To confine our attention to terrestrial matters would be to limit the human spirit. –Stephen Hawking

Stephen Hawking is in the news today, big time. Why? He says that intelligent aliens almost certainly exist, and that we should definitely not try to contact them. In fact, he argues, we should stay as quiet as possible and try to avoid detection. To quote him:

If aliens visit us, the outcome would be much as when Columbus landed in America, which didn’t turn out well for the Native Americans.

We only have to look at ourselves to see how intelligent life might develop into something we wouldn’t want to meet.

I was floored. And I was even more shocked when I realized that this opinion was a common one among my scientific peers.

With all due respect, I completely disagree. If an alien’s ship managed to come all the way from another star system to within range of Earth, we would already know an incredible amount about them. What follows is what I would say to them. (And you should feel free to opine in the comments.)

We know that, like us, you grew to prominence on your planet, evolving over hundreds of millions of years to become the most successful species on your world. We know — like us — you gained mastery over your environment, learning to utilize resources and tools to construct a myriad of things that would have never existed without your intervention.

And, unlike us, you have managed to build a ship to sustain you during an interstellar voyage, far away from any natural power sources (like stars). This is a fantastic achievement, and we are a long way off from anything approaching this! Your technology is far, far advanced from ours. It’s very likely that your astronomy skills — particularly for finding planets you’re interested in coming to for their natural resources — are superb, and vastly superior to our own.

In other words, if you’re looking for a world in order to harvest resources from and we’re a good fit, you’re going to find us whether we advertise or not.

But we are young, and in our technological infancy. It was only 10,000 years ago — about 400 generations — that we started planting seeds and growing our own food. It is only now, at the present day, that we are beginning to learn how to live within the means of what our planet can sustainably provide. And you must have figured that part out in order to develop the technology and devote the resources to sustainably survive without a planet or power source at all.

There are so many questions we are striving to learn the answer to, that we are only even beginning to pose well. And yet, to survive a long-term space journey, any alien race must have already figured out an answer to these and many other questions. The two big ones that I want to ask are these:

  • We have evolved to be selfish hoarders, always hungering for more, and to expand beyond the means of our resources. How did you overcome the limitations of your evolution?
  • The resources available to plunder on our planet are limited, and it is almost unimaginable to imagine surviving a long amount of time (many years, at least, but probably many generations) without any power source at all! But you did it. What was your solution to your energy needs?

But to imagine malevolent aliens? Why? Destroying us would be like crushing a colony of microbes just for kicks to them. Their technological level must be at least hundreds, if not tens of thousands of years beyond ours. Can you imagine even the greatest military force from the Napoleonic Era even lasting a few weeks against our modern warfare technologies? It simply wouldn’t happen.

But what irks me most of all is the cowardice behind a viewpoint that we shouldn’t rush to meet a peer in this Universe. It would be like forgetting the best part of being human: our bravery, our sense of adventure, our will to explore, our thirst for learning and discovery, our curiosity, and our desire to experience all that existence has to offer.

I am eager. I want to meet them. I want to know the answers to those questions. Right now, when I put the numbers I think are most likely into the Drake equation, I find it very unlikely that there ought to be another intelligent civilization within a hundred million light years of us. But if there is, I’m going to try to find them.

So if any aliens are reading this, PICK US! HERE! All of humanity may not be ready for you, but some of us are. If you come, the rest of us will come around. And I’ll be among the first to welcome and greet you. Be gentle with us and be careful with our delicate biology. We have a lot to learn, and could use a great teacher. I hope to hear from you soon.




  1. #1 Brando
    April 26, 2010

    I think it was Carl Sagan who proposed the important question to an alien civilization: “how did you not destroy yourselves?” But you bring up another important question, ironically one that was brought up in the pre-Apollo era film “This Island Earth (1954)” 🙂

  2. #2 TaeWoo
    April 26, 2010
  3. #3 Noam GR
    April 26, 2010

    I too found Hawking’s statement… surprising.

    What use would a civilization that has master interstellar or intergalactic trave have in our resources? — Unless their sheeps run on human flesh, I should think that they have long ago come up with efficient means of extracting whatever energy, minerals, etc. is necessary for their endeavours.

    This would be tantamount to me destroying an ant colony so that I could steal a few crumbs of sugar.

  4. #4 Noam GR
    April 26, 2010

    (Holy typos! — I don’t know wat happened. Edit:)

    I too found Hawking’s statement… surprising.
    What use would a civilization that has mastered interstellar travel have for our resources? — Unless their ships run on human flesh, I should think that they have long ago come up with efficient means of extracting whatever energy, minerals, etc. is necessary for their endeavours.
    This would be tantamount to me destroying an ant colony so that I could steal a few crumbs of sugar.

  5. #5 NewEnglandBob
    April 26, 2010


  6. #6 Sophos
    April 26, 2010

    I highly doubt that there are any more intelligent civilization.

    If they do exist, and landed on Earth, chances are that they speak languages that we don’t know and communication would be difficult.

    I personally think that contacting them is stupid because we don’t know what they are thinking. Probably we’re just trying to look around in the space while they’re already intending to conquer the whole universe.

    Well, humans are selfish beings. So are aliens (if they do exist). Why would they talk to something that is of no use to them? They would rather send us back to their civilization and experiment on us. Nobody in their civilization would believe that they’ve found human if they don’t do so anyway.

    Maybe you can say that you are ready to see them. But if they ever landed right in front of you, I think (just a thought) that you would be shocked and terrified till death.

  7. #7 AJKamper
    April 26, 2010

    P.S., aliens:

    Bring cookies!

  8. #8 Don Rowe
    April 26, 2010

    I have to agree with the notion that if a race capable of extremely fast inter-stellar travel wanted to find us they would.

    I see where Hawking is coming from, though. It seems to me that human history is very sparsely punctuated with altruistic, or solely exploratory, ‘new-travel’ events. There’s always been an undertone of colonisation, conquest or personal (from the level of individuals up to countries/empires) gain.

    I’d would be skeptical about an alien race roaring around the galaxy with the sole purpose of helping out infantile, ignorant, ‘intelligent’ species as they go. It’s much more likely that they’re here for something.

    Ethan, the first of those two questions you pose presupposes an altruistic attitude to that alien species’ travel. It would be very possible that the aliens obtained advanced technology simply because necessity dictated their expansion beyond their home rock.

    But, as I said, at the end of the day it doesn’t really matter. If they want to find us, they will. I do hope we develop a cooperative relationship, but I’m not counting on it.

  9. #9 Douglas Watts
    April 26, 2010

    I agree with Hawking. There is a good chance that a sophisticated enough alien to reach Earth would be as rapacious as humans, and being sophisticated enough to come here, it could easily take over the planet and do what it wants with us, which most likely would not be good for us, or not done with our consent.

    Also: “This would be tantamount to me destroying an ant colony so that I could steal a few crumbs of sugar.”

    We do that all the time, and are now doing it to our entire planet. Why would an alien race care more about the condition of Earth than we do? We certainly don’t care about it, even though it’s the only place we know of that supports any life at all.

  10. #10 daedalus4u
    April 26, 2010

    I think that Hawking’s statement reflects his emotional state of health more than a considered opinion on what is likely. The idea that aliens would take resources from Earth is nonsense. There is no bulk commodity resource on Earth that is not orders of magnitude easier to get in space.

    The one thing that Earth does have (which is likely to be of immense value to any aliens), is an intelligence that is unlike their own. If they do have any unsolved scientific problems, looking at it through another (and unrelated) intelligence may lead to breakthroughs that they are unable to achieve on their own.

    The other thing that is of immense value is the biology of Earth, a biology that evolved separately from their own. It is extremely likely that our biology and theirs would be incompatible, they would be unable to use Earth biomass as food. All eukaryotes are related, and so all eukaryote proteins can be broken down by eukaryote lytic enzymes. That might not be the case with alien biology.

  11. #11 mad the swine
    April 26, 2010

    “Their technological level must be at least hundreds, if not tens of thousands of years beyond ours. Can you imagine even the greatest military force from the Napoleonic Era even lasting a few weeks against our modern warfare technologies? It simply wouldn’t happen. ”

    You assume that technological advancement is teleological, ie, that a species more advanced than us in terms of interstellar travel would be more advanced in every aspect of technology. That assumption is (possibly) unwarranted.

    That being said, any species capable of interstellar travel could throw comets at us from the Oort Cloud until humanity was wiped out, so there’s that.

    Anyway, to address some of your other arguments against what Hawking (who I agree with, by the way) said:

    0) A preliminary note: general relativity and the light-speed barrier means that interstellar manned (aliened?) space exploration is extremely costly; the visitors would be permanently separated (by time as well as space) from the culture that produced them. Given that, aliens that arrive in our system will most likely be colonists, coming in force, in large numbers, and with no intention of returning to a ‘home’ that is, probably, centuries away. (FTL travel would change this dynamic, of course, but it looks impossible so far.)

    1) Even if one assumes that alien visitors would ‘come in peace’: not all the Europeans who came with Columbus were hostile. The missionaries, for instance, who worked to eradicate Native American beliefs and cultures, going so far as to take children away from native parents and put them in orphanages for their own good, making it illegal to speak Native American languages, etc., had only benevolent intentions – ‘civilizing the savages’, etc. Quite frankly, I don’t want to be ‘civilized’ in such a fashion. Any historian of colonialism can think of a thousand more examples of unintended harms done by well-meaning colonials. What about the introduction of invasive species? If alien visitors are carbon-based, oxygen-breathing life, their pets and food species can surely find something to eat on Earth, and anything they have that photosynthesizes would do just fine…

    2) You’re assuming “extremely fast” space travel, etc. with a very high level of technological advancement, but this may not be the case. Generation ships could very nearly be built with modern (or even Apollo-era) technology (there are just a few bugs to work out); in fact, this is most likely the only practical means of interstellar travel, given the enormous energy requirements for travel at relativistic speeds. Visitors in a generation ship could well not be particularly advanced, technologically or socially, and could have in fact regressed over the centuries. Which leads me to:

    3) Your assumption that interstellar travelers must be extremely socially advanced in order to live sustainably. To be quite honest, the most straightforward way to ensure that every member of a society (and society as a whole) lives within its means is to have a powerful central authority brutally enforce consumption and population controls. Given how that sort of central authority has tended to act on our planet, I doubt that our weakness (as a species) would prevent them from crushing us like bugs. The purpose of power is power, etc.

    4) “And you must have figured that part out in order to develop the technology and devote the resources to sustainably survive without a planet or power source at all. ”

    Or perhaps they developed the technology in the course of destroying their own planet, which is why a colony ship is showing up on our doorstep (cf. Larry Niven’s Moties). Perhaps they’ve been enduring enormous privations for the sake of sustainably living on their ship and can’t wait to get off and stretch their legs or leg analogues. Just because a species *can* live sustainably doesn’t mean it will, or even wants to. Think sailors on shore leave.

  12. #12 Helmut
    April 26, 2010

    Unless I’m mistaken, we’ve been “broadcasting” an unusual amount of free oxygen to alien spectrometers for a couple billion years now. And I doubt we’re turning that beacon off anytime soon. I don’t think a couple decades of radio are going to make a difference.

    And the the anthill analogy is a good one, with a tweak. We(humans) kick over anthills all the time, because they’re next to our feet and we’re bored little kids. We’re not going to send a human to Pluto to kick over an anthill.

  13. #13 Jackal
    April 26, 2010

    Evolution favors whatever is good for survival. Often, that means being capable of killing off the competition. Humans don’t go around robbing anthills, it’s true… But if that anthill is on a plot of land we want to develop, we bulldoze it without a thought.

  14. #14 Sphere Coupler
    April 26, 2010

    I think to reasonably address this question one has to step into the Aliens shoes and see it from their perspective.

    Any advanced alien civilization that could reach us may have occurred in one of two ways, the aliens used up their home world and are looking for a planet to colonize(in this case look out) or they reached a level of intelligence where altruism dominates and they have a non-interference policy(and we would never know).

