- The Milky Way: a galaxy that we call our home,
but one that is unimaginably ancient.
For some 13 billion years,
it has drifted through of the cosmos,
watching the very universe transform around it
as well as changing herself.
In many ways, the current era
represents a kind of middle age for our galaxy.
She's far less active than her wilder youth,
maybe less magnificent to behold on a calm summer's night,
having now swollen in a mass over the eons
through the cannibalistic gluttony of neighboring galaxies.
But like talking with a parent, we can't help but wonder
what must those younger years have been like.
There are billions of other suns in the modern galaxy,
possibly thousands of civilizations
sprinkled across the swirling menagerie of stars around us.
But what about those early times?
What must it have been like
to have lived in the formative years?
What must it have been like
to have been the first ones to awaken?
We do not know when or even if
other civilizations emerged in our galaxy,
but to provide some context of what it must have been like,
we're gonna dream of another civilization
in those early years,
a people that we'll call the Imins.
They will serve as our vehicle,
our guide to the science and conditions
such a civilization may have faced.
The story may be a fiction,
but it allows us to work through
the very real science of our early universe.
As we will see, though,
being first isn't always as appealing
as one might naively think.
And in fact, it may even come lined with a certain sadness,
a poignant tragedy to the whole affair.
(winds whooshing) (gentle music)
Let me take you back to a time 11 billion years ago.
The Milky Way as we know it today does not yet exist,
as it's still in the process
of forming through the gradual mergers
of many dwarf galaxies.
The dominant actor of these mergers,
known as the Milky Way Progenitor,
is just 5% the mass of the modern galaxy,
a seed of what one day will grow
into the behemoth that we know today.
Imin children would learn that their galaxy
contains less than 10 billion stars
and has a fairly typical clumpy shape,
for the Milky Way's beautiful spirals
had not yet formed either.
Looking at a star chart,
the Imins would find themselves
located near the outskirts of the proto Milky Way.
To the Imins, this made perfect sense.
Throughout this time,
a much higher proportion of stars were massive stars,
immense cosmic engines
that would regularly explode in violent supernova.
The radiation produced by such events is so powerful
that it could extinguish entire planets
of their resident life,
even from distances of many light years away.
Since the density of stars
was much higher towards the galactic core,
it made sense the Imin home world was near the edge,
nestled within the the benign galactic suburbs, if you will.
Stars were generally more massive than that of today,
and so it's perhaps no surprise
that the Imins lived on a world
orbiting a bluer star than that of our own,
for it was 60% more massive
and thus burned hotter as a result.
Whilst humanity would classify the star as an F0 dwarf,
the Imins never split stars up into such distinct classes.
Rather, they thought of stars as part of a continuum.
Because of this heavier star,
the stellar luminosity was seven times greater
than that of our sun,
which explained why their planet
was nearly three times further away from their star
than the Earth is,
for only here was it cool enough
for liquid water to remain stable on the surface.
As a result of this greater distance, though,
their star ironically appeared 40% smaller in their sky.
Although the Imin home world
received about the same amount of total radiation
from their star as the Earth does,
the radiation had a different profile,
producing far more high energy radiation,
in particular blue and ultraviolet light.
In early years,
this UV light kickstarted life and evolution,
experiencing much faster mutation rates
than those seen on the Earth.
Life here soon developed photosynthesis,
which came to thrive under this blue star,
but so intense was the blue light component
that many plants and indeed animals here
had evolved blue pigmentation,
reflecting some of the blue light away
as there was simply too much otherwise.
Having developed in such an environment,
the Imins could recognize
far more hues and tones of blue than we.
They had dozens of names for different shades
that the human eye could ever even distinguish.
Blue was seen as the color of life
and red the color of death
due to the color of the hemoglobin in their blood.
Before the Imins developed technology or science,
they would look up at the night sky
and see it littered with blueish white stars
that they interpreted to be living points of light
penetrating the cosmos itself.
But they also saw reddish patches and blobs
proliferating their sky,
which they once believed was blood staining the heavens
from battles between their mythical deities.
Centuries later, the Imins would realize
that these were in fact luminous star-forming regions,
as stars were forming at rate roughly 30 times higher
than the Milky Way that we know today.
When the Imin astronomers first suggested this idea,
they were considered heretics
to many of their religious leaders
with often dire punishments.
But over time, Imin culture accepted
that these weren't regions of death,
but rather regions of birth.
The home world was about one third the mass of our Earth,
which stemmed from the younger age of the universe itself.
You see, the cosmos was just 2.8 billion years old,
and so there had passed far less time
for stars to manufacture
the heavy elements needed to build rocky planets.
