February 14, 2019 • 36 mins
Are wormholes a real thing out in space somewhere?
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Episode Transcript
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Speaker 1 (00:08):
Hey, Daniel. So we did an episode about teleportation, whether
it's possible to go from one point in space to
another point in space instantly, that's right, without actually moving
through space. And the episode was very popular, but we
got a ton of comments on Twitter and the Facebook's
about something we may have missed. That's right. A lot
(00:28):
of people commented that we didn't talk about one possible way,
one important possible way to move to another part of
the universe very rapidly. Yeah, like there's a loophole in
the laws of the universe. Perhaps I don't think this
counts as a loophole. I don't think it counts as teleportation,
but we'll dig into it. Him and I'm Daniel. Welcome
(01:08):
to our podcast. Daniel and Jorge explain the Universe, in
which a physicist and a cartoonist try to take the
universe apart, break it into pieces you can understand, and
download them one at a time into your brain. Today
on the episode, we're going to talk about possible loophole
in the laws of physics worm more molds. A lot
(01:34):
of people commented when we talked about teleportation that wormholes
might be another way to get from one place in
space to another place in space without actually moving through space.
And I'm going to take issue with that that. Yeah,
wormholes might let you move um rapidly from one place
in space to another, but it's not technically teleportation. But
(01:56):
we'll dig into that in a moment. So, yeah, wormholes,
they're they're kind of the basis of one of my
favorite movie sci fi movies, which is Okay, good Contact interest,
Why is Contact your favorite movie? It's one of my
favorite movies just it's such a great, well me made movie.
The storyline is is great, and it's just kind of
this great character portrait of Jodie Foster's character kind of
(02:19):
searching for answers out there in the universe. Yeah, it's
also one of my favorite movies because it touches on
a bunch of really interesting themes. First of all, of course,
it's fascinating to have to potentially get a message from
outer space that's like everybody's dream, right. But the other
thing I really like about that movie is that it
shows the process that a lot of the excitement of
the plot is in unraveling the message. Right. You don't
(02:40):
just get the message and boom you understand it. It's
like in English, and it makes perfect sense. It's a
puzzle and they have to figure it out and think
about it, and then it clicks into place and all
of a sudden, this gibberish turns into into physics and math.
And to me, that was really exciting to see that
process played out. Yeah, and I liked how you Know
is based on a book written by Carl Sagan. Do
of that, yes, Yeah, And so he really thought about
(03:02):
the whole process of like, if we had to build
this giant machine from a message from aliens, have would
that happen? You know, what sort of international cooperations or
organizations and how how would the engineering be done? And
he really thought through all these kind of interesting political details. Yeah.
I think Carl Sagon probably spent a lot of time
(03:22):
thinking about how to talk to aliens and how to
respond if they talk to us, and all sorts of stuff.
I bet that dude smoked a lot of banana peals
and had a lot of deep thoughts on the topic.
Ate a lot of banana, right, probably ate a lot
of bananas as well. That's why I don't think that
puts you in the same frame of mind is smoking
the peels. But it's probably helpful. Yeah, but anyways, in
that movie, Jodie Foster's character goes to another galaxy through
(03:48):
a wormhole. Like that's what. Sorry, I may have spoiled
the plot, but they build a machine and it takes
her through a wormhole and she travels to another part
of the universe with through it. I think it's okay
to spoil the plot twenty year old movies at this point,
or Hey, you don't need to never talk about that movie.
I think it's all right. Yeah, um, yeah, they in
that movie they have like this intergalactic network. It's like
(04:09):
a subway system where you can like zip from one
place to the other um in order to get around
and and it's a sort of a common trope that's
like the thinking of humans as new on the scene
and then maybe somebody else in the galaxy has already
built this incredible infrastructure. And it's a common way that
science fiction writers approached this problem of we're so isolated,
we're so far from everybody else. How could we possibly
(04:31):
have either an interstellar civilization of just humans or interact
with and and live with and develop with and talk
to communicate with aliens and other star systems When everything
is so dang far apart. Yeah, so warmholes is kind
of one way you could do it, at least in
science fiction, is have these tunnels through space that connect
really far away points. That's right. Typically you do either
(04:54):
fasten the light travel or warp speed or wormholes. Right,
and so we've covered two of those already, So it's
time to dig into wormholes. Try to jump into the hole.
It's worm our way into this holy topic. Well, as usually,
we were wondering how many of you out there knew
what a wormhole was and whether or not they're real,
(05:15):
that's right. So I walked around and I asked a
bunch of random people, one of whom was my wife,
if they knew what wormholes were and if they thought
they were a real thing out there in space or
just sort of an idea and a head of science
fiction authors, So does have you listening think about it
for a second. Do you think wormholes are real? And
do you know what they are? Here's what people had
to say. Um, and the question was if that would
(05:38):
be possible. It's a real thing, like it's out there,
it's pretty somewhere. I don't think so. No, Yeah, that
seems something like I would see like in a scientific
or like a sci fi movie. But yeah, I don't.