    Any Alien would have “also” had the need to evolve, first learning to master their home world then escape the planets gravity, then escape their solar system , mobilization within a galaxy might take quite a while, is their any reason to think that the evolutionary process is any faster in some parts of this galaxy than in others?

    Wouldn’t we have started at the same line? or would those closer to galactic center or galactic edge have a head start?

    Given the fact that resources would be readily obtainable for Aliens with Galactic mobility, some reasons to be alarmed would be Genetic harvesters, Competition eliminators, or Aliens driven by domination, Master/Slave objectives.

    I personally would rather find them, than they find us, we are no different than the environment that made us “stellar debris” and that environment was chaotic and violent, Our human species has reflected that thruout history…is their any reason to believe that other beings made from the same material wouldn’t have the same attributes?

    Then again, maybe their already here and have played a part in our own evolution…viruses!

    It’s a given that protein is the building block of inteligents and protein is readily available to carnivores, so just using those two parameters, we could be looking at a ravinously, inteligent Alien looking for Dinner.

    I agree with Sir Hawking…and in my own words, “lets play hide and go seek a little longer” till we know with what we are dealing.

  15. #15 Haydon
    April 26, 2010

    Hawking has expressed these sentiments repeatedly in the past….this is nothing new. I know I read some of his public speeches online from his website at least 5 years ago, and these statements were included in one of those speeches. I also concur with Hawking. It’s not a cowardly argument at all, its a reverence for that which is more powerful than ourselves and a realization that most forces do not act with our well being as a priority.

  16. #16 Douglas Watts
    April 26, 2010

    If we assume the aliens are carbon-based life, they had to travel a long way to get “here” and require conditions that, in our solar system, are most readily available on Earth. Presumably, such long range visitors would be interested in colonization, if only to get them off a space ship and onto a planet. Assuming their physiological needs would be somewhat similar, but not identical, to ours, then it would be logical to assume they would view the Earth as a unique opportunity for terra-forming, and they would convert the climate and atmospheric and biospheric state of Earth to one most suitable to them, just as many on Earth envision we do on Mars. Their adaptations would probably not be well suited for us, and it’s doubtful they would take much heed of our protestations.

    There’s also the ugly prospect they may hunt and kill us for sport, as Australians did to the Aborigines of Tasmania, and sell curios made from male human scrotums.

  17. #17 MPL
    April 26, 2010

    My reaction was that alien civilizations don’t overlap with ours in space (obviously), and are unlikely to overlap in time either (so far we’ve got 5,000 years of cities out of 5,000,000,000 years of life or so).

    Perhaps we should start thinking about looking for (and maybe leaving) a tombstone visible from space, rather than interstellar sitcom reruns (please don’t take this as morbid—even evidence of an alien civilization, never mind large amounts of information about them, would be one of the most important discoveries ever. A civilization that knows it has a finite time-frame could see it as an act of charity to leave a record).

  18. #18 Vince Whirlwind
    April 26, 2010

    I disagree with your assumptions, Ethan.
    Why would you assume that these aliens have “overcome the limitations of their evolution” and are not “hungering for more, and to expand beyond the means of [their] resources?

    Malevolence doesn’t come into it.
    We don’t cram billions of chickens into shoebox-sized cages because we are malevolent, we do it because this is the means we have devised to produce the goods we require. From the chickens’ point of view it would seem appalling, but ethically we have a very selective approach to judging our actions.
    Why would an alien race treat us any better than we treat battery hens?

    Great technological advancement is absolutely *not* concomitant with ethical development: it was the Nazis who developed the rocket technology which eventually put Man on the moon.

  19. #19 Douglas Watts
    April 26, 2010

    Be gentle with us and be careful with our delicate biology.

    Given that we humans, in just the last 30 years, have brought all of our closest primate relatives, the great apes, chimps and bonobos to the verge of extinction by killing them and willfully destroying their habitat, I doubt this request would pass the straight face test with our new alien friends.

    Like Hawking said, it’s best we hide, but more so from embarrassment. Our track record of planetary stewardship really sucks and it is the most “advanced” cultures that are doing and/or funding the worst of the pillaging.

  20. #20 Sphere Coupler
    April 26, 2010

    Hey, I think it’s a great thought to think that out of the blue in the deep dark forest (if there is still one left!) that a strange being could walk into camp and be accepted…

    Rereading the comments about the anthill analogy made me think that we as humans have always “disturbed” nature to see what happens.We continue to this day, “to kick the dandelions and smash protons”. It is apparently in our nature to do so.

    It is also the nature of the Universe to interact and disturb the nearby entities at least on a local scale.
    The philosophy that I hold is that we, as curious humans, a product of the Universe, who strive to understand their existence, can be boiled down to:

    Humanity is the Universe’s attempt to understand itself.

    And as survival of the fittest has taught us, as a earth inhabitant, the shorter the learning curve…the better off we are.

  21. #21 Douglas Watts
    April 27, 2010

    There’s also the question of whether an alien civilization visitor would grant us, and any other denizens of Earth, any legal rights. No human culture grants any other species legal rights. Not the same species = no legal rights. Hell, we don’t even grant members of our own species equal, legal rights. Why should we summarily presume an advanced, exotic alien species would grant us what we refuse to grant to blue whales, whom except for a language barrier, may well be just as intelligent as us? I do not dismiss the possibility of Ethan’s prognosis but it seems to rest on a very thin reed.

  22. #22 donncha
    April 27, 2010

    @12: We’re not going to send a human to Pluto to kick over an anthill.

    No, but we may well do it for the hell of it once we get there 🙂

  23. #23 Sphere Coupler
    April 27, 2010

    Let me rephrase comment 20 to a more realistic and less egotistical statement;
    All life, is the Universes attempt to understand itself.

    The extinction of life thru our domination limits our ability to learn and survive.

  24. #24 John Quiggin
    April 27, 2010

    A much simpler refutation of Hawking is available. Using any technology conceivable on the basis of our current theories of physics, the energy and other resources required to reach Earth from the nearest plausible starting point (at least 50 light years) would outweigh by a factor of millions any resources that could be carried away (again using a conceivable technology).

    Hence, if aliens could reach us they must either
    (a) not be motivated by a desire for resources; of
    (b) possess inconceivable technologies, presumably unrelated to what we think of as ‘resources’.

  25. #25 Helmut
    April 27, 2010


    That was kinda my point. We wouldn’t go to Pluto solely to kick over an anthill. If we’re there for other, more worthy reasons, the existence of said anthill isn’t likely to have any effect on whether we go or not. So it’d be senseless for the ants to hide their hill for the sole purpose of keeping us from landing on Pluto.

    In other words, if aliens are coming to earth because it’s oxygen-rich/life-supporting/Goldilocks-zone, it’s been that way for billions of years and is unrelated to the existence of intelligent life. Same thing with wiping out competition, they could have nipped us in the bud millions of years ago. So there’s no use in hiding, but tons to gain.

  26. #26 JTW
    April 27, 2010

    “Hence, if aliens could reach us they must either”

    You forget one already mentioned several times (and one Hawking and others have stressed time and time again), and that’s colonisation.
    These aliens most likely will indeed not want to cart off the riches of earth to their home world (apart from maybe a few souvenirs for the family to show where they’ve settled down, like the British did when they moved the treasures of Egypt to London for example, never asking the natives what they thought of it).
    They’ll come to stay, settle here, turn earth into v2 (or 10, or 100) of their own home.
    And we’ll just be an annoyance to be dealt with. As we’re rather widespread and not likely to welcome another large advanced culture sharing the planet with us, we’ll have to be crushed, exterminated, or at the very least enslaved and culled.
    And as stated any culture advanced enough to have developed interstellar travel will almost certainly have the means to crush us like so many ants.

  27. #27 Roman
    April 27, 2010

    “What follows is what I would say to them”

    Come on, you know very well what will be said:


  28. #28 MPL
    April 27, 2010


    It seems likely that any aliens who are out traveling to temperate worlds can find them without relying on it sending a “hello there” radio transmission (we are on the cusp of being able to do so ourselves). So our intelligence is no incentive to colonists.

    They could crush us like ants, but they might as well move into a house that isn’t full of bugs to start with. I know I would.

    It seems pretty unlikely that you could travel fast through space anyway. We probably have several centuries or millennia before anyone shows up, more than enough to catch up or kill ourselves off first.

    If they do have the means to travel through space quickly, they must have access to so much energy, that the idea of colonizing a planet starts to seem like a silly extra. If I had to guess, faster-than-light travel and “moving Mars into a temperate orbit and teraforming it” are on roughly the same level of difficulty.

    Finally, even if they are coming to exploit us, we have no idea what for. Maybe they want to take biochemical and cognitive diversity, not real estate, and that could be a mutually-beneficial transaction.

  29. #29 Marcus Ranum
    April 27, 2010

    They’d come and destroy us. After watching a few of our movies, they’d see that we constantly portray ourselves as immediately coming into conflict with (and miraculously destroying) every alien species we encounter. Since we started transmitting TV shows and radio broadcasts it’s been nothing but a stream of evidence that we’re dangerous and extremely unstable vermin that ought to be “cured” with a well-aimed high-vee chunk of rock.

  30. #30 Marcus Ranum
    April 27, 2010

    Can you imagine even the greatest military force from the Napoleonic Era even lasting a few weeks against our modern warfare technologies?

    They might cleanse Earth because of the ants or the fungi. Sure, the humans are brutal, and stupid – but there is life on Earth that is stupid, utterly ruthless, and much harder to eradicate than humans. The sensible thing would be “I say we take off and nuke the entire site from orbit. It’s the only way to be sure.”

  31. #31 Faz
    April 27, 2010

    Dammit, we can’t let the aliens get our unobtanium !

  32. #32 Shailendra
    April 27, 2010

    Not going towards their aggressiveness, I strongly believe that they if ever came to us, firstly it won’t be for mineral needs, that’s for granted. I can’t believe that any civilization so advanced, & still depending on exhaustible sources of energy. Even if they are according to their advancement they would have depleted much earlier. It is basic psychology that any civilization with advancements becomes mature and peaceful. Just imagine the violence in the world of 1500s, 1800s and now.

  33. #33 Roman
    April 27, 2010

    “It is basic psychology that any civilization with advancements becomes mature and peaceful. Just imagine the violence in the world of 1500s, 1800s and now.”

    You mean Gulags and Holocaust?

  34. #34 William T
    April 27, 2010

    Why aren’t they here already? There’s been plenty of time, and if there is a colonising race of aliens about in the galaxy they should have spread out everywhere by now. Unless of course earth has luckily been hidden from the view of the ‘alien habitable zone’ (or is somehow just out of range from the next nearest habitable planet)….

  35. #35 Jib Halyard
    April 27, 2010

    “He says that intelligent aliens almost certainly exist”
    This is the first flaw in his logic. We have zero data to even hazard a guess as to whether there is other intelligent life in the universe. the universe could well be teeming with intelligent life. but based on our non-existent dataset, there is an equal probability intelligent life has only occurred once in the universe (and by definition we are it).
    Hawking is making a pretty big assumption from a sample size of 1.

  36. #36 KE
    April 27, 2010

    The probability of the simplest living cell coming together from chemical components is something like 10^-40000.
    This probability is so small that it is used by creationists as an argument against evolution. But this in itself does not make it wrong. It gives a hint of how many universes there are.
    Assuming there are 10^100 opportunities for life’s building blocks to combine themselves in each universe, it takes approximately 10^39900 universes to create life.

    There might be some intermediate mechanisms and pathways that improves the odds. But the conditions required for these mechanisms may themselves be highly improbable. And my belief is that there is no way you can get from 10^-40000 to anywhere near the 10^-100 that would make it probable that life would form twice in the same universe.

    So there is no reason to worry about aliens because they most likely do not exist.

    Sorry for this dry and off-topic post but I sometimes feel that astronomers are a bit arrogant about biology… taking life for granted and not taking into account how improbable it really is.

