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Space Science

Why Do We Assume Extraterrestrials Might Want To Visit Us? (scientificamerican.com) 259

Avi Loeb, former chair of the astronomy department at Harvard University and who chairs the Board on Physics and Astronomy of the National Academies, writing at Scientific American: It is presumptuous to assume that we are worthy of special attention from advanced species in the Milky Way. We may be a phenomenon as uninteresting to them as ants are to us; after all, when we're walking down the sidewalk we rarely if ever examine every ant along our path. Our sun formed at the tail end of the star formation history [PDF] of the universe. Most stars are billions of years older than ours. So much older, in fact that many sunlike stars have already consumed their nuclear fuel and cooled off to a compact Earth-size remnant known as a white dwarf. We also learned recently that of order half [PDF] of all sunlike stars host an Earth-size planet in their habitable zone, allowing for liquid water and for the chemistry of life.

Since the dice of life were rolled in billions of other locations within the Milky Way under similar conditions to those on Earth, life as we know it is likely common. If that is indeed the case, some intelligent species may well be billions of years ahead of us in their technological development. When weighing the risks involved in interactions with less-developed cultures such as ours, these advanced civilizations may choose to refrain from contact. The silence implied by Fermi's paradox ("Where is everybody?") may mean that we are not the most attention-worthy cookies in the jar.

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Why Do We Assume Extraterrestrials Might Want To Visit Us?

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  • by WoodstockJeff ( 568111 ) on Friday January 22, 2021 @01:42PM (#60979396) Homepage

    ... we're waiting on THEM to come to US, because we don't have enough gas money.

    • by garyisabusyguy ( 732330 ) on Friday January 22, 2021 @03:30PM (#60980002)

      This story is the best explanation that I have seen: They're Made out of Meat [mit.edu]

      An excerpt:
      "They're made out of meat."

          "Meat?"

      "Meat. They're made out of meat."

          "Meat?"

      "There's no doubt about it. We picked several from different parts of the planet, took them aboard our recon vessels, probed them all the way through. They're completely meat."

          "That's impossible. What about the radio signals? The messages to the stars."

      "They use the radio waves to talk, but the signals don't come from them. The signals come from machines."

          "So who made the machines? That's who we want to contact."

      "They made the machines. That's what I'm trying to tell you. Meat made the machines."

          "That's ridiculous. How can meat make a machine? You're asking me to believe in sentient meat."
      .
      .
      .

  • They already tried Uranus. They found it a shitty place to be.

  • Radio stations don't think in terms of any specific person in their audience and whether or not they are worthy enough. If the UK couldn't stop pirate radio, how are all these civilizations going to coordinate the complete end of all broadcasts?

    Everything gives off radiation. To somehow shield all transmissions and radiation from all parties in all galaxies is a spectacular / science fantasy effort.

    There aren't aliens because life isn't self forming. That is the simplest explanation.
    • There aren't aliens because life isn't self forming. That is the simplest explanation.

      That is anything but the simplest explanation.

    • Re:not the problem (Score:5, Informative)

      by Waffle Iron ( 339739 ) on Friday January 22, 2021 @01:53PM (#60979448)

      We don't have receivers sensitive enough to pick up signals from interstellar distances unless they've been deliberately beamed in our direction.

      • We do, but the transmissions need to have power output on the order of the energy generated by a star. If their omni-directional radio transmitter is powerful enough to not be drowned out by noise on it's way here, it's probably capable of reducing anything in its vicinity to ashes in short order.
    • Proof? There is actually more proof to life being self forming than otherwise, but I suspect you may be incapable of understanding this fact.
    • by gweihir ( 88907 )

      There aren't aliens because life isn't self forming. That is the simplest explanation.

      Indeed. We know we are here. (For how much longer is another question....) But a universe with one planet that has a species on it may be a rare thing indeed and one with two of that may be even rarer and when you require these two to be somewhat in proximity, forget it.

      • Proximity in time as well as space, as it stands we probably wouldn't even show up in the fossil record of we died out tomorrow
      • by dryeo ( 100693 )

        It seems to take a lot of time for advanced life to evolve. 4.5 odd billion years in our one example but likely at least 2/3rds of that so a planet has to be stable for 3+ billion years. Modeling shows that takes a lot of luck and feedback mechanisms. The Sun itself has increased in brightness by at least 25% since the Earth was formed, all while the Earth has almost steadily had liquid water on its surface.

