So today’s topic is wormholes, and we will
be trying to clear away some of the confusion about this idea today and hopefully avoid
adding any more confusion to the mix. This will not be easy since we can’t discuss
general relativity in too much detail. As I mentioned back in episode one of this
series you need an awful lot of math to actually see the genuine explanation for how these
things work, the non-math explanations and analogies you probably already know. If you do have that math background I recommended
Leonard Susskind’s series on general relativity at the start of the Faster Than Light series
and I’ll recommend it again now. Like any of the video links you’ll see today
you can just click on that to pause this video and watch that and come back here and un-pause
this one when you’re done but in this case, since that series is several hours long, I
would suggest finishing this one first. Since we can’t do the math I’m just going
to talk about the types of wormholes, of which again there are a lot, and the various categories
of them, and some lesser known neat things about them. Categorization tends to be arbitrary but here
is our list of topics for today: 1) Basic Concept of Wormholes
2) Non-Traversable Wormholes 3) Traversable Wormholes
4) One-Way Wormholes 5) Two-Way Wormholes
6) Intra-Universe Wormholes 7) Inter-Universe Wormholes
8) Exotic Matter and Wormholes 9) The Casimir Effect
10) Naked Singularities 11) Quantum Entanglement and Wormholes
12) Travel Time in Wormholes 13) Time Travel using Wormholes
14) Other Uses of Wormholes Everybody knows what a wormhole is, in terms
of basic function, it’s a gateway from one place to another. We often represent this in science fiction
as a circular mouthed tunnel that after some time gets you to your destination at the other
end of the tunnel. Incidentally we usually would refer to these
as the mouths and throat. Some wormholes are one way, in which case
only one would technically be a mouth but obviously we are not going to label the other
mouth for a one-way wormhole with the anatomically correct term for that digestive analogy. Now we can’t go into the math of wormholes
but I can answer some of misconceptions and questions that often come from those who don’t
know the math. For instance, we usually represent wormholes
as 2D gates, or mouths, in science fiction but a naturally occurring one ought to be
a sphere, but it doesn’t actually have to be one and a lot of models for making these
things artificially with exotic matter favor the more 2D version as being way cheaper on
exotic matter. We’ve discussed exotic matter before in
this series and we’ll review it later on, but it’s generally required in most wormhole
theories to permit you to use them for travel. Similarly when we show models of these things
where it shows two flat grid planes connected together by a tunnel, the throat, it makes
people wonder if you could exit midway through, but you can’t because there is nothing to
exit through. It’s easier to visualize I think as a balloon
where you’ve poked it with a finger in two separate place and kept pushing till your
fingers met. Only that’s still basically 2D and you can
imagine sneaking outside the rubber, same as you picture the entrances to each end of
the tunnel as 2D. There’s nothing to sneak outside to though. These aren’t subways tunnels or elevators
cutting through space time where you watch them whiz by faster than light on some straight
line between the two mouths. The throat of a typical spherical wormhole
in a black hole example is actually a sphere of space inside the event horizon. So a wormhole does actually take time to traverse. They’re not instant and we’ll look at
that more later. Sometimes conceptually it is easier to think
of the black hole variety as more like the layers of our planet, crust, mantle, and inner
and outer core. The crust being the event horizon, and the
mantle a vortex like region the way down, the throat would then be the outer core and
the ‘narrowest part’ would be the shell at the edge of the inner and outer core, your
ship can’t be bigger than that. And not all wormholes have to have a single
tunnel either, some versions allow multiple exits and for that matter one of the newer
theories regarding hawking radiation is that it gets out by lots of individual wormholes. Later on we’ll look at a new theory of growing
popularity that contemplates the idea that particles that are entangled with each other
might be connected by tiny wormholes. Wormholes also don’t have to be the same
size, no more than the mouths of a classic tunnel have to be. But you can only send something through that’s
smaller than throat, or it will be ripped apart, same as a train slamming through a
tunnel that suddenly narrows, it’s just more 3-Dimensional rather than the long chain
a train can be since only its cross-section matters for passage. You also can’t stick anything through a
wormhole that is as massive, or more massive, than it is or you’re going to destabilize
it. Destabilize in this context would usually