  37. #37 Alan Langley
    April 27, 2010

    The probability of the simplest living cell coming together from chemical components is something like 10^-40000.
    This probability is so small that it is used by creationists as an argument against evolution. But this in itself does not make it wrong. It gives a hint of how many universes there are.

    More likely, the chances of a living cell developing from the usual ingredients would be as inevitable as a chemical reaction.

    As for notions about infinitely branching universes, all discussion of such idiocies should be firmly suppressed by scientists if they want to be taken seriously by those who control the money.

  38. #38 mad the swine
    April 27, 2010

    “The probability of the simplest living cell coming together from chemical components is something like 10^-40000.”

    Abiogenesis doesn’t work that way.

    “Assuming there are 10^100 opportunities for life’s building blocks to combine themselves in each universe, it takes approximately 10^39900 universes to create life.”

    Statistics don’t work that way, either.

  39. #39 Jim Ernst
    April 27, 2010

    If you have the ability to detect goldilocks planets, and travel to them, which planets would you choose to consume? Ones that show signs of a technological civilisation, or ones that do not? Personally, I would exploit the resources of non-technical planets. The chance of a spirited defense is significantly less. Just because Earth couldn’t defend itself against interstellar attacks doesn’t mean that no civilisation could. Why would they take the risk?

  40. #40 Andrew S.
    April 27, 2010


    Only 10^100 opportunities in the entire lifetime of a given universe? I’d say that’s probably how many happened in the course of, I dunno, a year, when the earth was young. You’re looking at INDIVIDUAL CHEMICAL REACTIONS – it only takes the right one.

    Also, you fail statistics anyway, but hey.

  41. #41 Chris London
    April 27, 2010

    Talk to a Linguist and/or cognitive scientist and you will soon understand that chances are good that we will be able to communicate with an alien species about as successfully as we can currently communicate with whales, dolphins, etc., i.e. not very well at all.

    Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us.
    — Bill Watterson

  42. #42 ScentOfViolets
    April 27, 2010

    Am I that old? Has no one read Hoyle’s superb “A for Andromeda”? If aliens come here, it’s because we’ll have built them.

    Of course, there’s always the Black Cloud theory.

  43. #43 Cambrico
    April 27, 2010

    Bill Murray said, during the last seconds of the Basketball game in Space Jam, “never trust a human” or something like that. I think not friendly aliens will have two options: blow up the planet at once or regret it forever if trying to colonize us.

  44. #44 plutosdad
    April 27, 2010

    What use would a civilization that has master interstellar or intergalactic trave have in our resources?
    It depends on how easy heavy metals are to harvest from asteroids and gas planets. If it’s easier to break up rocky planets then they will do that.

    Unless they have a sense of morality and don’t destroy intelligent life. Sure you wouldn’t deliberately kill bugs if you don’t need to, but many humans would not care, and certainly wouldn’t feel guilty. Who knows what an alien would feel. Saying that “of course they won’t destroy us” is an undefendable and made-up based on faith as saying “they will destroy us” – we have no basis for even having an opinion.

    I’m reading Singularity Sky right now, and it’s full of uploaded consciousnesses, the ones born as programs have almost no ability to relate to carbon life that dies, and in their quest for new sensations they destroy and consume everything, and don’t seem to realize what they are doing.

    Really, we barely seem to understand the motivations of other humans, how can we possibly understand alien life?

  45. #45 Thomas Neil Neubert
    April 27, 2010

    Yes, cowardice is irksome, especially from a species that has driven so many species of animals and plants to extinction (e.g. beginning in prehistoric times with the mammoth and Neanderthal man).

    As for welcoming Travelers from other star systems, knowledge of such Travelers is systematically suppressed on most planets. Such knowledge is generally viewed as politically destabilizing.

    It has long been known that the only effective means of exchanging vast cultural knowledge between the 10,000 habitable planets of the 100 billion Milky Way star systems is by physically transporting people. (Great intelligence can reside in any suitable body, e.g. homo sapeins or genetically modified octopus dofleini.)

    When crossing the galaxy, the limitations of physics, economics and biology cannot be ignored. There is no faster than light travel. Starships are unimaginably expensive. Space travel is horrendously hazardous to living organisms. (e.g. living beings require massive shielding from cosmic rays) One can never return from such an uncertain galactic voyage. The psychological stress of galactic travel is enormous. Few choose to be such Travelers. Magician of Time is the common name given to those who smuggle Travelers across the galaxy; because when they return to a planet 1000 years later; they are apparently unchanged primarily due to the twin paradox. Whereas most of the previous inhabitants of such a planet have long ago died; and as well many cultural political institutions may have been replaced.

    As for an advance species wishing to play extinction with the species of another star system; such psychopathic civilizations (who have not outgrown the child’s game of pulling wings off of insects) seldom can survive upon their home planet long enough to develop star travel. As well they are monitored by the Magicians, who will not be interfered with by anyone. Thus being visited by a single extraterrestrial psychopath let alone an extraterrestrial psychopathic civilization is remote.

    Hawking’s fear of psychopaths is misplaced upon extraterrestrials; rather the great psychopaths to be feared reside upon planet Earth. Just look at 20th century planet Earth genocide.

  46. #46 Jeremy
    April 27, 2010

    I think it all depends on whether or not this advanced species is exploring in a search for scientific answers, or if they had to abandon their own planet. Say they are an advanced race with scientific expeditions travelling all over the universe and they discover our planet. They would probably be very peaceful, not want to disturb us just as the cameraman that films lions in the African plains is always far away with a telephoto lens under a blind. We would probably never even know we were or are being watched and studied. Now if this species developed similar to ours, carbon and water based lifeforms who’s planet is similar to our own, and their own homeland had been left uninhabitable by some force of nature, then I would think that they were seeking us out for a reason and that we would be in danger. Just think about it. Say there was a planet local to us that we knew of and had the technology to transport the majority of our population to it. Our sun is dying and in turn growing and enveloping our neighboring planets, we are on the brink of extinction. This nearby planet though, while home to a growing and learning race of semi advanced life, is the perfect habitat or close enough to what humans need that we could start anew on this planet. Do you think we would not swipe aside the planets original inhabitants without a second thought? We’ve had no problem doing just that here already. Just look at all the species that have gone extinct directly due to man’s interaction and greed.

  47. #47 Raging Bee
    April 27, 2010

    It is only now, at the present day, that we are beginning to learn how to live within the means of what our planet can sustainably provide. And you must have figured that part out in order to develop the technology and devote the resources to sustainably survive without a planet or power source at all.

    How do you know they did this in time to prevent their own native ecosystem from being destroyed?

    We have evolved to be selfish hoarders, always hungering for more, and to expand beyond the means of our resources. How did you overcome the limitations of your evolution?

    What leads you to assume they did?

    But to imagine malevolent aliens? Why? Destroying us would be like crushing a colony of microbes just for kicks to them.

    Or like clearing us out of the way to they can exploit a world rich in useful life-forms, which maybe they couldn’t do on their homeworld because it’s already taken by people with the ability to resist them.

    Did it ever occur to you that, if this species was already starfaring when they came to Earth, then maybe not all of them would be living on planets like their homeworld? And if their homeworld real-estate is already bought up, then the offworlders might be looking for more pleasant climes than they currently have, and realize that taking Earth would be easier than buying already-crowded land on their homeworld.

    I’m all in favor of meeting other species, but when we do, we’d bloody well better be able to: learn and adapt their knowledge and technology quickly; and fight them effectively if necessary.

    April 27, 2010


  49. #49 Josh Martin
    April 27, 2010

    You guys don’t think that intelligence is vastly dependent on the sociality of the species? As humans become more intelligent and more interconnect we progress. We don’t kill Aborigines for fun any more and a large percentage of us wont even eat chickens that are stuck in shoe box sized cages. We are constantly understanding more about other living beings capacity to suffer. Other races, species, and even humans thousands of years in the future are taken into consideration. I largely suspect that any species with the capacity for intergalactic travel will of came to their own altruistic conclusions about universal environmentalism. The capacity of intelligence is dependent on our ability to live with each other and share ideas.

  50. #50 DataJack
    April 27, 2010

    Ethan, I for the most part agree with you. However, I think that advanced civilizations are much more abundant in both time and space then you do. I also think that the c barrier is unbreakable, in every way. Therefore, I think it is exceedingly unlikely that any of those civilizations leave there home systems.

    Perhaps artifacts would be sent to other worlds, but which ones? There are billions to choose from. And what would a given star system be like after the millions of years it would take an artifact to get there?

    I just don’t see an advanced civilization attempting to send a probe (much less a “world ship”) to a place it won’t arrive to for thousands or millions of years.

  51. #51 Cody
    April 27, 2010

    Excellent perspective Ethan! (Disappointing 10e8 ly estimate, but not really the least bit surprising.)

    My analogy was, it’s like driving NYC to LA to get a few drops of gasoline. In Contact (the film), Ellie says, “…it’d be like us going out of our way to destroy a few microbes on an anthill in Africa,” her opponents respond, “…and how guilty would we feel if we [did that],” at which point the argument stops. But the appropriate response would be, we ought to feel stupid paying astronomical sums of money to travel great distances and then just destroy some lesser creature.

    Does Hawking think that humans would behave so? Spend trillions of dollars to travel hundreds of trillions of kilometers, for herbs, spices and precious metals, maybe fancy dyes!? Haven’t there been some cultural revolutions in the last 500 years?

  52. #52 Cody
    April 27, 2010

    I forgot to mention, I think the best resolution of Fermi’s paradox is a combination of the actual numbers are very low, and, interstellar travel, and even communication, is just much much more difficult than we currently imagine (I can’t get over the inverse square falloff of radiation with distance, and the ridiculous distances involved. Of course, if they were using say narrow laser-like beams, then we wouldn’t expect much stray signal to detect either.)

  53. #53 Mu
    April 27, 2010

    Ethan discounts the possibility that the aliens meeting us had a really bad experience with a different species they encountered eons before, and came to the simple conclusion that other intelligent lifeforms capable of getting off their planet = bad. They might have scores of robot ships cruising the galaxy with only one objective – find civilizations broadcasting and destroy. Even we could build something like that.

  54. #54 andrew
    April 27, 2010

    i think real estate, not resource extraction, is the thing to worry about. technologically powerful civilizations might be able to synthesize whatever they need from the raw materials freely available in space – but they probably won’t be able to engineer stars, or change the orbits of planets to their liking. what if what they really want are colonies? warm, atmosphere-bearing planets, ready for minimal adjustment to their way of life – that sounds like it would be a lot less trouble than completely terraforming a barren planet, or living in caves and under domes.

    so, if the aliens come from a planet with very different gravity from ours, and are used to living in very different temperatures, and if they find our planet to be severely toxic, we’ve probably got nothing to worry about.

    otherwise, we should probably hope that we never run into one another.

  55. #55 Marcus Ranum
    April 27, 2010

    It depends on how easy heavy metals are to harvest from asteroids and gas planets.

    “We are Zleeztakk!! We are come for ure LED ZEPPELINZ and IRON MAIDENZ!”

  56. #56 Douglas Watts
    April 27, 2010

    I’m always amazed at how many people think space aliens would be looking for “resources” — and immediately define the term to mean things like metals and ores, etc. Metallic ores are one of the most commonplace materials in the universe. They’re everywhere. Radioactive ores are everywhere. All 92 elements are everywhere.

    But what is extremely rare is life and planets which can support it life. Those are the needles in the haystack. If our Solar System has independently evolved life forms with radically different fundamental chemistry than ours, where are they? Why no sign?

    So it seems likely any aliens would have an acute desire to stop at Earth if they are carbon-based life forms, if only because planets habitable to carbon life are extremely rare. And once arrived they would want to colonize the planet. We would be like squirrels or rats in their eyes.

