The Drake Equation: What Are the Odds That Aliens Exist?

By Korey Haynes | October 19, 2018 9:56 am
a telescope array at night

Humans are even now looking for signs of aliens with projects like SETI. Credit: Seth Shostak/SETI Institute

The Drake equation is one of astronomy’s most famous attempts to answer the question: Are we alone? It asks not just about any life, but the top shelf stuff: intelligent life with the ability to communicate with beings outside their planet. Microbes or floating sentient clouds don’t make the cut. We want aliens that will talk to us.

To be clear, this means there could be life out there in the universe that the Drake equation would discount. But in terms of knowing how likely we are to receive alien signals, it’s a great way to organize our questions. It starts from a sky-high view of the necessities for life and then zooms in, each component of the equation narrowing or broadening the possibilities (and getting harder to determine).

Starting With Our Telescopes

The equation asks first about the average rate of star formation in the galaxy. This doesn’t sound particularly applicable to life, but that’s the beauty of the Drake equation. It realizes that to have a species, you have to have a planet, and to have a planet, you must have stars. So we’ll start with making stars. For a long time this was the only number we had hard evidence for. We can measure star formation rates in many galaxies, ours or any other, by looking at the fraction of young to old stars.

We also need to understand something called the initial mass function, which explains how many big, little, and in-between stars emerge out of a stellar nursery. This number ends up being “a couple,” or 1.5-3 stars born per year, according to the most recent science. This may not sound like much on the face of it, but keep in mind the billions of years the universe has been churning. It adds up quickly.

The second number is the fraction of stars that have planets. This was a mystery for a long time. Astronomers could speculate, but until the past few decades, we really didn’t have solid evidence. Thanks to Kepler and WASP and all the other exoplanet surveys, we now have a lot of planets and star systems to judge from. Our best guess for this number is roughly 1: that is, there’s roughly one planet for every star in the galaxy. Of course, some stars like our own sun have many planets, and others none, but we’re talking averages here.

Looking for Life

The next question is, once a star has planets, how many of them are capable of supporting life? This is where we start hitting roadblocks. We only know of one planet that does have life. We can argue about whether Mars could have in the past. We can define habitable zones where planets can support liquid water on their surfaces, but what about worlds like Europa, with subsurface oceans? What about tidally locked planets around dwarf stars? The number is highly variable. We think it’s somewhere between 3 and 5 right now, but that could be higher or very much lower, depending on how you define habitability.

And then we start really plunging into the unknown. What fraction of planets that could support life actually develop living creatures? Again, we know of just one so far that has. This number is very much an unknown. Is this 100%? Or do we count Titan and Europa and Mars and Venus and say it’s only 20% in our solar system?

Past this, what fraction of planets with life host intelligent life? Possible good luck here: 100% of the planets with life we know of have intelligent life. On the other hand, out of the millions of species that have existed in Earth’s history, only one of them has achieved sentience. So maybe the odds are not so great. Maybe there are a lot of planets with giraffes, but none others with humans.

Can the Aliens Talk to Us?

Artist's rendition of a planet

How many planets that could harbor life actually do? Credit: NASA/Ames/JPL-Caltech

This next bit is part of what separates the Drake equation from general thought experiments about the existence of life in the cosmos. It asks how many intelligent civilizations come up with technology that lets them broadcast evidence of their existence into space (purposefully or not). We’ve been sending out radio waves for decades, and we’re only getting louder. It’s of course possible for an intelligent civilization to remain quiet, but we’re interested in the ones we can communicate with, which means they have to give some signs.

The last factor considers how long these civilizations hang around. One that exists for only ten years before an asteroid destroys it, or destroys itself by nuclear war, will be harder to find than one that broadcasts for hundreds, thousands, or even millions of years. During the Cold War, many argued that it looked like our civilization — and therefore most others? — might not make it past the nuclear age. The window between developing radio technology and nuclear weapons was pretty brief for us.

On the other hand, you can argue that once a lifeform escapes off-world and starts to colonize other planets it becomes much harder to wipe out as an entire civilization. One asteroid or plague wouldn’t do it. So maybe those civilizations quickly become immortal.

If you combine all these numbers, you can end up with conservative estimates that give a total number less than 1; as in, we are alone in the universe. More optimistic numbers can yield tens of millions of possibilities. Drake’s original estimates were between 20 at the low end, and 100,000,000 at the upper end. So while we’re making progress on some of these figures, we’ve still got a long way to go.

ADVERTISEMENT
  • Mike Richardson

    When I was a kid, all of the factors in the equation were unknown, and were filled in purely by educated guesses. However, in recent decades, we’ve come to realize planet formation seems to be a function of stellar birth and evolution. As the article indicates, virtually all stars have one or more planets. We’re also developing techniques to detect the atmospheres of extrasolar planets, and analyze whether or not they could support life as we know it. Of course, any detection of a signal by SETI would skip several steps in the equation towards settling the question of whether or not we are alone in the cosmos.

    • Michael Cleveland

      Don’t you mean “analyze what kind of life they could support”? Almost any gaseous atmosphere that is likely to be present after planet formation will support (or not interfere with) some kind of life. It seems likely that higher, highly mobile (and thereafter, intelligent) forms will require an oxygen burning metabolism, but life comes in many forms.

      • Mike Richardson

        No, I meant first of all, to determine atmospheric composition via spectroscopy. After that, scientists could then determine what types of life (as we know it) the atmosphere could conceivably support. Given the reactive properties of oxygen, an abundance of that gas in a planet’s atmosphere might be an indicator that it is being continually replenished by biological processes.

