Practice English Speaking&Listening with: The Fermi Paradox & the Aurora Effect

Difficulty: 0

Welcome to a short in-between episodes episode.

The reason Im releasing this now is there was a draft paper released recently, titled

The Fermi Paradox and the Aurora Effect: Exo-Civilization Settlement, Expansion And

Steady Statesand it started getting discussed and I had several requests to do a video explaining

it, so I thought wed go through it and then get into some of the pros and cons for

the theory.

Lets start with the title.

If youre watching this episode odds are you already know what the Fermi Paradox is,

which is the apparent contradiction between how empty of life the Universe appears to

be, and just how huge, ancient, and filled with potentially habitable planets it is,

or basically, where are all the alien civilizations?

But the Aurora Effect is probably unfamiliar unless youve read Aurora by Kim Stanley

Robinson, author of the Mars Trilogy.

Well use the definition from the paper, thatGood worlds are hard to find”, which

is to say, just because you might find a planet you could settle and terraform, doesnt

mean its really one youd invest the effort into, or for that matter be able to

transplant a civilization there that could successfully grow.

History is full of settlements that failed or stalled out after all.

Let me start by saying that I have issues with the theory, which Ill expand on once

Ive laid out what that theory is.

So, lets first go through that paper in a more relatable way so we understand what

its all about.

If you assume that most systems dont have a place anyone wants to live or will thrive

at, it really puts a dent in the classic expansion model for the galaxy.

That assumes you colonize in a first wave from Earth, or our solar system anyway, and

then those colonies colonize those near them eventually, who do the same.

This is a very common approach for modeling galactic settlement timelines and we often

refer to it as percolation because you can then model it like a fluid going through some

porous substance.

How many worlds are viable for settlement and how quickly those settlements grow to

being willing and able to dispatch a daughter colony of their own, rinse and repeat.

Models based on this are very sensitive to a number of variables, and can thus produce

a wide range of galactic colonization timelines.

For instance, if our colonists can and want to settle every star system, can travel at

1% of light speed, and we assume the typical colony begins with 10,000 people, doubles

in numbers every 50 years like we did in the 20th century, and will colonize a new system

when they get to 10 billion people, they need to double 20 times, to go from 10,000 to 10

billion, and it will take them just a millennium after settlement to get to colonizing their

own new systems.

Just to keep the math easy, if they only travel at 1% light speed and only settle within 10

light years, it takes them another millennium to get a colony ship to all those systems

in range, so basically your colonization wave percolates out at 10 light years per every

2000 years.

It means you colonize at 0.5% of light speed, you travel at 1% but spend half your time

stopped and growing in numbers.

Galactic Colonization, everything within 100,000 light years, would take 20 million years.

That sounds like a long time, but to put that in perspective, a single rotation of our galaxy

takes roughly a quarter of a billion years.

So, this 20 million-year timeline means not much in our galaxy has changed, At the local

level, a score of centuries wont rearrange the locations of neighboring stars much either,

so we treat the galaxy as basically static.

In other words, the stellar motion can be ignored for colonization.

However, you can play with those numbers a lot, or even outright discard the model when

using something like our Gardener Ship approach.

If your ships can move at a modest fraction of light speed, say 10%, then most of the

percolation time is growing your numbers on each new planet, and you can advance from

each one a lot further for each step, since they can hurl new colonial ships much faster

& further each time.

You might make steps of 100 light years every two millennia, colonize at 5% light speed,

and settle the whole galaxy in just 2 million years.

You are also way less likely to stall out on any given front because youve got such

a large range encompassing so many settled worlds that if some dont grow quick and

send out colonies, many others are plugging that gap, like broadcasting lawn seeds.

On the flip side of this, if you have to go slower, or if many worlds just arent desirable

for colonization or if they grow much slower or tend to lose a desire for colonization

and dont send out ships once they can, then you percolate far slower and might even

stall out completely.

If we were assuming it took 100,000 years to grow enough to make each new jump and it

was 10 light years a jump, youre creeping outward from Earth at just a percent of a

percent of light speed and will need a billion years to colonize the galaxy, during which

time you can basically discard the notion that humanity is even doing this, as your

civilizations are diverging massively at each step so that even your nearest neighbors or

mother world are basically different species and you might argue about who colonizes what,

since theres not likely to be much team spirit even in your local expansion area.

This is even more hindered if you cant expect to find a suitable candidate in 10

light years of you.