  57. #57 Andrew
    April 27, 2010

    Regarding the Ant-Colony-Sugar analogy:

    As ridiculous as it would be for me to run outside and raid an ant colony for sugar, I sure as heck don’t think twice about annihilating said ant colony for aesthetics on my driveway, and if I find ants are starting to expand from the outside world into my territory, I don’t hesitate in destroying the interlopers, and I may even casually lay out traps to prevent further intrusion, if I don’t follow the ants back to the source and destroy it. I also don’t really step carefully, or even consider the ants I might be crushing beneath my stride.

    If the analogy of aliens to humans is humans to ants, the last thing I’d advise my fellow humans to do is behave as the ants do and try to invade the space of the aliens, and I certainly wouldn’t advise my fellow humans to take active steps to call attention to ourselves.

  58. #58 Raging Bee
    April 27, 2010

    Here’s another problem with your rosy scenario: you’re seeing SOME aliens traveling in starships to meet us; you’re assuming that they’re both able and willing to use their technology to meet their needs without disrupting their home environment. But are these two things being done by the same group of aliens? Probably not, since the two events are taking place FAR from each other. Chances are, there’s one group living in stable harmony with their home ecology, and another group saying “Screw this, you tree-hugging socialist wusses, we’re gonna conquer a new frontier like our brave forefathers did!”

  59. #59 Rob R.
    April 27, 2010

    PZ: It looks like there is a theme going around the science blogosphere, triggered by a few remarks from Stephen Hawking.

    Stephen Hawking says we should avoid any aliens—they’ll destroy us.

    Sean Carroll agrees, but think it’s highly unlikely.

    Phil Plait disagrees that aliens will destroy us, also thinks it is unlikely anyway, but also thinks it more likely we’d be demolished by von Neumann replicators without seeing the aliens at all.

    Ethan Siegel is optimistic and wants to run out waving his arms for attention. He scares me the most.

    I’m with ya Dr. Siegel – Bring ’em on!

    April 27, 2010


  61. #61 Raging Bee
    April 27, 2010

    “God-Soap” labels from outer space? ALL ONE ALL ONE!

  62. #62 rijkswaanvijand
    April 27, 2010

    Clytus I’m bored.. What plaything can you offer me today??

  63. #63 Brando
    April 27, 2010

    “the planet…Urrrrrth”

  64. #64 Albion Tourgee
    April 27, 2010

    The time slice problem makes this speculation about encounters with sapient aliens kind of far fetched. Human history has lasted what, about 5000 years of several billion since the planet cooled down. Not a big temporal slot. In space we think we know how you can maneuver pretty easily but moving around in time seems fairly improbably, so the aliens would have to just happen to get here in our very small time window, not just find us in the vast spacial expanse of the universe.

    The size of the universe makes us probably a bit less significant in the larger picture than we like to think of ourselves. It makes some people feel better to imagine a special relationship with God or that aliens are going to happen by anytime soon (or if they do, pay attention as they go by). It’s interesting to me that this posting has inspired as much commentary as I ever see on these blogs, which are full of interesting and meaningful stuff.

    I’ll just add that I’m also quite surprised at Hawking — I mean if some aliens were all that far advanced of us to have mastered interstellar travel in a way that would allow them to stop by here and engage with us, is it at all likely to make the slightest difference whether we were trying to hide quietly or trying our best to make contact? But promoting this Hollywood film idea of malevolent aliens only encourages the nutty paranoid mentality that infects our politics and culture. Aliens beware, especially in Arizona!

  65. #65 Brett
    April 27, 2010

    I agree with you that we should strive to find intelligent life. I also think Hawking is losing it. He was a great physicist, but those days are past and now he’s trying to stay relevant by making silly comments.

    However, I think you made a lot of assumptions about our visitors that are just as likely as unlikely. How do you know that they didn’t leave their planet because they’ve destroyed it. Just because they made it all the way here doesn’t make them morally superior. And, more importantly, just because they made it before we did does not make us morally inferior. I see no need to apologize to our visitors and ask them to teach us how to be better. I welcome the opportunity to learn about their culture and science, and I hope their interest in us is the same.

  66. #66 daedalus4u
    April 27, 2010

    Once a civilization has the technology to build self-replicating machines, then anything else they want is only a matter of time.

    If they are traveling at 1% of the speed of light, it would take them longer to get anywhere than it would to terraform a random planet like Venus. With self-replicating machines with a time constant of a year, I could terraform Venus in a millennium. It would be faster to terraform a random planet than to travel an extra 10 light years to find one that was already habitable.

    A lifeless planet would be easier than one with life because you don’t need to sterilize it first. You need to sterilize it first because Earth bacteria likely make compounds that aliens would find objectionable. Sterilizing Earth would be tough. There are bacteria that live many miles underground at temperatures over 100 C. It would be faster to terraform Venus than to sterilize Earth.

    To sterilize Earth you would need to heat the top 10 miles or so to at least 150 C. You could do that with asteroid impacts, that is how you would change the day/night length. Throwing debris in orbit would facilitate constructing the sun shields you use to regulate the temperature. The critical factor is how long it takes for the temperature 10 miles down to get up to 150 C. You can’t really do much until after that happens. Only the outer 100 meters or so has to be cool for the planet to be habitable. That happens pretty fast.

    Moving the Earth closer or farther from the Sun would take longer, but isn’t that difficult. You move large asteroids like Ceres in a near Earth trajectory that adds or subtracts from Earth’s orbital velocity and then takes Ceres back around Jupiter for another trip. Plan it out 20 orbits in advance and it would take very small momentum changes to keep the trajectory correct.

    But why would they want to live on a planet? If they have been traveling for thousands of years in a starship, then they are not used to being on a planet.

  67. #67 Jesse
    April 27, 2010

    Stephen Baxter brought up something interesting about evolution generally: if an alien species is exploring at all, it’s because they are “wired” to do so. And further, if they are resource-depleting omnivores (who use say, generation ships for a period and then find random planets to eat up) then they could fill a galaxy in short order.

    At 1% the speed of light it would take 10,000,000 years to cross the galaxy in one shot. If you assume planets are separated by 100 light years on average, and each planet generates 2 more colonial fleets after a century, then each stage takes 10,100 years.

    After 101,000 years you have hit 2^10 systems, or 1,024 of them. After 202,000 years it’s 1,000,000 systems. Within 1.01 million years you have colonized and destroyed 1,125,899,906,842,620 planets, and done so in a radius of 10,000 light years.

    That assumes, BTW, that the technology doesn’t change a whole lot in the interim, and there isn’t any reason it has to. (Even us humans don’t tend to give up stuff that works really, really well).

    Something tells me that if such aliens are around, and use resources in anything like the way we do, we’d basically be doomed if they decided to use Earth to make more colony ships.

    (Baxter wrote in Space that the real issue was that we were just lucky in that Venus and Mercury and the asteroids proved better resource depots).

  68. #68 Duncan Ivry
    April 27, 2010

    Ethan, I support many of the commenters which do *not* agree with you — with your naive and unfounded opinions –, and I do it because of the reasons they give, and repeat what I have said before: Go back to astrophysics!

  69. #69 James F
    April 27, 2010

    Whatever you do upon meeting the aliens, do not release any birds!

  70. #70 Andrew
    April 27, 2010

    But promoting this Hollywood film idea of malevolent aliens only encourages the nutty paranoid mentality that infects our politics and culture. Aliens beware, especially in Arizona!

    I don’t see it so much as malevolence as sheer lack of concern combined with vastly superior technology. Like I said above, I don’t work myself into a lather about ants, nor do I engage myself in campaigns of destruction. I just destroy ants that enter my home and utilize what is an utterly trivial effort on my part to eradicate the source. Heck, I can’t even say that I’d be especially more careful about, say, a colony of chimpanzees (who are decidedly intelligent and conscious beings with language and culture), if they decided to try and colonize my backyard.

    True, it might be less effort to relocate rather than eradicate the chimpanzees, and I might be more inclined to treat them well due to my natural identification with megafauna, but ultimately I don’t care in the slightest what the chimpanzee thinks they’re entitled to, or what it wants from me. Similarly, I can’t trust that an alien species would care in the slightest what rights humans think they have to our planet or even care about our well-being. They might just move in, clear-cut our fields, kill anything that tried to fight back and slowly encroach on our territory as they see fit.

    Sure, they might not start a genocidal campaign, but the idea that they obviously wouldn’t treat our planet in the same way we treated the various ecosystems of our world we’re not native to doesn’t really strike me as a well-founded opinion.

    It definitely could be the case, but I’d rather follow Professor Hawking’s advice and lie low until we can igure it out one way or the other.

  71. #71 Thumpinator
    April 27, 2010

    All of you who say that earth doesn’t have anything which an alien civilization would want are wrong. I can think of at least one thing we can do which would make us a target for takeover by an alien civilization. First of all let’s assume that one of the main goals of the alien civilization is to expand its presence in the universe. Second let’s assume that travel between the stars is really really expensive. Third let’s assume that the alien civilization has developed artificial intelligence or merged with its technology. What is the most cost effective why for this alien civilization to expand? Well I think that it should be obvious the alien civilization will trick dumber more primitive civilizations into downloading a virus/uploaded alien/super intelligent AI. Now maybe that won’t be the first message they send us, they could first send a lot of useful data and technology to butter us up for the kill and hide their real motives. Hell I think that plenty of you are dumb enough to build the aliens artificial bodies if they asked nicely and told you how. Once they are here it shouldn’t be hard for them to release a nanovirus and turn the human population into brainless zombies. The aliens get a planet light years distant for the cost a few radio waves. Humanity is too dumb to survive even an indirect encounter with a civilization 50 or 100 years ahead of us.

  72. #72 Eff Gwazdor
    April 27, 2010

    Of course nobody here has mentioned cultural products as being a resource. Our global culture is most certainly the most interesting thing about us – information can be combined in meaningful ways in far more ways than can organic molecules. This is especially true if, as most scientists do, you reject the ideas put forward by the Sociology of Scientific Knowledge guys that the scientific description of the universe has more to do with our culture than any concrete and objective truth. If that is not so and scientific truth is universal, what an absolute hilarious bore it would be to hear Earthling scientists go on about their primitive theories. Culture, on the other hand, as a product of a chaotic, nonlinear, ultra-complex system can never be modeled, is always a unique signature. I think aliens would be most interested in what we eat for breakfast, how we tie our shoes, music and philosophy and sex and stuff.
    If interstellar traveling aliens do exist they have most likely augmented their ancestral biological intelligence and it is most likely that they are highly culturally complex; a society of replicating and mutating sentient information structures on a technological substrate. As such, it seems that the most efficient way of traveling at lightspeed would be for them to send a probe including this functional substrate to a certain place, and then beam a signal comprising their information to coincide with its arrival. Then an outpost can be set up. One way to welcome such a life form would be to build as best we can such a receptor and substrate, and heavily advertise its presence. Of course we won’t get it exactly right, but beyond a certain level of technology, the advanced intelligence will be able to work with what we provide. In a way, we’ve already begun this task without having planned it, and it is important to ascertain whether our technological systems can be commandeered by what amount to highly complex alien computer viruses.
    If aliens do explore other systems, it is highly likely that they will send a very lightweight probe first. Such a probe could gather the cultural resources that the aliens are seeking without notice. In order to monitor potential exploration of our system, it is essential that we send probes out to the oort cloud to monitor for alien signals originating within our system; the outgoing call will be much easier to hear than the incoming call.

  73. #73 Magnetar Melon
    April 27, 2010

    If the anarchy present in international politics extends to the intergalactic level, then it’s probably best in realist terms to be a passive observer at the moment. We wouldn’t have any power to wield over a civilization thousands or millions of years ahead of us in development.

  74. #74 Douglas Watts
    April 27, 2010

    If we accept c as a barrier, then “robot probes” to our solar system would be ineffectual, since they could not report back data for centuries, and most likely could not even do that because the signal strength would be too tiny and would be lost in the background. So, the only rational purpose for any visitation would be colonization, with the colonists having no hope of ever making a return trip. And for any carbon-based, DNA based life, Earth is the only habitable planet in the solar system, or anywhere near it.