mean releasing the majority of the wormhole’s mass outward while a smaller portion collapses
inward… which is essentially a supernova. Obviously if the wormhole weren’t very massive
this wouldn’t be as bad but unless we were talking about some of the ultra-tiny kinds
of wormholes you might use for just sending signals or tiny fast streams of matter you
wouldn’t want to be in the same solar system when one exploded…
… you wouldn’t want to be near the smaller one either but at least there we’re talking
booms of the non-planet destroying variety. Now there’s tons of types of hypothetical
wormholes and quite a few of the naturally occurring versions are ridiculously tiny and
hanging out in the quantum foam, often the idea is to take one of those and expand it,
or that they might have naturally expanded as the Universe expanded. We’ll talk about that a bit more when we
get to the Casimir Effect later on. Before we move into our second topic though,
let me just make one point. Wormholes are incredibly theoretical, and
there are tons of different models. So a lot of times you’ll get stuff about
their behavior that sounds very contradictory and that’s because it usually is. Each model is different. We’ll be sticking to the ones that decently
follow from general relativity today. You can go nuts trying to keep them all separate
and unfortunately a lot of folks I know with intermediate knowledge on this tend to make
the mistake of locking down on just one version and tend to be guilty of saying “No that’s
not how it works.” When there’s actually plenty of models where
that is how it works. Okay so topic 2. Non-Traversable Wormholes. This is pretty straightforward conceptually,
it’s a type of wormhole you can’t pass through, either because the throat collapses
before you get through or from a more practical standpoint one that would just kill you trying
to make the passage. This arguably includes any wormhole with an
event horizon and basically any black hole. The original wormhole concept, a Schwarzschild
wormhole or Einstein-Rosen Bridge is one of these and trying to find a wormhole that isn’t
is obviously the goal. Einstein and Rosen were trying to avoid a
mathematical singularity, essentially of a dot like point of infinite density at the
center of a black hole, which these days with better computing power we generally think
is partially wrong anyway, with concepts like Singularity Vortex Sheets, and nobody took
the solutions that spawned the notion in the mid-1930s too serious until John Wheeler screwed
around with it in the Early 60’s and pointed out such a wormhole would collapse almost
instantly. I should probably remind everyone at this
point when we talk about the interiors of black hole and use comments like ‘very quick’
or ‘almost instantly’ that time runs at an absurdly slow rate inside a black hole. Time doesn’t stop when you fall into a black
hole, not past the event horizon anyway, it just keeps getting slower and slower as you
go deeper down. For you, assuming you were falling into one
of the really big ones at the center of many galaxies that don’t have tidal forces so
strong they’d shred every atom of your body before you got inside, you’d fall just like
normal from your perspective, it would be very fast since you’re accelerating fast
but to an outsider, who can’t actually see you anymore, but magically could for our analogy,
your trip would seem to take longer and longer as you fell. So a fast event inside a black hole might
only take a second of internal time but take eons externally. But in a nutshell a non-traversable wormhole
is just that, one you can’t traverse. You can take that very narrowly to mean just
those for which nothing can get through, even a photon or particle, or more widely to mean
one where it would just kill you trying, even if your particles exited the other side. Traversable Wormholes, topic 3, are the ones
you can pass through. Most versions of this involve using exotic
matter to keep the throat open so it doesn’t destabilize and again we’ll look at that
more later. It is usually considered to be a lot of exotic
matter though, the Morris Thorne Wormhole called for about 100 million suns worth of
this stuff we’ve never found a single particle of while the Visser Wormhole only requires
a modest Jupiter-sized amount of it. Incidentally you will sometimes now hear the
Morris-Thorne Wormhole called an Ellis Wormhole, or Ellis drainhole, since more recently it
got noticed H.G. Ellis and K.A. Bronnikov had both independently figured out
the concept in 1973, it’s the same thing in this case so Ellis gets the credit for
first figuring it out. So Kip Thorne loses the credit for discovering
it first but still gets the true accolades because he got the notion of traversable wormholes
back into circulation in the late 80s and shortly after that a lot of other versions
were uncovered from the renewed interest. I’d give a similar credit to Matt Visser
though, as one of those early enthusiast after interest got renewed. Thorne and Visser opened the door that made
