Perhaps the reason we haven't heard from any extraterrestrial civilizations is because of the "Aurora Effect," named in honor of the 2015 novel Aurora by Kim Stanley Robinson
Host | Matthew S Williams
On ITSPmagazine 👉 https://itspmagazine.com/itspmagazine-podcast-radio-hosts/matthew-s-williams
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Episode Notes
Perhaps the reason we haven't heard from any extraterrestrial civilizations is because of the "Aurora Effect," named in honor of the 2015 novel Aurora by Kim Stanley Robinson. Essentially, the theory states that the alien nature of exoplanet environments imposes limits on interstellar settlements.
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Resources
Beyond “Fermi’s Paradox” XIV: What is the Aurora Hypothesis? -Universe Today: https://www.universetoday.com/147880/beyond-fermis-paradox-xiv-what-is-the-aurora-hypothesis/
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For more podcast Stories from Space with Matthew S Williams, visit: https://itspmagazine.com/stories-from-space-podcast
The authors acknowledge that this podcast was recorded on the traditional, unceded lands of the Lekwungen Peoples.
Welcome back to Stories from Space, I'm your host Matt Williams, and today I want to get back into our friend, the Fermi Paradox. And look at another resolution that considers why humanity has not found evidence of intelligent life in the universe, yet.
So, to recap, the Fermi Paradox basically posits that, given the age of the universe, the size of the universe, The abundance of planets and star systems and galaxies, and the fact that the ingredients for life are apparently everywhere in abundance, humanity should have heard from an advanced civilization by now.
The fact that we haven't, therefore, requires a resolution. And as we covered in previous episodes, there have been many, many proposed resolutions to this paradox over the years, which included the Hart Tipler conjecture, which states that, simply put, nobody's out there.
There's also what Carl Sagan recommended in his famous rebuttal paper, where he said that the fact that humanity hasn't heard from extraterrestrial intelligence yet can be explained any number of ways, in that the absence of evidence is not the evidence of absence.
There's also the Berserker Hypothesis and other variations on that that state that intelligent life is periodically wiped out. One such variation suggests that there may be cosmological phenomenon that periodically does that. Others stress that intelligent life is going out of its way not to be found.
And then of course you've got the Great Filter Hypothesis by Robin Hanson. Who just happened to be a guest on our show in one of the earliest episodes, which states that something out there is preventing the evolution of life from its early stages to its more complex and space-faring stages, which may include a penchant for self-destruction.
And of course, it's based largely on humanity's own experience in the 20th century, the development of atomic bombs and thermonuclear warheads and environmental destruction. Perhaps all life in our universe is destined to reach a point where they'll either destroy themselves or they'll exceed the carrying capacity of their natural environment.
There's also the Transcension Hypothesis, which states that advanced life is simply too advanced, too beyond anything we would recognize as living and intelligent.
Well, today we're going to consider yet another proposed resolution, which essentially states that we are fundamentally flawed in our thinking that advanced lifeforms would expand to fill the universe, that they would become interstellar and settle system after system or even entire galaxies, and that the reason for this is that space is hard.
That's the simplest way of saying that. Exploration and settlement in outer space of other planets, other environments, it is not something that any species can easily do, and that this places constraints on how much a civilization can become spacefaring, and this is known as the Aurora Hypothesis. Which was inspired by the Kim Stanley Robinson novel of the same name, released in 2015.
And as with just about everything Kim Stanley Robinson has written, the novel offered an extremely detailed and in-depth look at the subject matter. Which in this case was an interstellar mission where a crew sent from Earth in the relatively distant future. They have a generation ship which combines various propulsion methods and has literally every Earth environment recreated within two rotating toruses that provide simulated gravity.
And they've made the multi-generational mission to Tau Ceti. A nearby satellite star with the intention of settling on an exomoon that orbits Tau Ceti e, which is a confirmed exoplanet. It's a super-Earth, meaning it's several times the mass and density of Earth, and so its moon, which is roughly Earth-sized in the story, and is transiently habitable.
Meaning it's got an oxygen atmosphere and water on it, but apparently no life. Anyway, the story details the crew's journey. We get into a very, very rich treatment of life aboard the ship. And then they arrive at their destination. And I don't want to spoil the story, but the point is that interstellar missions are fraught with peril, and we really have no idea what awaits us at the other end.
And exoplanets, exomoons, distant planetary environments could be hostile in ways that we cannot anticipate, or which elude detection until the last minute. And much like his Red Mars, Green Mars, Blue Mars series, Kim managed to merge an awful lot of research and real-world proposals. He managed to synthesize so much information.
So the generation ship itself, the propulsion methods, the toruses or tori, Based on the Stanford Torus concept and the considerable amount of information that was available at the time due to the explosion in exoplanet studies and theoretical research that looked at the conditions for habitability and what we really don't know about such conditions just yet.
In any case, among other things, this book inspired a 2019 study titled “The Fermi Paradox and the Aurora Effect, Exo Civilization Settlement, Expansion, and Steady States.” This study was led by Adam Frank at the University of Rochester and Caleb Scharf, the principal investigator of NASA's Nexus for Exoplanet System Science, as well as researchers from the Center for Exoplanets and Habitable Worlds at Penn State University and Columbia.