    Earth is a pretty unique place in the neighborhood of 10 light years diameter from us. It is the only habitable place for carbon-based life forms. Nothing else even remotely fills the bill.

    So colonization and inhabitation would be the only purpose for a visitation. And it would most likely not go well for us, since our visitors would be massively more technologically endowed.

    Hawking for the win.

    Now we need to stop destroying our one and only inhabitable planet.

  75. #75 ScentOfViolets
    April 27, 2010

    Why wouldn’t the aliens just beam a signal that contains information about how to build a computer, the program to run on it, and the information you wan to initially input? Presto, an agent speaking on behalf of the aliens. No physical travel necessary, zero chance of any accidents in space, near-lightspeed velocities, and for pennies rather than megabucks per kilogram.

    Why anyone would send physical stuff when the radio route is so much more accessible is beyond me. And that’s another answer to the Fermi paradox.

  76. #76 Will
    April 27, 2010

    I would not assume that “[the aliens] grew to prominence on [their] planet … to become the most successful species on [their] world.”

  77. #77 Abby Smith
    April 27, 2010

    It sounds to me as though Stephen Hawking has seen “Avatar” a few too many times.

    Honestly, I believe that it is fundamentally impossible for humans NOT to look for extraterrestrial life. It is an escapable characteristic of our race to be curious, and to seek…if not companionship (for we are social creatures), then a confirmation of the unknown – that we are not alone. We love questions. We love to seek answers. What lies beyond our field of perception is the greatest unknown of all. How can we not long to know what is out there?

    I wonder what Carl Sagan would say if he were alive to hear this today. I’d like to know.

  78. #78 Abby Smith
    April 27, 2010

    Additionally, isn’t it to late to “cease sending out radio signals”? We’ve been emitting them for decades, so the “damage” has already been done. At any rate, it seems the odds are in favor of worlds incredibly distant from ours, worlds which might only receive the first of our radio signals, much less travel to and arrive at our planet by the time we are only a speck of ash.
    (Apologises for the poor wording!)

  79. #79 Douglas Watts
    April 28, 2010

    Honestly, I believe that it is fundamentally impossible for humans NOT to look for extraterrestrial life. It is an inescapable characteristic of our race to be curious …

    Hawking is saying that, in the interests of the our species’ survival, it might be a good idea to moderate that “innate” curiosity with some analysis of its potential consequences. Humans do not have a good track record of thinking before doing.

  80. #80 red
    April 28, 2010

    “Destroying us would be like crushing a colony of microbes just for kicks to them.”

    I wipe off my kitchen counter and tables all the time so I can do my work.

  81. #81 Roman
    April 28, 2010


    “Talk to a Linguist and/or cognitive scientist and you will soon understand that chances are good that we will be able to communicate with an alien species about as successfully as we can currently communicate with whales, dolphins, etc., i.e. not very well at all.”

    Or read Lem’s “His Master Voice”.

  82. #82 Charcoalrum
    April 28, 2010

    Destroying us would be like crushing a colony of microbes just for kicks to them.

  83. #83 Henry
    April 28, 2010

    Hawking ignores the possibility of a change in ethical norms as societies progress. Focusing on the mistreatment of Native Americans in the past or the fact that animals do not have equal rights today obscures the point. The trend has been for greater empathy for different cultures and different species. Consider the relatively better treatment of the Maori in New Zealand compared to Native Americans. In more recent decades, consider the extensive growth of the environmentalist, animal rights and ethical consumerism movements.

    The relationship could quite likely be causal. Perhaps empathy for those in different groups helps societies flourish, so a malevolent alien race is unlikely to be able to develop interstellar space travel. Or my favourite theory, that ethical preferences are a “luxury good”. If you’re in poverty, the pressure to feed your family means you probably don’t care very much about the plight of other cultures or species. As your income increases, you can afford to be concerned. A alien species that has achieved interstellar space travel is probably sufficiently wealthy that it can afford to sacrifice profits for fuzzy feelings.

    If then, we can expect alien visitors to be benevolent, there are potentially very large gains from meeting them. Aside from the sheer excitement that it would undoubtedly produce in much of the world’s population, the gains to trade would likely be enormous. Imagine what sort of technologies an interstellar traveling species would have.

  84. #84 Michel
    April 28, 2010

    Problem is that the first v images that went out there… are of hitler making speeches…
    Talking about first impressions.

  85. #85 Michel
    April 28, 2010

    tv images that is

  86. #86 Thomas
    April 28, 2010

    Henry #83, even benevolent aliens could do a lot of harm when they try to convert us to their lifestyle or give us a tremendous inferiority complex.

  87. #87 Alan Langley
    April 28, 2010

    Eighty plus comments. All firmly founded on an impossibility. Assuming, of course, that there really are only three spatial dimensions.

    If rocket science is the best that science anywhere in the universe can ever hope to achieve, and according to Ethan, that’s as good as it will ever get, then there will never, ever, ever, exist a culture stupid enough and willing enough to waste a horrendous amount of its resources to manufacture enormous generation starships capable of putt-putt-putting between the stars over a period of one or two hundred thousand years or so.

    I’d really like Ethan to devote at least one future article savaging the notion of the possible existence of at least one higher spatial dimension.

  88. #88 Alan Langley
    April 28, 2010

    I forgot to mention.

    Congratulations on a record number of responses.

  89. #89 Jesse
    April 28, 2010

    Alan – the problem isn’t that rockets are the best technology — we can conceive of some Casimir-effect propulsion system, or solar sails, or zero-point.

    The issue is whether c is a limit. Assuming it is, then that limits what you are doing. Even if I found a way to harness the properties of space-time itself (Rene Alcubierre proposed this, but IIRC it was proven mathematically untenable) you could get to just under c but it would still take a load of energy and a lot of time. Those could well be fundamental physical constraints.

    And physicists have already spoken of higher dimensions, as it’s a fundamental part of string theory (which proposes an 11-dimensional universe, with the other dimensions rolled up small). But that doesn’t do you any good for travel unless the universe is shaped in very specific ways. For instance, if you look at the universe as the surface of a sphere, in two dimensions along the surface distances are longer than if you go through it in the third dimension.

    But if you add another spatial dimension you’d have to assume the distance traveled is shorter than in our familiar three. Going back to the sphere analogy, the third dimension does no good if the universe is flat and bounded.

    Thus far I don’t think there’s any evidence space is that highly curved. Off the top of my head, we know that gravity is spacetime curvature through another spatial dimension (those diagrams you see with the black holes demonstrate this in a 2-D context) and we just don’t see curvatures that would allow for fast interstellar travel except maybe near black holes. Even then, it’s a small region. There’s some talk of whether black holes could be gateways but IIRC that isn’t terribly mathematically tenable either.

    There’s one method, using ring singularities, that would work in your scenario, as an interesting characteristic of gravitational fields is that if you have a ring (of any material) the total force on you in the center of it is zero. The same would be true of a ring-shaped black hole. But the ring-shaped event horizon would create a region of space with all sorts of interesting properties, but I am not sure if you could space warp with it.

  90. #90 ScentOfViolets
    April 28, 2010

    If rocket science is the best that science anywhere in the universe can ever hope to achieve, and according to Ethan, that’s as good as it will ever get, then there will never, ever, ever, exist a culture stupid enough and willing enough to waste a horrendous amount of its resources to manufacture enormous generation starships capable of putt-putt-putting between the stars over a period of one or two hundred thousand years or so.

    Ah, another text lost to the mists of time – Hoyle’s “The Black Cloud”. Here we have a truly massive spaceborn intelligence that lives for hundreds of millions or hundreds of billions of years that has no problem with trips that average no faster than 0.01 c or less. Given that “massive” in this context means roughly the mass of Jupiter, this intelligence had to be extremely careful to not wipe out life on Earth (it’s mere presence in the Solar system almost brought civilization to the brink of collapse.)

    I suspect the way most people are thinking is the way people at my church tend to behave – as a middle-aged white male who attends only occasionally and does little volunteer work, I’m not at odds with the middle-aged women who do a lot gardening and church work. However, they tend to develop profound antipathies towards other middle-aged female parishioners who also do lots of church work and gardening.

    So yeah, if we’re similar enough to aliens who Want Our Women, I’d imagine that if it were at all technologically feasible, there’d be some sort of conflict. Between us and intelligent interstellar clouds, maybe not so much.

    April 28, 2010


  92. #92 Rob R.
    April 28, 2010


    Persistent Evidence of a Jovian Mass Solar Companion in the Oort Cloud

    We present an updated dynamical and statistical analysis of outer Oort cloud cometary evidence suggesting the sun has a wide-binary Jovian mass companion. The results support a conjecture that there exists a companion of mass ~ 1-4 M_Jup orbiting in the innermost region of the outer Oort cloud. Our most restrictive prediction is that the orientation angles of the orbit normal in galactic coordinates are centered on the galactic longitude of the ascending node Omega = 319 degree and the galactic inclination i = 103 degree (or the opposite direction) with an uncertainty in the normal direction subtending ~ 2% of the sky. A Bayesian statistical analysis suggests that the probability of the companion hypothesis is comparable to or greater than the probability of the null hypothesis of a statistical fluke. Such a companion could also have produced the detached Kuiper Belt object Sedna. The putative companion could be easily detected by the recently launched Wide-field Infrared Survey Explorer (WISE).

    Big deal?

  93. #93 Mu
    April 28, 2010

    Alan, I think you overestimate the cost for a generation ship. Even something as large as an aircraft carrier, 80,000 tons, launched at today’s prices, $10,000/lb, would only be $2 Trillion. We spent more than that for our little Iraq adventure. Now image the world united under one suitable megalomeniac with a “vision”, and you can send out dozens of those.

  94. #94 Vince Whirlwind
    April 28, 2010

    There’s a persistent line of argument above which goes along the lines of
    “What use would a civilization that has master interstellar or intergalactic trave have in our resources?”

    “What use would a civilisation that has mastered nuclear fission have in the humble chicken egg?”
    …and yet, we cram billions of chickens into tight cages in order to harvest their eggs.

    As for the “trend towards greater ethics”, I believe this could only exist in rose-tinted dreams.
    Recent footage of the world’s most advanced democracy using a helicopter to deliberately destroy a dozen unarmed civilians in Iraq springs to mind. And exactly how anybody could draw a downwards-sloping trendline past the era of Hitler, Stalin, Pol Pot, Zionism and the Taliban is quite beyond me….

  95. #95 William
    April 29, 2010

    I agree with Hawking, but I admire Ethan’s curiosity.

    However, I find a flaw in each – specifically assuming human motivations or behaviors for any would be E.T. interlopers. It seems a stretch to assign such motives as exploration, conquest, exploitation, etc when all we have to go on is our own psychology.

    Moreover, it not only is true that

    “if you’re looking for a world in order to harvest resources from and we’re a good fit, you’re going to find us whether we advertise or not.”

    but, I’d add that we would not likely be the first world any E.T.s visited, and whatever their purpose was in coming here, they are probably well prepared for and quite efficient at.

  96. #96 crd2
    April 29, 2010

    We have to remember no resource on earth is unique EXCEPT the organic life forms. We would be whats collected. Perhaps they would figure out how to make us into a vaccine for one of their dieseases. Or maybe grind us up for use in alien hemmroid cream, for our soothing qualities. I honestly belive if intelligent life did come here it would be for the biology and not much else. Therefor, as Hawking says it wouldnt be good for us.

    Dont forget the great lengths we go to after returning from space to avoid any harmful diseases or bacteria. So once they did find us they would need time to do research. This leads me to think that aliens coming and abducting people or cows may not be so far fetched. We to would take samples and study them if we found life on another planet. We wouldnt just fly down there, take off our helmets and start walking around asking to speak to their leader. We’d want to make sure it was safe first, lest we contract a disease, bring it home, and wipe out our species.