it both an interesting and respectable field of speculation and simultaneously opened the
door for an awful lot of wonderful science fiction, including two of my favorites, the
Stargate Franchise and Star Trek Deep Space Nine. I know some folks like to argue the Kirk vs
Picard issue of who was the better captain but for me it always goes to Avery Brooks’s
portrayal of Benjamin Sisko, especially after they let him shave his head and grow a goatee. So with the door open we got a lot of versions
of wormholes that might work in this or that cosmological model including some that didn’t
require much or any mass at all, exotic or mundane. Of course those also broke down into one-way
versus two way wormholes, and raised the question whether they exited into our universe or a
different one. Topics 4 and 5 are pretty straight-forward
then. Some wormholes are one way streets, so if
you wanted to go back you’d need a separate wormhole nearby the first one’s mouths. Stargate went this route though they let you
shut it off and dial back to the original place, or any other destination in the catalog
you had an address for. They also let you send signals both ways and
I never understood the justification for that, beyond the importance of it for plots needing
conversation through the thing by radio. The original basis for that is probably the
idea of black holes connecting to white holes. A white hole is the exact opposite of a black
hole in that you can’t push anything inside, whereas in a black hole you can’t push anything
outside. The original concept for this out of the Einstein
Field Equations was that a black hole was a future state and a white hole emerged from
that same black hole in the past, this is just one of the many time travel things that
comes up with wormholes as a concept which we’ll discuss later on too. Those versions did actually attract matter
just like normal but nothing could actually get in past the event horizon. It was also proposed the white holes would
be in another universe, something we’ll get too shortly, or were outright creating
one, acting as a big bang inside the core of the black hole that spawned a whole new
spacetime, a concept you’ll have encountered in many sci-fi stories, and it’s retained
a lot of popularity among physicists too though it’s not the sort of thing you can really
prove. As I recall it first hit popular culture in
the 1979 Disney film The Black Hole, and the year before as a cameo in Hitchhiker’s Guide
to the Galaxy. The idea fell very out of favor after Stephen
Hawking proposed the idea of black holes evaporating rather than being eternal objects. This was actually a few years before those
came out but ideas take a while to percolate. This is the big one-way wormhole option though
since you can’t go into a white hole and you can’t go out of a black hole. Nothing would stop you from making a second
pair near each other and backwards of course, and wormhole networks, especially the Roman
Ring, are something we’ll also get to. Two way wormholes, our fifth topic, simply
includes any you can go both ways through. That probably doesn’t require anymore explanation
since it was the one-way variety that we really needed to talk about. Big thing on these is that you can generally
see them, or see the other side. By default it would look a lot like a warped
snowglobe of what was on the other side. Now topics 6 and 7 are the idea on intra and
inter Universe wormholes. An Intra-Universe Wormhole opens up somewhere
in your own Universe, and thus is handy for travel. The default wormhole of fiction is the Intra-Universe
Two-Way Traversable Wormhole. It has the big advantage of letting you get
around your own Universe quite quickly. It has the big disadvantage of raising the
specter of time travel and the associated paradoxes we discussed back in episode two. More on that later, but this is the ideal
wormhole in most cases. Topic 7, Inter-Universe wormholes, is one
that connects two different universes. This first emerged in regard to white holes
and the original Schwarzschild Wormhole or Einstein-Rosen Bridge. These are generally one-way wormholes too. If you’ve ever seen the 90’s sci-fi shows
Sliders, this is what they were sliding through. I don’t remember what specific handwave
they were using, if any, for why this always opened up on Earth and a close parallel of
our society, rather than randomly dumped into space, or at a Big Bang, but it should be
noted the idea isn’t necessarily confined to the Many Worlds Quantum Interpretation
of Alternate Timelines. It could just be another Universe, totally
unrelated to our own. There are a ton of different multi-verse options
kicking around, much like wormhole theories. I do like this one – and let me emphasize
I like it, not that I think it is firm science – because it is an option for getting out
of a dying universe and one ironically related to where life would probably hang out near
the end. A couple weeks ago we did the Civilizations
at the End of Time first episode on Black Hole Farming and I pointed out two things