        • Michael Cleveland

          Quite so, and I should have noted. Any significant amount of oxygen in an atmosphere would be a fairly good indicator of oxygen-expiring life forms, and open the possibility of higher mobility life.

    • Popcorn Joe

      There are many other planets in the universe where humans live… “In my father’s house are many mansions, (“planets”), if it were not so, I would not have told you”.

      • Michael Cleveland

        Prove that mansions means planets. The Bible doesn’t say planets or worlds, so from where (besides “it just feels good”) do you get that interpretation and how do you support it?

        • Popcorn Joe

          I cannot prove it Michael… Can you prove it isn’t the meaning? The word mansions in the ancient Greek meant things other than a huge expensive house.

          I choose to believe he meant many other worlds. If I am wrong, I’ll find out someday.

          • Michael Cleveland

            You can find out now. Read the quote in context. It has nothing to do with planets (unless you think heaven is on some other spherical rock in space).

          • Popcorn Joe

            Yes; indeed I do believe Heaven is another world in the Universe, many other planets and this solar system we live in is where Lucifer and the angels who followed him were banished.

            We are all ancestors of those fallen angels with some DNA from Adam and Eve mixed in some of us… Cain went East of Eden and took a wife and built a city.

            You may believe whatever you like, I will do likewise.

          • Michael Cleveland

            You might want to start by looking up the definition of ancestor, but that’s small against using personal belief to put the meaning in scripture instead of using scripture to give meaning to belief. You could read the whole passage again in the context of the spiritual, but you won’t.

          • Popcorn Joe

            What I choose to believe falls under the category of my business.

          • Starfire

            Exactly!

          • Michael Cleveland

            Absolutely, until you offer up your belief as fact on a public forum as a rebuttal to a comment. Fair game thereafter.

          • Popcorn Joe

            I didn’t say what I wrote was factual… I happen to believe it is… This is a public forum and everyone is able to offer their opinions… If you don’t agree with me it is your prerogative, no personal insults are necessary… Or GFY, Good for you.

          • Michael Cleveland

            Well, it doesn’t get any more disingenuous than that. No personal insults given, but every opinion offered here is subject to rebuttal. The subjects discussed in this forum generally deal with scientific issues, so when you jump in with rationally unsupportable opinions, you’re apt to catch some flak. If you cant take the heat….

          • Mensch59

            I love believing stuff which isn’t scientific or historically factual or supportable by evidence also.
            /s

          • Michael Cleveland

            Believe as you will; no argument with that, so long as you aren’t confusing belief with fact (though I would rather understand than believe, which sort of negates the “anything goes” approach) and presenting one as the other. They are not necessarily the same. In those instances where the sets of belief and fact do intersect (i.e., what I believe turns out to be supportable by empirical evidence), belief shifts toward understanding (“I believe” yields to “I know”), and is no longer belief. Note, however, that “evidence” is the key word in that shift.

          • Mensch59

            Follow the evidence and allow the evidence to challenge belief is a good epistemic rule.
            It’s pretty much undeniable that we base our methodologies (which lead to shared knowledge) on taken-for-granted assumptions. Would you go so far as to logically equate a taken-for-granted assumption (e.g. an objective reality exists which can be explained by the laws of physics and this reality is shared by rational observers) with a belief?

          • Michael Cleveland

            No, not belief, not a taken-for-granted assumption. Within the limits of our ability to rationally observe the Universe, observation provides consistent and sharable results. In the broadest sense, we all observe the same things. If there is something outside of our ability to observe that negates that shared meaning, we do not have access to it. We observe that a consistently functional objective reality exists and we can share and agree on that observation, so it is not subjective, not based on unsupported faith or assumption. I do not believe day will follow night tomorrow because it has always done so, but because I understand the mechanics behind it. “God exists” or “God doesn’t exist” are beliefs (in many hands, taken-for-granted assumption), supported not by observation but by unfalsifiable faith.

          • Mensch59

            How would you re-write this section of the Wikipedia article?
            “Scientists usually take for granted a set of basic assumptions that are needed to justify the scientific method: (1) that there is an objective reality shared by all rational observers; (2) that this objective reality is governed by natural laws; (3) that these laws can be discovered by means of systematic observation and experimentation.[Heilbron, J. L. (editor-in-chief) (2003). The Oxford Companion to the History of Modern Science. New York: Oxford University Press, p vii.] Philosophy of science seeks a deep understanding of what these underlying assumptions mean and whether they are valid.”

          • Michael Cleveland

            The word “assumption” implies that we tentatively accept objective reality in light of a certain mutability, that perhaps we don’t have enough information, and if we did, the assumption might prove to be false. This is certainly true of “theory.” Theory is the highest level of understanding of an concept that we have achieved at any given time, but because we constantly strive to improve that understanding, theory is necessarily mutable as new information improves our knowledge. However, we are not dealing with theory. The underlying fundamental laws of the Universe are not mutable (as our understanding of them may be). They have functioned consistently since we have been observing the world around us. The laws do not change, nor do we have any reason to believe that the objective reality they reflect is a false view. Hence “assumption” is a poor word to use in this context (as it always has been). The collective effects of that reality on our selves negate any solipsistic view that would make reality subjective to the individual. We may have disagreements over ideas, but we share a fundamental agreement with that reality, i.e., that dawn brings light, the spot from the roof leak is not going to disappear from your kitchen ceiling without intervention, there is a sensation of wetness from contact with water; if you fall off a cliff of a certain height, you will die, the predominant color of clear, midday sky is blue, and so on, ad infinitum. Point a telescope at an object in the heavens, and you can share positional information that will allow anyone else to view the same object with another telescope anywhere in the world with allowances for time. There is no evidence of any kind that such an objective reality is falsely conceived, hence the Wikipedia statement is semantically incorrect.