    • Even if life is forming easily, intelligent life capable of making technology is another matter.

      It took only a few hundred million years to form life on Earth, but it took another 4 billion before that life had invented a radio.

      If it had taken another billion more, the Sun would already be killing it.

      • by dryeo ( 100693 )

        That's the thing, it is technological life that we're really interested in, and it is likely much rarer then simple life. Even intelligence without things like thumbs to manipulate the environment and speech to pass on knowledge will never have much in the way of technology.

        • Even intelligence without an abundance of fossil fuels may never have much in the way of technology.

          The fossil fuels we have are very much a quirk of historical climactic and evolutionary conditions, where trees began spreading on land but there weren't any fungi or bacteria that could decompose them, so they piled up and got buried (requiring other particular climactic and geologic conditions) and compressed into what we now call fuel.

    • There really is no explanation that makes sense. Any chain of cause and effect (be it god/aliens, big bang etc) must start with an event that has no cause, or else go back in time forever and ever or I guess form a cycle (our future selves created our ancestors). None of these provide an ultimate cause. What could possibly be one anyways?
    • Just can't hear them (Score:5, Interesting)

      by Immerman ( 2627577 ) on Friday January 22, 2021 @02:28PM (#60979652)

      True, but there's no particular reason to believe we'd detect their broadcasts amongst themselves, even assuming they used radio. As receiver technology improves, broadcast power falls; to the point that there's a fair chance humanity is near, if not past, the time of maximum total broadcast power for in-system communication. And even if an identical civilization to ours were developing around the nearest star, Proxima Centauri, from over four light-years away we probably couldn't detect their broadcasts against the radio noise generated by the star itself.

      Meanwhile for longer-range communication, between stars, and probably even between planets, extreme tight-beam communication seems likely for efficiency's sake. In which case the only way we could possibly detect the signal would be if we happened to be perfectly in line with the target - which is phenomenally unlikely, especially for interstellar transmissions.

      That does leave non-communication transmissions - we might be able to detect military radar transmissions from the hypothetical Proximans, but radar is relatively tight-beam, so they'd still have to be pointing it at us, and it wouldn't be an obviously artificial signal unless it had complex modulation for some reason. In fact, that's a potential explanation for some of the anomalous unmodulated signals we have seen. But again, as technology becomes more advanced the necessary signal strength falls. Not to mention radar is of limited use for a space-faring civilization, where you're operating in three dimensions, and nothing obscures line of site - passive sensors are likely to be used to track the position of objects, with active sensors likely being tight-beams designed to gather more detailed information.

      And then there's incidental radiation - the emissions from photon rockets or light sails would likely be detectable, but again, efficiency favors tight-beam transmissions that are unlikely to be pointed at us. And they wouldn't be definitively artificial aside from their anomalous source - perhaps the (possibly) unmodulated Wow! signal was us being in the path of such "exhaust".

      Beyond that - rocket engines might be visible, but they'd fade to nothing against the brightness of a star, or even the reflected brightness of a planet. And our telescopes aren't yet powerful or subtle enough to detect anything but the brightest of planets against their star - so we're definitely not going to see engines. Same goes for pretty much any other "incidental" radiation a civilization might put out.

      With current technology about the only way we could detect an alien civilization that wasn't trying to communicate with us, would be if they did something that significantly altered their star's output. One possibility is dumping heavy radioactive elements into their sun, either for disposal or perhaps to produce a beacon to draw the attention of aliens like us - we've detected at least one such star, but again, there's nothing explicitly artificial about such a thing - it's unlikely, but it could happen naturally.

      Perhaps the most likely way to detect an alien civilization would be if they built at least a partial Dyson swarm to collect massive amounts of solar power, whether via satellites or solar-powered orbital habitats. In which case the anomalous dimming as parts of the swarm obscured the sun would be obvious... and we've detected a star doing that too. But again, there are also natural explanations, so while it's worth noting as a star worth paying attention to, we'd still need to detect a clearly artificial signal to know for sure that there were aliens there.

    • >There aren't aliens because life isn't self forming. That is the simplest explanation.

      No, it really isn't. We exist, therefore there's only two options:

      1) Life was self forming here, in which case we would expect it to be plentiful in the universe, though perhaps the odds are low enough that none of it is near enough to be detected.

