4 Reasons why We're Probably Surrounded By Alien Civilizations
advertisement
VOICE OVER: Peter DeGiglio
Scientists believe that the solar system could be entirely SURROUNDED by alien life!
4 Reasons We’re Probably Surrounded by Alien Civilizations
Human beings on Earth live about 25,000 lightyears away from our galactic centre. Our planet speeds around the sun at about 66,000 miles per hour. We have our own, unique place in space that, seemingly by some miracle, has allowed life to thrive. Except, what if it isn’t actually that miraculous at all? What if, really, there are many reasons as to why we should be (even are) surrounded by other, alien life in the cosmos?
Let’s get straight to it with reason number one; the commonality of life in the universe. When looking at instances of life, we, of course, have only one sample to draw upon - life on Earth. And there are plenty of studies and theories - including the rare Earth hypothesis - to suggest that maybe that’s all there is. But, equally, and in more recent times, we’ve seen more and more papers published arguing that life, actually, could be all around.
One such paper was published in May 2020 by the Columbia University astronomer David Kipping - with a key takeaway being that it’s potentially nine times more likely that life is common in the universe, than rare. The study models the likelihood of abiogenesis - of the emergence of life - on other planets as per what we know to have happened on Earth… and concludes that there’s good reason to believe that it would happen again, on another Earth-like world. For Kipping and his team, however, the likelihood of intelligent life isn’t as high, with close to a fifty-fifty chance. But, still, the suggestion is that if there are any alien species out there, then some of them will have developed into an advanced civilization.
So, what are the chances that they’re close by? Reason number two as to why we could be surrounded is the growing list of potentially Earth-like exoplanets. Exoplanets are planets outside of the solar system… and charting them is actually a relatively new prospect for astronomers, with the first official detection of an exoplanet coming as late as 1992. But, as of March 2021, there are now more than 4,400 confirmed exoplanets in the sky. Meanwhile, the topmost predictions for how many there could be in the Milky Way claim that there are multiple billions of other worlds in just this galaxy.
Of course, not all of those will be Earth-like. But according to a June 2020 paper by a team at the University of British Columbia, we can estimate that one in five sun-like stars does have an Earth-like planet in its habitable zone. Which amounts to around six billion celestial masses within the Milky Way that are something similar to our pale blue dot. If we then imagine that, first, life can exist somewhere other than Earth… and, again, reason that it’s nine times as likely that it’s common than not… we could estimate that something lives on at least 5.4 billion planets that aren’t our own. Then, if the chances of intelligent life really did turn out to be roughly fifty-fifty… we’re talking more than two billion alien civilizations.
What’s important to realise, though, is that this is still just one conclusion we could reach. It still stands that, actually, we’ve only recorded less than five thousand exoplanets in total, and that only a fraction of those could claim to be in a habitable zone - as we currently understand it. It also still stands that we haven’t discovered even one alien lifeform so far, intelligent or not. But a growing number of scientists and astronomers do argue that the galaxy really could be bursting with life, nonetheless. It’s just that we need to work out how to access it.
On to reason number three as to why we’re probably surrounded… time. We know that the Milky Way has been around for around 13.5 billion years. And we also know that it hasn’t always been the exact same cosmic mass as it is today. It has shifted and developed over time and, indeed, the evolution of our galaxy to this precise point is one of many key reasons why we can exist right here, right now.
In the search for alien life, we so often speak of habitable zones… we’ve already mentioned them in this very video. But we’re usually contemplating them as a physical space. As a band around a star wherein a life-supporting planet could orbit. Alongside all of that, though, there are temporal habitable zones. Moments in (and periods of) time when conditions align to create the best chances to form life. And the interesting thing is that, according to one study, the Milky Way’s optimum time for life was long ago, to the tune of five-and-a-half billion years back in cosmic history.
A December 2020 paper by CalTech calculated that the probability of life in the Milky Way peaked around eight billion years after it formed, and around 13,000 lightyears from the galactic centre. Earth and the solar system are now almost double that, at around 25,000 lightyears away from the heart of the Milky Way… and five-and-a-half billion years further down the timeline. We took a closer look at this study in another recent video on our channel, so check that out after this! But, say there was a population boom at an earlier stage in our galaxy, then couldn’t we now expect there to be various, ancient civilizations dotted around us? And, if they’ve potentially been evolving for billions of years longer than life on Earth has, then could they potentially be far, far more advanced than we are? Again, there’s no way to know for sure until we encounter one… but the thought begins to make the whole of human history feel really quite small, alongside the potential for everything else!
But even though there has seemingly been time enough, there are potentially planets enough, and studies show that the likelihood is that alien life does exist somewhere… the disappointing reality remains that we still haven’t discovered anything. A growing number of scientists believe that there must be extraterrestrial intelligence in the universe, and probably in our galaxy, but nobody has found it. So, reason number four why we’re probably surrounded is because we’re not yet advanced enough to know what’s really going on.
