Are We Alone? charticle


From David McCandless's Information Is Beautiful Studio comes a magnificent charticle about the search for extraterrestrial intelligence. Above is just the top portion. See the whole thing at BBC Future, "Are We Alone?" (via Wired)



  1. While it’s an interesting calculation, it’s relevance or reliability is completely questionable. To quote the X-Files, “the truth is out there.” There are however many alien civilizations that there are and a mathematical calculation can’t determine that number with any certainty. It could be zero, it could be a billion. Aliens could exist in a way that we aren’t able to detect or communicate with. Either way, we probably won’t find them and they won’t both coming here. My guess is that if they exist, they probably have the same impending fuel shortage issues that we’re facing just to run their civilization, much less travel the stars.

    1. Right on.  The whole question is premised on notions of “intelligence” and “civilization” that are problematically anthropocentric.  If there is life off Earth, much of it may resemble bacterial, fungal, or viral life.  If there is “intelligent” life off Earth, that intelligence may resemble dolphin, chimp, cephalopod, or crow intelligence.  If there is “civilization” …  well, what exactly IS civilization?

      Until mankind becomes fluent in whale, dolphin, ant, and gorilla, any notions of communicating with off-Earth “civilizations” is fantasy.

      1. If there is “civilization” …  well, what exactly IS civilization?

        From what I remember from social studies in high school, civilization is defined by a few phenomena.  The first one is permanent residence of a group of people larger than a family.  Another is alteration of the environment and harnessing natural resources in an organized way for human use.  Yet another is specialization of activities within the population, trades essentially.

        The main thing I keep remembering from high school was that agriculture is a necessary technology for civilization to develop.  And today all civilizations have agriculture.

          1. I suppose it’s similar. But ant colonies are family groups that are direct progeny of the queen.

            I’m not a sociologist, so I honestly don’t know what I’m talking about any better than the next one down the line

          2. Even with farming, ant colonies are more like family villages than true cities. But if you wanted to call them “non-intelligent civilizations”, I’m sure nobody would mind.

          3. An ant colony is not really an aggregate of different individuals though, the colony only has one single genetic future, and colonies are more like cells in a body than societies.

      2.  The equation isn’t really trying to calculate how many “civilizations” there are in the galaxy, but how many civilizations capable of communicating with US there MIGHT BE in the galaxy. Once you accept that, you can see the value of the equation: as we get a better handle on many of those numbers, we’ll have some sense of the scope of the task of contact.

    2. Even if they don’ t have fuel shortages in the offing, presumably physics still works for them, making space travel over long distances essentially impossible.

      1. Just remember that while you guys are bickering away at the speed of light, quantum entanglement is *instantaneous*.

        1. Yes, entanglement is instantaneous, or close to it.  But you have to remember that entanglement can’t move information faster than light anyway.  So it’s fun to think about in SF, but it’s useless as a method of FTL.

    3. I find your last sentence very unlikely. There is plenty of energy in the universe, in the solar system, and reaching our planet (solar, fusion, fission), we’re just not quite there yet in terms of accessing it effectively. This is a problem that our civilization should be able to crack in a century or two at most- it took less than 300 years to go from the wood powered steam engine to nuclear fission, after all. Once you’ve got cost-effective solar you’re good to go for the next 5 billion years or so.

  2. I like that, instead of simply being the standard Drake equation, this actually allows entry of values based on estimates. Although it’s a bit depressing that, skeptic that I am, I find that today’s skeptical estimate is (spoiler alert!) one communicating civilization in our galaxy, and a paltry 78 billion in the universe.

    1.  I got almost exactly your results after I made my adjustments. Two factors that I changed drastically were the average number of habitable planets per solar system (they start with 2.5, pretty high I suspect) and the percentage that such a planet develops life (they start with 100%, I’m not buying that.)

      1. The Rare Earth hypothesis says that “life” is extremely common.  It looks like microbes formed on Earth in a hurry as soon as it cooled off enough.  It won’t be surprising to find life several places in our Solar System.

        But “animal life” might be vanishingly rare.  It’s only existed for a fraction of the lifespan of the Earth, and may depend on a bunch of really rare factors.

        If the hypothesis proves true, we might be really really alone.

        1. And intelligent life is likely to be a lot rarer than animal life still. We know of only one (or, well, no more than a handful depending on how you count some of our extinct relatives) example out of millions of species of advanced organisms that exist or have existed on Earth.

  3. In the cosmic scale, the likelihood of us being alone is microscopic.  It’s a  big universe with all kinds of things going on.  Even a 1 in a billion chance is enough for millions of other life forms out there.

    That said, the likelihood of us actually making contact with another civilization is also small, and in our lifetimes almost impossible.  But there could be a black swan event just around the corner.

    1. Except even “1 in a billion” is a guess, at best. Until we discover stars with life bearing planets we don’t know how common they are. Because it could be “1 in 300 billion”; which would leave only us in the Milky Way. Or “1 in 100 Sextillion” making it rarer still.