there, that once the stars go out your only power source is black holes, and that one
of the ways to tap black holes for power is to leach off their rotational energy until
they stop spinning. Schwarzschild Wormholes, the original one
basically, derive from solving Einstein’s Field Equations for a black hole that is not
charged and is not spinning. Solutions for rotating black holes or charged
black holes or both came later. They also predate the idea of Hawking Radiation
as eternal black holes, and Hawking Radiation remains totally theoretical and has a lot
of critics who still favor the eternal black hole notion, it’s the big strike against
white holes too, and the idea of them opening up into new universes. A civilization looking to tap those black
holes can use the rotational energy to live like kings for a very long time, until the
black hole stops spinning. If it can’t live on the Hawking Radiation
after that, either because there is none or it’s just too low and slow to keep your
civilization together, you will have a non-rotating black hole sitting in front of you. I’ve always thought there was something
poetic about the notion of just jumping in to check first hand if black holes did lead
to other Universes at that point, since you’ve got nothing to lose. Of course you’d have at least a quadrillion
years before you’d need to check that hypothesis. I have a soft spot for suicidally brave actions
too. As a sidenote, folks were asking me after
that video about maintaining those structures for timelines that made a trillion years look
like an eyeblink and as I said at the time I have no idea how anyone would, but something
that came up a lot is proton decay, the idea that even protons might have a half-life. They might, when I was school we thought it
might be 10^30 years, it’s been pushed up to a minimum of 10^34 or 35 years more recently,
but under the Standard Model it doesn’t have a half-life and that’s a prediction
of Grand Unified Theories, particularly SUSY or Super Symmetry, along with magnetic monopoles
which also still haven’t been observed. I don’t think Super Symmetry is dead, even
though it’s been declared that in a lot magazines in the last few years, but it certainly
taken some hard blows from predictions of it not panning out, especially at the Large
Hadron Collider. One the big purposes of the Large Hadron Collider
was to help check super-symmetry but another is to hunt for exotic matter, which leads
us into to topic 8. Now we’ve talked about exotic matter before,
specifically imaginary mass and negative mass. Exotic matter is a fairly loose term, some
would include dark matter as an example but I know some folks who strongly disagree. Presumably because to them exotic means rare,
which dark matter certainly is not, I generally view it as having exotic properties compared
to what we know now. Either way with wormholes it usually means
negative mass, same as when we talked about warp drive last time. The purpose it serves with wormholes is to
make the throat stable so it doesn’t collapse. From a strictly conceptual standpoint you
could think of it as rafter shoring up a tunnel. In practice it’s usually a thick or thin
shell of the stuff down under the throat in the black hole version of the things. It exerts a positive gravitational force,
repulsive rather than attractive, and that can keep the throat open. It’s also the way stable and naturally occurring
wormholes might arise, since naturally occurring exotic matter could have taken primordial
and tiny wormholes and widened them with time. Quite a few physical theories tend to figure
there’s trillions of little wormholes blundering around everywhere. The Morris-Thorne or Ellis Wormhole on the
other hand is huge, in order to use a black hole whose tidal forces wouldn’t shred a
human apart, we talked about that more in the black hole duology of videos, but bigger
black holes are a lot safer to be near ironically. In this case they have a mouth several hundred
astronomical units across, that isn’t arbitrary and was selected specifically for survivable
tidal stresses so you could go a lot smaller but this one needs something like a hundred
million stars worth of exotic matter to hold open. That generally means it’s the sort of thing
you’d build at the center of a galaxies to connect them to other galaxies, or maybe
have a handful in one galaxy at most. The Visser Wormhole on the other hand aims
for a mouth about a meter across and needs a Jupiter mass worth of the stuff. Visser also offered an alternative to ramming
head first into exotic matter which would generally tend to be fatal and possible destabilize
the wormhole too. Visser usually has this as a polyhedron whose
struts are full of the exotic matter instead, so you just go in between them. And again way smaller, just big enough for
a person to squeeze through, but that’s enough. Truth be told that’s a lot more than enough. You could presumably go way smaller, so your
wormhole’s mouth was only big enough to pass a laser beam through and have communications
as a result. That’s in the range of mass where could