Indeed, there was about 20 times less of the stuff
than the modern era.
The Imin system was the fortuitous product
of a particularly metal-rich star forming region
some 2.5 billion years ago
that was just 300 million years after the Big Bang itself.
The region had enjoyed being fertilized
with metals from numerous nearby first generation stars.
And whilst many of the stars that formed subsequently
were not well suited for life, the Imin star was.
But it was a lean system.
The porosity of metals in the cosmos
meant that giant planets hardly ever formed.
Instead of a Jupiter,
the Imin system's most massive planet
was a roughly Earth-mass frozen wasteland
in the outskirts of the system,
and then a few of the minor dwarf planets
scattered between them.
The Imin home world's lower mass
had some important ramifications.
Its smaller size meant that it cooled
far quicker than the Earth,
and so even though it was only 2.5 billion years old,
Imin geologists believed that plate tectonics
may soon shut off
as the crust was in the process of forming a stagnant lid.
The lower mass of course also meant a smaller physical size.
It about 75% Earth's diameter,
had 56% of the surface area,
and a softer surface gravity of 63% that of the Earth.
We can imagine that Imins would've evolved
with lighter frames and bones to we humans,
perhaps having a slender, tall figure.
Since surface pressure is proportional to gravity,
the air would also be lighter on the surface too.
With less oxygen to breathe,
perhaps the Imins would've evolved
a slower metabolism to adjust,
perhaps even having multi-century lifetimes
as a result of this.
The lower surface gravity meant that the planet
had a weaker hold on its atmosphere than the Earth,
leading to a puffier gaseous envelope.
As light passed through this deeper atmosphere,
the greater column depth increased the absorption
and scattering of light within it,
leading to a bluer sky.
This also led to more protection
from the damaging ultraviolet radiation
from their home star.
With a deeper atmosphere,
the ozone layer afforded greater protection
from UV light too.
But even so, UV flux was significantly higher on the surface
than that of the Earth.
This radiation damages cells, rips apart genetic material,
and threatens life so much
that initially all life on the Imin planet
had developed underwater or underground.
Eventually, the land was conquered though
when a new genetic repair mechanism evolved
that could repair both single and double-stranded DNA.
Within the cells of all Imins,
damaged DNA is moved to a compartmental ring-like structure
where nucleotides from the the outside of the ring
could then fuse and repair it.
Many billions of years later,
a similar mechanism would eventually be discovered on Earth
within an extremophile bacteria
known as Deinococcus radiodurans.
For thousands of years,
Imin culture, society, and civilization flourished.
They developed mathematics, science, astronomy,
and studied the proto Milky Way around them.
They discovered many wonders through these activities.
Amongst the billions of stars around them,
they would witness countless supernovae,
tidal disruption events,
and watch stars wink out into black holes.
The cosmos was gloriously generous
when it came to high energy events.
Within the center of their galaxy,
they discover one gargantuan black hole
and another slightly smaller one slowly spiraling into it.
Further afield, they'd see a zoo of galactic mergers,
galaxies binding, smearing, and stretching across space
as gravity inexorably brought them together.
To the Imins, the universe was a place of feverish change,
a cosmos where merging and coagulation were a common theme,
but a place that was inherently violent, dangerous,
and largely hostile to life forms like themselves.
In all of those wonders,
the fervent maelstrom of activity, merging, and birth,
the Imins eventually wondered were they alone?
Imin astrobiologists had reasoned that stars like their own
were the best place to look for life.
Specifically, they hypothesized that stars
of similar mass to our sun
would likely not produce enough high energy radiation
to foster the rapid mutation rates
that their planet had experienced,
something that the Imins generally considered a necessity
to enable intelligent life to one day evolve.
Higher mass stars were also no good,
surely too short-lived.
After all, their own star was already approaching
the end of its main sequence lifetime,
and probably only had about half a billion years left
before things turned sour.
The Imins were an inherently deeply social species.
Their slender form made them a frail people,
one that only survived through cooperation with each other
and their superior intellect
over the rest of their biosphere.
Solitary confinement was fatal to an Imin,
so torturous that they would die
in the face of prolonged absence of social contact.
For them, the search for life in the universe,
for others like themselves,
was a deeply seated compulsion.
It wasn't just a scientific question.
Their entire culture
became increasingly organized around the search.
The fear of being alone was so keen
that whenever an Imin scientist
warned that it was a possibility,
it would spark mass outrage
and backlash within their society.