          • Michael Cleveland

            Sorry, anywhere in the world in inaccurate; in the same north or south hemisphere would be correct, but the point is the same.

          • Michael Cleveland

            Apologies. That was far too long and wordy. I’m a bit under the weather today and not very efficient. To put it more succinctly, “Assumption” implies a degree of uncertainty. We accept, but we leave an escape route. The Wiki article is conceptually mis-guided in claiming the need to assume. We have had the laws of reality under systematic scrutiny for centuries and have lived with them as the absolute controlling factors in our lives for hundreds of millennia. If we haven’t figured out by now that we live in an objective reality governed by discoverable natural laws, something is pretty wrong with our mental processes. Again, “assumption” is semantically inappropriate.

          • Michael Cleveland

            One last comment: the last statement in the Wiki article re: the philosophy of science is laughable. You know what a philosopher is: a fellow with an opinion and the grammatical skills to impress you with it.

          • Mensch59

            RE philosophers of science: this list might falsify your premise. “List of philosophers of science” article on Wikipedia.
            If “assumption” is semantically inappropriate for the context of what warrants collective confidence in scientific methodologies, then you could edit the article.
            Have you ever tried?
            Wikipedia is after all “a free, open content online encyclopedia created through the collaborative effort of a community of users known as Wikipedians.”

          • Michael Cleveland

            I should probably have put a smiley face on my definition of philosophers, but I was serious about the silliness of searching the closets for the validity of objective reality.
            I have worked on Wikipedia in other subject areas, but I quit because I’m dissatisfied with some of the process. I understand the ideal in their rationale, but Wiki’s insistence on using only linkable secondary online references instead of primary source material, which does not necessarily exist online, is unreasonable and counterproductive. After a few too many “please correct this” messages, I gave it up, as I need to give this up. There are half a dozen comments here that I would still like to respond to–some interesting, some pretty outrageous, but I’ve been putting too much time into this discussion, and need to get caught up with other things necessary but usually less interesting.

          • Mensch59

            Thanks very much for the exchange of commentary and your thoughts on assumptions about objective reality.
            It was a real pleasure, Michael Cleveland.
            Peace.

          • Michael Cleveland

            The pleasure has been mine. I relish the whole range of these discussions, from the tinfoil helmet crew to reasoned thoughts like your own and some others who frequent the forums. Thought for thought’s sake. It doesn’t get any better.

          • sabelmouse

            but for the bits edited in favour of vested interests, for instance pharma.

          • Mensch59

            True.

          • Popcorn Joe

            A science article is it? Oh really? I thought it was about do aliens really exist… So I really did believe my comment was in topic with angles being aliens and how aliens came to Earth.

            I didn’t expect any flak, but I can take flak… I was a USAF pilot for near 21 years and served for 23.

          • Michael Cleveland

            If you read it, you will see that yes, it is a science article, thought not scientifically accurate, for reasons already stated in the discussion. That suggests to me that you are not familiar with the Drake equation, which was an ill-conceived attempt to quantify the probability of alien life and technology in the Universe. I also spent 24 years in the Air Force, most of it providing Intel that may have driven some of your flying missions. Thank you for your service.

          • Popcorn Joe

            Hmmm… The posted comments I read prior to posting my comment were the most unscientific I have ever seen. Thank you for your service also.

          • Popcorn Joe

            Yougot an upper vote from an old friend I used to know.

          • okiejoe

            “Mars is Heaven.”

          • bwana

            And Venus is Hell!

  • OWilson

    I can add one more function to the equation.

    What are the odds we can answer the Big Question of other life in the universe in the mere blink of time we humans will be around?

    50 years? 500 years? 5 million years? 5 billion years? (too late for the Earth)

    Maybe an infinite number of “habitable” planets and moons, but not one bit of evidence other life is actually out there!

  • http://www.mazepath.com/uncleal/EquivPrinFail.pdf Uncle Al

    In 1900 the Earth was radio silent. By 2100 or so civilization will have crashed – overpopulation, energy, arrant stupidity, a butterfly wing. Even if outworlder something were detected, there would be no return call.

    • Kerfuffl

      I periodically come across your comments. I seriously think you need to consult a mental health professional.

      • Michael Cleveland

        Actually, he’s hit the nail pretty squarely with this comment. I don’t always agree with Uncle Al, but he has a style, and your reaction says more about your intellectual health than anything about his mental health.

        • Kerfuffl

          I wasn’t criticizing this comment, but more aimed at the quantity of his posts. If you click through to see his profile, he has more than 15,000 comments on a wide range of topics on a bunch of sites. Skimming those made me think he needs some help, but I am just a random observer, not a professional. No insult intended.

          • Michael Cleveland

            I’ve been a long-time follower, and have learned mostly to see where he is coming from, though he can be odd. He’s a cynic and a poet, which I find easy to identify with, even when I disagree strongly.

          • Vilma D. Stutzman

            I am gaining $20000 each and every month by freelancing from convenience of my house you could also do the same. In office work you dont have that freedom which you desire, therefore office job seriously sucks. But in On-line income, you have got the financial freedom to enjoy your time with your loved ones any time you prefer and also go on holiday vacation with them any month you prefer. Here Is what I do> CABLINK.TUMBLR.COM

    • 7eggert

      I can’t count the number of civilizations that have already gone extinct and the number of wars fought to end all wars.