conceivably have one orbiting a planet like a communication satellite and doesn’t require
planets worth of mass, exotic and mundane, to build. And from a tranhumanism perspective if you
can send data you can send people. For those of you trying to figure out the
most plausible artificial wormhole route would be, I would say, and just in my opinion, that
Visser’s Polyhderal Wormholes are probably the best. I’ll attach his 1989 paper on it in the
video description, it’s actually only 7 pages long and the math is in there but I
think you can still get a lot out of it even if you can’t follow the math. Now for the longest time exotic matter, and
the unreality of it, was probably the big thing preventing folks from researching wormholes
more, as they appeared to be something that couldn’t be traversed even if you could
somehow survive a trip into a black hole, between the tidal stresses and concerns of
slamming into mass. But there are some artificial ways to arrange
the geometry of mass making singularities like making a spinning ring shaped black hole,
maybe by putting a lot of smaller black holes or neutron stars into Klemperer Rosette. More importantly we have gotten good indicators
that exotic matter, or something with the characteristics of it, might exist somewhere
other than in theoretical models. Which takes us to the Casimir Effect. In the classic example we take two conductive
plates and stick them just a few billionths of a meter apart, and we suck out all the
air in between them and around them so it’s a vacuum. There’s no field so nothing should happen,
but what we observe is the plates feeling some force between them. This can be either attractive or repulsive
depending on how we arrange the plates. Now this wasn’t experimental, Hendrik Casimir
predicted this in 1948. Trying to prove it, trying to make two large
smooth plates barely an atom’s width apart but still not touching, is obviously kind
of tricky. The further the plates are away the weaker
the force should be. It wasn’t until 1997 at Los Alamos someone
managed to pull this off with any real certainty, and actually using a sphere and a plate instead
of two plates, and it got nailed down even better in Italy in 2001. Until then no one was really sure this was
happening, theory no matter how good is always very iffy until you’ve got experimental
data. Now prior to that there were already plenty
of notions for what might cause this mysterious force between the plates but Vaccum Energy
was the one generally considered most interesting. The important thing was that you could generate
a negative pressure. Now a negative pressure is a fairly straightforward
concept, we use lower or higher pressure all the time, heck the whole point of an airplane
wing is to ram through air at say 10 psi pressure and cause most of it to fly under the wing,
increasing the pressure to say 11 psi, and less to go over the wing, at maybe 9 psi,
generating a net upward pressure of 2 psi and keeping the plane from falling out of
the sky. We do the reverse for the spoiler on a car
to push it down so it can maintain contact with the road. But there’s no air, no pressure, in the
chamber with the plates. It’s genuinely negative pressure. A lower pressure than nothing. Well there’s an energy associated to normal
pressure, all those particles flying around whacking things have kinetic energy, temperature,
mass, they have positive energy. So to have negative pressure you need negative
energy. Less than zero. Now negative energy isn’t quite the same
as negative mass but functionally it can probably be used as a substitute and it’s not a bad
indicator that negative mass particles might exist or could be created. Or that those negative matter struts in the
Visser wormhole might simply be charged up with negative energy for instance. Or charged down I suppose. Okay, topic 10, Naked Singularities. One of the problems with black holes of course
is that all the neat stuff is going on beneath the event horizon. A naked singularity doesn’t have this, the
original notion being that if I spun a dense chunk of matter fast enough it would form
into a ring exposing the singularity. This violates the Cosmic Censorship Hypothesis
Roger Penrose came up with in 1969 which argues that if you saw a naked singularity reality
would break down. Well, causality would break down but honestly
that amounts to the same thing. Of course it explicitly excludes the Big Bang,
which gets exempted from a lot of things. I think people forget sometimes there were
some very solid objections to the Big Bang theory when it first got proposed that stuck
around for a long time and its blatant violation of Thermodynamics was just one of them. History often makes out such debates as being
wise visionaries versus stubborn old cranks or irrational lunatics but usually that’s
not how it was. Not that there is ever a shortage of old cranks
and lunatics or a surplus of wise visionaries, they just tend to be more evenly distributed. If Naked Singularities did exist and didn’t