Ironically, in the midst of their
scientific search for alien life,
this resistance nurtured a parallel vein
of denialism and anti-science across the planet.
Within their society,
a sense of depression and anxiety grew as piece by piece,
science began to hint that there was indeed
something very special about their home.
Some of this anxiety was countered by just sheer denialism,
but at the same time,
the underground use of narcotic compounds grew in popularity
to provide a momentary reprieve.
Amongst these, most potently chlorofluorocarbons, or CFCs,
had a unique and effective numbing effect on the Imin brain
with apparently no side effects.
This led to their eventual legalization
and ultimately ubiquitous use across Imin society.
This wonder drug soon found use
in many parts of industry too,
particularly for refrigeration and aerosol repellents,
thanks to its low flammability and toxicity.
CFC production and use
saw an unprecedented rise during these years
and was aggressively marketed
in a hope to quell public anxiety.
Yet even numbed,
the obsession for life in the universe was so strong
that it dominated Imin culture by now.
Across the planet, many states began to impose
that schools cannot teach
that there's anything unusual about the Imin home system,
that it must be typical
and life was therefore surely common,
just waiting to be found.
Eventually the mediocrity principle
became a central dogma of the educational system,
but in quiet moments many Imin scientists
would admit despairing the forceful ignorance
of the growing contrarian evidence.
For by now, their astronomers had discovered
that planets like their own were in fact incredibly rare
and that much of the galaxy
simply looked too violent for life.
Yet publishing such findings became increasingly difficult.
The insatiable thirst for alien life
was frequently exploited for personal gain
by many members of Imin society.
These bad actors would tell the world
what they wanted to hear:
that a nearby planet had alien structures on it,
or they'd received a private radio communication
from another star,
or that they'd interacted with aliens
or alien technology directly.
Eventually, the truth of these fallacies
was of course revealed,
causing the anti-science sentiment to be propelled further
as trust increasingly broke down
between scientists and the public.
Around this time,
a group of Imin meteorologists became alarmed
at new observations of their planetary atmosphere.
Their luscious, thick ozone layer
that was so crucial in protecting their world
from their star's high UV flux
was seemingly disappearing.
It was soon realized that the unthinkable was true:
that the wonder drug
that their society had become so addicted to
was the root cause.
CFCs were destroying ozone molecules
and had already started to form
a small hole above the planet's poles.
Their work took years to finally get published,
with many refusing to print such controversial findings.
But to the dismay of the scientists,
the discovery was almost completely ignored,
with society carrying on as usual
and science outlets preferring to discuss
the latest UFO sighting instead.
Science literacy was so poor by now
that many simply didn't understand the finding
and certainly didn't like its implications.
The Imin meteorologists were accused
of performing mental gymnastics,
or that this was simply a natural cycle,
or that no ozone was actually fine
because the planet didn't always have ozone
when life once lived underwater anyway.
All the while,
the hole in the ozone layer grew larger and larger.
In these days,
there was a historic meeting of Imin astronomers.
They summarized decades of ultra precise searches
for bio signatures and techno signatures
as well as their deep understanding by now
of the stellar population around them.
The inescapable conclusion
was that they were most likely alone,
most likely the first.
Coupled with the pressing problems
plaguing their society and ecosphere,
any optimism for alien contact left the room that day.
But some of the Imins at that meeting saw a solution,
or at least one of a sort.
They might not be able to have
a two-way dialogue in the here and now, no,
but they could have a one-way dialogue.
Imins could preserve
their knowledge, culture, and achievements
and transmit it to future civilizations.
In that way, at least someone would know what they once did.
Someone would know that at the very minimum,
they once existed.
In the years that followed,
a growing movement came together
for what became known as the Last Hope Project,
a kind of time capsule design to preserve
Imin knowledge and identity somehow across the stars,
even if they were facing their imminent demise.
It never became more than a minority,
but these Imins desperately worked together
through the possible options, ideas, and feasibility.
They worked tirelessly without pay or often sleep.
Volunteers from across their globe came to help
or just to try and support this Last Hope.
As the ozone layer eroded across the planet,
crop yields plummeted,
leading to famine, ecological refugees,
and regional conflicts over diminishing resources.
Imins found themselves
imprisoned within their homes during the day,
unable to go outside under the harsh UV light.
At night, they'd wander outside and gaze up at the sky,
still smeared with red blobs of star-forming regions,
a reminder that they were too soon for this cosmos.
The ultimate fate of the Imins, I leave to your imagination.
But regarding their final dream, the Last Hope Project,
I'll offer one last comment.
The Imins were the first by quite a way,
and their time capsule would go undiscovered
for many billions of years.
