter” scientists have discovered is just “cloaked alien civilizations”? :D

  • sangos

    Stupid filters and paradoxes. We do not hear ET radio because ETs with radio are too rare too far.

  • T Pugh

    The list needs to include the idea that it just takes this long for civilizations to occur and they have all started looking and listening recently.

  • Grey

    I think, and hope we will survive long enough to find other life. Every year, as our technology improves, the average person is allowed more and more destructive energy. And that’s ok to some extent, there are a lot of peaceful technology that can be used for destructive purposes. Hunting rifiles, for example can allow a person to kill a lot more than say, an axe.

    The difference is, I think that the amount a person can travel in a day is expanding way faster than the normal amount of destructive technology is allowed. For example, terrible examples of course, if a crazy man wanted to kill everyone with a sword, we could turn is different direction and he could never kill everyone. Like today, if a man wanted to kill everyone, we could all drive different directions and he could never get everyone.

    So, I think in the future when another crazy man wants to kill everyone, we can all just run/fly/warp/burrow/tardis (depending on your future of choice) different directions and outrun the blast. Whether we are alone is a different topic. Life is out there, but intelligent life is harder to find.

    Whether we can actually find intelligent life, or they find us, in my opinion, depends on if we can break the lightspeed barrier. Either we can brake the speed limit, and it will be broken (my money is on research into traffic jams, time goes by way slower in traffic), or the light speed barrier cannot be broken. It doesn’t really matter, whether it can broken or not, we are still going to try to travel faster than light. Our normal day to day scientist won’t act any different. If lightspeed can be broken, either aliens will find us first, or we will find them first.

    I think either aliens have already found us, or we won’t find them for a long time. We have only been looking for less than a century. And even when we encouter alien life, we will be either vastly superior or vastly inferior.

    Relatively speaking, our advancement into science is incredibly new, and even into the next 1000 years, we still would have only been space faring creatures for 1000 of the 200,000 years we have been around. Its a blink of the eye.

    In either case, we (as a species) are safe with aliens. I don’t think there is anything here aliens could want from us other than information, just a page in a encyclopedia. There’s nothing we could offer them, other than a wealth of juicy romance novels. Water, slaves, a habitable planet, all useless to a species capable of traveling the distance to us.

    I know our history of meeting underdeveloped civilizations have been brutal, but to an alien that could travel to earth, we would be more like ants to them than a rival species. Not even worth the antspray.

    Earth may seem appealing, but it’s not. Not compared to the infinite space of space, where everyone own a few acres and it’s always sunny.

  • AugustineThomas

    This is what happens when you let too many atheist scientists together.. They turn into lunatics.

    • Eric B.

      Yes, because deist scientists have a much better track record.

      [eye roll]

  • jimbow

    it maybe that as a civilization gets older their radio transmitters gets lesser power, (it starting to happen with ours) so we just can’t receive their broadcast. Why they have not sent one our way, why should they we can’t get along with our self why chance it.

  • zlop

    “evolution of complex life requires an exceedingly large number of perfect conditions”? — Life can exist anywhere, even in intergalactic space. A working fluid and warm temperature is sufficient.

  • dakota

    It also might be that other species technology is so advanced that they see us as a developing sentient life and would not like to interfier.with our evolving process or whatever.if this were the case that means we have a bright future.there nust waiting until were ready to pass the mantle of responsibility.

  • NewsMaster69

    I just hope there’s a lord of the rings planet out there…..

  • Danarius Compopolous

    Something missed by the author here is that discovering life on a foreign planet would potentially give humanity renewed drive and purpose and may be the key element missing if intelligent species do commonly eradicate themselves at approximately the technological level we are at. It would lay aside certain religious beliefs for good, which is something many of us believe is required for humanity to progress. Seems like the longer we go without discovering alien life the more convinced even intelligent people can become of our singular, isolated creation at the hands of a specific god rather than the likely truth of rare acts of spontaneous genesis all across the universe. The question of whether god exists will always be there though, and I honestly think that’s a good thing even if religion itself is questionable at times.