      These are games, nothing more.  It’s useful to illustrate that even if life meets our perception of “rare” (because that’s a qualitative point) then there’s still a good chance that it exists. But it could be either much more rare, or more common than any equation allows for.

      1. I think the equation works best if you just plug in the number of planets-with-intelligent-life that you think there ought to be.  Then you can solve to find the value for that “1 in a billion” term that will make you happy.

    1. There’s the answer to the Fermi Paradox. There are actually thousands of communicating civilizations in our galaxy alone, but due to licensing restrictions their transmissions aren’t available in our solar system.

    1. I have never understood this particular strand of criticism of the Drake Equation. As far as I can tell, Frank Drake never thought — doesn’t think — we’d get anything close to a definitive product to his equation.  Rather, he was — in 1960 — trying to set the stage for the sorts of questions we would have to answer in order to get any sort of approximation of the product of his equation.

      I recall that when I first heard of the Drake Equation — watching Cosmos when I was 9 years old — Carl Sagan suggested that the answer for N-sub-p, number of stars with planets, might be just 1 in 10.  With no blame to Dr. Sagan in the late 1970s, we now know that number is probably quite a bit off and closer to 1 in 2 or better.  It’s a far cry from solving for N in the Drake Equation, we’re looking at the right things that we need to address the question at all.

      Questions about how readily life might occur and evolve will start to get a lot better answers as we explore Mars further and hopefully probe Europa and Enceladus in the years ahead.  But, at least, by looking at the factors Drake identified, we can begin to frame the question.  I think that’s all he was trying to do.  And I think he did it pretty well. 

  4. “Sometimes I think we’re alone in the universe, and sometimes I think we’re not. In either case the idea is quite staggering.” — Arthur C. Clarke.

  5. Even if the universe contained, say, 100 civilisations with intelligence and technology that exceeded our own AND they all had advanced space travel capabilities, what are the chances they’d ever stumble across us?  

    The universe is so vast that there are just too many places to explore and analyse.  If you were to visit every solar system and it took you one earth year to complete each expedition, that’s at least 10 sextillion years of work for you to look forward to.  Even if you were to process an entire galaxy in one earth year (let’s just pretend that was possible using automated probes and robots), you’ve only reduced your workload to 80 billion years.  

    So the odds of human civilisation ever encountering another civilisation before all the stars die off is incredibly tiny.  It would probably be more interesting to just seed/terraform habitable planets in the milky way and then re-visit them millions of years later, somewhat like the concept in Prometheus.

  6. Drake and Sagan and all them cats failed to consider exactly how dangerous a place the galaxy really is.  A better version of Drake’s equation would include a ratio like “percentage of our galaxy or any other that is safe for life.”  Also throw in “percentage of planets with a tide-producing moon” and “percentage of systems with a large Gas Giant mid system to deflect killer asteroids away from the inner system.”

    There’s probably a decent amount of life, or at any rate there probably has been.  But it ain’t that f*&^ing common.  The greatest part of the universe just ain’t fit for habitation.

    1. And that’s assuming that you don’t let the real pessimists in…

      It only takes one dumb/nasty/paranoid civilization to set the Berserker Probes loose.

    2. Without changing your main point, it always struck me as just as dubious to suppose alien life would need very particular things like tides, instead of simply developing a different way without them.

    3.  Those variables – e.g., “percentage of planets with a tide-producing moon” – are all covered by the catchalls like “probability life will evolve on the average habitable planet.” Breaking the equation down like that is useful, but you’d also have to add a factor for “probability that presence of a tide-producing moon is necessary for the development of life”…

  7. Never felt part of the human race, and never will. Each night I wish that something would land and take me away; go on, dissect me – at least I won’t have to go to work the next day. It’s so incredibly boring here, and it’s all so childish with religions, petty wars, and acts of aggression.

  8. As Hawking has stated, We’re likely not alone, but the day another civilization stumbles across us will be the last day humans see the sun rise.  Pray that day never comes.

    1. I hear “They” have been here for years, as seen by the attached  pic from the Mars Rover that has been suppressed by NASA, in which they are messing with the Rover, or rather, Mission Control.

      Forgot to say — I think that given what we have to go on – what usually happens when even a well-meaning technologically superior civilization encounters a less advanced one, the less advanced civilization almost always doesn’t benefit.

      So, Ser xaulted1, I appreciate your choice of paraphrase.

  9. DRM quips aside, any digital radio transmission we receive from an alien civilization, given degradation and interference, would most likely resemble background noise.   If you want to talk about probabilities, out of those 2bn Goldilocks planets, how many of them would have civilizations reaching the analog-radio phase, like for us between 1900 and now?  And how many of those transmissions just happen to float by us as we’re tuned into whatever frequencies they happen to be on?   That seems like a pretty narrow sweet spot to me.   A less-than-educated guess would be, uh, not many.