If you can only make a successful colony around maybe 1 in 100 stars similar enough to our

own, and only maybe 1 in 100 of those has a planet thats a desirable candidate for

terraforming, youre only going to have a couple candidates within a 100 light years

of you, not the many thousands we normally assume when discussing this topic here on


If your ships arent relativistic, and youre focused on terraforming planets, thats

a real long voyage to ask folks to make for the honor of living on desolate wastelands

for the many millennia it will take to terraform them properly.

And it is the basic reasoning behind the classic scifi space opera of galactic empires with

only a few million inhabited worlds.

That colonization process is very slow and very hard and very disorganized and can peter

out as colonies fail or just barely prosper and arent interested in repeating the Herculean

task of colonizing again themselves.

It also implies you might have dead colonies, ones that just failed and that went extinct,

and timelines long enough that even if an older alien one did so on a world we came

across, we might not even know they had.

Thats also a popular notion in scifi, that great civilizations arise and eventually end,

leaving little or nothing behind in their wake when a new civilization evolves and sends

out its sons and daughters to do as they did before us.

On such timelines you really cant treat the galaxy as a static place either, not only

might a civilization that once looked like a vaguely spherical blob have smeared itself

across the galaxy as all the stars moved around, but they might actually be taking advantage

of local stellar motion for colonization.

If you are going the slowboat route of colonization, taking many centuries to prepare for missions

that might move not much faster than our modern space probes, you might bypass nearer stars

in favor of ones moving toward you.

So the paper lists a number of parameters and assigns various values to them, those

values we need not consider, they werent chosen out of a hat, but still are fairly

arbitrary, even if reasonable guesses.

And like Drakes equation when youve got a lot of parameters, many of which you

cant nail down to even an order of magnitude, you cant draw many concrete conclusions

from them.

Were not going to walk through their math, though its an interesting model.

Some of those parameters are the fraction of systems that are settleable, the density

of systems, which is not uniform, some regions of space will be near wastelands while others

will be much closer and richer in worlds than our own region.

Weve also got probe or ship range, and velocity, as those both are major factors

in not just how far and fast you can go, but how many candidate worlds you have access

to and if youre even willing to do it.

Others include probe or ship build and launch times, lifetime of the settlement, average

stellar motion if youre going slow enough you need to factor that in, and many more.

This includes the notion that if settlements are dying off, folks would have to resettle

them to continue expanding.

Now this gets back to the Fermi Paradox more directly by reminding us of Michael Harts

Fact A in his original conjecture about the Fermi Paradox, which is sometimes called the

Fermi-Hart Paradox because Hart is basically the guy who began the discussion of the Fermi


Fact Ais that there are no aliens currently on Earth, obviously not everyone agrees with

that but its the basis of discussion for the Paradox, since theres obviously no

Paradox about where all the aliens are if the answer is out in a farm field crushing

corn stalks to make modern art.

I also usually dont like calling that a fact, as a lack of evidence to me is more

of an assumption than a fact.

Ive never seen leprechauns, dont believe they exist, but Im hesitant to sayFact:

Leprechauns are not on Earth”.

Whichever, its the basic assumption of the Fermi Paradox along with the idea that

while Earth and its life might be fairly special, its probably not so special we

wouldnt expect lots of other places where life can pop up and get a foothold and potentially

be spawning other civilizations that might be interested in colonizing new worlds too.

But theres a second half of that, because while it says there are no aliens currently

on Earth, it also implies none in the past too.

By fossils and genetics, we can rule out us being an alien colony that got abandoned,

unless it either happened a few billion years ago, since we can see a clear relation to

other life on Earth and a common origin, or that they took more of the bioforming route

and basically adapted themselves into our existing world very subtly, which is possible

but tends to involve a lot of weird choices and handwaves to make much sense without ramming

into the fossil record.

That brings us to an outright failed colony, one that just didnt take off and was being

done to minimize disruption to the local and current life, and could maybe escape notice

in the fossil record.

Just to throw one out there for daydreaming, if some aliens came here 65 million years

ago and settled near Yucatan, they might have domed things over at their base to avoid too

much back and forth ecological leakage while they were setting up and since they and their

own life would probably not match well for existing conditions.

Thats something wed do, even if we meant to totally replace the ecosystem already on

a world, wed want to study it in detail first and keep ourselves isolated.

If after a few centuries things just werent working out, we werent growing much, and

many of those born since were fond of the existing ecosystem and didnt want it destroyed,

I could see them abandoning the colony or setting the reactor to blow up and vaporize

all the extraterrestrial life, leaving behind a big crater.