      We try very hard to not make the same mistakes, but people like Trump keep insisting that we do.

      • Michael Cleveland

        We are simply residing in our normal place on the civilization rise and decline curve. We are long into our down side. Frustrating, but it’s a complex, high-energy dynamic, and there’s nothing anyone can do about it. You would be surprised at how little political fortunes have to do with it. It is more directly related (in hugely oversimple terms) to parents working hard to make life better for their offspring. Enough generations replace the work ethic with an ethic of entitlement. Trump isn’t to blame. Obama isn’t to blame. They don’t drive, but are driven by the currents of an irresistible social dynamic.

        • OWilson

          Leaders are merely a product of their times.

          Churchill inspired an entire nation, old, young, male, female, to fight evil to the very end and never surrender, in its darkest days.

          Once the job was done. he was immediately and unceremoniously consigned to the trash heap, by a landslide.

          They brought him back to power again, at the height of the Cold War, after Stalin successfully tested the atom bomb dropped from a plane. :)

    • bwana

      So pessimistic! “overpopulation, energy, arrant stupidity, a butterfly wing” may greatly impact civilization. These will be a correction to human population but I doubt any of these will end it. We may have to take a few steps backward to getting going again but we’ll still be here.

      Now, an asteroid of the magnitude that contributed to the extinction of the dinosaurs has a far better chance of wiping out the majority of life on Earth…

  • Michael Cleveland

    This has always seemed to me a rather pointless exercise in pure speculation, since few of the inputs are anything but guesswork, and some of the assumptions are more likely wrong than not. For one thing, there are so many different ways that intelligence can manifest itself that technological manifestations are probably much more rare than the equation allows for. Octopi, dolphins, dogs, and elephants are unlikely radio builders or star travelers. There is also the problem Uncle Al mentions below, that the few tech civilizations that might develop probably occur in a fairly narrow window of time. There are many such potential windows in 13 billion years. By the time we find a signal, they may be long passed. We certainly are doing it to ourselves. We are in the process of destroying our own life sustaining parameters on this planet, and the chance that we will escape to other environments before the destruction is complete is vanishingly small. That makes our window…what, less than 200 years out of 13 billion? How representative are we?

    • 7eggert

      It’s not pointless, it’s an exercise to realize that even though most odds are tiny, multiplying these by large numbers will still give you big numbers. You know these people saying “The chances are too tiny to even look for E.T.”.

      • Michael Cleveland

        It’s pointless because multiplying fractions of guesses by fractions of guesses yields no useful information. The answers the equation yields are meaningless if the input is no good. GIGO.

        • 7eggert

          Use the lowest estimates and you get a lower boundary.

          • Michael Cleveland

            No, you don’t, because the low estimate is not an estimate (which assumes some knowledge of the input parameters). It’s a WAG that comes from inputting WAGs to the equation. Neither of the boundaries has any meaning or validity because most of the input numbers have no empirical validity (and all it takes is one bad one to render the whole exercise moot).

          • 7eggert

            Then use even lower estimates so you can’t have a bad one. except if the bad one would be “God did only create us and nobody else”.

          • Michael Cleveland

            It’s not about God, it’s about the process. An estimate is an informed approximation. You have no informed approximations to work with because you have insufficient empirical data with which to build them. Guesses and assumptions are not informed approximation. You have only an unsupported assumption that there should be other life in a Universe so large, and that a certain fraction of it must be technological, but while it’s an attractive idea that may seen self-evident, for the purposes of the calculation, it is only an assumption, with nothing yet to support extra-Terran life of any kind even in our small solar system. Until we have more empirical data, any input to most of the operative life elements of the equation is fantasy, built on nothing, and the result of guessed input of even one of those elements renders the whole effort meaningless. It tells you nothing.

          • 7eggert

            The question is not “how many civs are we to expect”, but “should we expect to be the only ones”. The Answer ist “No”.

          • OWilson

            Sounds a little like an anthropomorphic entitlement to me. :)

            The universe does not give a whit about the “expectations”, and beliefs of the life forms that are clinging to the skin of a space rock!

          • Michael Cleveland

            Expect? Maybe, but what we expect is irrelevant to the process. This equation purports to give answers, under the guise of high-sounding mathematics. There is no math. When the input has no empirical value, the outcome has no validity. Anything that comes out of this equation is meaningless, because any input regarding the life elements is meaningless. Does it seem reasonable that there should be other life out there? Certainly, but you can’t learn anything about it from this equation. You can’t put numbers in just to get the result you “expect.”

  • Deplorablewinner

    The Drake Equation is an exercise in probability, of course, and makes for interesting conversation among certain geeks. But, it’s all irrelevant because ETs, and aliens, have been visiting, and interacting with Earthlings for thousands of years. Not only that, but our Mars Rovers are documenting a former civilization there, before some catastrophe event left it in rubbled ruins. Further proof is evidenced in crop circles, sightings,moon structures, UFO crash recovery, and photographic documentation. This article is 40 years out of date.

