Why We May Be Surrounded by Older Alien Civilizations

A few thousand years ago, the first human

civilizations

emerged, flourishing in the fertile crescent of Mesopotamia, the Indus Valley and the banks of the Nile River. Our population, technology and culture have been advancing since then until now we are approaching to touch the Nearby worlds around us As our machinations turn to the stars We wonder if other

civilizations

arose elsewhere before us It seems reasonable to consider that there could be some civilizations

older

than us, but if we could be

surrounded

by

older

civilizations, one is even much older than us, so sit back, have a cup of tea and join me, professor kipping, as today we explore the concept of civilizational longevity and discuss new research from our team on this topic.

It was astronomer Carl Sagan who brought the issue of civilization's longevity into popular thought with his writings and his wonderful Cosmos series in 1980. Sagan reasoned that civilization was unlikely to be at the same technological level as us; they would be behind or ahead, but it would seem highly unlikely that there would be the same level of development as us critically, although sagan thought about communication. with extraterrestrial civilizations mainly in terms of radio communication, since humanity has only had radio technology for about a century, that means that if another civilization is far behind us, they would not have radio technology yet and therefore , they would be undetectable until Sagan's path.

So it was thought, but this focus on radio technology is perhaps nothing more than a product of the times as in those years, the search for extraterrestrial s-e-t-i intelligence was framed almost exclusively as a search for communications or leaks Radio, given the enormous acceptance of radio as a means of communication here on earth this made a lot of sense to those at the time, but since then we have seen a transition from radio to new technologies such as lasers and fiber optics. Modern thinking has moved away from a pure search for radio and these days we often talk about the search for techno signatures, while radio is certainly an example of a techno signature, the concept is much broader and includes all types of effects, such as the detection of its satellites in orbit for their transits through their cities through thermal emissions and even their pollutants in their atmosphere through atmospheric characterization.

With this thought in mind, it is not obvious that this basic premise that younger civilizations will be less detectable than older mature civilizations really holds after all, as a civilization develops, they could devise technologies to hide and cloak. your presence on our team. We've even proposed a specific technique they could use to do exactly that, if you're interested check out our video description and article on that topic, in contrast, a younger civilization, like one in the middle of an industrial revolution, would pollute. your atmosphere with smog pollutants and synthetic refrigerants like cfcs could in fact be much more reckless in their effects on your planet and long term sustainability is not yet a primary concern but let's go back to sagan's quote with this thought in mind, simply stating that a civilization is not likely to be at the same technological level as us, that is only part of the picture, probably what we care about most is whether they are far behind or far ahead of us and given the fact that our emerging technologies could plausibly detect these civilizations.

In this way, this question takes on a new and important meaning to illustrate this. Consider the following scenario: In the near future, the newly completed Colossus 70-meter telescope detects a series of heat islands concentrated along the coast of a nearby Earth-like planet, which is widely interpreted. As evidence of cities, we just detected an

alien

civilization, but now they don't know it. Just knowing that they have cities is pretty limited information. They could be hundreds of years behind us or hundreds of years ahead, so when our world leaders meet. To discuss their next course of action, the question of how developed these

alien

s are would likely be of central importance to the decisions being made, one can imagine military leaders strongly advising against attempting contact if they are ahead, on the other hand, if they are behind this it could be considered a low risk venture and a chance to develop a friendly relationship from the start when they are not a threat.

This line of thinking interested me in this problem, especially in light of how the modern era of tetanus signature was toppling many. From the assumptions and conventional logic of Sagan's era, even if we ignore the question of contact or detection, the question of whether the nearby civilizations around us are going to be more or less developed than us is clearly a question of enormous importance. and I have to admit it. It's a lot of intellectual fun to ponder these questions to try to figure out our place in the cosmic scheme of things, so I sat down with Dr.

Adam Frank and Dr. Caleb Schaaf to address this in a new article I'm publishing. happy to say has recently been accepted for publication in the international journal of astrobiology and is linked below a modern version of sagan's reflections, so to speak, to advance the question of the longevity of civilization, we need a mathematical expression that describes the statistical distribution. of lives, remember that a statistical distribution simply describes how various possibilities are distributed, for example, a uniform distribution describes the role of a die, since all possibilities are equally probable. Now we're going to spend a little time on this because it's really critical to At first glance, the bottom line, determining the lifetime distribution of technological civilizations, seems like an impossible task, how is it possible to make progress on that?