I don't think they're a real thing. I think so,
I'm pretty sure, all right, I believe it's a distinct possibility.
I don't. I will not say for sure that it
(05:59):
is or it isn't, but I do believe the possibility
remains open that there is ways to traverse through space. No,
why not? I don't know. They just have this sci
fi sheen about them. Probably maybe I don't know. I'm
a chemical engineer, so it was not really my field,
but it's possible. Yeah, in this case, I think a
(06:20):
lot of people seem to have heard about wormholes, Like
almost nobody has said what what the wormhole um? And
a lot of people believe that they exist and and
a lot of people believe that scientists will be able
to make them. Yeah, a lot of people seem to
know them from science fiction. Like it's kind of a
well known science fiction idea and used a lot in
science fiction. Yeah, it's a common trop um to solve
(06:43):
that problem with with your your plot having people spread
all over the galaxy. And so it's definitely something we
should talk about because it's something that's out there. So
I wonder if if that's a thing, like, if you
show it enough in science fiction, eventually people will think
it's just an engineering problem. I thought you were gonna
say something else. If it's an if it appears in
science fiction oft enough, does it become real? That would
(07:06):
be pretty cool, right if if things that were right
into novels eventually turned out to be reality because they
were written into novels, that would be a cool sci
fi novel right there. Yeah, well, sort of in a way.
I mean, it's sort of becomes possible in the minds
of people, and so engineers then go like, hey, what
what will we need to make this happen? And so
then um, yeah, you kind of have to believe that
(07:28):
it's possible before you can try to do it, right,
That's right. It might seem like a bit of a stretch,
but I definitely include science fiction authors in the sort
of spectrum of intellectuals who are responsible for creating the future.
You know, in my mind, he goes from science fiction
authors who do whatever they need to do to get
inspired and think of crazy ways that that technology might
change our society, to physicists who think is that at
(07:51):
all possible, like even technically that could even ever happen,
And once physicists sign off on it, then yeah, it
gets dumped on the engineers like make it so. Yeah.
But science fiction authors also have to know the science right,
Like they can't just say like, hey, here, here is
a pink unicorn that make helps you travel through space.
Oh man, I don't know how much science fiction. I
(08:13):
read a lot of science fiction, and a lot of
it doesn't sound science at all. I just said they
have to read signs, not understand signs. So what is
a wormhole? A wormhole is a connection between two parts
of space that otherwise seem very distant. Okay, And it's
(08:38):
not a teleportation. It's not like I'm here in Los
Angeles and I want to go to New York and
I disappear from Los Angeles and then I appear in
New York. That's teleportation with you, you appear in another
place in space without actually moving through space. A wormhole
is a very different solution. A wormhole says, can we
create a connection between l A and New York? And
(08:59):
I'm not talking about elon Musk underground tunnels or anything crazy.
I'm saying, can you bring those two parts of space
close together. Can you connect them so that you are
still moving through space? But that the distance is very short? Right?
So what does it mean to connect two points that
are distant to each other? Meaning like, I'm here in
Pasadena and next to me is another point in space,
(09:22):
so I can move to that point in space. But
you're saying that my point in space that I'm in
right now could also potentially be connected to another point
far away from here. That's right, And to understand this
you need to relax a little bit your concept of
what space is. Right, If you're thinking of space as
like emptiness, like the backdrop, the stage on which the
theater of the universe takes place, that's an old idea
(09:45):
and it makes a lot of sense based on your experience, right,
that's what how it seems to work. But that's but
we have a more modern idea of space. Now. Space
can do all sorts of weird things that that nothingness
or emptiness or backdrop can't do, right, and most importantly,
space can bend. Space has a shape. Okay, you know
this is a very confusing topic for a lot of
(10:05):
people to get their minds around, meaning that space is
not rigid, you know, like a big empty warehouse that
just it's it's there and it's fixed and it's square.
You're saying space is more like I think the idea
is more like spaces like like the ocean, you know,
like it's like like we're swimming in water and this
thing can kind of squish and bend and flow and
(10:26):
and and push you in different directions. That's right. The
ocean is a useful analogy because it tells you that
this space can do all sorts of interesting things, and
that we're embedded in it. And it's not an emptiness,
it's a thing. It's a physical thing with behaviors. Right.
