what's going on guys welcome back so we're going to watch some more kurzgesagt
and tonight there's actually going to be two videos hopefully so look out for that
one it's just going to be like a daily dance uh video breaking down you know the news from
the newsletters and then after that releases it'll be like once a night um so anyway you should go
sign up for that because it's free breaks down all the latest science every single day so yeah come
get involved we'll talk about kelsoon uh still not there the alpha but i'll talk about it more
when it's ready anyway let's watch some curves gaza human history is told by the energy we use
at first we had to use our muscles then we learned to control fire we industrialized
the world using coal and oil and entered the atomic age when we learned how to split a nucleus
at each step we increased our energy harvest to a scale never seen before and advanced as a species
currently we're slowly transitioning to renewables and if we're lucky fusion
energy will become viable in the future as humanity progresses further if we don't
destroy ourselves or our habitat we will likely gain complete control of our planet's resources
at that stage we'll probably begin to look outwards for new places to expand into
but space is hard and establishing a serious human presence in the solar system will require ungodly
amounts of energy luckily we know where to find it the sun the ultimate source of energy a furnace
100 quintillion times more powerful than our most efficient nuclear reactor it shines with the
energy of a trillion nuclear bombs per second so how do we get this energy not some of it all of it
if we want to collect the most energy physically possible we'll have to build the largest most
ambitious structure in the universe the dyson sphere aim that's not true so if you've watched
other videos there's actually uh more hypothetical and theoretical ways of collecting more energy
than this uh particularly if you had a you know a super massive black hole with some advanced
technology you could capture even more energy but you know you should go check out what was it
the black hole engine video i can't remember mega structure that encompasses a whole star to capture
its power output for an intelligent species building a dyson sphere is a technological leap
on a par with the discovery of fire the transition from a planetary species to an interstellar
species it would usher in an age of exploration and expansion on a scale we can barely imagine so
what would it look like with all the telescopes we have uh you know including gaia they have we
have the technology that's in principle capable of detecting dyson spheres that are out you know like
a few thousand light years away and that assumes they're at the same distance of a sun-like star
that earth is from ours right a red dwarf star though would be visible to guys eyes with a
smaller dyson sphere out to like 100 light years but a giant or supergiant star would actually
probably be visible from almost anywhere in the galaxy and with like 1.7 billion objects surveyed
in the latest data release of gaiam we could see dyson spheres that are under construction
you know you could correlate with other infrared observatories you could even maybe find completed
dyson spheres that you know that are radiating enough energy but you know at the right now uh
with the full amount of data kind of indicates exactly zero tyson spheres in the milky way which
is a little bit depressing but that doesn't mean that they aren't out there just means that you
know they're out there we haven't seen them yet and these dyson spheres could exist at greater
distances or around smaller lower energy stars or have larger diameters uh you know then guy is
capable of detecting and there are future infrared observatories uh coming that will be atom you know
detect them out at even bigger distances so that's exciting and uh there's been some calculations
like with our observations that we've already made we can do it a statistical calculation that less
than three percent of habitable planets orbit stars that eventually turn into white dwarfs
build a dyson sphere around them granted you know current estimates put the number of habitable
planets around g-type stars that might ultimately evolve into white dwarfs at like 300 million
so they could still be upward of nine million civilizations that have built a dyson sphere
around their white dwarf home style if there are any out them they will be found eventually
and the people who find them are gonna go down in history for making you know probably the biggest
discovery in the history of humanity so if you're interested in claiming that accolade for yourself
you know i would recommend looking around white dwarfs solid shell enveloping the sun
is probably not the way to go a large rigid body like that would be vulnerable to impacts
possibly shattering it would be liable to drift and could crash straight into the sun
a more viable design for a dyson sphere might be a dyson swarm an enormous set of orbiting panels
that collect the sun's power and beam it elsewhere such a swarm would give humanity basically
unlimited energy but building it won't be easy the sun is very big so we need a lot of satellites
if each satellite is a square kilometer we'd need around 30 quadrillion to surround the sun even if
they're built as lightly as possible we need about 100 quintillion tons of material and then we need
the energy to actually put the parts together and deliver them to their positions around the sun
on top of all that we need to have a infrastructure set up in space to start building
let's assume for the purposes of this video that our descendants will take care of that
and want to create the megastructure we can sort the challenges into three main categories
materials design and energy to get the vast amounts of raw materials required for our dyson