    • Michael Cleveland

      It’s not even an exercise in probability, since none of the life inputs are supported by data. As for your interactions, where have you been while the crop circles have been shown repeatedly to be elaborate hoaxes (that anyone with a board, a string, and little imagination can make)? And where, pray tell, are you getting this nonsense about a Martian civilization? There has been no such documentation except for the usual blather among the wackadoodle crowd. You have been watching and reading too much fringe element nonsense, and too little real science. Extraordinary claims require extraordinary proof, but I would give you a break and settle for anything that rose to the level of evidence. Put on your tinfoil helmet, turn the knobs, and see what you can pull in.

      • Deplorablewinner

        I have, what I believe is, a finely tuned BS meter. Since l have retired, l spend a couple hrs a day surfing the net. You’re right that there are fringe elements that suck in the gullible. However, there is an insurmountable volume of evidence that indicates we, as a species, are intertwined with ETs that influenced our evolution thru the ages. If you haven’t come to that realization, then you are not allowing yourself the freedom of thought that expands our horizons. Btw, there are hundreds of crop circles that are so intricate and complicated that defies the belief that a group of intoxicated Englishmen with sticks, and bricks, could not duplicate in a thousand yrs. Are you visiting these sites, or is your opinion something that just bubbled up from your gut?

        • Michael Cleveland

          You sound like you’ve been watching too much “Ancient Aliens”. The so-called science in that series is so weak it could be taken apart by a scientifically inclined grade schooler. There is no “insurmountable volume of evidence.” There is no credible evidence whatsoever, just ill-reasoned speculation from the fringe set. Interesting thing is, some of the deceit is so artful that one could believe that it is not the result of gullible ignorance, but intentional and knowing misdirection. But maybe that’s my own BS meter at work.

          • Deplorablewinner

            Time will tell.

  • nik

    It took something over 4 billion years for the dinosaurs to develop on Earth. They lasted less than 200 million years without much change except to get bigger.
    It took some 4.5 billion years for humans to develop, and be capable of leaving the planet, and only because a freak accident wiped out the dinosaurs, and allowed mammals to produce us some 65 million years later.
    Given that 4.5 billion years is roughly one third of the estimated age of our universe, it likely that development of any creature with human abilities is very very rare. We may well be alone in our galaxy, which is probably good news for us, and/or any other life in our galaxy, if ”intelligent” life develops with humans characteristic for destruction of everything, including its own species……
    However, there is hope!
    The next approaching Malenkovitch glacial period should prune humanity down considerably, and may even cure it of some of its worst faults, if it survives.

    • Michael Cleveland

      In essence I agree with you, but it’s worth noting that we can never know how the dinosaurs would have developed had they remained. Predator/prey relations require that the former have some superior advantage over the latter. That isn’t it’s only source, and it’s over-simple, but a smarter predator eats better, so you might say that predation probably breeds intelligence (prey also get smarter for defense, and the race is on). I have long maintained that the input for the probability of intelligent life in the Drake equation is misguided in that the development of technological ability has a much lower than stated probability because there are so many different non-technological ways that intelligence can be expressed in evolutionary systems. Too often we still view our own world as us and them, intelligent, not intelligent. We get things like that wrong a lot.

      • nik

        The Dino’s had been around for something in the region of 175 million years, they were the top predators, and as such had no competitors and therefore no reason to change. Those that survived the asteroid hit, still haven’t evolved into anything more than they were. I dont think that they ever would have changed significantly.
        The oldest primate fossils are about 4 million years old, and the oldest human remains, so far, around 300,000 year old. So from primitive primates to ”space men” took a little over 2% of the time that Dino’s were around.
        Humans were not top predators, and were not physically much of a match for any of the major predators, so they had to develop in other ways, which predators could not match. That way was to use cooperation, planning, and techniques to outwit both their predators and their prey. That selected IQ. Which brought us to where we are now.
        Humans are all that remains of a range of large upright primates, if you dont count chimps and the like as ‘upright.’ I think that their next improvement, logically, will be an even greater jump in IQ, probably as much again as we have over Neanderthals.
        That may be underway even now.

        • Michael Cleveland

          One more go at this. Some flaws in your reasoning: first, dinosaurs were not top predators. They counted some top predators among their numbers, and they were the dominant animal life forms on the planet (discounting insects), but they had everything from large to small, carnivore, omnivore, and herbivore. They were in competition primarily with each other, which is why they had every reason to change, and did so in vast degree. They were not an evolutionarily static population. They grew, they quickened, they strategized (in the Darwinian sense), and some at the top and bottom almost certainly got smarter, some went extinct along the way. Odd that you should say survivors haven’t changed. There was only one very tiny group of dinosaurian survivors, who have since evolved into the enormous variety of birds living today. As for where humans are going, it’s true we are still evolving, but because we have circumvented much of the harsher forms of natural selection, it’s probably in the opposite direction, away from higher IQ’s, or perhaps a split between higher and lower intelligence, since the tendency is to reproduce with equals, more or less.

    • bwana

      We may have indefinitely forestalled that glacial period by man made global warming…

      • Michael Cleveland

        It has been postulated that global warming might actually bring on another ice age, by increasing evaporation from the oceans, thereby increasing cloud cover and causing a reactionary cooling. I think that’s an overly simplistic idea, not to be realized in a vastly more complex system, but the concept has an easy attractiveness.

