An observable universe is a big place
that's been around for more than 13 billion years. Up to two trillion galaxies made up of
something like 20,000 billion billion stars surround our home galaxy. In the Milky Way alone, scientists assume there are some
40 billion earth-like planets in the habitable zone of their stars. When we look at these numbers, it's hard to imagine
that there is nobody else out there. It would change our perception of ourselves forever
if we found others. Just knowing that this vast place is not dead
would shift our perspective outward, and could help us get over
our irrelevant quarrels. But before looking for our
new best friends, or worst enemies, we have a problem to solve:
What are we actually looking for? [Kurzgesagt intro] In a universe that big and old, we have to assume that civilizations
start millions of years apart from eachother, and develop in different directions and speeds. So not only are we looking over distances of
dozens to hundreds of thousands of light years, we're looking for a civilization
ranging from cavemen to super advanced. So, we need a conceptual framework
to enable us to think better thoughts that make us able to search better. Are there universal rules that
intelligent species follow? Currently our civilization sample size is only one, so we may make incorrect assumptions
based solely on ourselves. Still, better than nothing. We know that humans started out with nothing
but minds and hands that could build tools. We know that humans are curious, competitive,
greedy for resources, and expansionist. The more of these qualities our ancestors had, the more successful they were
in the civilization building game. Being one with nature is nice, but it's not the path
to irrigation systems, or gunpowder, or cities. So it's reasonable to assume that aliens able to
take over their home planet also have these qualities. And, if aliens have to follow
the same laws of physics, then there is a measurable metric for progress:
Energy use. Human progress can be measured very precisely
by how much energy we extracted from our environment, and how we made it
usable to do things. We started with muscles,
until we learned to control fire. Then we made machines that
used kinetic energy from water and wind. As our machines got better
and our knowledge of materials expanded, we began to harness the concentrated energy
from dead plants we dug up from the ground. As our energy consumption grew exponentially,
so did the abilities of our civilization. Between 1800 and 2015,
population size had increased sevenfold, while humanity was consuming
25 times more energy. It's likely that this process
will continue into the far future. Based on these facts, scientist Nikolai Kardashev
developed a method of categorizing civilizations, from cave dwellers to gods ruling over galaxies: The Kardashev Scale;
a method of ranking civilizations by their energy use. The scale has been refined and
expanded on over the decades, but in general it puts civilizations
into four different categories. A Type 1 civilization is able to use the
available energy of their home planet. A Type 2 civilization is able to use the
available energy of their star and planetary system. A Type 3 civilization is able to use the
available energy of their galaxy. A Type 4 civilization is able to use the
available energy of multiple galaxies. These levels differ by orders of magnitude. It's like comparing an ant colony
to a human metropolitan area. To, ants we are so complex and powerful,
we might as well be gods. So to make the scale more useful,
we need subcategories. On the lower end of the spectrum,
there are Type 0 to Type 1 civilizations: Anything from hunter-gatherers, to something
we could achieve in the next few hundred years. These might actually be
abundant in the Milky Way. But a civilization that is not
actively transmitting radio signals into space might be as close as our nearest stellar neighbor,
the Alpha Centauri system, and we would have no way of
realizing they exist. But even if they transmitted radio signals
like we do, it might not be very helpful. On an interstellar scale,
humanity is practically invisible. Our signals may extend over
an impressive 200 light years, but this is only a tiny fraction
of the Milky Way. And even if someone were listening, after a few light years
our signals decay into noise, impossible to identify as
the source of an intelligent species. Today, humanity ranks at about level 0.75. We have altered our planet: we've created huge structures,
mined and stripped mountains, removed rainforests, and drained swamps. We've created rivers and lakes, and changed the composition and temperature
of the atmosphere. If progress continues,
and we don't make Earth uninhabitable, we will become a full Type 1 civilization
in the next few hundred years. Any civilization that becomes a Type 1
is bound to look outside, because it's likely that it's still curious,
competitive, greedy and expansionist. The next reasonable step towards transitioning to Type 2
is trying to alter and mine other planets and bodies. This might start with outposts in space,
transition to infrastructure and industries near the home planet, move on to colonies,
and end with terraforming other planets, by changing their atmosphere,
their rotation, or position. As a civilization expands and
uses more and more stuff and space, its energy consumption scales with them, so at some point, they may embark on the largest project
a lower Type 2 civilization can take on: harnessing the energy of their star
by building a Dyson Swarm. Once this megastructure is finished, energy has become practically unlimited
for molding the home system however they see fit. If they are still curious, competitive,
greedy and expansionist, and now have complete control