Across the many ecosystems of Earth, humans reign supreme. We’ve built towns and cities across most of the world map, and we’ve travelled to almost all Earthly locations. And yet, our successes outside of Earth’s atmosphere are… limited. There’s no doubt that our space travel achievements thus far should be celebrated, but they still only amount to a small number of far-slower-than-lightspeed machines (only two of which - the Voyagers - have ever broken out into interstellar space) and a handful of human travellers making it to the next-closest thing to us, the moon. Our impact on the wider universe is, then, at this stage, very small.
The Great Filter is an often-debated concept whenever talk of advanced civilizations comes up. It proposes that there is something, at some stage of civilization development, that puts a halt to it all. There’s some kind of biological or technological hurdle that very few civilizations can pass, and that’s why space appears to us to be so… silent. The next question is: Has humankind already passed the Great Filter, or are we yet to encounter it? If that second scenario is true, then it could be that we’re just not at the required level to engage with alien civilizations, yet - and we might never be. Meanwhile, those select few alien groups who have passed the Filter, have steadily grown and grown all around us, despite us being naturally oblivious to them.
Finally, filter or no filter, it could simply be that we haven’t allowed ourselves enough of an opportunity yet, to encounter and understand any potential alien groups. In a joint-authored 2016 paper by Cornell University students Evan Solomonides and Yervant Terzian, it’s argued that we could be waiting 1,500 years before any real progress is made toward first contact with aliens. The study, entitled “A Probabilistic Analysis of the Fermi Paradox”, reminds us that we’ve only truly been searching in earnest for aliens for about a century… and also predicts that less than one percent of the Milky Way has been reached in any way, by anything. Which offers one explanation as to why we so far haven’t crossed paths with aliens, but also opens up the possibility that there could be plenty of them out there… it’s just so unlikely at this stage that we’ll have clocked them, or they’ll have clocked us.
So, there we have it. It can be argued that it’s statistically likely that aliens abound; it’s becoming clearer and clearer that there are enough exoplanets in the Milky Way to host them all; according to one recent study, there’s been comfortably enough time for them to have emerged in this galaxy; and the final explanation as to why we’ve not spotted them yet is because we’re not advanced or clever enough ourselves. Or we’re just too impatient! And those are four reasons why we’re probably surrounded by alien civilizations.
Some visuals provided by Getty Images
Human beings on Earth live about 25,000 lightyears away from our galactic centre. Our planet speeds around the sun at about 66,000 miles per hour. We have our own, unique place in space that, seemingly by some miracle, has allowed life to thrive. Except, what if it isn’t actually that miraculous at all? What if, really, there are many reasons as to why we should be (even are) surrounded by other, alien life in the cosmos?
Let’s get straight to it with reason number one; the commonality of life in the universe. When looking at instances of life, we, of course, have only one sample to draw upon - life on Earth. And there are plenty of studies and theories - including the rare Earth hypothesis - to suggest that maybe that’s all there is. But, equally, and in more recent times, we’ve seen more and more papers published arguing that life, actually, could be all around.
One such paper was published in May 2020 by the Columbia University astronomer David Kipping - with a key takeaway being that it’s potentially nine times more likely that life is common in the universe, than rare. The study models the likelihood of abiogenesis - of the emergence of life - on other planets as per what we know to have happened on Earth… and concludes that there’s good reason to believe that it would happen again, on another Earth-like world. For Kipping and his team, however, the likelihood of intelligent life isn’t as high, with close to a fifty-fifty chance. But, still, the suggestion is that if there are any alien species out there, then some of them will have developed into an advanced civilization.
So, what are the chances that they’re close by? Reason number two as to why we could be surrounded is the growing list of potentially Earth-like exoplanets. Exoplanets are planets outside of the solar system… and charting them is actually a relatively new prospect for astronomers, with the first official detection of an exoplanet coming as late as 1992. But, as of March 2021, there are now more than 4,400 confirmed exoplanets in the sky. Meanwhile, the topmost predictions for how many there could be in the Milky Way claim that there are multiple billions of other worlds in just this galaxy.
Of course, not all of those will be Earth-like. But according to a June 2020 paper by a team at the University of British Columbia, we can estimate that one in five sun-like stars does have an Earth-like planet in its habitable zone. Which amounts to around six billion celestial masses within the Milky Way that are something similar to our pale blue dot. If we then imagine that, first, life can exist somewhere other than Earth… and, again, reason that it’s nine times as likely that it’s common than not… we could estimate that something lives on at least 5.4 billion planets that aren’t our own. Then, if the chances of intelligent life really did turn out to be roughly fifty-fifty… we’re talking more than two billion alien civilizations.