So, addressing the Hart and Tipler conjecture and the assumptions of the Fermi Paradox, the researchers began by examining the speed at which exo civilizations could settle across the galaxy. And, according to Hart and Tipler, the accepted value was 10 percent the speed of light, which is theoretically attainable if you have the right kind of advanced technology.
Or just a lot of energy at your disposal. And they also assumed that not all systems would have habitable planets and that any systems settled by this exo civilization would eventually send out their own probes and passenger ships, creating a settlement front that expanded across the galaxy over time.
They also included the possibility that Earth may have been visited in the distant past by a civilization, but no evidence of this contact remains. And last but not least, there was the distinction they drew between a habitable planet and a settlable planet, or as they put it, often there is the assumption that any planet can be terraformed to the specific needs of the settling civilization.
But the idea that the purpose of probes is to build habitable settlements and that all stellar systems are viable targets for such settlements, goes to the agency of an exo civilization. In our work, we therefore relax this assumption. In addition, some stars may host indigenous forms of life, which may preclude settlement for practical or ethical reasons.
And this they refer to as the “Aurora Effect,” which, in keeping with the plot of the novel, basically means that even though a planet looks good for settlement, And that it has all the necessary attributes, an oxygen-rich atmosphere, liquid water on the surface. That does not necessarily mean that a civilization will be able to create a successful settlement there, or that any settlers that do arrive on the surface won't be dead after a generation or a few.
After factoring all this into a series of simulations, they reached a number of conclusions. First of all, they determined that the amount of time it would take for an exo-civilization to settle across the entire galaxy is less than or compatible to the present age of the Milky Way.
However, once one factors the Aurora Effect into the equation, it creates a scenario where only certain parts of the galaxy can be settled, and when you add to that the notion that the lifetime of civilizations is finite, or Frank Drake's infamous L parameter, then it appears that certain clusters of the galaxy are destined to be settled and resettled while surrounding areas will remain unsettled.
If Earth is in fact within a region that doesn't correspond to a resettlement cluster, then it's entirely probable that we would not have been settled or visited for a long stretch of time by any extraterrestrial civilizations. And, what is interesting about this is that it's reminiscent of percolation theory, which NASA scientist Jeffrey A. Landis first proposed in 1993.
And according to Landis, astrophysics itself imposes a strict limitation over how much space an exo-civilization could settle with time. And that includes the effects of relativity. Communication time lags and time dilation, also natural phenomena like gamma-ray bursts, asteroid impacts, and the potential for hostile organisms, or rather just organisms that an exo civilization's people are not at all accustomed to and therefore will prove fatal.
And from that, Landis argued that settlement would not be a linear phenomenon, where civilization just begins to grow outwards at a consistent or accelerating rate, but rather that
civilizations would percolate outwards, which is characterized by growth and regression. And it also calls to mind the seminal essay by Milan Cirkovic called titled “Against the Empire” where he challenged the assumption that exo civilizations would follow an imperial model.
Which is to say, rather than simply expanding outwards and trying to acquire more territory that civilizations would be encouraged to adopt the city-state model in which they Plant their civilization in a handful of systems and develop them fully, then perhaps send out probes to explore more distant star systems, but that they ultimately remain within a relatively confined area space.
Because when it comes right down to it, the challenges of expanding through space and placing settlements on distant planets, Within our solar system alone, or within neighboring solar systems, the challenges are absolutely huge.
As the saying goes, space is hard. Beyond our atmosphere, and our protective magnetosphere, anywhere beyond low Earth orbit, for that matter, astronauts have to deal with the vacuum of space, the extreme temperatures, and of course, cosmic and solar radiation.
And the interstellar medium, that too is equally hostile. It too is characterized by high levels of radiation compared to what we're used to here on Earth. And any mission, any spacecraft attempting a journey between star systems, they're going to have to deal with so many unknowns. Not the least of which are the collision hazards.
Tiny micrometeorites or even tiny particles could really ruin your day if you're an interstellar spacecraft and you're traveling at a fraction of the speed of light. And collisions with charged particles. Cosmic rays are a perfect example of this. When they impact with the spacecraft's hull, even if the hull is reinforced to shield against radiation, Those particles will then create secondary particle showers inside the spacecraft.
And so crews inside are exposed to neutron flux that is almost as lethal as being exposed to things like gamma rays. And speaking of which, there is the phenomenon of gamma-ray bursts where supernovas or merging compact objects like white dwarfs and black holes, they release a tremendous amount of very harmful radiation.
And above all else, just the amount of time it takes to cross space from one planet to the next, from one star system to the next, is tremendous. So, in addition to this considerable body of research that says that space itself will impose limits on a species ability to grow and expand and become, An interstellar civilization.
You also have the aurora effect added into this, which says that planetary environments, which you eventually arrive at after crossing the extremely hazardous and dangerous abyss of space, are not necessarily going to be hospitable or habitable, even if they appear so, they could be inherently hostile to foreign life forms.