violate causality it would in principle make some types of wormholes a lot easier to make. It’s also an option under Loop Quantum Gravity
which has gotten to be a popular area of research and theory in the last few decades. Topic 11, Quantum Entanglement and Wormholes. Back in episode one I discussed quantum entanglement
and some misconceptions about it, one of the folks commented on me leaving out ER=EPR,
and I told him I was saving it for our look at wormholes. This is one of Leonard Susskind’s more recent
ideas and in a nutshell suggests that entangled particles are actually connected by a non-traversable
wormhole. This doesn’t actually change anything we
discussed in that episode but I wanted to wait till we had discussed traversable versus
non-traversable wormholes to bring it up. Since they’re non-traversable, the ER standing
for Einstein-Rosen bridge which we already mentioned weren’t traversable, you still
can’t use entangled particles to send information faster than light. Personally I love the idea, the notion of
little Planck scale wormholes connecting two entangled particles that breaks when they
cease being entangled is just neat. No idea if it’s true, but it’s gotten
pretty popular and I think it deserves mention. It’s a very elegant solution and I always
like those in science. Topic 12, Time Travel in Wormholes. Not Time travel with wormholes, that in a
bit, but a question that comes up sometimes is how long it takes to travel through one
and if it is instant. It isn’t, though it kind of depends on when
you are officially beginning the wormhole. Wormholes are sometimes classified by basically
how horribly deadly the trip would be and traversable ones are usually labeled as benign,
there’s also ‘absurdly benign, which the Visser wormhole usually qualifies as. In the context of spherically symmetric wormhole
you’ve got to drop down through the mouth, down the throat, and out through the other
mouth. That does take actual time and as I mentioned
earlier your time is very slowed down. It doesn’t really have anything to do with
distance between the two mouths in real space though. I’ve seen some calculations that worked
out to be about second for the absurdly benign and small Visser Wormhole and the better part
of a year for the bigger Thorne or Ellis Wormhole, but I never duplicated them or checked if
that was internal time for the passenger or time passed in the external Universe, again
time slows down inside a black hole, and I suppose it technically wouldn’t matter as
we’ll see in a moment but so much focus is put on using these things as time machines
that very little gets put on the time spent inside one. If it took you centuries for instance, in
external time, to get through one it’s a bit dubious if it’s all that advantageous
to have them for anything not light centuries or further apart. Okay Topic 13, Time Travel and wormholes. We already covered all the weird temporal
paradox stuff back in episode two so I’m just going to explain how that happens with
a wormhole, and why it presumably doesn’t matter how long it takes you to go through
one in external time, just your own subjective scale. As we know from special relativity if I take
an object up to high speeds time slows down for it, so if I take off in spaceship and
fly out at near the speed of light and loop around and come home a century later I might
only have experienced a few years myself. So we make a wormhole, stick one mouth in
orbit around Earth, and fly the other off at relativistic speeds somewhere. The tug ship with its wormhole leaves in say
the year 2200. So far this isn’t a big deal, but as they’re
almost there, traveling at near the speed of light but not quite at it, a message catches
up saying the deal’s off, the colony’s representative on Earth cancelled the order
and to bring it back. Now when they turn around and loop home it’s
been a century back on Earth, it’s the year 2300 but only a few years for them. The clocks at the mouths of the wormhole are
synchronized so at the mouth that stayed at Earth it’s a century forward in time but
on the space ship only a few years have passed. The crew is fine, they haven’t only aged
a few years but they haven’t traveled in time. But when an inspector checking the stabilizing
elements of the wormhole slips and falls through he’s spewed out in the year 2203. Now Hypothetically you could move both ends
of a wormhole to keep them synchronized but the big thing is that one mouth is back in
time from the other if you don’t, so jumping through sends you back in time. This is ultimately the biggest black mark
against wormholes because it seems unavoidable that you could use them as time machines and
the general feeling is that time travel has to be impossible. Of course this only applies to Intra-Universe
Traversable Wormholes, one way or two way. If they exit out into another Universe or
you can’t send information through them then cause and effect, causality, is safe. Though you almost invariably would get mouths
of wormholes that went back in time, this doesn’t necessarily result in violating