      2) We were created - in which case at the very least our creators are out there somewhere (or at least used to be), and it's incredibly presumptuous to assume we're their o

      • No, it really isn't. We exist, therefore there's only two options:

        2) We were created - in which case at the very least our creators are out there somewhere (or at least used to be), and it's incredibly presumptuous to assume we're their only creation.

        And of course (2) really just kicks the can down the road a bit - if we were created then the same two possibilities apply to our creators. And their creators, etc. ...

        For (2) it follows that the Creators are Turtles [wikipedia.org] ...

    • You're forgetting two important details: RF falls off at 1/d^2, and RF is a terrible media for interstellar communication.

      To pick up a signal, it has to be strong enough. 1/d^2 means the signal has to originate somewhere very close for us to detect it.

      If you're an integrated interstellar society, you can't use RF to communicate. Travel time between stars is too slow to keep your civilization integrated - it would fracture into a separate civilization in each star. So if they exist, they're not using RF t

  • Do we ? (Score:5, Insightful)

    by KimDotOrg ( 7630658 ) on Friday January 22, 2021 @01:46PM (#60979414)
    Two problems: aliens most likely do not even know we exist, so it would be finding a needle in a haystack of astronomic proportions. Secondly, even if they knew, they probably can't solve the problem of interstellar travel either.
    • by cusco ( 717999 )

      Interstellar travel is a problem of time, and **our** concept of time is not the only possible one. You think that because with current technology a trip to Proxima is impossible because it would take a couple thousand years. Only the bible says that lifespans max out at under 100 years, if a species has an average lifespan of 200,000 years then a trip between stellar systems is not an unthinkable way to spend part of it.

      Personally I think that a species is likely to merge itself with its technology befor

      • by cusco ( 717999 )

        Whoops, 'Voyager in Night'.
        https://www.goodreads.com/book... [goodreads.com]

      • by gtall ( 79522 )

        Zotar: Okay leaving Alpha Centuri, what's next on the agenda, Egon?

        Egon: this little blue world about 4.7 light years away. How long'll that take us, Zotar?

        Zotar: let me punch that into the navigation computer. . . it says about 10 years.

        Egon: Damn, now we get to watch the same movies for another 8 million times.

        Zotar: Oh screw it, let's go home, the cats have already beat us there and they found some monkeys to feed them, change the cat litter, we'll never get a deal like that.

        Egon: Damn cats! They've stol

  • Maybe they're looking for El Dorado. Maybe they're looking for a short-cut around the universe by heading in the opposite direction. Maybe they're visiting us on a dare; "I double-dare you to visit that death-world".

  • Curiosity? (Score:5, Funny)

    by rnturn ( 11092 ) on Friday January 22, 2021 @01:48PM (#60979424)

    "We come in peace... and to see for ourselves whether you're as stupid as your radio transmissions indicate."

  • Comment removed (Score:5, Insightful)

    by account_deleted ( 4530225 ) on Friday January 22, 2021 @01:48PM (#60979426)
    Comment removed based on user account deletion
    • by tinkerton ( 199273 ) on Friday January 22, 2021 @01:54PM (#60979464)

      You ever read those stories about spontaneous self combustion? Apparently some of them brought a magnifying glass.

    • Re:We study ants (Score:5, Insightful)

      by BladeMelbourne ( 518866 ) on Friday January 22, 2021 @01:54PM (#60979466)

      Exactly. A fraction of the population does. A fraction of the world also studies anthropology and the origins of species.

      It is reasonable to assume that some alien life forms will as well. Not every member of a particular species, but a fraction.

      • To add further to this, so do many lesser lifeforms on our planet "study" ants. Not only do these take notice of ants and watch them out of their own curiosity, some in fact eat ants all day long.

        The analogy by Avi Loeb is flawed most particularly where it assumes there was just one other kind of alien life in the galaxy. It is much more likely that when there is other life that it goes through many stages of evolution just as we did, and that there may be many aliens advanced enough and within our vicinity

    • Remember he's not saying that there is zero interest for all the civilizations that could visit us. He's saying that like ants there might be very little interest other than maybe scientific curiosity. I think Hitchhiker's Guide had a far better take; the Earth was blown up for an interstellar expressway. The main reason Earth was important was it was computing the Ultimate Question. Otherwise there would be little importance to the Vogons or whoever.

    • Right, but the probability of any particular anthill in the world ever being studied by people is really really small.
    • by Jeremi ( 14640 )

      We study ants as a species.