swarm will have to largely disassemble a whole planet of the planets available mercury is the
best candidate it's the closest to the sun and very metal ridge so this idea of a dyson swarm
sort of thing i believe it was actually proposed by a guy called george zworski i think that's how
you pronounce it george so georgie boy actually did a bunch of numbers uh for this project as well
to dismantle mercury uh build this dyson swarm it's pretty interesting you should go check it out
um but he calculated we might be able to do this within like the next 25 to 50 years which is a
you know i have a problem with that so let's maybe talk about this like theoretically this
is completely possible for sure but uh there's still some practical things we should talk about
which i don't think make a lot of sense uh like some technological hurdles which i'm not sure
how we're going to overcome just yet close to the sun also means less moving stuff around
and mercury has no atmosphere and only about a third of the surface gravity of earth making it
comparatively easy to launch material into space next we should consider the design of our swarm
remember one of the key pieces of vorsky's plan is that we mine mercury to the point where there
isn't like any mercury anymore right in like 40 years and we aren't even close to developing the
technology to do this yet like one of the deepest minds on earth the gold mine in south africa is
at its deepest point only about 2.1 miles below the earth's surface and it took 15 years to get
there from 1981 to like 1996 and that was with a significant amount of drilling and manpower
so we have to presume that mercury is intended to be mined by robotic probes self-replicating probes
obviously would be most efficient but we don't have these you know much less self-replicating
ones so they're probably a few decades off from developing those so just a mind we have to develop
technologies to mine orders of magnitude more quickly than currently exist and with autonomous
robots that are you know capable of self-replication from scratch which
would have to be by i guess smelting metals and fabricating the other materials necessary
from those raw materials of mercury and not just robots replicating but the the robots will also
have to be able to like autonomously replicate from scratch and not just robot replication
you'll actually the robots will also have to be able to basically autonomously fabricate
from scratch again the solar collectors needed to like bootstrap the energy to keep mining mercury
so i don't think this is going to happen in 25 years i'm hesitant to say they won't exist in 50
i mean like the easy part of this is developing autonomous mining robots that can like fly around
in space without getting their circuits fried by the you know the close proximity to solar
radiation the rest of it much harder and last we need the energy to build and launch the swarm
itself taking apart a planet and launching things into space requires an enormous amount of energy
for example if we used all the fossil fuels and uranium on earth and we were perfectly efficient
we could only launch as much mass as mount everest into space a rather meager accomplishment compared
to planet trees that's a pretty cool calculation to get the energy needed to build a dyson sphere
it's almost as if you're going to need the power output of a dyson sphere but that's okay there's
plenty of sunlight to be had on mercury so let's get to work humans are expensive to keep alive
and are very sensitive to the environment so we'd want to automate as much as possible
ideally we'd have a small crew of controllers who oversee an army of autonomous machines
doing the actual work there are four major pieces of technology required
solar collectors miners refiners and launch equipment the solar collectors are going to
give us the energy we need to disassemble the planet to start maybe we deploy something like
one square kilometer of them either as mirrors or as traditional solar panels
they'll provide the energy to run our miners which strip mine the surface of the planet
and our refiners which extract valuable elements and fabricate them into our swarm satellites
to get them into space we need a creative and efficient solution they've really thought about
this rockets are too expensive and difficult to de-orbit and reuse instead we'll want to use a
sort of railgun a long electromagnetic track which launches our satellites at high speeds our swarm
satellites will be packed tightly i remember doing a calculation about a railgun from halo
you should go check out that halo video unfurling like an enormous origami once in orbit from this
point we can take advantage of exponential growth using the energy of the existing parts
of the swarm to build more infrastructure on mercury and launch new panels faster and faster
each panel provides the energy to build another those two work together to build the next two
four become eight eight becomes sixteen and so on within just about sixty doubling times the sun
would be completely surrounded by solar panels and this can happen quickly if a square kilometer of
solar collectors takes a month to build we could be done in a decade if only our infrastructure on
the planet's surface can keep up with the quickly growing budget of energy even simpler is better
conventional solar panels are far too intricate and short-lived our satellites need to operate
without repairs or intervention for astronomically long times and they need to be cheap to produce
they're most likely going to be enormous mirrors which refocus sunlight to central collecting
stations like in concentrated solar power on earth to build and launch them efficiently
they must be incredibly light made of little more than polished metal foil
bound to some support another interesting question to consider is what happens to mercury's debris
like volsky assumes that like 51 of the mass of mercury is usable for building this dyson
