how to move the sun stellar engine nothing in the universe is static welcome back so before we get
into it the daily dance is live so it's basically just breaking down the latest in science and
business each and every day with some memes and humor in there to keep it fun and it's very short
so you can keep up to date very easily you know become smarter in a flash so if i didn't say it
before that daily dance newsletter is completely free in the milky way billions of stars orbit the
galactic centre some like our sun are pretty consistent keeping a distance of around 30
000 light years from the galactic centre completing an orbit every 230 million years
this dance is not an orderly valley more like a skating rink filled with drunk toddlers this chaos
makes the galaxy dangerous solar neighborhood is constantly changing
with stars moving hundreds of kilometers every second only the vast distances between objects
protect us from the dangers out there but we might get unlucky in the future at some point
this theme playing in the background is totally inspired by uh the good the bad the ugly theme
could you guys hear it if you haven't seen that movie by the way that is like one of
my all-time favorite movies it is so good we could encounter a star going supernova or a
massive object passing by and showering earth with asteroids if something like this were to happen
we would likely know thousands if not millions of years in advance but we still couldn't i mean
the millions of years one's a bit debatable um like sure we know andromeda is gonna you know
and the milky way are gonna literally collide but that'll likely result in you know nothing
no stars colliding so everything's so far apart um so the millions of years one is like galaxy's
only a hundred thousand light years across so don't really need to worry about do much about
it not like we're gonna be around we move our whole solar system out of the way
to move the solar system we need a stellar engine a mega structure used to steer a star through the
galaxy it's the kind of thing that might be built by an advanced civilization with dyson sphere
level technology that's thinking about their future millions of this would be a pretty easy way
to find aliens right we should be able to detect any uh stellar movement that doesn't look too
you know natural years ahead of time but how do we possibly move the hundreds of thousands of objects
in the solar system the good news is we can ignore all of that we only need to move the sun all the
other stuff is glued to it by gravity and we'll follow it wherever it decides to go there are
lots of ideas about what a stellar engine might look like and how it would work we've picked two
grounded in our current understanding of physics that could be built in theory the simplest kind
of stellar engine is the shut-off thruster a giant mirror it works on the same principle as a rocket
like rocket fuel the photons released as solar radiation carry momentum not a lot but a bit
for example if an astronaut turned on a flashlight in space it would push them backwards very very
slowly a stellar engine will work a little better than a flashlight because the sun produces a lot
of photons the basic idea of the shut-off thruster is to reflect up to half of the solar radiation to
create thrust and slowly push the sun where we want it to go in order for the shut-off thruster
to work it must be kept in the same place not orbiting the sun although the sun's gravity will
try to pull us in it would be supported just keep thinking like mexican standoff in the solar system
because of this theme playing in the background by radiation pressure which props the mirror up
this means the mirror would have to be very light made of micron thin reflecting foil
from materials like aluminium alloys the mirror's shape is important too just keep in mind
if you talked to people like three thousand five thousand years ago about you know geosynchronous
satellites in orbit or altering the earth's atmosphere so much so that the climate changes
or even talking about like redirecting rivers or drying up whole lakes running out of oil that
would be crazy and it would be um fathomable for these people but it only took us like 100 years
satellites it only took decades so you know if you give us a billion years maybe we could do this
maybe it's not that crazy enveloping the sun in a giant spherical shell wouldn't work because that
would refocus light back to the sun heating it up and creating all sorts of unpleasant problems
instead we use a parabola which sends most of the photons around the sun and in the same direction
which maximizes thrust to prevent accidentally burning or freezing earth with too much or too
little sunlight the only safe place to build a shkadov thruster is over the sun's poles
this means we can only move the sun vertically in the plane of the solar system
and one direction in the milky way which limits our travel options a bit but that is basically it
for a civilization capable of building a dyson sphere this is a relatively simple endeavor
not complicated just very hard to build at full throttle the solar system could probably be moved
by about a hundred light years over 230 million years over a few billion years it gives us near
complete control over the sun's orbit in the galaxy but in the short term this might not
be fast enough to dodge a deadly supernova that's why we thought we could do better
so we asked our astrophysicist friend if he could design a faster stellar engine for this video
he did and wrote a paper about it that's been published in a peer-reviewed journal you can
find it in our sources document we're going to call our new stellar engine the kaplan thruster
it works a lot like a traditional rocket shoot exhaust one way to push yourself the other
it's a large space station platform powered by a dyson sphere that gathers matter from the sun to
power nuclear fusion it shoots out a very fast jet of particles at nearly one percent the speed of
light out of the solar system a second jet pushes the sun along like a tugboat the kaplan thruster
requires a lot of fuel millions of tons per second to gather this fuel our thruster uses very large
electromagnetic fields to funnel hydrogen and helium from the solar wind into the engine
the solar wind alone doesn't provide enough fuel though and that's where the dyson sphere
comes in using its power sunlight can be refocused to the surface of the sun
this heats small regions to extreme temperatures lifting billions of tons of mass off the sun this
mass can be collected and separated into hydrogen and helium the helium is burned explosively in
thermonuclear fusion reactors a jet of radioactive oxygen at a temperature of nearly a billion
degrees is expelled and becomes our primary source of propulsion from our stellar engine
to prevent the engine from just crashing into the sun it needs to balance itself you could
even use planet hunting telescopes like kepler to look for really weird light signatures that