      • nik

        The CO2=global warming propaganda, is based on a myth, and is total rubbish. The actual revised increase in CO2 since the beginning of the industrial age is 20-40 ppm, which is minuscule.
        In the last 600 million years CO2 has varied from 7000 ppm down to the present 400 ppm, and there is no evidence for a ”runaway greenhouse” in all of that period.
        The Earth is presently in an Ice Age, that so far has lasted several million years, which is why there are polar ice caps. Normally, outside of an Ice Age, there are no ice caps!
        As Mike says, below, the paradox of an approaching glacial period is that it first get warmer. The reasons are several but some of the main reasons are deforestation, and desertification, both natural and man made, and as Mike says, the increased evaporation, and consequent increased precipitation, caused by the heating combined with the Malenkovitch cycle triggers the process towards a new glacial period.
        Snowfalls become heavier, and therefore take longer to melt, so the permanent snow-lines, gradually advance. This snow reflects more sunlight and causes cooling, and the whole process is a positive feedback system, and is exponential, or asymptotic.
        I consider that the whole CO2= global warming scam, is just a smoke screen to keep the population ignorant of the reality.
        Surprisingly, Trump is correct in his assessment that the ”science” to support the CO2 = global warming is faulty, and its reasons are highly suspect, and are more to do with political economics than ”saving the planet.”

        • Steven

          I’m not finding the logic of your argument standing up against the physical evidence. We’ve not seen increased snow that has been extending the permanent snow-lines, as you call them. What we are seeing, as evidenced by satellite photos over the years, temperature readings around the world, and ice sheets in Greenland is that the planet is warming in what should be a cooling period prior to another cyclical ice age. The polar cap are shrinking, average sea levels are rising with the average temperatures, and large sections of ice (in the Antarctic) are breaking off as the ice lines recede. We are also seeing s reduction in the Greenland ice as entire rivers of melting ice are cutting into the Greenland ice sheet. These are observed phenomena that don’t care what anyone “believes”. Believe what you want, but know that the science and observable facts don’t care.
          I don’t know how old you are but I won’t be here much past 2050 if I make it that far. My son will be and probably until 2075. His children will be here in 2100 and they will all be thinking what morons we were for not doing something to stem or reverse the current CO2 additions to the atmosphere when it might have made a difference. We “know” now and have known for decades the effects of pollutants from fossil fuels on our future weather patterns and sea level rises. By 2100, Florida, at the current rate, will mostly be a memory as the ocean takes it back. We will actually start seeing “climate refugees” long before then.
          Make up and confuse whoever you want as we probably won’t be around to be told we were wrong. In the mean time, we are seeing the exact predictions on our weather come true. Bigger and stronger storms; 500 year floods annually, new high temperature records (locally in places around the world and the overall average), increased Forrest fire seasons, etc. When you see the last 18 of the past 19 years being the hottest on record, you have a trend. Short as that timeframe is, on a global weather scale, it’s still a trend. You can ignore the facts but they don’t care. The results will be the price we pay for our ignorance. And Trump is only right if his lies coincidentally align with the truth.

          • nik

            First, you have to understand that CO2 has nothing whatsoever to do with the present climate changes.
            Second, you have not understood what I have written.
            Quote; …”the paradox of an approaching glacial period is that it first get warmer.”
            This increase in temperature, increases evaporation, increases precipitation, and so the world has experienced the coldest ever recorded winters, and the greatest ever recorded snowfalls, in both the north and southern hemispheres. These records were the reason that the term, ”Global Warming” which failed to materialise, was changed to the all encompassing, and ambiguous ”Climate Change.”
            Increased temperature, in turn increases energy in the weather system, so storms get more violent. etc.
            In Antarctica the ice is advancing, in some places so fast that a colony of penguins was recently stranded several miles from the sea. So far in fact that they were threatened with extermination, because they could not reach the sea to feed.
            In another incident, a group of scientists, who had chartered a ship to view and photograph the receding ice, found that the ice advanced so quickly, in SUMMER, that their ship was iced in, and two ice breakers were sent to free them. One of the Ice breakers was also iced in, and the crews and scientists had to be rescued by helicopter.
            Its perfectly normal for ice sheets to break off in Antarctic, and has nothing whatsoever to do with ”climate change.” In fact increased snowfalls will cause pressure in the ice and it will then advance further out to sea, where it will be vulnerable to sea movement, which causes the fracturing.
            The Arctic ice will continue to melt because it is warmed by the Gulf Stream, which is part of the ”Atlantic Conveyor” warm water current. Prior to the ”Little Ice Age” about 1000 years ago, the North West Passage was open every summer, for ships to pass through, It still has not returned to that situation. So Arctic ice melting, is, again, nothing unusual, and has nothing whatsoever to do with the tiny amount of human produced CO2, as obviously 1000 years ago, that was not a factor.
            Over the length of the inter glacial period, nutrients left behind by the retreating glaciers, which are excellent fertilisers, get washed down through the soil, until they are out of reach of tree roots, the trees then suffer from malnutrition, which in turn causes weakness. In addition, the exceptionally low level of CO2 means that trees are already struggling, to survive. This makes them vulnerable to disease, and fire. In one year, one mature tree can transpire 150,000 litres of water. When water is evaporated, it cools the surrounding area. Many office block Air-Con systems use this. Multiply that effect by a few trillion trees, and you have significant climate cooling, world wide. When trees are removed either naturally or by man, the climate heats up. Deserts are known to have the most extreme climate, with scorching temperatures by day, and freezing by night. The Arab kings used to cool their palaces by putting water out at night, and collecting the ice in the mornings.
            Deserts have been spreading constantly for the last several thousands of years, and man has assisted in this, by deforestation, worldwide. This is the reason the climate is warming.
            Finally, CO2 is NOT a pollutant, its an essential component for all life on Earth, without it there would be NO LIFE on Earth. Its present level at 400 ppm, now, and throughout this inter glacial period, is the lowest it has been since the Permian extinction, 270 million years ago. The colder it gets, the less CO2 will be released by the oceans, and this will exacerbate the worlds problems, for food production.
            PS.The permanent snow lines are in the polar regions, and in mountains, so unless you visit them frequently, you will not see the changes. Some glaciers have been reported to be advancing.