And a very common way to think about the bending
of space is to think about the bending of space
in a higher dimension, and typically people use a two
(10:48):
dimensional analogy. Now this analogy is flawed for one very
important reason, which I'll tell you after we're done with
the analogy, but it is still helpful in thinking about
how space can move. So typically people think about space
and two to pensions so that then they can then
they can think about the bending of space and three dimensions,
because it's really hard to think in four dimensions, right,
bending of three dimensional space and four dimensions is hard,
(11:09):
so let's just start with two. So you imagine your
typical notion of two dimensional space might be like a
rubber sheet, okay, and then we think about the bending
of that spaces that bending in the third dimension, Like
you put a heavy ball on the rubber sheet. What
happens while the sheet bends right? Where you can imagine
twisting a rubber sheet or or folding a rubber sheet over. Right,
(11:30):
If you fold a rubber sheet over, then two parts
which would be far apart if you moved along the sheet,
could be very close to each other in that third dimension, right,
Or if you roll it up right, imagine rolling up
a two dimensional um sheet of space, then you have
like a toilet paper roll or a toilet paper universe
in which parts of the sheet are touching other parts
(11:51):
of the sheet that are outside or inside on the roll,
and then they're actually very close to each other. Oh
you mean, like I can walk forward for a long
time and I think I'm going straight, but really I'm
going around and around this toilet paper. That's right. And
a wormhole would be a connection that's not along the paper.
It would be a more complex connection to be a
connection from one um one roll around to the next roll,
(12:15):
or to the to the inner roll, or to the
more outer roll. Or if you imagine just a simple
simple rubber sheet where you're folding it like a taco,
it would be a connection between the two sides of
the taco, and you can go the long way around
by moving along the sheet. But a wormhole would be
a more unusual connection, would be a connection that sort
of shortcuts. And space can do these things, right. We
know that space is more complicated than just emptiness, and
(12:38):
it has a shape, and that shape can be complicated. Right.
It can bend, it can stretch, you can wiggle, it
can ripple. They could also just have strange connections to it. Right,
you can connect two parts of space that are distant
along one path, and you can make them very close
together on other paths. Right. I thought of a great analogy.
You know, how you when you're an how to do
(12:58):
with the banana most it's yellow? Um, you know when
you're in ikea and you're walking along and you're you know,
watching all the furnit turn and stuff, and then suddenly
you come upon like a here, here's a shortgut to
betting or here's her shortgut to kitchen, and it's like,
you're like, what what's going on? It's like the Ikea.
It takes you in a path that curves around every
(13:18):
every once in a while you can cut through some
of these folds of your path. That's sort of like
what a worm hall is, right, that's exactly right. And uh,
some hot times when I'm in Ikea, I really wish
I had a wormhole to just get me out of
here immediately and send me home. Oh my god. Well,
they really do kind of distort your spacetime in there
that you never leave. It's like a casino. There's no
(13:39):
outside windows. You can't tell if you've been there for
ten minutes or ten hours. It's sort of a nightmare. Now,
that's a that's a perfect analogy, um, And it shows
you how there can be two paths to get to
the same place, right, a long one and a short one.
And the thing that's tricky for people to understand is
how this space can be bent. And the problem with
the analogy we talked about earlier bending of two dimensional
space in the third dimension, right, it's that third dimension
(14:02):
that helps you get from one place to the other
because the bending is in that third dimension. So you
have to be able to move in that third dimension
or connect space in that third dimension. The problem with
that analogy is that we don't think our three dimensional
space is embedded in some four dimensional space. Right. The
bending of space is not in some other higher fourth dimension.
(14:23):
It's intrinsic, okay, rather than extrinsic. It's intrinsic. It's the
relationship between points in space. It's not that the space
itself is embedded in some four dimensional space that's twisting
it like a three D rubber sheet. Right. It's all
about the relationship between points in space. Right. But I
guess the weird thing is to think about these forks
(14:43):
in the road, right, like an I key, I'm walking around,
walking forward, and suddenly I have two options. I can
keep going on the loopy path, or I can take
the shortcut to the next loop. Right, that's right? And
so what does it mean to connect something in space
for us? You know? Like, does that mean that I
can either move to the side of myself or I
can move a bazillion light years away if I move
(15:07):
in a special direction. What does that mean to have
two points connected? That are actually far away. It just
means that there's two different paths with two different lengths
to the same place. Right when you say that other
point is a Brazilian light year was away, Yeah, it's
a bazilion light years the way if you move through
flat space, right, if you sort of like point yourself
in that direction and go right. But um, there can
(15:28):
be another path that's shorter. Right, But how do I
choose those paths? Like, how do I choose to take
the shortcut or not the shortcut? Well, there has to
be a connection there, and that's where the wormhole is, right.
A wormhole is that kind of connection. It's a connection
between two parts of space which otherwise are far apart,
to make them actually closer. And that's why earlier I
was saying it's not teleportation. You're still just moving through space.