      The chances of any particular anthill being studied, OTOH, are close to zero.

      In the analogy, Earth is just one anthill among millions.

      • We study ants as a species. The chances of any particular anthill being studied, OTOH, are close to zero. In the analogy, Earth is just one anthill among millions.

        But that's a different argument. The Harvard article is arguing that Earth hasn't been visited because we aren't very interesting. Your argument is we haven't been visited because there are so many similar planets with this level of intelligent life that the odds are against it. But if that's the case, we might not be visited by the Galactic

    • The any analogy is incredibly flawed. We study ants, extensively.

      And if those ants were shooting things into space we would almost certainly try to talk to them.

    • We study some ants. We do not study all ants.

      There's no particular reason to pick us, any more than there's a reason to pick the random ant colony in my backyard.

  • by Atticka ( 175794 ) <atticka@sand[ ]cafe.com ['box' in gap]> on Friday January 22, 2021 @01:48PM (#60979428)

    I mean seriously, not EVERY extraterrestrial may be interested in the human ant colony... but some just might be?

    • Yes some civilizations might be interested for scientific curiosity; but other than that, we may not offer civilizations that can cross space anything of value. Science fiction keeps inventing reasons why the Earth might be important that may not be all that important. V the Series said the aliens were interested in the water. Independence Day had the aliens wanting to strip the Earth of all natural resources. That's fine but the amount of energy and effort required to harvest those from Earth as opposed to
      • More resources out there than on the Earth and it's already in space. You would think we would see some mining/collecting going on before they decided to come here. Of course they may just nudge something our way ala Lucifer's Hammer before even thinking of visiting.

        Would it surprise me that humanity is the galactic equivalent of a first post and likely just as stupid and irrelevant, not even a little, but so far we're the only game in town.

    • Comment removed based on user account deletion
    • The probability of any specific ant colony being studied by a human is extremely low. Even though we study ant colonies.

    • by chill ( 34294 )

      Those that have solved the FTL problem can probably study us just fine from afar without popping in for a visit.

      For those that HAVEN'T solved the FTL problem, what makes you think they know we're here? What's the radius of our EMR [popularmechanics.com] so far? How many stellar systems are within 100 or so light years of Earth?

      Assuming no aliens with godlike observational abilities are hunting for us, there are only just under 15,000 [usu.edu] stars estimated within that radius. I'm not sure if that estimate takes into account just stars o

  • by QuietLagoon ( 813062 ) on Friday January 22, 2021 @01:51PM (#60979436)
    Who said anything about "special" attention. Why not just the regular, old, run-of-the-mill attention from a curious species?
    • The odds of one specific anthill being studied by a human are extremely low. Even though we do study anthills.

      The odds are we're not that anthill.

  • Inbetween the hiders, and those who are conquerers, and those who believe in the soft racism of patting the technologically backwards on the head and leaving them alone because they are precious as-is, there must be some of honor who would voluntarily offer lifesaving technology to whoever wants it.

    Tfa just presumes nobody wants to leave their home planets because it's dangerous. But all our experience shows this is both desirable for many, and mere technological challenges, trivial for a civilization 500

    • by alvian ( 6203170 )
      Maybe at first but bad experiences might put a stop to that. What do you think will happen if some aliens gave the human species technology that'll provide clean and cheap energy? I know what'll happen on Earth. Various government will be making bombs and weapon systems using that exact technology to gain supremacy. Let alone some governments, like the US, preventing the use of that technology to protect the economic collapse of current dirty energy producers. Maybe of whom funding the campaigns of politici
    • But all our experience shows this is both desirable for many, and mere technological challenges, trivial for a civilization 500 years ahead

      Got some evidence that "it's trivial"?

      There is nothing we know in physics that would let us travel faster than light, nor anything that hints at it being possible. And a generation ship doesn't get you an interstellar civilization. They get you two single-star civilizations.

  • "We may be a phenomenon as uninteresting to them as ants are to us; after all, when we're walking down the sidewalk we rarely if ever examine every ant along our path."

    No, but we would if we very rarely saw any ants or had never seen an ant before. If there were lots of ants (sentient species) then maybe not, but what if sentient species are actually very rare during any given time period?