over their home system, stellar infrastructure in place,
and the energy output of a star, the next frontier moves to
other stars light years away. For a Type 2 civilization, the distance to other stars might feel like
the distance between Earth and Pluto does to us today: Technically within reach, but only with immense investments
in terms of time, ingenuity, and resources. This begins their transition
towards Type 3. This step is so far beyond us that it becomes hard to imagine
what exactly these challenges will look like, and how they'll be solved. Will they be able to find a solution
to the vast distances and travel times of
hundreds or thousands of years? Will they be able to communicate and keep a shared
culture and biology between colonies light years apart? Or will they split into
separate Type 2 civilizations? Maybe even different species? Are there deadly challenges between the stars? So the closer a species gets to Type 3, the harder it becomes to fathom
what it might actually look like. They might discover new physics,
may understand and control dark matter and energy, or be able to travel faster than light. We might be unable to grasp their
motives, technology, and actions. Humans are the ants, trying to
understand the galactic metropolitan area. A high Type 2 civilization might already consider
humanity too primitive to even talk to. A Type 3 civilization might feel about
as like we feel about the bacteria living on the anthill. Maybe they wouldn't even consider us conscious,
or our survival relevant. We could only pray that they're nice gods. But the scale doesn't necessarily end here. Some scientists suggest there might be
Type 4 and Type 5 civilizations, whose influence stretches over
galaxy clusters or superclusters, structures comprising thousands of galaxies
and trillions of stars. Ultimately, there might be
a Type Omega civilization, able to manipulate the entire universe,
and possibly others. Type omega civilizations might be
the actual creators of our universe, for reasons beyond our comprehension. Maybe they were just bored. As flawed as this classification may be, this thought experiment is
already telling us interesting things. If our ideas about the nature of species that
form interstellar civilizations is sort of correct, then we can be pretty sure that there are
no civilizations of Type 3 and beyond near the Milky Way. Their influence would in all likelihood
be so all-encompassing, and their technology so far above our own,
that we couldn't miss them. The galaxy should flash with their activity
in thousands of star systems. We should be able to see or detect their artifacts or movements
between different parts of their empire. Even if a Type 3 civilization did exist in the past,
and died a mysterious death, we should be able to detect
some of the remnants of their empire. But when scientists looked,
they didn't find remnants of harvested stars, decaying megastructures
or scars of great interstellar wars. So they're very likely not out there
and never were. In a sense, this is very sad,
but also very reassuring. It leaves the galaxy to us and
others similar to us. So the most promising civilizations to look for may be
somewhere in the spectrum from Type 1.5 to Type 2.5. They wouldn't be too advanced to
understand them and their motives. They may have finished their first megastructures, and they might be in the process of
moving staff between stars, transmitting enormous amounts of information
into space, by accident, or on purpose. They would probably also look to the stars
and look for others. Then again, maybe we've got it all wrong. Maybe progress to Type 2
does not mean expanding outwards, and humanity is still too immature
to imagine otherwise. For now, all we really know is that
we haven't seen anybody yet. But, we've only just started looking. Until we finally find friendly super aliens
and can ask them to explain the rules of the universe to us, most of us have to make do
with learning stuff ourselves. Whether you're going back to school
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HOW TO FIND ALIEN CIVILIZATIONS β THE KARDASHEV SCALE
Description
The observable universe is a big place that has been around for more than 13 billion years. Up to two trillion galaxies made up of something like 20,000 billion billion stars surround our home galaxy. In the milky way alone scientists assume there are some 40 billion earth like planets in the habitable zone of their stars. When we look at these numbers it is hard to imagine that there is nobody else out there.
Sources & further reading: https://sites.google.com/view/sources...
Music in this one was sooo good
Maybe simulations and VR will make expansionist tendencies obsolete. Life inevitably decides to explore the inner space of their minds rather than the outer space of the universe.
E: if you're looking for more of a deep dive -- in a nutsack so to speak -- Issac Arthur's videos are great for this sort of topic...
The Kardashev Scale.
Playlists on things like the fermi paradox and potential alien civilisations.
Repeated topic but I like it cause it makes people think critically and reminds us that our species should work together.
Did not mention great filters - existential crisis averted
Imagine if we found out somehow that our entire universe was created for fun by an omega civilization
Yes!! Iβm really exited about this video because the Kardashev scale is something Iβm interested in and I find it really fascinating, also to think about progressing in this scale, so I always hoped theyβd do a video about it
Hands down best kurzgesagt video. Change my mind
If Earth is in Star Wars, I would see this version that alternative 1960s-1970s Earth in SWTOR era. https://tvtropes.org/pmwiki/pmwiki.php/Fanfic/EarthAForgedDestiny