  97. #97 Douglas Watts
    April 29, 2010

    This is a great post, and a great comment thread, so kudos to Ethan and everyone. Thanks.

    Occurred to me last night how much we presume an alien species must have a lifespan similar to ours. What if an alien species has a life span like bristle cone pines, which can live for 5,000 years or more? For a species with a normal life span of 5-10,000 years, interstellar space travel is not as near a big deal as it is for us. At least something to think about.

  98. #98 Charcoalrum
    April 29, 2010

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  99. #99 Sphere Coupler
    April 29, 2010

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    *Earth is the repository for the Galactic insane*

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    April 29, 2010

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  101. #101 Lloyd E Hargrove
    April 29, 2010

    “They’re Made out of Meat” by Terry Bisson would seem to fit within this discussion…

    Perhaps we’ve already been “discovered” and they would just rather forget about us at this point. Yeah, I could see that.

  102. #102 DaveH
    May 1, 2010

    Hawking is simply extrapolating from a well-known anthropological fact.

  103. #103 AD
    May 9, 2010

    One thing we do have- a giant spaceship that will provide all the life-support systems an oxygen-breathing, organic-carbon consuming species would need. It will remain thus for at least another billion years, before the star we are orbiting begins to get uncomfortably hot. For a nearby race of sentients driven out of their own solar system by a dying star, they may point some of their ships towards Earth, having noted the spectral signature of an oxygen-rich atmosphere and taking that as all the evidence they needed that it is eminently life-sustaining. At last after journeying hundreds of years, with the transport crafts near the end of their useful life, they alight upon Earth only to find it already hosting sentients (halfway through warming it up nicely for them). What to do?

  104. #104 AD
    May 9, 2010

    Too bad I am a week too late for this thread.

  105. #105 AD
    May 9, 2010

    Making my way through some interesting comments, a couple points:
    -Earth has only been oxygenated to present levels for <1 billion years, and consistently oxygenated to present atmospheric levels for ~0.6 billion years.
    -Aliens may not need any specific resource other than real estate.
    -Outgrowing your planet to me seems unlikely. Even now the most advanced postindustrial societies have limited or declining population growth. We may endure some terrible effects from global warming and concomitant widespread industrialization but on the geologic timescale these are mere growing pains.
    -On the other hand, planets remain habitable for long but limited periods of time. Aliens that have not yet transitioned into entirely electronically hosted intelligences would need to find another suitable oxygenated, temperate habitat, as their star goes red giant or nova.
    -Advanced organic aliens are not going to be anything but oxygen-breathing, carbon-based life forms. These are facts.

  106. #106 AD
    May 9, 2010

    Completing my earlier comment, the fact that the aliens would have to be hosted by a dying star further limits the chances that any given alien civilization will be a colonization threat to its traversible lightyear space.

    Then you have to figure that it may be that sentients tend to evolve towards a Matrix-like situation of disembodied, non-organic intelligences, needing only server space and solar panels to survive. This possibility limits further still the number of sentients in need of a new organic life support system.

    Finally, while some may conclude from the sweep of history on Earth that we inevitably evolve towards greater amiability and peace, it is possible that civilizations can enter alternate stable states of nonfreedom and oppression and still become highly technological. See the history of China. Or read 1984. And don’t tell me that being a brutal fascist regime prevented the Third Reich from having some very good scientists and engineers. But while this type of advanced planetary civilization is possible, it may not predominate or even be very likely, thus further limiting the chances of a rapacious alien colonizing society, although it does not limit the chances that they may be rapacious only out of need and self-interest (see my earlier points).

  107. #107 AD
    May 9, 2010

    Correcting an earlier typo- Earth has only been oxygenated to consistently high levels for ~0.6 billion years.

  108. #108 Jerry M. Weikle
    May 9, 2010

    If there are aliens out there, reading this, WE ARE HERE!!! I have questions, I want to know and understand. I would like to see you all arrive and then terraform our secondary planet that we call Venus, so that you can have a new Home World. I want to be neighbors, I want you to be a great teacher for humanity.

    I will welcome you…

  109. #109 amphiox
    May 9, 2010

    I think the question with regards to proper caution is this: Which is more likely to be the greater threat – deliberate alien hostility, or accidental alien negligence?

    If they are advanced and powerful enough to come to us, they might be so advanced and so powerful enough that they could do vast damage to us through the accidental byproducts of their activities, and not care to look out for us or even bother to notice us, the same way we might not care about the ant hills we plough over when we mow the lawn.

    If they come to this solar system to harvest resources, there are many sources much more accessible than the earth, but depending on how thorough they are, their activities could still severely damage us. If they, say, Dyson Sphere the sun inside earth’s orbit, we’re screwed. (And even if they Dyson Sphere the sun outside earth’s orbit, we can still kiss the science of astronomy and any future space exploration plans goodbye). If they mine Jupiter sufficiently to disrupt its gravitational influence on the asteroid belt they could be sending a shower of big rocks falling into earth crossing orbits. If they tap the Sun for hydrogen sufficiently they will alter the pattern of solar output and profoundly affect our climate.

    So it might well be best to contact them, to in effect say “We’re here! Please don’t step on us by accident!”

    And if so, we should hope that complex life is in fact relatively rare in the universe, rare enough that there might be a chance than even a supremely advanced alien intelligence will still value it for the sake of its rarity enough to be motivated to avoid accidentally harming it.

  110. #110 amphiox
    May 9, 2010

    One more thing to add – if spacefaring aliens come to the solar system to harvest resources, even if they do in fact take care not to harm us, it could still turn out badly in the long run.

    Again, depending on how thorough they are, they will be depleting the very same resources we need if we ever want to leave this solar system ourselves – which is essentially the same as sentencing us to slow death by increasing solar luminosity.

  111. #111 Samantha Vimes
    May 12, 2010

    Thank you! I was shocked at how common the idea was that any people that advanced would be devoid of kindness, and unable to recognize us as intelligent. Yes, *most* humans think we are the only intelligent life on Earth, but the explorers of an advanced civilization would, even if not the Jacques Cousteaus and Jane Goodalls of their kind, be more able to see the intelligence in us– we have technology!– than we were able to recognize it in octopuses, primates, elephants, corvids and keas.
    The possibility that ignorant or paranoid people would creep them out and make them unwilling to stick around and help is more likely than malice, I think.

  112. #112 Cordle
    May 14, 2010

    I tend to think that when we picture aliens, we instantly call forth images of various aliens we’ve seen depicted in movies and comics. However, there is a great possibility that aliens are unlike anything we can possibly imagine.

    Earth may be deadly poisonous to an alien species. Water, oxygen, nitrogen, could be incredibly toxic to them, much like mercury is to us. It’s possible that these species swim in mercury on their home planets.

    Another thing I like to think about, is the scale of aliens. We use the microbe and ant hill analogies, well it’s entirely possible that these aliens hail from planets so large that earth would be just like an ant hill to them: entirely unsuitable for life.

    It’s also entirely possible that these species hail from a planet and such an environment that they could be many times smaller than us. Even if they are carbon, water-based life forms, their physical structure may be nearly incompatible with the scope and size of Earth.

    We evolved to fit this planet. If intelligent alien species exist, so did they for theirs. Even in our own solar system, there are no two planets alike. Even the moons of Saturn vary in composition greatly. Any alien species hailing from a given planet or galaxy would likely find our resources useless, much like we find Mars’s resources largely useless.

    I do think it would be more likely that they would study us just as we study Earth’s biology. They might be doing that now from afar for all we know. We might be under the alien’s microscope/telescope. Who knows? Does the microbe know that we observe it?

  113. #113 Doug
    July 9, 2010

    “I tend to think that when we picture aliens, we instantly call forth images of various aliens we’ve seen depicted in movies and comics. However, there is a great possibility that aliens are unlike anything we can possibly imagine.”

    Indeed. What many overlook is that there’s no reason to not expect aliens to be, frankly, alien. A space-faring race is more likely to be a race of artificial self-evolving nano-constructor-bots than fragile organic “little green men.” They/it might have no interest in Life 1.0 such as us, nor retain any ability/desire to answer Ethan (or anyone’s) questions.

  114. #114 William Duncan
    July 16, 2010

    I have been a fan of science for as long as I can remember, and while I believe that making contact with an extraterrestial civilization would be a good thing. I also believe in caution, if we use ourselves as an example then caution would be advised. When someone comes to visit me at my home I expect the visitor to show some simple courtesy. Well this planet is my home, so highly advanced or not we should be prepaired to welcome friends and repel invaiders. In the past two decades we have made some amazing scientific decoveries and I am sure that when the time comes we will be ready for first contact.

  115. #115 wuffe
    August 7, 2010

    If it was a type III culture it would be interested in our sun for energy input. We wouldn’t even know they were out there. Perhaps they would see us as an intriquing species along their way as they amassed their energy intake. They would have the technology to certainly hide their satelites to absorb the energy. Attack of for resources? A type II would still be using its own sun for energy. Attack us? for resources? I suppose we could try shooting lead bullets at them. Right…

  116. #116 L B V PRASAD
    August 11, 2010

    Dear All,

    The question that is constantly raised even by learned wise men of this planet earth is :

    1)If an advanced civilization exists – then why were they unable to contact us?????
    Answer)We are an advanced civilization who have been to moon,having sent unmanned spaceship to roam around our other planets etc etc etc, then why were we unable to contact the advanced life existing elsewhere in the universe????????
    This is due to constraints of space & time & the technology required to cross THROUGH inter stellar travel.
    Besides human life span is extremely limited.Even if technology develops-it will be difficult to travel back & forth to a designated planet which is light years away.
    As regards the flying saucers-god alone knows how far it is true.The laws of nature are constant for all existing.
    Then if its so-how come the flying saucers challenge our gravity in manoeurations & incredible speeds.
    Also,how is it that we were unable to track their entry into our space when some of us have wonderful defence systems.How were we unable to missile down even a single flying saucer.
    As regards the roswell incident – god alone knows how far it is true.If it is really true,then the flying saucer should be exhibited to the entire world.
    These are my personal views.Please weigh them for yourself to come to conclusion.


  117. #117 L B V PRASAD
    August 11, 2010

    Dear All,

    where is the question of Aliens studying us!!!!!
    We all have heard that flying saucers appear only for few seconds in the sky & then flatly disappear. Can anyone study anything in few seconds.
    The likelihood of life existing in other star systems is 100%.However,not all forms of life may be extremely intelligent ones.
    They may be classified as under :

    1)Intelligent life beyond our comprehension (beyond our imaginations & wildest dreams)We cannot gauze nor will we ever be able to do so ‘cos their level of development is unseen by us & never felt on our own planet.Even the brainiest of our species will not comprehend forever.
    The abv category is “ULTIMATE”

    2)Highly advanced civilizations who are a million times more advanced than us -space travel being only one among them.They can create with their technology abundance of food,neutralize factors which are harmful to their day to day living (like pollution/recycling of waste etc)
    Zero accident travels within their planet with sophisticated radar systems for each & every mode of travel.
    Law & order dignified to ultimatum & automatic controls everywhere.
    3)Life as on earth types-as advanced as us.
    This category will be the most common in the universe & will be available at dime a dozen.
    4)Life lesser advanced than us – just beginning their bare minimum technological advances.At the start of it.
    5)Stone age creatures -just existing without purpose.
    6)micro organism stage.
    7)still under chemical reactions stage.

    All abv types of life exists in universe.Due to distances,we cannot meet or interact.

    Like some the great scientists have said -in the event of their visit to our planet…caution should be exercised & diplomacy too,else they will test their weapons on our race if we act crooked.
    As far as i guess-if flying saucers are really visiting us,then their planet is right behind our back yard.However our telescopes may be failing due to natural factors like a big cloud of gas hiding their vicinity or refractional causes due to which we are unable to detect.
    kind regards

  118. #118 Indra K Dutta
    September 23, 2010

    The fact is that we do not know anything about any alien species yet and anything is just a wild guess. No assumption is safe as far as aliens are concerned. Aliens can as egoistic, selfish and tyrannical as human on this planet or even worse. Or they could be angelic creatures with all goodness. Since our survival is important to us, we better be careful. We can not expect anything but wait and see.