    Also, what if it is the case that it is an evolutionary requirement to get to space that sentient beings must have a go

  • If you find out about a coup days before your trip to a s*iathole country, you'd likely delay. Why would aliens choose to show up during the most volatile, destructive point in Earth's history?
  • More like exterminate for the good of the universe. Do you really think they want to give us universal healthcare (actual universal), education, welfare, and handouts on their dime?

  • by bb_matt ( 5705262 ) on Friday January 22, 2021 @01:55PM (#60979474)

    ... there is every chance advanced civilisations in our universe simply haven't found us.

    Heck, even in our galaxy - you know, just 52,850 light years large. That's somewhat bigger than a walk down to the chemists.

    And if it holds true that FTL is physically impossible, there's got to be a damn good reason civilisations more advanced than ours aren't keen on travelling a few thousand light years to say "hello" - there's no point, even if they had somehow detected sentient life on our planet.

    Sure, if it was only a matter of a relatively short hop in terms of decades at FTL speed, a civilisation more advanced than ours may consider it.
    After all, the article makes the example of ants, but some humans are obsessed by small insects and spend their lives researching them.

    The thing is, if sentience is scattered across, say, just our galaxy, like a handful of 'dust', and FTL travel is impossible, then we the chances of encountering life from another part of our galaxy is ... well, the odds aren't in favour of it happening. ... unless it already has and we are the product of it, some millions of years in the past.

    Douglas Adams just did it best when pondering on intelligent life in the universe - and we didn't rate highly on that scale in terms of importance ;)

    • I think this is the key, unless they have a much faster than light travel method it'd have to be worth the cost to visit earth. (Un)fortunately there just isn't anything on earth worth it. The only thing I can think of that's unique to earth is our specific life forms, and if there are aliens likely it's really just our specific life forms which would be one set out of trillions of trillions.
      • Indeed!

        You also have to consider, if science is correct on the evolution of humans and that modern humans, as we are today, arose some 300,000 years ago ... how long it took us to colonise the entire planet since then.

        300,000 years in the lifespan of the universe is a blip. It hardly registers. But in terms of civilisations, and the rise of them, we could, in theory, say that the first 280,000 of those years were uneventful when it came to exploration.

        So, yeah, I'm extrapolating our own species exploration

    • Oracle, are we alone in the universe? [theoatmeal.com]

      Yes

      So there is no other life out there?

      There is. They're alone too

  • It is quite odd, given that the author, Dr. Avi Loeb, is a proponent of the alien origin of Omuamua, and even published a book [bostonglobe.com] on the topic (more here [salon.com]).

  • after all, humans are a pretty cretinous species. We might have done tremenduous accomplishment during the 10,000 last years, but we have had pretty bad ones too, like war and religion, the two most destructive forces ever.

    If the Roman empire had not collapsed because it was gummed up with christianity, mankind would not have been set backwards nearly 1000 years; the Industrial revolution could have happenned 1500 years ago, and if science had taken a stronghold on tought and had completely squelched rel

    • after all, humans are a pretty cretinous species.

      Spock: "Humans drafted the Magna Carta, invented the abacus, composed the Jupiter symphony, painted "Starry Night", danced a dying swan, built stonehenge, the imperial city, the pyramids of Gisa, discovered radium, spun sugar into cotton candy, fashioned gutta-percha into a ball, encased it in dimpled white, hit it 500 yards into a tin cup and made the practitioners of this feat rich men."

      --from "Spock versus Q".

      (I would also add: Humans eliminated smallpox, guinea worm, and (just about) polio.)

  • 1) we are alone in the universe when it comes to intelligent life, so there's no one to find us.

    2) intelligent species are so rare that they simply cannot find us in the vast galaxy

    3) intelligent species are common, making us at best a curiosity, likely by some obscure poorly funded xenozoologist who only publishes in mid- or low-tier galactic journals, so the very few alien scientists interested in studying us just don't have the funding to initiate first contact.

  • Any civilization scientifically advanced enough to make interstellar travel feasible from both a resource and time/capability standpoint could only have gotten there with a certain amount of societal curiosity. Even if it takes tens or hundreds of thousands of years to reach that level of technology, there has to be a drive and curiosity behind it to keep that development going. What scientist right now wouldn't love to go back and be able to observe human civilizations thousands of years ago, or even jus

  • these advanced civilizations may choose to refrain from contact

    Yeah. Just like the average shlashdoter refrains from contacting a girl because "reasons, and anyway I already have a girlfriend.jpg"

  • There's also this problem that we assume that creatures who do want to meet up with us would have the same scale as us. Could be that they've already been here but have been emitting radiation so small as to be undetectable by any instrument we have. Heck, could be they were already here but eaten by some bacteria on Earth.

