The universe is magnificent and vast. Hundreds of billions of galaxies, trillions of stars,
and even more planets. If even the tiniest fraction are habitable, then the Universe should
be teeming with life. And yet we see nothing, only vast emptiness. Where is everyone else?
The answer to this riddle could be as exciting as it is creepy: we are early, born before almost
all other life – but very soon this may change. Not only might aliens appear, they could quickly
surround us. An irreversible competition for the universe might be about to begin.
While this video is based on scientific papers, we are presenting interesting ideas based on
little data and lots of extrapolation, so take them with a grain of salt.
Ok! We need to look at three essential questions to understand the galactic competition:
How fast can bacteria build spaceships?
To become a starfaring civilization,
life as we know it needs to master a number of very hard steps.
It starts with dead stuff turning into the building blocks of life.
Then it needs to organize into self-contained cells. Those cells have to learn to work together
to form multicellular organisms. This keeps going until complex creatures with big brains learn to
use tools and language. Civilization has to be formed from cultures that value progress
and technological development. And then they need to actually venture out beyond their home planet.
We don’t really know how hard these steps are or how many of them are necessary. On
Earth life appeared basically as soon as the oceans formed. But then it took two billion
years to make the step from single cells to multicellular organisms, and two billion more
for us to appear. Culture, civilization and space travel developed super quickly though.
Do things always take that long or was this actually exceptionally fast? Also,
passing one step does not mean the next one is guaranteed: multicellularity evolved over 25
times independently on Earth, but there’s only one species that builds spaceships.
We don’t know how many steps life needs to pass and how long they take to give rise
to a technological civilization but there are probably many, and it is likely that,
on trillions of planets, life has been trying for billions of years.
Since we don’t see any other technological civilizations out there,
it might well be that we are a rare exception. We might be among the first
or even THE first technological civilization in the milky way.
But this is just one piece of the puzzle – on
top of that we may have just hit the perfect time window.
Why does humanity exist at this time in the Universe?
The universe is already 13.8 billion years old,
but it is unlikely that many other technological civilizations had a chance to appear before us.
Because in the earlier Universe life would have had a pretty hard time to emerge,
let alone thrive, because it was such a hostile environment.
Early stars constantly blew up, galaxies crashed into each other and supermassive
black holes vomited massive amounts of radiation. Enough to sterilize galaxies over and over again.
Our Sun was born right at the end of this cosmic death show. The Universe has never been more
welcoming to life than it is now. So humanity has arrived at a very convenient spot in time,
maybe the earliest reasonably possible for life to thrive. What about the future?
The Sun burns brighter than 90% of the stars in our galaxy and will keep getting brighter.
In about a billion years, it will boil all of Earth’s oceans and then become a giant that
swallows it whole. So in the galactic context, the sun is very short-lived.
Most stars are red dwarfs that can sustain habitable planets for tens of trillions of years!
Life on these planets has an incredibly long time window to appear and pass the hard steps. Even
knowing nothing about how rare or common life is, this makes it way more likely for technological
civilizations to appear on one of those long-lived planets some time in the future than in the past.
Because, if civilizations appear at random in the Milky Way within a time
window of a trillion years, then very few, if any, would appear before today.
Then a couple more arrive in this period of a billion years that we are in,
before all starfaring civilizations that could ever exist emerge all together.
This weird tsunami-like distribution is the result of both the hard steps model and something else:
A sort of deadline for any spacefaring civilization. Any civilization coming
after will find it hard to have room to survive, so all potential life has to cram in before it.
Humanity exists now because otherwise we might have missed this deadline.
What or who creates this deadline?
Why aren’t aliens already on Earth?
Humans are curious, expansionist and hungry for energy. We have spread over the world and made it
our own. Our technology has been improving over time, first slowly, then breathtakingly fast.
If these things do not change drastically, and our descendants want to prosper,
they will expand into space. We could construct a dyson swarm for endless energy and transform
planets into new homes. We could cross interstellar distances, allowing us to reach
for planets around distant stars. If we have the motivation we can become a galactic civilization.
A civilization that does this sort of stuff can be called “loud”, because its activity creates
“noise”. Signs that can be detected from far away. Imagine someone in a forest, cutting down trees,
starting fires and laying down roads. The more intense their work, the easier they are to notice.
An expanding technological civilization would probably
be hard to miss. Our telescopes would pick up all that energy and
we would clearly identify artificial interference with stars and planets.
Another consequence of this business is that it is very disruptive to the environment.
Clearing a forest means the end of its wildlife. Human activity has left no chance for a squirrel
civilization to appear. Not because we hated squirrels, it’s simply that the thought that
they might want to do that at some point never crossed our minds and we needed wood.
Similarly, if Loud civilizations were running around the galaxy in the past,
terraforming planets or harvesting the energy of stars, they may have prevented our existence.
Had aliens started colonising earth while we were still sludge in the oceans,
that sludge would never have turned into humans. This is how loud aliens create a
deadline for new civilizations appearing. The galaxy may have trillions of years
to create life, but there may only be a short window for it to spread and thrive.
Even if a loud civilization respects planets with naturally-occuring life and expands around them,
like humans do with wildlife reserves – any civilization on such a planet
would not be able to expand, ever. Trapped forever on a tiny island.
But here we are, so Loud aliens were probably never here.
What about aliens that don’t expand? They would be ‘Quiet’ aliens. They’re probably limited to one
star system and don’t have a noticeable impact on their cosmic surroundings. Humanity is like
this right now. We wouldn’t be able to detect ourselves from the other side of the Milky Way.
If they stay quiet forever, maybe because of their culture or abilities,
then they are not really a concern for us.
We only have one sample to draw from: Humanity, and right now we are on the path to becoming loud.
If we are not special, and succeed anyway, then any other civilization
with the motivation and resources to would eventually expand beyond its planet of origin.
Ok, what is the consequence of all these assumptions and ideas?
Grave consequences: Race to the Stars
If we are really early, then eventually, others will catch up with us. Civilizations will emerge
all over the place. And these new aliens will look at space, see no signs of life and come
to the same conclusion: they exist because Loud civilizations have not yet taken over everything,
but it only takes one Loud civilization to crowd them out of the entire galaxy.
They, like us, will face an important decision: do they stay Quiet, take it easy and tend to
their planet for as long as possible, or do they start expanding to take a chunk of the galaxy,
before someone else arrives? Meeting others does not necessarily mean war or conflict. But
it means that new borders will arise, limits that may persist forever. In the worst case,
a civilization could be completely enveloped by the empires of others,
eternally doomed to be a galactic backwater, without control over their fate.
So if we want a seat at the galactic adults’ table,
we best get to work. If we really are early, we have an incredible opportunity. To mold thousands
or even millions of planets according to our vision and dreams. And one day,
when we meet others, we can greet them and meet them as equals. Wouldn’t that be nice?
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