They knew that this was likely true,
so had to design something that could last for eons
without any moving paths, active power, or electronics,
yet something that could somehow
transmit information across the galaxy.
And so the Imins placed
a roughly 500 kilometer orbiting structure
around their star,
a thin sheet of material whose very shape
would reveal its artificial nature.
As this sheet eclipsed in front of the star,
distant civilizations might detect the dips in light
and see something strange.
Their first idea was to make it a triangle,
something so obviously different from the shape of a planet
that it would be clear that somebody built it.
But for many Imins, that simply wasn't enough.
A triangle didn't convey their science,
their art, their philosophy,
or what it was like to be an Imin.
And so the Imins devised a complex series of shapes,
swirling geometries with nested structures.
Like a fractal,
one could begin with a coarse, zoomed out picture
and learn some basic information.
But the closer one looked,
the more details, spokes,
and nuanced structures would reveal themselves.
In one of their greatest achievements,
Imin mathematicians devised an ingenious way
of encoding entire volumes of information
within these intricate shapes.
However, the largest structure they could feasibly build
was just 500 kilometers in length and width,
but that was tiny compared to the size of their home star,
blocking out less than 60 billionths
of the star's brightness during the periodic eclipses.
There wasn't much hope of anyone detecting that,
let alone the intricate spokes
and structure embedded within it.
But the Imins had a long game.
They knew that their star would die,
eventually leaving behind a tiny white dwarf
that would be not much bigger than their planet was.
So if the structure survived until then,
it would now block out
a respectable 0.2% of the white dwarf's light,
boosting the amplitude 34,000 fold.
Sadly, the Imins never saw the structure completed,
but they did witness the launch
of their automated 3D printers
that would go on to construct their Last Hope
in the centuries that passed.
The final product wasn't perfect.
In some places, the robots made mistakes
without any guidance from their masters.
Yet more, as the star eventually went giant,
the radiation levels were higher than anticipated,
deforming many of the most intricate geometries
the Imins attempted to encode deep within their Last Hope.
But the basic shape remained,
and within it one could decode sounds from their home world,
messages from children across the planet,
and extracts from their greatest poets and philosophers.
Flash forward to 11 billion years later,
the modern universe.
The white dwarf that was once the Imins' home star
has now cooled below 3,000 Kelvin,
making it barely detectable except to infrared telescopes.
In truth, the Imin structure
was never conceived to last this long.
Over the eons, abrasion from dust, nucleonic decay,
cosmic rays, and micro meteorites
have battered it into a distorted, twisted sheet of metal
floating through space.
Perhaps many years later,
we can imagine an astronomer
detecting the dim light of this ancient white dwarf,
a relic of the early universe.
Squinting at that graph of brightness versus time,
the astronomer might notice a dip in light,
a strange decrease that didn't look planet-like.
Perhaps there's a held breath, a burrowed frow, and tension
as the astronomer pushes the data through an interpreter,
seeing what shape could this object possibly be?
Maybe, just maybe this is the signal
they've been looking for all these years.
And then a sigh, another dud.
It's just a cloud of randomly shaped material,
probably just fragments of a broken up asteroid.
The screen shuts down.
The astronomer leaves.
And the Last Hope Project of the Imin planet
is never detected again.
The universe is vast, merciless,
and largely hostile to living things.
The Imin story that I presented to you is a fiction.
We do not know if there was life so early in the cosmos,
or indeed any time before now.
And quite likely alien life, if it exists at all,
would be far more alien than I've imagined here,
perhaps in ways that none of us can conceive.
What I hope this video gives you
is some insights into our early galaxy
and the consequences of these differences on possible life.
But also I hope that this video provides some reflection
about the fragility of life
and the path of our own civilization.
Our story hasn't been written yet.
We get to choose what comes next.
And much like the Imins,
already we suspect that our planet may be very rare.
Our fate, like theirs,
is inexorably tied to how we treat it.
The jewel of the solar system, perhaps even the galaxy.
So until next time, stay thoughtful and stay curious.
(warm music)
Thank you so much watching, everybody.
I just wanna take a quick moment
to give a big, big thank you
to our latest Cool Worlds supporters.
That is Graeme Benson, Nicholas Gebben,
and the Rand Corporation.
In fact, I'll be giving a talk at Rand
in Santa Monica on March 7th.
Details down below if you wanna see me in action.
If you too wanna become a Cool Worlds supporter,
then you click the link up above in the description.
If you haven't already, be sure to subscribe.
And until next time,
have a cosmically awesome day out there.