    1. That’s all included in the “can they communicate” and “how long will they try to communicate” parameters of the equation.  I put a probability of 0.05 for “can an intelligence communication” and a window of opportunity for “how long will they try to communicate” of 500 years. The optimists would find those very, very low.

      The thing is, when talking about SETI, one is usually thinking about deliberate contact beacons, and deliberate searches, not leakage of everyday RF (or laser, etc.) traffic. The odds of finding transmissions that are NOT intended as beacons are pretty low, because who would put that kind of power into e.g. a news broadcast?

      1. A TV transmitter that covers a big city might be a megawatt. How much power would you want in a beacon?

    1. So you think that we are not alone because of probability? The Drake equation is not actually evidence.

  10. The big question is whether or not they’ll be made of meat:

    1. I remember him when he used to review Amiga games for Zero magazine…

      I remember him from my GCSE German class. Do I get a prize?

  11. Thing is, even if there are 3-4 other civilisations in this galaxy right at this moment (relatively speaking), they’re likely to be so far away (as in maybe 10,000 light years away) that they’re not going to even care.
    It also seems likely that, if we manage to get out of this particular solar system the logistics of which are themselves mindboggling – sending a robot to Mars, OK, we’ve done that several times; keeping our home planet habitable over the next century, that’s going to be enough of a challenge to do so while keeping some semblance of the world as we know it now, let alone trying to make another planet meatbag-friendly.
    Things like Star Trek and Star Wars are fun but they’ve tended to mess with people’s minds about how empty the galaxy is.
    I’d say that it’s almost certain that there is other life out there. I’d also say it’s pretty likely that they’re not going to be relevant to our own lives for a long time to come. And I suspect that if we want to satisfy that expansionist urge that seems to lie within some of us, we may have to leave our bodies behind (or at least radically re-engineer them so we can live longer, withstand harsher conditions, and of course become less prone to stupidity), which of course raises the question as to we’d likewise have to re-examine what it means to be human and what our goals mean to us, and whether it’s worth bothering continuing to exist.
    Who knows, in a hundred thousand years, some /thing/ that’s emerged from this solar system may become the thing that other extrastellar civilisations FEAR.

  12. I’m more of a believer in the Fermi Paradox

    Basically it says either we are the first intelligent life or otherwise we should have met them already. Reasons, technology advances exponentially. If there are millions of other civilizations some of them should have developed before us, by millions of years. Being so far advanced they’d likely have long ago made self replicating space probes (think Curiosity Mars Rover + MakerBot) and that those probes, given so much time ahead of us, should have easily covered the known universe.

    There’s only a few explanations then why we haven’t seen these probes

    1) We’re the first intelligent life
    2) They all killed themselves (nukes, gray goo, bio-warfare, …)
    3) They all lost the will to explore (addicted to vr)
    4) It’s impossible to travel fast 

    1 seems highly unlikely and the rest basically say we’ll likely never meet aliens even if they exist.

    1. Had space probes presented themselves to us at any time other than the last couple of hundred years, we would have burned them and written a chapter of some holy scripture about them.

    2. How can we be so sure we don’t already have evidence?  The Fermi paradox says nothing about civilizations that refuse to believe in alien life.

  13. Due to some idiotic licensing restriction this is what UK viewers see when trying to visit the linked page:
    If the wholly owned BBC subsidiary “BBC Worldwide” can commercialise content abroad, then why the heck can’t a “Worldwide” organisation show its content on the “worldwide” web without shoving licensing restrictions in the face of the very license fee payers who funded them in the first place?

  14. I don’t think the question of is there other life out there. I can answer that one:


    The questions is A) how far away is that life, and B) will any life ever be able to possess a technology to overcome that ridiclous distance.

    As many Science Fiction authors have written about, unless you have FTL, and time relativity does not exist, there are going to be issues. Like the life being extinct by the time you get there, or your race being extinct, or either evolved to something you would not reconginse, etc…

    As unless you get unbelievably luck (or not depending on how things pan out), on literally an astronomically scale have have a planet super close by that you can reach using sub-luminal speeds, over a reasonable period of time, it looks pretty improbable that communication, let alone travel would every be possible.

    This is of course assuming no magical technology being developed into the future.

  15. To my mind, the two biggest problems with these calculations of how common or rare intelligent life may be in the universe or in our galaxy are that (1) we don’t actually know what are the conditions needed for life to arise, and (2) we don’t know how common it is for planets to maintain an environment stable enough over the long term for complex life to evolve.  It is not possible scientifically to answer these questions from a sample size of 1, which is all we’ve got. In other words, the Drake equation might be missing some key variables that we can’t even conceive about because our single example of life isn’t enough to make them apparent to us. 

  16. I hate to say this but they universe doesn’t normally fall in line with our mathematical calculations. Sure it possible could be true but more then likely not

Comments are closed.