    And avoid detection. Give me a break!

  119. #119 Kent
    September 29, 2010

    Dude…didn’t you ever watch star trek? I think the only entities we will ever meet will be of the Borg type, as all civilizations will ultimately encounter their own singularity event…as will we

  120. #120 Starwatcher68
    October 2, 2010


  121. #121 Xaviersx
    November 8, 2010

    Problem is, we can not assign to others what their resources, understandings, motives and actions would be. Just because we want to apply our values to the question does not mean that the situation would be so. And no so much avoid trying to find them versus poor ‘diplomatic first contact’, to approach our own nature of contact with more grace than we’ve ever shown here on this planet . . a reflection of our maturity more so than any intelligent life with a space hot rod since technology does not mean benevolence. And on a side, we’ve broadcasted enough movies showing what we’d most likely do, so fear what we’ve already said than what we’ll do in the future.

  122. #122 Dan grant
    December 5, 2010

    It seems so ridiculous to try and impose our own human reasoning on alien species, so much of what we do would seem unnecessary and arbitrary to even another species on this planet, any alien species could have any number of unfathomable reasons to wipe us out.

    Even if we did choose to apply human reasoning to what they might think, another possibility is they are expanding for expansions sake, they have got this far into the universe through ruthless expansion, in order to complete homogenise the universe into their being.

  123. #123 Sam
    January 4, 2011

    I think your ideas are incredibly naive and asinine. I hope you are never someone in charge of planetary security policy if we ever crawl out of the muck far enough to actually have such a unified idea for our species.

  124. #124 phone jammer
    July 19, 2011

    Got any proof they dont exist???? I believe in aliens and it has nothing to do with the reasons you stated. It’s common sense and personal experience. Also yea u seem to be trolling. If u don’t like the subject why even post in it? I hate politics and think they are all crazy so you won’t see me in the politics forum. Why not just go to what u prefer and leave the others to their preferences? Religion is the most closest thing to evidence that aliens exist. This is a troll. Nothing to see here.

  125. #125 Marie
    September 2, 2011

    I love it that your asking these Aliens to come forth with their answers to evolution which has possibly taken billions of years to master, but unfortunately, their not going to understand a single word of the English language, depite your great desire to reach this message to them.

    My pet cockatoo who is hand reared and whom speaks perfect English was greet by a wild cockatoo just a few weeks ago. He began to greet his new friends with words from the English language, “hello” “hello cocky” etc. Much to the wild cockatoos disgust and confusion, he rejected the new friend and went on his merry way. The communication barrier in this instance would most certainly be the greatest hurdle in learning from the more superior evolved lives that occupy our universe.

  126. #126 Raging Bee
    September 2, 2011

    We should, at the very least, be eager to steal their technology every chance we get. Especially the weapons and interstellar drives.

  127. #127 Wow
    September 2, 2011

    And the alien babes.

    Don’t forget those hot alien babes.

    Shatner has shown us how!

  128. #128 Jack Dawe
    September 30, 2011

    “Destroying us would be like crushing a colony of microbes just for kicks to them.”

    Not for kicks. Because if our civilization evolves any further, and in particular developes relativistic travel, we are a mortal danger to them — the same way a petri dish overflowing with botulism bacilli would be to us.

    “But what irks me most of all is the cowardice behind a viewpoint that we shouldn’t rush to meet a peer in this Universe.”

    First of all, chances are nine hundred ninety nine to one IT WOULDN’T BE A PEER. A star-faring civilization would, almost certainly, be so far beyond us that, even as biological units, we would be utterly outmatched. It would be like comparing a modern human with, say — not an insect or the like, which is the usual comparison — but with an opossum or, at best, sea-going mammal.

    What really irks me, to go along with your irksomeness, is that you would brand understandable caution and hesitation, in the face of such a potentially grave species-threatening situation, as cowardice. To me, your position is beyond folly — it’s grandiosely optimistic to the point of suicide.

    Or homicide — considering the future generations of humanity forever exterminated because you had to have things your way.

  129. #129 Alan
    November 9, 2011

    Most comments on this blog are assuming that an intelligent species will act as we have.

    The truth is, we cannot assume that an intelligent species will act as we have. Each intelligence will have it’s own unique experience.

    It is very likely they an intelligent species that has traveled to our planet, has figured out how to travel faster than the speed of light. Probably by some “worm hole” concept, or perhaps, a ship that vibrates into another plane of existence where the boundaries of time and space no longer apply (which would make it easy to travel faster than the speed of light).

    When we are talking about an intelligent species that has traversed the universe, we cannot think on a linear basis. We have to think with all possabilities AND IMpossabilities.

    Think about a time where we SWORE that it was IMPOSSIBLE to break the sound barrier. Now, it’s no big deal.

    For a species to evolve technologically to this point, it is prettly likely that they do not rely on fossil fuels, and have discovered another avenue of science to extract energy from an abundant source (aka free energy). Thus, no reason to come to earth for fossil fuels.

    There is in fact, an overwhelming amount of evidence out there that intelligent life is already here, and has been here observing the planet for at least 60 years (and most likely longer than that). Some evidence is saying that it was our first use of nuclear weapons that set off some intergalactic “red flags”.

    So if they HAVE been watching us for over 60 years, they could have easily wiped us out many times over by now, especially since we have opened fire on some of their craft (LA UFO During WW2).

    In conclusion, it is far more likely that intelligent life would be here to try and guide us into not destroying ourselves, or the planet for that matter.

  130. #130 Jack Dawe
    November 9, 2011

    I agree. It is far likelier that a more evolved, more well-adjusted alien culture would choose to nurture or observe humanity, rather than wipe us out.

    However, it is not 100% assured.

    It is also quite likely that, if there are alien civilizations within the surrounding 500 ly radius, they either know of our existence (through atmospheric analysis or the arrival of 20th century radio/tv transmissions) or suspect it.

    That, too, is not 100% assured.

    The scenario unfortunately creeping up on us with the passage of time and humanity’s own failure to break out of the cycle of violence that has afflicted us since we left the trees, is remarkably similar to the situation in the Cold War: we think the “other side,” (if there is another side) is rational, and would not do anything “rash,” but we don’t know.

    The real problem, however, lies not with us and our tangled history, nor with our projections of what aliens may or may not be like (all likely to be mistaken to one degree or another), but with the cold equations of physics, which demonstrate that any mass moving at 90% lightspeed, upon encountering a “stationary” mass, converts entirely to energy.

    So if the Space Shuttle were accelerated to such an extent, and launched directly onto the Earth, it would at the very least end civilization if not blow off the atmosphere and kill every living thing on the surface.

    The technology required to create a system capable of throwing objects to that speed, and bringing them in on a target world, is within a hundred years of terrestrial development.

    The entire question is, given our history, and the advance of technology, would any coldly rational extraterrestrial allow us to reach that point, bringing ourselves into range of being a lethal threat to them.

    Because when any object is moving near the speed of light, by the time you see it (and they’re difficult to see to begin with — a small fastmoving object may give off a blueshifted gamma trace, but that’s about it), by the time you see it, it’s arrived, and game over.

    So this is something that needs to be taken into consideration before we start madly flagging the Universe like a streetwalker on Saturday night, looking for a helpful lift. The answer we get may be more like that of a conscience-stricken serial killer — regretting the necessity, but determined to protect themselves — than CLOSE ENCOUNTERS OF THE 3rd KIND friendlies.

  131. #131 DblogEdition
    December 21, 2011

    I have been closely following the ancient allien theories on the history channel for some months now. I must confess that it will be bad for us to make contact with any extra-terrestial race at the point in time. If the rumors about alliens visiting our planet is true then it must mean that they are far more advanced than we are and might colonize planet earth. Yes. I said it., colonization of the earth.

  132. #132 allen
    January 14, 2012

    You say; “…. our bravery, our sense of adventure, our will to explore, our thirst for learning and discovery, our curiosity, and our desire to experience all that existence has to offer. ”

    Well what about every top scientist’s will to overcome and intellectually dominate their “inferior” fellow humans? Otherwise they would not be the leading scientist. Show me one humble scientist that has a job.
    So why would a smart alien whant to get together with you? Or a snake?

  133. #133 Leon
    January 19, 2012

    I find Both sides of this debate have great points . Does nobody believe that the higher intelligence a individual posseses the more distance it creates from its instincts to breed and eat : therefore gaining capabilites for free will and potenital to conduct acts of great compassion , or even evil ? I myself figure we just have to look at ourselves and the problems , we cause to what some consider ‘ Lesser’ beings on our own planet for example destroying rainforests the homeland of many of our rarest creatures . Hunting the likes of the big cats , whales and other species to extinction just for a nice rug or ingredients for our little luxuries , However as some people have previous commented why travel all that way just to bother some naked apes stuck on a rock

  134. #134 karl
    January 25, 2012

    When people talk about posing the question
    “How did you manage to overcome the
    limitations of your evolution and achieve
    interstellar travel?” Or “How did you
    manage to survive for long amounts of time
    without any means of power?” To an alien, well to
    be fair, how do we know those things
    are simply not impossible, and any alien civilisation that
    might exist/did either hasn’t been discovered
    or discovered us because they’ve long died
    out or are struggling to travel beyond
    their own galaxy? I think if we think these
    thoughts, then the answers are with us,
    and if it can be done, all the answers will
    appear in due time and it shall be done.

  135. #135 amelia
    January 26, 2012

    Aliens.Do they really exist ?

  136. #136 amelia
    January 26, 2012

    Are ALIENS dangerous ?

  137. #137 iTao
    March 14, 2012

    Everyone want’s to know a straight answer on aliens and what they are like, Do they even exist, would they hurt us? The truth is, If they exist, They are all different.

    Some may be out there looking to take over everything in there path while other life forms are out there fighting to survive. People seem to be categorizing Aliens as One species. Where there would be different types like there are different humans, we are not all the same.

    And we call our planet Earth, What if they other life forms like to call their planet earth? What if the Aliens like to call themselves ‘Human’.

    In my opinion, Alien’s do exist. Some may be less advanced as us, Like a common flower? While others are even more advanced then us and are still exploring around the home planet before taking off into the unknown.

  138. #138 Grever
    August 24, 2012

    Fantastic post however , I was wondering if you could write a litte more on this topic? I’d be very grateful if you could elaborate a little bit more. Cheers!

  139. #139 Joe
    September 11, 2012

    I think it’s an interesting topic, and there is many points to argue, in the end I think it’s all personal opinion. Here’s my stance.

    Aliens are portrayed as “the bad guys.” In fact, I recently saw a documentary on the history channel named something like “If there’s an alien invasion”.
    I think humans have kind of grasped a thought that, if aliens do indeed exist, they are going to be evil.

    I’m gonna cut to the chase. If we find aliens, what do you think we are going to do? Most likely take them in and study them, and this would more than likely be seen as an evil act, and they just might react with a war. Now don’t think this is irrational, because if they did the same thing, there’s no doubt in my mind we would interpret it as a threat! (Hostage situation)
    Besides, the communication barrier would most likely be near impossible to get over.
    I can’t keep my train of thought, oh well, posting it as is, good night.

  140. #140 sigge
    November 15, 2012

    A maybe more relevant question than what the aliens would do to us is what WE would do to them.. Humans are biologically predisposed for bloody murder and warfare (just compare to chimps that also have clan wars). Whenever we encounter another species (other predators eg), or other humans for that matter, that compete for reseources with us we resort to violence (or the threat of) in a majority of cases.

    If we in the future encounter an evolved alien species, it is very likely this encounter sooner or later will result in armed conflict. Especially if we feel threatened or if they in some way compete w us for resources.

    Also – bear in mind that FTL will probably never exist in any form ; so if aliens arrive at our doorstep they are here to stay..