    Something the Fermi paradox ignores too is we are in the relative early stages of the universe as it is estimated to currently be around 13 billion years old with a “lifespan” of trillions. We have only seen tens of thousands of generations of fast burning blue giant stars(compared to the trillions the universe will see) and have yet to see a single red dwarf die in the entire universe (nor will we for over a trillion years). The sun is literally in the second generation of stars in its class across the universe if you consider the sun’s lifespan to be the length of a generation. Thus we are potentially one of the first intelligent species to evolve in the entire universe, even if we are the billionth one. That’s a billion intelligent species scattered across trillions and trillions of stars across billions of galaxies. Not much density and not a long history in comparison to how much time lies ahead for the universe.

  • EquusMtn

    I think the most likely truth is that life is common in the universe, but technologically advanced life is rare. Why, in the 2-4 billion year history of eukaryotic life on earth, has intelligent life evolved only once (as best as we can tell)? The answer is simple: because intelligence isn’t
    necessarily advantageous to survival. Many kinds of unintelligent organisms have survived on earth for millions or billions or years; technologically capable organisms have been here only a few thousand. Thus it remains to be seen how advantageous technological capability can be; but if it was truly advantageous it would have evolved more often in the past. I’m not arguing that intelligence evolves and fails as much as that it rarely evolves in the first place. Oversized brains just aren’t necessary.

    Therefore, the “Great Filter” argument is also unnecessary as an explanation of the Fermi Paradox. I think the universe may be full of life that’s buzzing right along without a single thought of any kind.

  • garethWill

    i think at the moment we don’t know and there are just a lot of theories that need to be explored. to say the is is impossible is like saying the earth is the center of the cosmos or the world is flat. we need to do more observation and collect data to come up with a more conclusive idea.

  • TeddyOrwell

    How many people does it take who have seen flying saucers, including military officers and military personnel, air traffic controllers, police officers, and cases where there are mass sightings with loads of eyewitnesses and so forth before people stop saying that aliens haven’t visited us? They have and do, all the time. I and many people I know have seen them. I’ve talked to people who have met them. Remember folks, all it takes is ONE instance and it’s a real thing. Stop playing dumb. Let’s take this out of the realm of speculation and theory. They are here. They just aren’t engaging us openly yet. Take a look at how we behave on this planet. Do you blame them?

  • Dan

    So many of the posters are missing the point of Fermi’s paradox. We have peered into the universe right to it’s edge and have not found a single observable event or object that cannot be explained as completely natural. You get it? Natural, non-artificial, not built by anyone, not planned, not sculpted, not constructed. Fermi’s Paradox still stands. Not one poster has adequately explained it away.

  • Richard Boatwright

    There is always the possibility we are early comers to intelligent life. We may well be the first planet so far to advance to space travel.
    Sure, its much more likely we are in the middle of the pack But there is always that possibility.

  • SOMEGUY7893 .

    You know, what if alien life never invented Radio technology? What if they have a radically different alternative that to us just looks like background noise in the universe and Humanity is the oddball Civilization that has a totally unique technology?

  • BigN_Tasty

    Development of advanced technologies will not continue long enough for man to go interstellar because the men developing them are not sexually rewarded for it (ergo intelligent reproduction).

    The Great Filter is Women.

  • Anthony Edwards

    Recently, Astronomers have theorized that most planets form giant planets near their stars, and it takes a massive planet like Jupiter to sweep through and “gut” the habitable zone before smaller, life-possible planets can form. This is an extraordinary circumstance. First, the giant would have to have an erratic elliptical orbit that would take it close to the sun and collide it with the forming inner-planetoids. Then it would need another giant like Saturn to slow it back down and set it into a reasonably normal orbital pattern before the newer, smaller planets form.