causality, it’s when you get them close that it does. For instance if I’ve got one that’s 50
year back in time but 100 light years away a message sent from it, like “Warn President
Kennedy not to go to Texas” still takes 100 years to arrive and thus gets there 50
years later. You have to worry about link ups of many wormholes
though, in what’s called a Roman Ring allowing for causality violations though you can also
avoid them by configuring your ring correctly too. Okay let’s move on to our last topic, other
uses of wormholes, as well as some popular suggested uses that might not work. And if I don’t say otherwise assume I’m
talking about an Intra-Universe Two Way Traversable one. A lot of times with wormholes in fiction someone
will suggest you could make a perpetual motion machine by opening a gate near the ground
and the other end up in the air and just dropping a ball into the lower mouth, it comes out
the top, falls down picking up speed, goes in again and pops back out near the top getting
faster and faster on each drop. Now in practice it actually wouldn’t because
of air friction stopping the acceleration at terminal velocity but you could just put
a water wheel between the two mouths and dump water through, and harvest power. But under general relativity this won’t
work, the ball or water falling through the lower wormhole will actually do work passing
through it and lose the kinetic energy gained. The Traverse through the wormhole is effectively
back up again. You might fall down the first mouth into the
throat but you have to spend energy getting back up out of the throat and the other mouth
and it will always match whatever the change in potential energy was. So this doesn’t work, at least in models
consistent with general relativity. However using them as power sources is still
quite doable. I mentioned in the Terraforming video how
much easier wormholes, if they exist, make terraforming planets. You could for instance hang one in a 24-hour
orbit around your planet and dump the other end as close to the sun, or even in the sun,
as your mouth and stabilizing equipment can handle without being destroyed. Bang, mini sun. You could do the same and exit it out into
some water inside a steam engine turning turbines too. Bang, free power, or kinda free anyway, the
sun is just footing the bill. Ditto in the backside of a rocket ship, so
the exit mouth is just spewing out hot plasma from the star and pushing you along. We almost always picture these as being in
space but that isn’t necessarily required, one thing I liked about Stargate was them
being on the ground in modern times. Peter Hamilton’s Commonwealth Saga, one
of my favorite Scifi series, has them on planets with the novel inclusion of running trains
through them from world to world and power supplies too, so you can put all your nuclear
reactors on some worthless rock of a planet for instance and run superconducting cables
out through the gate to other worlds. Of course you can use them to bulk transport
mass too, sucking air off one world to terraform another, even sucking mass in or out to alter
the gravity. Though it’s worth remembering that any mass
going into one slightly disrupts it and putting through mass equal to the wormhole should
make it explode. When you’re trickling it through over long
time periods you can presumably stabilize it continuously but opening one up to suck
a planet through is not going to work in most models unless the mass of the wormholes is
way, way larger, which of course it would be if it had a throat the size of a planet,
remember the Visser Wormhole’s mouth is only a meter across and it needs a whole Jupiter
worth of exotic matter alone to create that. Now for Inter-Universe Wormholes this is maybe
useful too, since you could open one up to a hotter younger universe maybe, or a colder
older one. Getting heat or mass from the former though
they are usually one way and you’d expect to be on the outgoing end of the tunnel. But they could be two way or let you be on
the incoming end. It’s a nice cheat for entropy, but if you
could traverse one you can still cheat by just jumping into a younger fresh Universe
probably. Of course they make awesome weapons too, especially
if you can open them wherever you please as small as you like, letting you for instance
open up a tiny one to look through then opening another up in front of machinegun and the
bullets fly through targeted by the wormhole, upscaled you could send huge laser blast like
those we discussed in the Nicoll-Dyson Beam video out wherever you pleased. You could open one just inside the other ship
too, since it would cut right through armor and defenses, again these aren’t passing
through space in a straight line. The flipside would be defense, since you could
open wormholes up a decent distance from your planet or ship and get early warning of even
laser beams coming in and potentially precision open one in front of it that exited away from
your ship or planet. This of course assumes you can control where
they open. Currently to get a wormhole where you want