This would effectively erase most of the evidence they were here, and time would do a good job

removing the rest.

This is an example of how you can decouple Harts Fact A, no aliens here now, from

no aliens here ever.

So the paper argues theres an effective temporal horizon that would obscure our ability

to see previous visitors or settlements.

See the Cyclic Apocalypse episode though for why this normally wont tend to work for

expecting time to erase signs of prior civilizations, or short form, bones arent the only things

that fossilize or otherwise leave a long-term remnant, and civilizations would tend to leave

a ton of mysterious right angles in their geological records.

The caveat here is you must have been a fairly large civilization to leave enough of those

kinds of footprints that wed be likely to have some survive and numerous enough wed

find them.

So this is the basic notion: civilizations arise probably not too often, dont find

too much to colonize, take a very long time to do it, and often have local pockets grind

to a halt or die off.

When new civilizations arise, the time between these civilizations and their smaller scope,

means you could easily not even see them if theyd had a colony next door at some point

or maybe even on your own planet.

Well mostly bypass the papers discussion of stellar motions because I think that overdoes

things, if you are already assuming colonization so slow that each colonization front is incorporating

the motions of stars and the galaxy not being static into their plans, Id think you could

just assume they will throw their hands up in the air and not colonize just because of

the time needed.

Whether youre doing it by slowboat generation ships or probes that arrive and unpack and

replicate and build a civilization, time remains a hurdle that many are not going to want to

try jumping over, especially if thats such a long time that whatever is doing the colonization

isnt going to even vaguely resemble what their mother system has mutated into or the

original colonists who left.

Hard to get the dinosaurs to colonize the galaxy if they know it will be humans who

actually arrive, essentially.

All right, that brings us to the question: whats the flaw in the papers reasoning?

Channel regulars are probably raising an eyebrow with me at thatGood worlds are hard to

findaspect, asking why you even care about finding good worlds since we normally wouldnt

even expect spacefaring civilizations to much care about planets, to quote my friend Fraser

Cain, “Gravity wells are for suckersyouve just gone to all that effort to escape

your own planets gravity well, why would you go set up shop on another one?

So, when we talk about colonizing other star systems, we usually emphasize that you start

not by landing on a planet there, but by linking up to various resource-rich low gravity objects

like Asteroids and Moons, build rotating habitats there if you want or need gravity, and settle

planets if you want to, but only after youve setup your basic space based industry and


Planets may or may not have their value and might end up very prized by civilizations

as potential centers, but in their own right are no bottleneck to expansion.

If we assume that approach, it pretty much ends the theory under discussion today right


Interstellar colonization is mostly done by civilizations that back home already mostly

dont live on planets, as they build and breed their way up to K2 civilization status,

and while Earth-like planets might be highly valued, or not, most folks live in artificial

habitats already.

Theyve lived on one for the long trip to the new system, and ought to be happy enough

in one at the destination or even prefer those over spending centuries to terraform a planet.

Such being the case, virtually every star and planet, habitable or not, becomes prime

real estate, because to you they are really just an electric outlet and building supply


But even if those systems are more valued, as they may well be, you will tend to backfill

as you go, same as settlers always claim the best spots first and fill in over time.

So, lets get into the meat of my objection.

This concept is very dependent on the notion that colonists are likely to be either limited

or picky about what systems they settle and might tend to fail even then.

Thats a perfectly reasonable assumption inside the usual space opera context of just

settling Earth-like planets, but even ignoring the notion that were likely to build most

of the places we live in, not terraform them, we arent going to make our first colonized

world around another star.

Wed try for Mars or Venus first, and either we find out thats not practical, and either

stay at home or go the artificial habitats route, or for a more cybernetic or digital

existence, or wed have gotten practice making places like Venus and Mars habitable,

in which case we already know how to do it and if we can do them, thenEarth-like

gets very unimportant.

Worlds of similar mass and temperature to Earth might not be too common, but if we widen

the range to include wretched miserable rocks like Mars and Venus, then odds are you wont

ever have to look far for a star thats got a candidate, and you also have a couple

planets whose inhabitants wont find them unappealing and can supply colonists.

Even if you expand the habitable world definition to be safe, amenable star systems, without

exposure to dangerous stellar events like supernovae, pulsars and quasars, the time

horizons and backfilling of systems from continued growth will just leave gaps in your galaxys

colonization, not roadblocks.