You know, I think it's that aspect that really drew me to this issue, as probably regular viewers of this. The channel might even recognize the appearance, although one could write almost any formula imaginable for this problem, each very different from the other. In nature, we find that there are only a handful of distributions that seem to arise all the time, as if nature itself had a preference for them. Perhaps the most famous case is the Gaussian distribution, also known as the bell curve. A good example of this might be plotting the heights of, say, American men now that, since environment and genetics show rather less variability, there is a convergence of heights at around five feet nine inches with some fluctuations that mean a decline towards the edges now, since we want the lifespan of civilizations to be here, the lifespan of individual humans may seem like a useful point of comparison and by looking at that distribution we can see that it is a little different in shape , but one could argue that it is also approximately Gaussian, so on that basis could we use the Gaussian distribution for the lifespan of alien civilizations?

There is good reason to think that Gaussians do not do a reasonable job of explaining the distribution of human lifespan because the factors that affect our survival, such as medicine shelters, nutrition are widely available, although, frankly, not as widely available. you should, but imagine without that reliable source of food, each week would become a gamble: you will find food or not, if that probability of not finding food is even one percent, then after 100 weeks there is a reasonable chance that you die; In other words, we live every day under constant risk and the longer we persist, the more likely we are to eventually fail as long as you have a constant risk to your survival like this exponential distributions arise naturally, not Gaussian, for example if we measure lifespan. usefulness of gazelles in the wild, as shown here, the constant daily struggle for survival they face means that the longest-lived Gaussians are rare, but the forms are very common, a near-perfect exponential in In fact, exponentials arise all time in cases involving survivability, whether it's aircraft component failure rates or the life of your smartphone's battery.

Individual human lives do not seem exponential because the risk of death that accumulates each week is so small that our lives are often cut short by health problems that develop later in life, rather than say malnutrition, but civilizations disparate technologies are clearly a very different problem. Its survival every year, every century, will face existential threats, which means its distribution lifespan will look more like airplane failures than airplane failures. that of, say, a 21st century human being, for example, take the rate of meteorite impacts. A large meteorite like the one that is supposed to have wiped out most dinosaurs 65 million years ago clearly poses an existential threat if we look at the time between such impacts through cratering. data from the Earth and the Moon we find another exponential distribution; in fact, it can even be proven mathematically that for events that arrive randomly but with a fixed average rate known as a Poisson distribution, the time difference between each event must follow an exponential distribution. a general characteristic of the universe that is not limited only to meteorite impacts or aircraft failure rates.

Now yes, we might soon develop the ability to protect ourselves from meteorite impacts, but that's just one threat among a nearly endless list of gamma-ray bursts near supernovae, a destabilizing star. flyby magnetic field off an extreme volcanic event planetary instabilities obliquity drift nuclear war climate disasters global pandemics look, you understand that you've lived until 2020. The real point is that if these existential threats have a small chance of occurring every year, then the life of technological civilization should follow an exponential distribution there is something surprising and almost frightening about this whole process here we are thinking that the apes simply sat on a ball of rocks spinning in space using our minds to ponder existential questions and yet we only use our minds and some By logic and some reason we can deduce that the distribution of life of technological civilizations is probably exponential in nature.

Now of course we should remain skeptical about the validity of this, after all any hypothesis requires data to verify, but here we have a strong argument to propose this as the main hypothesis to explain this distribution. Crucial hypotheses need to be tested against data to become accepted models. Now we don't have data on extraterrestrial life here, at least not yet, but we can do the next best thing and look at the lives of the species. Here on Earth, using the fossil record and radiometric dating, we can see how long different species persisted in Earth's past. Plotting the data that I will link below in the description, you can see that the data is in fact well described by an exponential. where here the average or half life is 70 million years, now the skeptics among you might say look, this is all very well for the life of generic animal species here on earth, but that does not apply to intelligent beings like us, This does not prove that civilizations, ultimately a phenomenon quite different from mere species, must necessarily follow an exponential distribution when it comes to their lives, so to address this, there is something else we can compare to lives. of past civilizations here on Earth, human history is marked by ascent. and the fall of civilizations and we can date how long they last from archaeological evidence, after all, even the greatest civilizations eventually die.

I wonder if the Emperor Honorius watching the Visigoths cross the seventh hill really realized that the Roman Empire was about to fall. This is just another page of history, isn't it? It will be the end of our civilization. Turn the page. This figure with the source linked below in the description beautifully shows the timeline and life of past civilizations if we plot this as a histogram. The data is a bit sparse, but the general pattern is really like an exponential characterized by a monotonic decrease from zero. One thing to note here is that this data set is surely incomplete, especially on the short end, let me explain thatstatement with an example if a civilization lasts a century or less then it will leave less evidence for us to discover and therefore we are more likely to overlook it.

You can see this by fitting an exponential distribution to just the 200+ year data shown here by the white line and then we set it back to zero and as we see this predicts that we are probably missing about 30 short lived civilizations in our data set in general, although this suggests a half-life of a few hundred years, generally, so I think at this point, it is fair to say that we have multiple lines of reasoning and evidence to indicate that a distribution Exponential is the most plausible hypothesis for the way of life of technological civilization, but critically an exponential distribution is actually useless unless you know the rate of change of that exponential distribution. distribution its slope and which is characterized by a single parameter, the half-life, if the half-life of the population tends to infinity, then the exponential becomes a uniform flat line with all possibilities equally probable, but with an ultra half-life short becomes a cliff.