are potentially coming from these thrusters uh it sounds crazy but you know any way we can
like something like this to look for advanced species out there i think is a good idea and
something we should actually do if if you know if something's not prohibited by the laws of physics
we should definitely look further into it to do this we accelerate the collected hydrogen with
electromagnetic fields using particle accelerators and shoot a jet back at the sun this balances the
thruster and transfers the thrust of our engine back to the sun in as little as a million years
this engine can move the sun by 50 light years more than enough to dodge a supernova
at full throttle the solar system can be completely redirected in its galactic orbit
in 10 million years but wait won't we use up the sun this way fortunately
the sun is so massive that even billions of tons of material will barely scratch the surface
in fact this megastructure will actually extend our sun's life since lower mass stars burn slower
keeping the solar system inhabitable for many more billions of years with a kaplan thruster we could
turn the entire solar system into our spaceship for example by orbiting backwards in the galaxy
and colonizing hundreds or thousands of stars as we pass by them it may even be possible to
escape the galaxy entirely and stellar engines are the kind of machines built by civilizations
thinking not in terms of years or decades but eons since we know that our sun will die one day
a stellar engine could allow the far future descendants of humans to travel to other
stars without ever having to venture into the terrifying dark abyss of interstellar space
until we build a stellar engine we're adrift and subject to the whims of the galactic sea
we may not like where it leads us maybe our descendants will set sail and become an
interstellar species for millions of years to come i kept bringing up that mexican standoff and
the theme in the background i was just imagining like you know three stars that have this sort of
drive and they've you know arrived at each other and it's a mexican standoff
and they're just looking at each other you know and waiting to see which one fires at which one
it's such a mathematically interesting problem the
mexican standoff because it's like you have to decide which person you're going to shoot
and you know then the other one will see that you've shot that one so i shoot you
and i survive such an interesting problem to figure out um but i was imagining the sci-fi story
to that and that would actually be kind of fun wouldn't it like these three advanced alien
species and you know they're just in this mexican standoff and they don't know who to shoot first
because they want to survive right imagine they've got these giant you know mega laser
sun things that uh can just destroy a death star if you will but a star version so how realistic
is this kaplan thrust stump well clearly the math that works out they just said a dude wrote a paper
on it which is awesome by the way you know we wouldn't be able to do that today but i think that
sounds theoretically reasonable but there is massive problems with it it's very interesting how
he's going to shoot a giant whatever he's shooting into the sun you know that could cause some
significant problems to say the least uh and then you'd want to be careful as well where he's uh
firing that other thruster i wonder if he calculated how big the jet coming out the back
would be because it could actually be quite enormous um so i wonder this is such an
interesting question i love it i think this is a great idea if we were to venture too close
to other star systems that would be a very bad day for our solar system like a massive problem
even going slightly closer would be a massive problem you know the gravitational influence of
that other star would be a problem for our system uh you know there was a recent study that showed
if another star come too close you would only have to move neptune's orbit like a very insignificant
amount i think it was like zero point two or maybe even two that was like zero point two percent i
think um and that could result in mercury being flung out of our system ejected or you know the
big uh ice giants or gas giants are basically basically our solar system collapsing okay so
you can see the tiny perturbations that you know would result in catastrophe for our system and
you might then say well if we're capable of building this huge engine that can move this
stuff the sun surely we'd be out of you know put those devices around the planets to keep them in
uh motion and yeah i guess you could but this is all starting to sound very difficult um not
saying impossible but obviously moving planets is a lot going to be a lot easier than moving the sun
it would be very very difficult i'm i think if you're gonna do this you have to put thrusters
around the planets because yeah if you've got no control over the direction you're traveling
with your thruster you would need to otherwise your solar system probably going to collapse
or eject some planets and wreak all kinds of havoc and because our earth is in a very delicate place
uh you know in the habitable zone where liquid water can exist you know you go a little bit
further this way a little bit further that way outwards uh you know it's a really bad time for us
so then you'd have to consider contingency plans for that as well so all kinds of problems
and things you'd actually have to consider just because the engine works
mathematically doesn't mean it's very practical so keep that in mind
you know physicists forget that a lot because we just care about if the math checks out yeah cool
but i think it's definitely a possibility so we should definitely look at other star systems uh
with our telescopes to see if this is actually happening out there because it could be a way to
find aliens you know all we have to do is kind of look if there's any some kind of artificial
movement of stars having these engines these huge you know man-made things around the sun
they'll probably get destroyed fairly easily depending on where you put them around the
sun because you know our sun flares a lot around the equator so i guess you could just not put it
around the equator so you know because cmes and solar flare cms coronal mass ejections
literally shooting off mata from the sun uh that's gonna yeah really be a bad day for your engine
so i guess you could say okay let's put it around the pole poles and things like that
but messing with the magnetic field of the sun which we really don't understand where how it's
produced where it comes from it's on this weird 11-year cycle we don't even understand and this
11-year cycle just seems to be able to just stop occasionally um you know in the last 300 years
we've been so confused because there's there's periods where it just stops for like 75 years and
we don't understand this and we recently observed it in another star anyway so you put this engine
around the poles that'll do for today's video guys make sure you subscribe i'll catch you next time