  • So if they are billions of years ahead of us they probibly perceive radio as something so antiquated that most dont even know it exists and all their electronics are so efficient they dont really give of any rf signals. Just look how far we came in a bit over 100 years. And for sure they would not take notice of us. And if they did they probibly walk faaar around us like we would a bunch of angry chittering mice with primitive weapons. Its not like we are a nice species to deal with. Self serving, hostile a
  • There are people who make a career out of studying ants. Documentaries about ants. Probably a museum dedicated to ants. And we would visit the hell out of some alien ants if we knew they were there.

  • As a species we are more than likely too primitive to even bother with. As a planet we probably have a sparse collection of commodities to harvest. Heck, there are moons in our own solar system that likely contain more water than our oceans. There are planets that rain diamonds and asteroids with more precious metals than 10 Earths combined. In terms of galactic importance we probably don't even register. Why bother visiting a rock with very little to offer (not to mention pesky human critters running aroun
  • You *could* assume that there is this uber-advanced lifeform in the universe that is just so incredibly advanced that they don't feel like meeting us.

    OR, you could face the possibility that, in actual fact, we are the first species to reach this level of advancement in the universe. I mean, it took this long for *us* to show up... who's to say that it doesn't take this long for *every* advanced species? Who's to say we aren't the first?

    Then you would have to admit to yourself that not only is this sad, but

  • It's certainly true that, if life is common enough for there to be civilizations capable of popping over for a look, we probably aren't notably special; but that seems much less relevant to the question of "why no visit?" when you consider the capabilities anyone doing interstellar travel would presumably need to have.

    If you are commanding energy on the scale required to do interstellar travel, along with the necessary durability to not have all your probes dead on arrival, you are at the point where, wh
  • Consider the difference between airline travel and general aviation. Airliners follow well known routes, while GA flying is more random.

    Clearly, we are not on the interstellar routes that we know of, so that leaves the extraterrestrial version of general aviation. A few explorers will fly to the unprepared landing grounds, but they are small enough that most people will be completely unaware that it has happened. Most of the planet still does not have global radar coverage, so there are many places where th

  • Obviously...

  • Realistically, the search radius for someone interested in visiting us is about 100-200 light years. 200 if you consider when we started using electricity to facilitate communications over wires, which would act as antenna, to make us heard. It would be nearly a hundred years before we were deliberately trying to radiate electromagnetic waves.

    Anyone outside that range would not have noticed us.

    How many potentially habitable planets have we noticed within that range?

    And we've only been looking for extraterre

  • Why did Darwin want to go to the Galapagos Islands?

    k.

  • We've only been broadcasting radio transmissions for about 100 years now. There are only 76 stars that would have received those and a very small number of those would be conducive to intelligent life. So nobody has heard us and nobody knows we are here.

    Similarly, there may be millions of candidate planets around candidate stars in our galaxy. And many of those may have evolved intelligent life. But the thousand or 10,000 years that that life existed on those planets does not exactly line up with the ti

    • by lazarus ( 2879 )

      Correction. There are about 500 type-G stars within 100 light years of earth, not 76. Too bad you can't edit your posts on Slashdot. It is still highly unlikely that another intelligent species capable of transmitting and receiving electromagnetic communications would have evolved in 500 systems. And again, to my second point if they did, the odds of them having done so at exactly the time when either we would have picked up their transmissions or they ours is several orders of magnatude less likely sti

    • by ahodgson ( 74077 )

      Plus they'd have to want to talk to us. And have some way of getting here.

      Some species might be smart enough to not start shouting "I'm here!" to anyone in the neighborhood before learning how dangerous that might be.

  • A pile of ... (Score:4, Insightful)

    by fish_in_the_c ( 577259 ) on Friday January 22, 2021 @02:29PM (#60979662)

    I guess I guess I guess I guess... give you a big pile of I guess. Not really much science here. Piling assumptions on top of assumptions is pretty certain to get you a wrong answer. The fact is there is no proof extra-terrestrial life exists until we find some. Sure it MAY be reasonable there 'should' be some ASSUMING our guesses are correct, but there is simply no way to know what we don't know and that is science.
    So until we have some idea ( what circumstances cause the creation of 'life' , which might require have a better definition) AND we know that FTL travel is physically possible there is really no sense in arguing one persons guess over another.