Remember that from the previous use of land animals we find 70 million years for this number, but from human civilizations we get a few hundred years, but what about technological civilizations? In reality, none of these categories above are exactly what we need, although the shape is probably exponential. We don't know how steep that exponential really is at this point, you might be thinking we're stuck, that's it, there's no way forward from here. Hey, we've come this far, but now it's time to give up on this effort, how can I? Possibly we learn the slope of the exponential during the life of technological civilizations if we do not have a sample of the technological civilizations to look at well, actually that is not entirely true, we know a technological civilization, we are ourselves and although we do not know the final ending of this story, we have a minimum restriction on the lifespan of our civilization, now you hear it often. said that a single data point teaches you nothing and I want to make it very clear to you that it is wrong to see this imagine I go from one data point to two data points, what happens then, well, according to this fallacious rule that a data point teaches you nothing, we would suddenly go from knowing nothing to knowing something as we go from one to two data points, but there is nothing intrinsically special about the number two, the truly significant change occurs when we go from zero points of data, which by definition means we have no information about a data point, which by definition means we have some information now, if that sounds confusing, think of it like this, a data point is like a drop in the ocean, but what is an ocean but a multitude of drops?

A rich data set is in fact a collection of individual data points and each point provides information that no matter what you do, it will never amount to anything more than a single drop in a limitless ocean. What is an ocean? What a multitude of crops, so let's go ahead and try to learn the shape and slope of this exponential distribution from a single data point now if you've seen our previous videos on the topics of life probabilities and intelligence in the universe or even more recently the possibility that we could live in a simulation. so you can probably guess how we're going to approach this problem, that's right, you guessed it, we're going to use Bayesian statistics for the initiated.

Bayesian statistics is really just a school of mathematics dedicated to problems like these where you have limitations. information in hand but we are trying to discover the truth behind the data when one uses our singular data point with the exponential model in a Bayesian framework we find that the most probable half-life of a civilization is twice that of our current age, of course, there is a wide range of values ​​around this that are almost as good, but a clear peak emerges, as you can see here, in a very intuitive way, although we did not impose the principle of mediocrity here, we naturally recover something similar since we're halfway through this average life value, you'll notice that I'm being deliberately evasive in giving you specific numbers here.

I mean what is our age as a civilization in years from now? Well, the reason why I won't give. that number is because it doesn't matter, it doesn't affect what I just told you, you can define age in many different ways, but however you do it, the statement I just told you is still true, for example, if we define a civilization technological as Starting with the invention of radio, our age would be about a century, so the half-life of radiocentric civilizations is twice those two centuries, but someone else could define it as beginning with the period of industrialization or the development of cities or even agriculture.

In fact, all of those changes mark key transitions and ones that could plausibly be detectable in the foreseeable future as a techno signature; We can argue about definitions, but the basic result for the most likely half-life is that twice our current era is a general result of This analysis that holds independently of that discussion now means that lifespan is one thing, but in It's actually only part of the story because that mean or really an average simply characterizes the slope of the exponential distribution. Remember that the exponential has a very long tail and therefore in some cases.

In rare cases, there will be civilizations that last many times longer than our current age. If a civilization has a lifespan that is say 10 times that of our current age, then the typical age that we would find that civilization would be about half its lifespan, that is, five times that of our current age. our current age, so to give it some context, what this means is that civilizations that have a lifespan greater than twice our current age will have a current age that likely exceeds ours; in other words, they are older civilizations, let's add up how many civilizations that's what we can do with a little bit of calculation and that gives us about 40 percent and in turn that means that the other 60 are probably younger, so which at this point we could stop and state that this was a result. towards the sky the nearest civilizations and one should find that among them there is a more or less even division between younger civilizations and older civilizations with a slight preference towards the younger ones, but in reality this is incorrect because we have ignored a crucial subtlety what is happening to change everything, a simple but critical effect, I think the best way to explore time bias is to see it, let's create a small simulation, let's imagine I'm looking at a volume of space from above represented by this square, now let's breathe through of time and watch random civilizations appear in this region.

Each civilization has a different but random lifespan, which I'm going to determine by drawing from our exponential distribution. If the civilization has a lifespan greater than twice our current age, I will color it red. These are On the other hand, let's color in green the civilizations that are likely to survive ours, remember that, with our best guess for the exponential distribution form, about half of them live less than us and the other half live longer. just modify the exponential a little bit to make it an exact rule, a perfect 50 50 division just to keep things simple and clean in our visualization here, so that as time goes on we see civilizations appear, each with a random lifespan extracted from the exponential. keep track of the fractional number of green versus red civilizations we've created with this bar chart on the left side after an initial settling period, when the simulation starts it quickly converges to the half value we expect, great but a As we watch the simulation unfold even though we are giving rise to an even number of red and green civilizations.