requires either making both ends near each other and dragging them where you like or
opening one, figuring out where it exited, and collapsing it if it doesn’t get you
closer to your destination and restabilizing it again. And then probably towing it to a precise location
anyway. But even if you can’t control the destination
at all and it pops up randomly anywhere in the Universe, even outside the Observable
Universe, you just keep re-opening it till its close to some place that looks like a
nice candidate for colonization and then stabilize it there. This would have the amusing effect of meaning
the closest colonies to Earth, in terms of Transit time, might be a billion light years
away and you might need to pass through hundreds of gates each billion of light years from
each other to get to a star system only a hundred light years away. A common suggested use is just for communication,
very tiny wormholes just big enough to allow a signal through. An obvious continuation on this notion is
including them inside very large computers to allow you to avoid signal lag. This has the problem though of bottlenecking
depending on how much energy it costs to maintain a wormhole, how small you can make them, and
how much energy and time is spent putting each photon through. Wormholes aren’t free, they take a lot of
material to make, take time to pass through, and require maintenance to keep them stable. So if they exist and can be made small there
would still be a point of diminishing returns, whether that is so small you could use them
between each processor or so big only a full blown Matrioshka Brain wired up to twins in
other solar systems would benefit from it is impossible to yet say. But we’ve talked a lot about heat a lot
recently as the big constraint on a lot of our projects like maximizing calculations
or building huge planet-sprawling super-cities, Ecumenopolises. Wormholes presumably let you cheat at that
too. You could use them as a massive air conditioning
system for a planet that you dumped heat through and supercharge that by having another connecting
to places that were very cold. It would probably take a lot juice to make
and maintain that and pump the heat, but you could probably make it a net positive system
to cool a planet where you were grabbing huge amounts power to run it way beyond what you
should be able to without boiling the place. Of course if you got easy access to exotic
matter, negative mass, that could be very handy in constructing over-sized buildings
that ought to collapse under their own mass too. I mentioned in the Ecumenopolis video that
the big brother of a planet-wide city would be a multi-layered one or even what I dubbed
a Planet Cloud, sort of mini-Dyson Swarm around a planet, and wormholes would make building
one and running it far more energetically a lot easier. But very small and cheap wormholes arguably
make one redundant anyway. If you can make them easily and put them where
you want even a Dyson Swarm for habitation gets a bit redundant since you can make a
small one for just sucking up power from a star and transport that wherever you want,
while folks could have a house inside an asteroid in another part of the galaxy and just step
through to Earth, or even have a house with rooms on different planets, or in different
universes if you could make two-way inter-universe wormholes. That notion got played with a bit in Dan Simmons
Hyperion Cantos, houses with rooms on different planets, and the idea of houses with rooms
in different Universe gets played with in one of the later books in the Roger Zelazny’s
Chronicles of Amber. Pretty neat concept as an extension of our
modern one of the internet and cloud computing, where the physical location of your files
might be on the other side of the planet but right at your fingertips. I’m not sure how practical it would be but
it would be kinda awesome to have a closet in your apartment that opened up to a huge
walk in closet among millions in some huge warehouse on another planet, or a balcony
in your bedroom that opened up to some terraced vista on another world. So some fun food for thought to close things
out. I regret we couldn’t get into the math and
I hate to say that like all the other concepts we discussed in this series for getting around
the speed of light I don’t think this one will pan out. But it’s probably the most promising options
and I’d love to be proved wrong. Next Week we’re going to look at Tabby’s
Star, the candidate system folks have be suggesting might be a Dyson Sphere or other Megastructure,
and we’ll talk about SETI, the Search for Extraterrestrial Intelligence, and I’m going
to talk about some of the methods, some of the proposed method, and some of the difficulties
with them. In general channel news we’re still finishing
up a variety of projects and that shouldn’t be much longer. Make sure to subscribe to the channel for
alerts for new videos and channel news. As always, question and comments are welcome,
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have a great day!