  141. #141 Wendy Flay
    February 23, 2013

    If they are that advanced I doubt we could detect them if they wanted to stay hidden. We are an excitable and violent species So I think they would take their samples and leave quickly without us knowing.
    .If they have evil designs on our planet all they have to do is pop a designer virus into the atmosphere that wipes out humans and they can do what they want after things quieten down.
    It’s incredibly arrogant to think an advance alien would have anything to do with us. Say one did and what if he told us there was no God?
    What if he explained we were just an infantile, homicidal species with a father fixation?

  142. #142 Wow
    February 24, 2013

    America would make it their mission to bomb them back to the stone age…

  143. #143 Davethemage
    Earth alpha7-1
    March 21, 2013

    Why do people always assume that aliens need the same resources as life on earth, maybe the consume liquid gold and eat chemicals that would kill us in seconds

  144. #144 Thatguy
    June 27, 2013

    If everything corrected aliens influenced humanity esxplecaily technology maybe there just as freaked out as we are maybe if we welcome them they will come to earth friendly we don’t know everything.

  145. #145 Freakymonkey626
    June 27, 2013

    If we were to be contacted by Extra-terrestrial life it would be for 1 of 2 reasons : either they have travelled to this solar system for our resources on a planetary scale or they have travelled here on a scientific endeavour, of which both outcomes could become disastrous to all life on this planet.

    Outcome 1 ; resources : For this species to need resources it would could be two things they are after, the sun to provide energy to there craft or a goldilocks planet on which to resettle in both cases because of there advanced technologies they will get what they want, meaning our planet is left frozen and cold or we will not be the dominant species on the planet.

    Outcome 2 ; scientific exploration : The extra-terrestrials could also be on a exploration mission just as we are, trying to discover the universe, but even if this was true the species would be met with immense hostility and brutality from our armies that we could start a war we would not win but even if that didn’t happen it doesn’t mean we would be same and live in harmony because these creatures are not from earth meaning they could carry pathogens that terrestrial species are not immune to meaning we could have diseases appear we have no idea about curing and neither would this alien species because they do not know anything about us biologically and we would have no way to transverse our information to them.

    To summaries in nearly every occurrence imaginable when you think about it without rose tinted spectacles whether the aliens are hostile or not and considering nature only lets one species survive and it is always the strongest meaning if we were to ever be contacted it will most likely not end well for the human race.

  146. #146 Wow
    June 28, 2013

    In scenario 2, you’ve put black-tinted spectacles on.

    Have you just watched the recent Superman movie and taken Kent’s Dad’s opinion of this scenario to be factual and true?

  147. #147 Sean T
    June 28, 2013


    I take issue with your statement that nature only lets one species survive and it’s always the strongest. First of all, the first part of that statement is patently untrue. Obviously, there are multiple species extant on earth right now. Therefore, nature certainly allows multiple species to survive.

    Now I can only assume that being alive and sentient, you knew that. Therefore, I assume you meant that only one intelligent species can survive. However, one must be careful of how we define “intelligent species”. Are chimps and dolphins intelligent species? Research has shown that they can be taught rudimentary language skills, for instance. Therefore, we should probably consider them intelligent.

    Perhaps you meant something more like “nature only will allow one species that is intelligent enough to signficantly modify its environment to survive.” Well, if that is the case, then we don’t really have any evidence one way or another for that proposition, do we? Only one species has ever evolved that fits that definition, namely humans. We don’t really know one way or another whether multiple species fitting that criterion could survive.

    I would take further issue with your idea that an alien species would necessarily be “stronger” than humans. Stronger, in the biological sense, does not mean more intelligent, possessing more advanced technology, or anything like that. It really means better suited to its current environment. In that respect, humans probably would be stronger than an alien species, which likely would have evolved in a different environment than that of earth. It’s certainly possible that an alien species might be unable to deal with some environmental condition on earth that would not trouble us in the least. Perhaps the aliens evolved on a world where atmospheric pressure was double or half that of our atmosphere. Perhaps they evolved on a colder world and have more efficient enzymes that would kick into overdrive on our relatively warm planet, with harmful effects. Perhaps they are poisoned by some component of our atmosphere that’s not present in theirs. That’s not to say that they couldn’t overcome these limitations with technology, but that would put them at a disadvantage.

  148. #148 Sean T
    June 28, 2013


    What makes you think that humans are the dominant species on earth now? In biological terms, we are far outclassed by most species of bacteria, for instance. There are more E. Coli in your lower intestinal tract, for instance than there are people on the entire earth. If you look in certain places on earth, human presence is minimal or nil, whereas bacteria would be plentiful (for example, suboceanic vents). Both in terms of numbers and in terms of geographical range, we are far outclassed by bacteria.

  149. #149 john
    phoenix az
    October 28, 2013

    It is complete ignorance to ignore the possibility that a more advanced civilization would mean us harm. It is also ignorant to assume that they will mean us harm. If there were intelligent life out there what makes you think they aren’t just as savage as we are? There is a possibility that they aren’t and have overcome their differences but the probability of that being so is very small I would imagine. Hawkings is smart in what he said, you are an ignorant person if you ignore the probability of them being just as, if not more savage than we are as human beings. Surely an intelligent civilization has the same carnal desires of any form of life on this planet, to take and take until they die.

  150. #150 john
    phoenix az
    October 28, 2013

    Is it wrong to be fearful of the worst possible outcome? If the majority of mankind is under the conception that alien life capable of interstellar travel is wrong and contacting such a being will mean the eradication of humanity, are you willing to make that bet? I believe that is more of what Hawkings was talking about rather than a one sided view of the situation as most of you seem to misinterpret.

  151. #151 Wow
    October 29, 2013

    It’s wrong to be fearful of the worst possible outcome.

    Sanity would be

    Expect the best, prepare for the worse.

    Your method leads to paranoia.

  152. #152 Wow
    October 29, 2013

    ” Research has shown that they can be taught rudimentary language skills, for instance.”

    Unlike the average Fox News listener.

  153. #153 Eric
    April 10, 2014

    An intelligent rebuttal to the “let’s assume aliens are benevolent” assumption:

  154. #154 Stan D
    August 3, 2014

    I realise that aliens may come for resources, but i think that if they have advanced in technology so far, along the way they must have learnt to negociate, and learnt empathy and such emotions. So they may realise that life on other worlds is precious and should be left to live peacefully. Also, if you look at us, so far at our current level of advancement one of the only reasons that we have gone to explore other worlds is curiosity; we have not gone out seeking materials. So I think that the first time the aliens find us, it will be out of curiosity.

  155. #155 PJ
    Perth, W.Australia
    August 3, 2014

    From my perspective, we may explore different worlds not only out of curiosity, but with the intention of finding resources as well. To fund such expeditions must, at some stage, have a reward potential to justify the event.
    Spaceship1 was not created just for the curiosity of space flight. Yes, it has shown a way of economic flight into space, but it is also a way to generate funds for the owner. Curious people pay to get that thrill of going into space. There now is Spaceship2; eventually 3, & so on. Eventually exotic materials will be brought back from Mars for exploitation after lunar mining is under way.
    We do not tend to explore for no return at some stage.
    As far as alien contact is concerned, we will never know their intention until arrival. There may very well be many ‘blue marbles’ out there which may be more attractive. We may be lucky that the amount of pollution we have been radiating for the last century could be a red flag. On the other hand, that could mean we miss out on our education of universal existence.

  156. #156 Wow
    August 5, 2014

    Eric, if aliens are dangerous, then by their ability to get here they are unstoppable, therefore we lose nothing by giving up the fear of alien invasion.

    It’s almost entirely impossible for an alien to be able to digest us or our flora and fauna, so the only things to require of us by invading is our resources.

    And they’re vastly more available from practically any other solar system body.

  157. #157 Starde
    on line
    September 20, 2014

    First of all how can you say they are highly advanced beyond our capacity then compare ourselves with them? You even use the word “our peers”. They are hardly our peers, they are more advanced than we are and will be for a few thousand years. So, we are not equal to them. These being have been visiting earth for thousands of years even father back than the Pharaohs in Egypt. They probably look at us as a cancer in the universe, given how we seem to be obsessed with violence and annihilating ourselves. We must appear primitive and ignorant. Probably a very low life form. Since everything is interconnected, our bombing and using greater and greater weapons to blow up the planet must have an affect on the entire universe. Perhaps, given the abductions which seem to be about talking blood, impregnation and cattle killing, they must be doing scientific experiments. Perhaps knowing our future they plan to reseed the world with a more highly developed species that is part us and part them to replace us, once we blow ourselves off the planet. And like Noah’s ark, they are collecting DNA from all manner of species on this planet. It seems mankind is hell bent on destroying himself without any stopping or common sense. So, these beings have given up on saving present humans are only culturing us for the new world that lies ahead. Hopefully in the new world they will have made us smart enough to begin a new society, one without profiteering, greed, hate, ignorance and ego.

  158. #158 Wow
    September 22, 2014

    Well since they would have had to cross interstellar distances to get here, where we’re having trouble getting to our nearest natural satellite (hell, not even getting to near earth orbit), that is ample evidence of a greater technological advance.

    Since light speed means that any reasonably distant (therefore able to hide from passive detection) alien life will be by the time the message gets to us have had a few centuries of technological advancement in the meantime also indicates the balance of society.

  159. #159 Wow
    September 22, 2014

    Misread the query.

    However, it’s entirely possible and permissible to compare us. Even to say that there is no comparison: THAT IS STILL A COMPARISON, merely one that leaves all measures on one side, the other getting so little as to be ignorable.

    An ant still gets compared to humans. Even though I’ve never met an ant I couldn’t beat in any contest of wits or strength.

  160. #160 The Watchman
    October 7, 2014

    They’re already here, it’s called ISIS and they kill anything their book tells them to.

  161. #161 donald johnson
    manila for now, the united states is my home
    October 19, 2014

    i am pretty sure they are here now. i am sure this planet has a lot to offer in raw materials, mineral, and biological. i am positive the could crush us like ants. i feel that in the next few years we will see applications on viral attacks, and more sightings of ships, but for now, while they still conduct experiments and figure out what to do with the life forms already here, they will tolerate our presence on this planet. they have visited here many times and have several bases here, not just 1 alien race but many. time will tell how they choose to dispose of us.. i am sure the planet can be terraformed to meet their needs, if it already isnt being changed as we speak,.. there is a lot happening now to distract us from the idea that they are already here, we have made deals with them for technology, and some biological weapons, and it is being decided on to use to cleanse the planet. the vast majority of humans will be killed, and enough left to be used for labor and menial and dangerous jobs will be all that is left. evolution is a way of life and death you know,..good luck.

  162. #162 Vera Mack
    United Kingdom
    February 28, 2016

    There are differing resources that may be of value, other than mineral or animal. If their own planet has suffered by way of a polar shift, and if their energy requirements are based on gravity/magnetism, planet earth is perfect for colonisation.
    Also, the saying that if your plane is going down just hope your pilot is a pessimist, not an optimist, as he/she will be more likely to make a safe landing. I agree with the ‘pessimistic’ view of Mr. Hawking. If we can keep our heads down, I think we should.

  163. #163 Wow
    February 28, 2016

    There’s a hell of a lot of “if” in there. And a complete lack of anything explaining why and how “energy requirements are based on gravity/magnetism” such that the earth is prime real estate and no other form of power generation, such as solar or wind, geothermal, tide, fusion or fission are available and much cheaper to roll out than a vast interstellar invasion.

  164. #164 Jay
    September 2, 2016

    This man’s logic is flawed on every level!

    If there is even a 1% chance that Aliens could and would simply wipe us out to take our planet then that is too great a risk! Assuming Aliens even want to speak to you is as arrogant as most humans already are! It is the arrogance of your own self importance that you base our entire species existence on. I got news for you, we crush bugs and animals all the time, sometimes just because we can! We even destroy our own habitat because we’re too stupid not to.

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