The second flaw is that it probably wont be a process of planet-hopping anyway.

Even if planets are preferable, especially to folks who live on them, a future population

of this solar system is likely mostly to be people who werent born on a planet, and

live inside a great big cylinder, or on a computer chip, and neither of those cares

much about either travel times or the destinations planets, just so long as the destination has

free matter and energy to exploit.

The former already live on a spaceship, since a rotating habitat is a spaceship, and the

latter can literally just send copies of themselves.

Remember, we all suffer from confirmation bias, the tendency to search for, interpret,

favor, and recall information in a way that confirms one's preexisting beliefs or hypotheses.

We all currently live on a planet, so our bias is to naturally think that planets are

good things to live on and in the future, our descendants will continue with that trend.

However, thats dangerous thinking because if we asked a farmer a couple of centuries

back whether the majority of the worlds population would live in cities in the future,

they would have laughed at us.

They would have rightly argued that the majority of folks live as farmers and if everyone moved

to towns or cities, there wouldnt be enough farmers to feed all the city dwellers.

Now, we know from our history that the farmer was ultimately wrong.

Mechanization and technology revolutionized farming and today, the majority of folks now

live in urban environments.

We have to be careful not to apply the same confirmation bias to the notion that humanity

will always want to live on planets too.

By the time were ready to aim for galactic colonization, well be a K2 civilization

or moving toward that.

Our solar system will be peppered with thousands or millions of space habitats, possibly far

more, and the majority of humanity will not have set foot on a planet let alone lived

on one.

They wont be wedded to the notion that planets need to be colonized any more than

we are wedded to the notion that most of us need to be farmers.

Another objection is just this general notion that civilizations can go extinctthey


They can collapse and weve tons of examples, but they dont just die off without external

pressures, usually a rival civilization eroding them, even more so when they are high-tech

and thus resilient to things like natural disasters.

Collapse is not synonymous with extinction then, its just an alteration, usually to

something tougher and stronger, except for when discussed by a historian who had a crush

on the civilization under discussion and dislikes the barbarians who ended them.

I dont usually like to broaden the term evolution to include social aspects, but its

valid on longer timelines and particularly in this case.

Applying the survival of the fittest litmus tests to a large sample size, you should generally

expect civilizations over time to get better, not worse, at surviving.

You can argue that evolution, which generally breeds to make things tougher and more adapted

to their area, does not apply to high-tech civilizations, but it basically doesnt

because through forethought, planning, and strategy we can do better than random odds.

Which again kind of negates the notion that such civilizations will dwindle on new worlds,

when theyre drawing on centuries of planning and prior experience and know what challenges

await them.

And even if we accept the idea that a combination of slow colonization, a low fraction of settled

worlds of stars available, and modest long-term success rate for colonies would createsilent

bubblesin our galaxy, that wont necessarily solve the Fermi Paradox.

It will strongly depend on the visibility of civilizations; even if Earth is in the

middle of a thousand-light-year bubble of space thats not settled yet, or not anymore,

the closest Dyson swarm or space beacon may still be visible.

Especially as the folks living there know they are not alone and not hidden, since their

launch would have been a big and recorded event, thus have every reason to be heard

and none to hide, and we see none.

Or short form, its a good theory for the more classic notions of planet colonization

but like a lot of Fermi Paradox approaches for intelligent life being reasonably common,

its leaning too heavily on classic notions of settling new places.

What wed tend to expect is our own system boasting many trillions of people living in

space habitats that arent too interested in living on or colonizing planets.

If youre curious about some of the solutions weve discussed for that, check out our

Generations Ships Series and Outward Bound Series, and if you want to know more about

other solutions for the Fermi Paradox or the problems with them, try our Fermi Paradox


And of course all of those, along with this paper, focus on the idea that while our technology

will improve, it probably wont get a lot of the neater advantages often seen in science

fiction that tend to violate the speed of light or the laws of thermodynamics.

This upcoming Thursday well relax about that a bit and contemplate some of those more

hypothetical technologies so advanced they are indistinguishable from magic, and what

their implications would be for the civilizations that wield them, in Clarketech.

For alerts when that and other episodes come out, make sure to the subscribe to the channel.

And if you enjoyed this episode, hit the like button and share it with others.

You can also support the channel on Patreon.

Until next time, thanks for watching, and well see you Thursday!

The Description of The Fermi Paradox & the Aurora Effect