  • crwre

    The so-called Drake equation is a joke.
    Depending on the numbers plugged into it, the result can be billions or zero.
    An equation that can mean anything means nothing.

    • Michael Cleveland

      Yes, we have been discussing that at length below. Good to have someone on my side.

      • Steven

        Michael: I pretty much agree with what you’ve been saying your posts. I think you have a realistic and healthy amount of cynicism in your thinking. How can any equation, where it’s possible that the variable may be essentially a zero, yield a positive result when you’re multiplying the factors. The timing issue (of when and how long any civilization will last and maintain a high level of technology) may be very short (on the astronomical scale of the universe) to make any overlaps lottery winning scarce.
        Plus, another factor only briefly mentioned in the string of post and replies, is the distance factor. Although noted, given that whole speed of light restriction, that it will take so many years for signals to pass back and forth, that the civilization that sent the message may be long ago dust by the time our reply would reach them.
        Then ther is another bigger issue. If you are using any estimate that includes distances beyond our own galaxy (about 100,000 light years from end to end), you start adding in distances that are orders of magnitude higher as the distances between galaxies is another entirely different scale than those within our single galaxy.
        So, just in our galaxy alone, a lightspeed limited signal could take anywhere from around a decade to over 100,000 years to make a round trip. Assuming you had a powerful enough transmitter to be heard a a powerful enough receiver to hear the response above the galactic noise. To add into the equation other galaxies, adds very little to increasing the chances of interacting with these other civilizations. Yes, the probability goes up that they exist, butbthe probability of contact of adding the rest of the universe adds very little to any result estimated that only includes our single Milky Way galaxy.
        Just taking the long road to make the point that however you apply or think about the Drake equation, you should limit it to just the few hundred billion stars in our single galaxy.

        Now, if you want to add to the equation the probability that we discover a FTL process which has no limitations on distance travel at near instantaneous times, then you can talk “universe” of potential civilizations. But, until we find or are given that FTL technology, we need to be just a bit more realistic in how we apply the equation. Just my opinion.

        • Michael Cleveland

          My problem with the Drake equation is that any life-related inputs are made up, imaginary, because there is nothing real world to base a figure upon. You can’t just make up numbers to plug in to a mathematical equation, and expect the product to mean anything, regardless of whether you include the Universe at large or limit it to the galaxy. As for FTL, you will only ever see that in Sci-Fi. There is nothing in the Physics we know now that points the way to any possible future Physics that allows FTL. It’s pretty solidly forbidden. The few speculations about work-arounds require–if they work at all–energy inputs on the order of the output of a moderately sized star, and they are so wildly speculative anyway that they work far better in sci-fi than they ever will in the real world. FTL is out. Travel at any significant fraction of c is out. You target a destination star that is putting out a constant stream of radiation across the whole spectrum from radio to Gamma rays. Your velocity dopplers those radiations to higher energy levels, and time dilation increases the effective energy still further. You are in a state of constant impact with particles of interstellar dust; tenuous at rest, but at those speeds, much more like flying a conventional craft through atmosphere. Count on more radiation from those impacts. Shielding that would not boil away over a high-velocity interstellar trip is mass- and energy-expensive–impractically so. The only solution for human interstellar travel is by way of relatively slow generation ships, but you would definitely want to know where you were going before setting out on a journey of multiple generations. The ships would have to be the size of a small planet, with room and activities to keep its human populations from going insane. I suspect it would be necessary to breed humans for special traits that would make such long journeys possible. You might get an AI algorithm to watch the shop while everybody sleeps, but suspended animation is high risk even if we get good at it, and do you really trust your PC to drive?

          • Steven

            Michael: I have a BS in Mathematical Physics and a Masters in Information Systems. So, no need to mansplain the physics or math issues of space travel or the Drake Equation to me. It’s a theoretical construct, which is still in the early stages of having different parts of it verified or shown to be incorrect by new observations and data collection. So, yes, while I agree with the issues you raise about it, it’s just a theoretical concept.
            Also, one cannot base what we will be capable of many years from now, assuming we don’t send ourselves back to the Bronze Age, on how well the technology works now. So thinking about running a starship with the computers and their issues of today is not a realistic way of stating the problem. Either we find a way to go FTL or fold space or whatever, or we’re are basically stuck in our local star cluster, say within 10 light years or less. Even that is problematic at sub light speeds. But, if Einstein was correct and there is no FTL to be found, then I’m pretty sure all those alien sightings and stories are 100% bogus as they have the same issues with distance. Agreed?

          • Michael Cleveland

            Absolutely agreed. You can say the aliens have stumbled onto an impossible physics, or recognize the stories are, as you say, 100% bogus (and no credible evidence to the contrary). Easy choice, just pull out your O. razor and have at. I think my favorite kook is Corey Goode, hopping all over the Universe with his alien-begotten tachyon drive (plug that into your physics book. Hoo-haw, and Buck Rogers go bragh.)
            Truth be known, I think in the end, when we find there is no way around Einstein, we will do whatever it takes to get out there, and there will be generation ships, or something on that order. Intrepid humans would always rather test the quicksand by putting both feet in it. And why not? Maybe, just maybe, if you stand on your tiptoes….