What’s important to realise, though, is that this is still just one conclusion we could reach. It still stands that, actually, we’ve only recorded less than five thousand exoplanets in total, and that only a fraction of those could claim to be in a habitable zone - as we currently understand it. It also still stands that we haven’t discovered even one alien lifeform so far, intelligent or not. But a growing number of scientists and astronomers do argue that the galaxy really could be bursting with life, nonetheless. It’s just that we need to work out how to access it.
On to reason number three as to why we’re probably surrounded… time. We know that the Milky Way has been around for around 13.5 billion years. And we also know that it hasn’t always been the exact same cosmic mass as it is today. It has shifted and developed over time and, indeed, the evolution of our galaxy to this precise point is one of many key reasons why we can exist right here, right now.
In the search for alien life, we so often speak of habitable zones… we’ve already mentioned them in this very video. But we’re usually contemplating them as a physical space. As a band around a star wherein a life-supporting planet could orbit. Alongside all of that, though, there are temporal habitable zones. Moments in (and periods of) time when conditions align to create the best chances to form life. And the interesting thing is that, according to one study, the Milky Way’s optimum time for life was long ago, to the tune of five-and-a-half billion years back in cosmic history.
A December 2020 paper by CalTech calculated that the probability of life in the Milky Way peaked around eight billion years after it formed, and around 13,000 lightyears from the galactic centre. Earth and the solar system are now almost double that, at around 25,000 lightyears away from the heart of the Milky Way… and five-and-a-half billion years further down the timeline. We took a closer look at this study in another recent video on our channel, so check that out after this! But, say there was a population boom at an earlier stage in our galaxy, then couldn’t we now expect there to be various, ancient civilizations dotted around us? And, if they’ve potentially been evolving for billions of years longer than life on Earth has, then could they potentially be far, far more advanced than we are? Again, there’s no way to know for sure until we encounter one… but the thought begins to make the whole of human history feel really quite small, alongside the potential for everything else!
But even though there has seemingly been time enough, there are potentially planets enough, and studies show that the likelihood is that alien life does exist somewhere… the disappointing reality remains that we still haven’t discovered anything. A growing number of scientists believe that there must be extraterrestrial intelligence in the universe, and probably in our galaxy, but nobody has found it. So, reason number four why we’re probably surrounded is because we’re not yet advanced enough to know what’s really going on.
Across the many ecosystems of Earth, humans reign supreme. We’ve built towns and cities across most of the world map, and we’ve travelled to almost all Earthly locations. And yet, our successes outside of Earth’s atmosphere are… limited. There’s no doubt that our space travel achievements thus far should be celebrated, but they still only amount to a small number of far-slower-than-lightspeed machines (only two of which - the Voyagers - have ever broken out into interstellar space) and a handful of human travellers making it to the next-closest thing to us, the moon. Our impact on the wider universe is, then, at this stage, very small.
The Great Filter is an often-debated concept whenever talk of advanced civilizations comes up. It proposes that there is something, at some stage of civilization development, that puts a halt to it all. There’s some kind of biological or technological hurdle that very few civilizations can pass, and that’s why space appears to us to be so… silent. The next question is: Has humankind already passed the Great Filter, or are we yet to encounter it? If that second scenario is true, then it could be that we’re just not at the required level to engage with alien civilizations, yet - and we might never be. Meanwhile, those select few alien groups who have passed the Filter, have steadily grown and grown all around us, despite us being naturally oblivious to them.
Finally, filter or no filter, it could simply be that we haven’t allowed ourselves enough of an opportunity yet, to encounter and understand any potential alien groups. In a joint-authored 2016 paper by Cornell University students Evan Solomonides and Yervant Terzian, it’s argued that we could be waiting 1,500 years before any real progress is made toward first contact with aliens. The study, entitled “A Probabilistic Analysis of the Fermi Paradox”, reminds us that we’ve only truly been searching in earnest for aliens for about a century… and also predicts that less than one percent of the Milky Way has been reached in any way, by anything. Which offers one explanation as to why we so far haven’t crossed paths with aliens, but also opens up the possibility that there could be plenty of them out there… it’s just so unlikely at this stage that we’ll have clocked them, or they’ll have clocked us.
So, there we have it. It can be argued that it’s statistically likely that aliens abound; it’s becoming clearer and clearer that there are enough exoplanets in the Milky Way to host them all; according to one recent study, there’s been comfortably enough time for them to have emerged in this galaxy; and the final explanation as to why we’ve not spotted them yet is because we’re not advanced or clever enough ourselves. Or we’re just too impatient! And those are four reasons why we’re probably surrounded by alien civilizations.