So really, it's not just space that's hard, it's also planetary settlement that's hard. And as Kim Stanley Robinson explored in his novel, Aurora, this raises the question of, can a species that has evolved to live within a planetary environment, Ever really expect to transplant itself and members of its species to another planetary environment.
Now of course there's the idea of terraforming, the idea that we can transform these planets to suit our needs and the needs of our species, but this is also a significant challenge. Looking at Mars and detailed studies about how we could terraform the environment there, it is acknowledged that Creating a truly habitable environment on Mars where human beings can walk around outside without the need for pressure suits, where all they need is some warm clothing and where they could actually breathe the air that that could take thousands of years.
At the very least, it could take 1, 000 years. There's plenty to be said for being able to warm the planet up to the point where you can walk around outside comfortably with just an overcoat, but you'd still need to carry around bottled oxygen. And this assumes that Mars is a sterile planet, that there's no longer any life there, if ever there was.
But what if, in fact, there is indigenous life there, possibly underground, and that warming the planet up, altering the environment, that's likely to have a significant impact on that life, which could include indigenous lifeforms migrating to the surface to take advantage of the new environment. It's warm enough up here.
There's still all that carbon dioxide to metabolize. So suddenly the settlers are exposed to this entirely alien bacteria in the air. And what effects that going to have on them? And imagine if in fact, we're dealing with exoplanets and exo moons that have much more in the way of habitability conditions than Mars currently does.
Settlers could arrive there thinking that, oh, the atmosphere has plenty of oxygen, it's breathable, and they start walking around without their helmets, only to find out that they've been breathing tiny microbes that have evolved in even more alien conditions than what would be possible on Mars. So, under the circumstances, An advanced species that is sending out settler ships to distant star systems.
Well, those settlers may find themselves up against some tremendous challenges and environments for which they are simply not suited. Evolution has not prepared them for exposure to this alien environment. And in this case, if, in fact, there's indigenous life on all these planets, the settlers would then be faced with the ultimate ethical dilemma.
Do we try to find a way to live among these hostile organisms in this potentially hostile environment, or do we forcibly change it to suit our needs? In which case, we are committing genocide, ecocide against unique life forms that evolved in a completely different environment than our own.
So under the circumstances, faced with a monumental challenge and a very harsh decision, do we wipe out native species in order to have a better chance at surviving here, exo civilizations
may opt to give up and simply go home, return to the comforting environment of their home planet or their home system, and or construct space habitats.
Engineered environments where you know that everything is built to a certain standard, and where the biological life support systems, which would be essential for any off-world living, are built according to your home planet's model. Now, of course, like every other proposed resolution to the Fermi Paradox, The Aurora Hypothesis has the weakness of being data-poor.
I mean, we really don't know enough about exoplanet environments to make any determinations either way as to just how habitable they are. We are hoping to change that in the coming years and decades. But short of actually going to these planets with probes and sampling the air and soil. We won't know with any confidence that, that these environments are in fact safe for humans or terrestrial organisms.
And while this hypothesis and others, they criticize the Hart-Tipler Conjecture and other versions of the “uniqueness hypothesis” for being based on some pretty huge assumptions, this one also makes assumptions. It's reliant on assumptions because we don't know.
But like all the other proposed resolutions, it is very interesting food for thought, and unlike others that assume that all species in our galaxy or in the universe are going to be subject to the same behavioral patterns or motivations, anything of that nature there, where it only takes one to defy that trend in order for the whole hypothesis to fall apart, the Aurora Hypothesis and similar arguments, they are based on something universal.
Space is hard. Exoplanet environments are also likely to be challenging and dangerous once we reach them. And given that the laws of physics exist the same everywhere, we have to assume that Other species are going to be bound by these exact same considerations. They too are going to be subject to relativity, space radiation, hostile organisms.
They're going to face those exact same challenges because, as the Copernican Principle teachesus, thelawsofphysicsareuniversal,andspaceisprettymuchuniformintermsofits distribution and the fact that the ingredients for life, as we know it, are everywhere in abundance. There's no special, unique, or advantageous position to be in, as far as we know.
Quite literally, every discovery, every new investigation, and new frontier of exploration, since the time of Copernicus, has reinforced that. So, that is one strength that the Aurora Hypothesis has over many other proposed theories. Despite relying on several assumptions, it does have something universal about it.
Something that can be argued as applying to all life everywhere equally at all times. And as always, the only way to combat the depths of what we don't know is to keep looking, keep researching, keep theorizing, and coming up with testable hypotheses that we can then test once the data is available.
And that is the Aurora Hypothesis, the latest installment in our ongoing look at the Fermi Paradox, and attempts to address the question, where is everybody, are we alone in the universe or not?
Tune in next time, where we will explore other proposed resolutions. We'll take a look at how human beings could settle on the largest moons of Saturn and within the Saturn system someday. And, of course, there will be more interviews and more retrospectives on the lives of major scientists and people who have contributed to our growing understanding of the universe.
In the meantime, thank you for listening. I'm Matt Williams, and this has been Stories from Space.