  • Jeffrey Jdakid Rivera

    The universe its self is a being a being of great knowledge made up of everything physical when we look at the universe itself from a distance we can clearly see that all of the galaxy clusters make up an intricate web that resembles our own complex nervous system…the universe expands then contracts like the human lung when we breathe…humanity was made in the universe’s image…I believe that all life intelligent life in the universe is at the same point of evolution as humankind and technologically at around the same level of development… We must think of intelligent life as a universal phase where it’s the universe itself that’s evolving to express itself with intelligent life so at one point soon i believe we will have the answers we seek and all of the signals we will receive from our extraterrestrial siblings will be overwhelming the human genotype I believe is the universal expression for sentience regardless of the size or appearance of extraterrestrial’s based on the size and environment of its planet I believe that every sentient being in the universe follows this sacred five – point 4th dimensional sentient form ⭐

  • Steve Marethyu

    I’m sure that this has been factored into the equations, but given that while there a billions of stars, many are also significant distances away from us. Even this one exoplanet that is relatively close would require 492 years of sending messages at the speed of light, before we would see it. We’ve only been looking out into the universe for about 100 years in anyway that would allow us to receive such messages. In some ways, I’m impressed by the rare Earth hypotheses, but I am also doubtful that if there are civilizations out their on other planets that we would manage to actually hear their signal. Sure there a billions of galaxies with billions of stars, but the universe is also a vast place.

    I’m doubtful that 100 years is long enough to say for sure that there is no life out there. Even if there is life, it might take 492 years, or 10,000 years or a billion years to send a message back. Certainly, such contact would revolutionize our understanding, but how different would our planet be once that time has passed, or these other species of intelligent life after their message manage to find us here in our corner of the Milky Way.

  • Steve Marethyu

    I find this estimate, though Fermi was much smarter than me, to be really suspect. How rare are we saying that life has to be? There are lots of factors that would account for us not hearing any radio waves over the last century. First, if the way we have accomplished this level of civilization and technology is any indication, other intelligent life would require a planet that has heavy elements, which to my (limited) understanding means a couple of cycles of stars, prior to their own. This means that there has definitely not been messages sent for the last 13 or 10 or probably even 5 billion years. After the elements are formed in now dead stars, life has to evolve, which seems to take a long time as well. That would seem to me, to limit the range of the universe that we could even be receiving messages from. If a message left 6 billion years ago, but the planet is 6.1 billion light years away, we’ll have to wait 100 million more years to receive it.

    Certainly, these closer planets, 492 light years and such, offer a better opportunity. However, if there is some level of rareness to life, or at least intelligent life, and if the closeness of these planets means that they have a somewhat similar background to us, it seems like it is unlikely that they would have been that much ahead of us in the evolutionary chain. If we’re ahead, but they develop the technology tomorrow to send out messages, it’ll be close to 400 years before the first chance of them seeing our messages, and that assumes that we sent it in the right direction and nothing interferes with our signal.

    To me the biggest challenge to this notion that our not hearing means there isn’t life, or it tends to die out before sending or receiving messages is the great vastness of the universe. Our society could last 100 million years sending out messages into the universe, and much of the universe would have no idea we existed for billions of years, and then only if they happen to be listening during the 100 million years that our message passes their planet.

  • Brian Weekes

    Very negative. Yes we may find a dozen worlds in local space that were once habitable and now lifeless with the signs of a past self-annihilation. Just the same I prefer to view such things with optimism rather than pessimism. We are still here and we show no signs of destroying ourselves. There is plenty to be hopeful for.

  • brycly

    If there is on average a 1-100 chance of a planet producing life capable of interstellar travel, and they eventually explored/colonized an average of 20 star systems each, then we’d only have a 20% chance of them making contact with us. That said, it’s also possible they are aware that earth has life so they avoid it. Until we can image extra-solar planets or they make contact we can’t know for sure how rare interstellar life is.

  • tek26

    The Great Filter is an interesting hypothesis that has been kicking around for a while, but it’s also very speculative. The author’s first mistake is to take this hypothesis so seriously that he falls into the fallacy of thinking that if something is possible then it’s therefore true.