    Fermi's paradox may simply be solved by FTL travel being physically impossible , in which case the energy for any 2 civilizations of far enough distance to have any useful communications is beyond the means any civilization and/or that our civilization happens to be so far away that no one can contact us. They may have already sent a signal and we might get it 10000 years from now.

  • We think aliens would want to visit us because we want to visit them.

    I think they do NOT want to visit us because we have sent our radio and TV broadcasts out to the universe for decades.

    Either they listen / watch and are horrified, or they listen/watch and find us so hillarious they don't want to chance us changing. Especially after the last American President.

  • by kbahey ( 102895 ) on Friday January 22, 2021 @02:33PM (#60979680) Homepage

    Well, we may not be interesting as a species, but life as a whole is very interesting ...

    If there is intelligent life elsewhere (which I doubt, bear with me), I would think they want to know how life elsewhere looks like, what ingredients does it use, and how it evolved ...

    Life is most likely carbon based everywhere there is life, and requires water. Silicon based life, a staple of science fiction, is unlikely given how strong the bonds it forms (look around you for rocks, they are very stable). Life requires weak bonds that form, but can also can be broken, and carbon (with oxygen, hydrogen and a few other elements) provide the necessary substrate for life.

    But there is no guarantee that life everywhere is built on DNA/RNA and proteins, like what we have here on earth.

    On earth, it took a few hundred million years for life to get going, and it stayed at the primitive unicellular bacterial or archeal stage for billions of years. The evolution of eukaryotes (fungi, plants, animals including you and me) took a very specific event that occurred only once in earth's history: a cell engulfing another bacterial cell. This is the common ancestor of all eukaryotes, and the inner cell is what is known today as mitochondria. This event enabled the host cell to have much more energy than previous cells, and paved the way for multicellular life to emerge.

    So, I will not be surprised if bacterial level life is discovered on Mars (whether active now, or went extinct at some point), or the moons of Jupiter and Saturn. What will surprise me is complex life elsewhere in the universe, given this engulfment event, and it possibly being the Great Filter for the development of complex life, which gave rise to intelligent life.

    So, back to the article: if there is intelligent life elsewhere, they will be as curious as we are in whether life exists elsewhere, and how it is similar or different from what they have. Detecting an imbalance of certain gases in the atmosphere (e.g. an abundance of methane and oxygen) would be a tell tale sign that there is a biological process going on. They would be curious as to how this works, and how it evolved.

    So, we may not be interesting, but life and how it developed into a sentient species is very interesting ...

    • by alvian ( 6203170 )
      At first yes but what about after encountering dozens of life outside their planetary system? That initial wonder and curiosity will wear off and they'll lose interest.
      • by kbahey ( 102895 )

        Agreed.

        But they would have answered the questions: is life similar everywhere? Does it use the same biochemistry? Has it all evolved from a common source (panspermia) or independently? Is any of those sentient? Are there civilizations elsewhere? And so on ...

        For me, I am inclined to think that life is very rare, at least ...

  • We've already fucked everything that we can on the Earth. Yet, we still want to fuck more.

  • When we don't have clear data on something, we normally will place what we currently know on the center of a normal distribution curve, as the best bet will be on the fact what we currently see is probably going to be the normal.

    After we have discovered that Planets were physical objects like the Earth, we mainly needed to assume that they had life on them too, Men from the Moon and from Mars. Further study found that these places lacked many of the characteristics that are needed for life to exist, so now

  • Interstellar space flight is just really hard to do. There's a lot of crap out there we can't see, maybe they can see it but imagine plotting a corse through tens of thousands of rogue planets, asteroids and simple dirt? What does happen to your million ton vehicle when you pass through a million tones of dust at 2% of the speed of light?
  • As a vegetarian I dont know what a chicken tastes like, but it is likely ET might tell its colleague, "it tastes like chicken"
  • because humans made a disaster out of our society and our planet, so it would go like this: https://i.postimg.cc/L81h8WBN/... [postimg.cc]
  • ...humans are narcissistic, it's all about us.

  • Who wouldn't travel a billion light-years to put up a probe up some redneck's ass?

    It's what they do in the galaxy for fun.

Disclaimer: "These opinions are my own, though for a small fee they be yours too." -- Dave Haynie

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