          • Bobby Braswell

            Yes

    • OWilson

      The Media and politicians, intentionally ignore the qualifications and provisos inherent in all intelligent scientific predictions, as in If, May, Could, Likely, Degrees of Confidence.

      I am only a mere one IF and one May, from winning the Mega Millions Jackpot.

      (If I buy a ticket, I may win it all!) :)

    • Bobby Braswell

      Agree

  • Bobby Braswell

    What does it matter? We can’t reach “them”. “They” can’t reach us. And the probability of us locating “them” is almost zero. Our planet will likely be incinerated before it happens. Their’s probably already has been. The “creator” played a cruel trick on us by making the universe so big. So, why spend all the time and money even bothering to try? The Drake Equation is nonsense. The effort to try to find extraterestrials is silly childsplay. And we’ll never be able to engage in interstellar travel. Stop dreaming, you naive gullible children.

    • bwana

      And why will we never to able to engage in interstellar travel?

      • Michael Cleveland

        We might, with certain sacrifices, but regular traffic is impossible or so impractical as to be virtually impossible . We can never achieve any significant fraction of light speed for human travelers (think doppler effect of radiation from sources in front of the craft, for one thing, impacts with interstellar dust, for another), so interstellar travel would require vast generation ships traveling at relatively slow velocities, and which could be self-sustaining only with fairly significant populations, subject to annihilation from a variety of unpredictable and/or unavoidable events. It’s not likely to be worth the risk to visit places of uncertain hospitableness–inhabited or not, just for sight-seeing.

      • Bobby Braswell

        Because the nearest star is 4.5 light years away.

        • bwana

          That is only 45 years away at 10% the speed of light…

          • Bobby Braswell

            Only? So, how do we nourish and keep astronauts alive for 45 years with nothing to do but mosey around a spacecraft? And how do we travel at 10% the speed of light? It’s all a bunch of science fiction nonsense.

          • bwana

            A lot of things have been considered science fiction in the past and are now fact. Don’t be too fast to discount possibilities!

          • Michael Cleveland

            45 out, 45 back, a lifetime, and at only 10% of c, time dilation won’t help. Robot probes would be more practical until you have identified a destination worthy of human scrutiny, but be aware that even if we found something worth visiting, 10 percent of c is not very practical, and more likely deadly than not.

  • Lorie Franceschi

    When I was a kid and exposed to the Drake equation, it made sense. Did I really think that Earth was the only planet that had intelligent life? No, I knew, just using a teenagers knowledge, that there had to be intelligent life out there. Were they less, equal or more advanced than we were techloolnolgy wise than we were in the ’70s? Who could say. But back then even living in the suburbs, you could look up and see millions of stars, you know the odds of intelligent life out there was really high. Now could we talk to them, visit them or they visit us, that was unknown and still is. But if you look up today away from all the light pollution and see all those stars, you know there is intelligent life out there, we just don’t know if we can contact them. Or if they want to contact us. So until we know for sure, you just have to believe there are others out there. Otherwise why send up all those satellites looking for planets?

  • Clever Hans

    Doesn’t matter, interstellar distances, let alone intergalactic distances, are so large that we are effectively alone in the universe

  • Christopher Barrett Aups

    Isn’t one of the problems is what we understand as humans? Everything we understand is at a HUMAN level, so there are things we cannot understand. Aren’t we looking at what is very similar to life on Earth?

    As humans we do not fully accept how life is formed, except that we know that life is a result of reproduction, certainly on this planet. There could well be life what we may not be able to visualise, life that we simply cannot understand, intelligent or otherwise.

    I would hazard a guess that the universe has rather a lot of life, but possibly almost all of it communication could be very difficult or impossible. We also have to consider things like distances which are astronomical in the true sense of the word. We send out signals, but would any alien life actually receive them or understand them. Signals also have to receive their destination. Our technology, while getting better, may not be sufficiently advanced. Finally, and perhaps on a gloomy note, we as humans may be blocked from making contact due to our destructive nature.

    • Michael Cleveland

      It can’t be written off to human limitations. We have very solid reason to understand that the laws of Physics (which underlie all other scientific laws) are the same everywhere. The complexity of the chemistry of life requires a base that permits such complexity, hence we can safely accept the very high probability that life, wherever we find it, will be carbon-based. Silicon allows for some complexity, but not as much, and probably not enough. I also believe there is a very high probability that life is abundant in any Universe with laws that permit it to form in the first place (but remember the all important rule: belief is not synonymous with fact). My argument here has been against the Drake equation, which uses made-up numbers to get an already anticipated solution. It’s bad math, bad science, bad reasoning. It is unlikely that we will make contact with any alien life form. The distances involved are prohibitive, the ideas for getting around the problem of those distances are science fiction (with emphasis on the fiction–purely speculative, pretend answers). The likelihood that very many other life forms achieve any kind of technology is very small against the enormous possible number of manifestations of intelligence, and the likelihood in this Universe that we will exist simultaneously with technological aliens under those conditions is so miniscule that it renders speculation all but moot. If they are out there, and if they are smarter than we are, they may have sense enough to avoid shouting their existence, because if I am wrong, and there are entities who can get here, we should not want them to know where we are. To assume smarter means more benign stands a good chance of being a death wish. If you doubt that, look around you.

NEW ON DISCOVER
OPEN
CITIZEN SCIENCE
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

ADVERTISEMENT

See More

ADVERTISEMENT
Collapse bottom bar
+