One can't help but notice that there appear to be more red dots than green. What is happening to see if this is an optical illusion? another bar chart on the right side showing the fraction of green versus red civilizations at each instant, not always but just at each snapshot in time, as we suspect that there is indeed a constant shift towards red civilizations even though the red ones and the green ones are just As we are likely to be born, we somehow end up with more rats at any given time. Some of you may have realized what is happening here.

Longer-lived civilizations seem more common simply because they last much longer. Look, the green ones are born. with the same frequency, but their short lifespan means they quickly disappear from the map as a result of this. When we look around us in space, we should expect that most of the civilizations around us will outlive ourselves. Temporal bias that we can even take. This goes a step further and considers the age of these civilizations rather than their lifespan and age, of course, are related, but they are different concepts. You may think that life is simply the age at which civilization ends.

Let's use exactly the same simulation as before, but now. I'm going to color the civilizations according to their age, from young in green to old and red; In fact, if you look closely, you'll see the dots change color as they age right in front of your eyes. Let's show another bar chart. On the right side to see what's going on here, I'm counting the fraction of civilizations that are younger than us in green versus older than us in red. Now the age bias is not as extreme as the life bias but again we see a red shift what this means in simple terms is that if extraterrestrial civilizations exist and their lifespans are distributed following an exponential distribution as we have good reasons to suspect, then the natural consequence would be that most civilizations around us would be older than we are not younger, this is a profound and very important result, it would mean that we are

surrounded

by ancient aliens and no, I am not talking about aliens who visit and build pyramids or some other nonsense, I'm talking about the statistical properties of their distribution.

As far as this time bias effect is concerned, we can actually even give you a ratio of how many civilizations are younger and older than us using the Bayesian framework before we find that around 25 a quarter of the civilizations should be expected to be civilizations are younger than us and 75 percent older, so what that means is that among the four civilizations closest to us three are probably older, so if we go back to my thought experiment of detecting an alien city at the beginning of this video, then the conclusion of our article is that chances are in the absence of any other information, they would indeed be older than us, unless they are plausibly more advanced.

Now the next question you might ask yourself is how much older than this they could really be. The nature of the exponential distribution means that that tail drops quite a bit. rapidly, so civilizations that are much older than us are likely to be very rare, even if the time skew effect is taken into account, when we break it down we find that about 10 of the civilizations would be 10 times older than us. ours, which might now seem like a low probability, but among the 10 closest civilizations that means one of them is more than 10 times older than us, given the rapid pace of technological development over the last century here on Earth , the mind boggles as to how much more advanced such a civilization could be how they would think of us.

Those results represent the key ideas of our article, but I want to emphasize that we do not know how often intelligent life evolves on other planets, it could be that there are no civilizations in our stellar neighborhood or even in our galaxy and therefore when we talk about the civilization closest to us, it could be someone who is on the other side of the universe or, conversely, it could be someone who be only a few dozen light years away, either way, no matter the The results of our paper are the same. The civilizations closest to us would probably be older to me.

This article is important because it changes the way we think about the search for intelligence. Our notions of contact and communication change radically when we consider that they would probably be far away. After all, they would surpass us in technology, how would we react if aWill the hunter-gatherer society in the Amazon rainforest send us a message floating down the river on a piece of wood? Would we start jumping up and down to initiate communication or would we just walk away? I don't know the answer to this, let me know what you think, though down in the comments, how would the interactions between these unbalanced societies occur?

The Fermi paradox can be explained through a large number of possibilities, for example, we may simply be alone in the universe, the only technological species, a possibility we have discussed before here on this channel, on the other hand, such There may be other tangible species out there, it's just that the gap in technology between us and them is so great that there are no longer two. benefit to communication either way I hope to have shown you that, however hopeless the problem may seem at first glance, we can quite remarkably make some reasonable deductions about our potential neighbors using only the tools of statistics and logic, perhaps by now.

That's the best we can do here at the Cool Woods lab. We will continue to push the boundaries of what we know to address these fundamental questions about our place in the universe. We refuse to stop being curious and wait. that you will be joining us on the trip, in fact, the research I told you about today was partially supported by donors to our group, donations that support the real research in our team and that now you too can join by clicking the link next. in the description, so until the next video stay thoughtful and curious.

Thank you very much for watching everyone. I'm sure this video will spark a lot of fun discussions, so post them below in the comments. I also want to take the opportunity to thank two of our new donors, Martin Krobo and Jeff Suter, thank you so much for your support guys, your donations are helping us make real progress in research here on our team, so until next time , have a great day and see you in the cosmos.