    There COULD be a filter, or something holding life back and causing it to collapse when it reaches a certain level. That COULD mean that if we detect lots of extraterrestrial life then it means we are not unique and COULD be headed for a Great Filter event. That COULD be an explanation for the so-called Fermi Paradox.

    But, it also could be that the underlying assumptions behind this are fundamentally wrong. For instance, the answer to Fermi’s question about why we don’t see aliens everywhere could be that they are out there, but there is just a very low chance of communicating with an advanced technological civilization that just happens to be close enough to have received our radio signals over the past 100 years and willing and able to communicate with us during this narrow window in which both civilizations were able to transmit and detect radio waves.

    Even if we did detect another alien civilization, does that mean the Great Filter concept is valid and we’re all going to die? No. That claim rests on the assumption that there should have been life all over the galaxy and they should be here by now and if they aren’t, then they must have all died out. Therefore, we will die out too. C’mon. That’s way too many leaps. It took 4.5 billion years for our civilization to appear. It could take less or more for other civilizations to appear. Or, we could be the only one. There are too many unknowns to assume that the Great Filter is correct or that detecting life is an indicator that we are all going to die.

    The bottom line is, I think the Great Filter is mainly just a fancy way of saying good news is bad news and pretending there is some scientific basis for that. But, in reality, it is nothing but pure speculation…and a good way of trolling people on the internet to click on your website.

  • Nathan james

    If there is a quantic deminsion in comparison to our dimension, then our dimension is quantum to another and so forth. We are not alone, we just can’t see each other yet. Science is a scary thing. Leaps in technology have been occurring more rapidly in the past 100 years. Since the existence of humans, we have only been intelligent as we are now for a short period of time, and since the ball started rolling, the hill has only become steeper and steeper and I believe will continue to do so. I call this era we live in “the eureka period”, and it is only a matter of time before life as we no it changes dramatically. Think about the difference between now and 1980. Now think how much different now could be from 2050.

  • Christopher

    Because mankind is too primitive to think that maybe a species would create a space fleet and be mobile for best chances of survival. Exploding stars, worlds becoming unstable, continuous exposure to micro lifeforms that evolve to attack us, and many more things. Could be rendered no longer a threat using a mobile empire..

    The universe is interactive.. People thinking there is lack of evidence for aliens are simple minded. Sorry.. They avoid the other questions.. Do they want to be found? Would they stay in the same spot or would they move around so if anything is out there it can’t get a beat on them?

    We have the ability to look at the stars and wonder if there is anything out there. We also have the ability to look at our stupid insignificant species and see that even though we are divided we still manage to push further. We can see that we are generally violent species.. Any intelligent species with the ability to understand how things on their world could be a suggestion of possibilities in the universe.. May not want to be found just in case there is something else out there that could threaten them.

    If there is other lifeforms out there? Then the only thing humanity has is time.. Time to become as strong and smart as we possibly can to get the best chances from surviving a species that may want to be found.. Look at human nature.. Now look at everything you see around you in nature. Everything is under one law.. COMMUNICATION.. Everything you see is a message. Examples below

    Example 1. We seen birds, we wondered how they fly, and now we make the most powerful birds in the sky.
    Example 2. We got pushed around by storms and we built shelters.
    Example 3. We got pushed around by plagues and we made medicine.
    Fully interactive mechanism with every single action or reaction causing thoughts in our minds that lead to NEW never before seen on earth actions and reactions.

    Use that same power to wonder if there are species as mean as us that made it to interstellar travel.. Even if they are not mean they just need to be intelligent enough to understand there could be mean things out there. Also how life responds to life in very complex ways. Like finding a remote tribe that has never seen technology and showing them technology. Some can become happy and some can get super mad. Once again.. Would they want to be found?

    Id be worried about the ones with the cojones to engage us.. Never engage another sentient being unless you are willing to deal with them when their social system evolves to deal with you..


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