swarm thing what about the 49 that's left over basically it becomes an asteroid belt and sure
the robots might pulverize the debris but even small debris moving at the high speeds that have
orbiting the sun would probably you know pose a pretty bad threat to uh the first stages of
the dyson swarm so let's assume that the solar collectors are made of like crystal and silicon
the threat posed by these would still be pretty substantial like to avoid them you'd have to equip
each one with thrusters you know a computer and sensors so they can like move to avoid
the debris right and suddenly you've increased the complexity of this swarm by huge amount as
well as made each like thing uh less efficient since you're going to lose energy every time
one of them has to move which would be quite a lot because like 1.6 times 10 to the 23
kilograms of space debris floating around you know that's that's a lot of energy uh to move at all
collecting one percent of the sun's energy is an unbelievable change in our species energy budget
we could create the infrastructure to beam basically unlimited amounts of energy around the
solar system for all sorts of projects colonies on other worlds terraforming planets constructing
more megastructures or even traveling to other stars so the wireless transmission of this
electricity is possible but like the doing of it is really complicated
there's basically two ways you could you could beam power to earth right the first is through
microwaves and the second is probably like three lasers so you know this poses some interesting
problems like microwaves are probably the best way to do this but right now the furthest that
scientists have been able to transmit electricity via microwaves is like 148 kilometers and the
majority of that electricity was pretty much lost in transmission the team behind this tech
actually estimated that its maximum efficiency is about 64 and that's over 142 kilometers
meaning it's going to take several centuries to like get back the energy of building the sphere
uh you know electricity beam from space obviously has to travel further distances
lasers are another possibility but they're even less efficient than microwaves and the current
record for transmitting electricity via laser is like one kilometer so you know a few decades
off from being able to do that in earth's orbit much less um you know mercury's but i heard uh
starlink is going to be doing this with uh i mean elon was going to be doing this for starlight so
that's interesting it could be the start of an interstellar civilization based on physics alone
this is not just possible but easy it's such a simple process and such a necessary step for
any species to expand beyond their home planet that many astronomers think there are probably
dyson spheres already out there in the milky way we haven't spotted any yet but they could
be there a dyson sphere would be undetectable to visible light telescopes since these spheres would
completely block the star's light right but even like a highly reflective surface absorbs you know
some energy and if you absorb energy over time you actually have to re-radiate it away in order
to maintain a stable temperature and that means that this energy has to go out into the universe
even if there's no visible light so like earth at night it radiates energy away in the infrared
just like one of these dyson spheres would do so you could detect these dyson spheres with infrared
telescopes like gaia and then there's also another way um like when you draw an inference about
distance based on the light that you observe and then make a measurement in a completely different
way like you know by geometry those two figures actually have to line up and the fact that gaia
has seen a few misalignments actually could indicate that we've seen an alien megastructure
um you know it's only human nature for our minds to kind of jump straight towards the most crazy
explanation the most reasonable you know is that these interesting objects are probably just not
single stars they might have like a unseen binary companion which is super common in our universe
and the fact that there's no excess infrared radiation uh which is a requirement of dyson type
structures probably points away from the you know megastructure hypothesis just remember the absence
of evidence is not evidence of absence it just helps to constrain the likelihood it's far from
certain that humanity will ever get to this point our attention is too often focused on short-term
political gains and conflicts that will not matter in the long run but if we survive the challenges
we've set ourselves we could potentially become the first species in the universe to create a
structure with the scope of a star if we do it the only limitation left will be our own imagination
cool video so basically a dyson swarm isn't worth building just yet because there's really no way
we'd be able to start it it may be 25 even to 50 even if it was worth building but uh
you know who knows maybe in 50 years it will be or even earlier 25 maybe it will be possible to start
this with the rate of which we're going you know it actually might be possible so i'm not going to
say it's impossible i'm just giving you some you know hurdles we're going to have to overcome if we
want to build one of these things you should also check out that trailer for that uh orbital movie
which was literally created by a youtuber it looks great it's about like some megastructure
around like an earth-like planet so i just want to shout out another fellow youtuber should go check
the trailer out you have talked about how our civilizations might actually be able to harvest
energy from black holes you know with some kind of dyson sphere construction so if you want to hear
about that you should definitely go check out the black hole videos we've watched of cursed gazettes
because i'm pretty sure we talk about them in most all right that'll do catch you next time