(15:50):
If we define teleportation as moving to another location without
moving through space, then a wormhole is not teleportation because
you're still moving through space. You've just shrunk the distance
you have to travel by bringing those two things closer together,
by creating a path between them that's short. And the
only way this is possible is if space can do
these weird things. If space can twist and bend and
(16:12):
and have bizarre shapes to it. M always see you're saying,
teleportation is more like you disappear from here and you
appear over there. But traveling through a warm hole is
basically just um, just still traveling. You're still moving. It
just so happens to be a shortcut, that's right. It's like,
you know if you say, hey, can you teleport something
from the fridge to the couch, and I like, you know,
(16:35):
make a lasso, and I dragged the fridge over to
the couch, and I'm like, hey, look, I don't have
to get off the couch to get something out of
the fridge anymore. That's not really teleportation, right, I've just
brought the destination closer to me so that I can
reach it without getting off the couch. Right, Although for
me either way, you did it for me, so I'm happy.
You're like, I don't care about the details. Just get
me that drink, my next banana, right, I don't pay
(16:58):
you to bother me with the details. Um. Yeah, And
so it's a semantic distinction. I only I don't really
usually care about semantic distinctions, but a lot of people
were curious about why we didn't talk about wormholes in
the teleportation episode. And that's why because in my mind,
it's not really teleportation. Also, it's actually maybe possible, whereas
teleportation is, like, you know, much more difficult. You're being
a physics lawyer, Yes, I was being a physicist. That's
(17:21):
sort of my job, is his lawyer. Before we keep going,
let's take a short break. So, yeah, so that's a wormhole.
(17:42):
It's connect It's like when you short circuit two point
in space. That's right, Yeah, you bring them, you make
you create a path between them. Um, a short path
between two points that are otherwise really far apart. That's
where a wormhole is. Yeah. So this seems to really fantastical.
Is this real? Is this actually based on the laws
of physics? That this is possible? It's an amazing idea, right,
(18:05):
And the craziest thing about it is that it does
follow the laws of physics. If you brought this concept
to the International or the Intergalactic or the Universal Court
of Physics, they would say, yeah, that's allowed. WHOA, what
does that mean? How kind of how can the laws
of physics allowed? Is? Well, you know, um, it violates
our intuition and it seems really odd. But a lot
(18:27):
of things in the universe violate our intuition and seem odd.
And those are the most fun things, right, Those are
the things that make physics so interesting. Um. But we
say that it's theoretically allowed because we figured out some
rules of the universe. Right. We watch the universe, We
watch apples fall off trees, we see balls moving through
the air, we watch planets go around suns, and we
observes various things, and then we develop laws that describe them. Right.
(18:49):
So in this case, we're talking about general relativity, right
Einstein's field equations. That's say, here are the rules of
how space can be bent. I remember general relativity described gravity,
and gravity is not a force like other forces, and
that we have like a quantum mechanical description of little
particles being sent back and forth to transmit the force.
As far as we know, gravity is a bending of space.
(19:11):
And so general relativity tells us what are the rules
for bending space? And there's a list of rules. Right,
space can do this basically do that's basically do the
other thing. So when we say is something theoretically allowed,
what we mean is does it follow those rules, Right,
And so the rules say that you can bend space
so much that it comes around and kind of touches itself. Again,
(19:33):
that's right, wormholes satisfy those equations. According to those equations,
wormholes are allowed. And that that doesn't mean that wormsholes exist, right,
It means that they are allowed. It's like saying, you know,
before anybody had ever build a tesla, you might say,
we'll do the laws of physics prevent anyone from building
this awesome car. They can go two miles an hour
and looks really cool. You might say, yeah, the laws
(19:55):
of physics allow it, but nobody has ever built a
tesla before. Right, In the same way, worm holes are
allowed by the laws of physics. But that doesn't mean
necessarily that there are any, right. And then, and black
holes were also in this category for a long time, right, Like,
we thought black holes were possible, but we had never
absorved one or seen evidence of one. That's right. Black
(20:16):
holes were just theoretical for a long time. And it
came about exactly the same way. People were playing with
the Einstein equations and saying, well, what's the weirdest thing
we can get space to do? Right? One, can you
can you do this, can do that, can do this
other thing? And they found all these solutions to the equations. Right,
a solution of the equation is a description of space
that follows all those rules. And from the case of
black holes, they figured out if you have a really,
(20:38):
really dense object and you get this bizarre thing in
space called a black hole. And it was decades before
anybody actually observed one. It was for a long time
people didn't know is this just theoretical, I mean, this
is right, or is it something that's actually real, or
is it just you know, is it proof that the
equations are wrong? Right? It sort It seems like a bizarre,
nonsensical prediction of the equations. And that's the kind thing
(21:00):
we're always doing in physics. We're saying, let's take the
equations we have, let's see what they predict, and let's
go out and look to see if we can spot that.
Because if you can spot it, it means probably more
likely that the equations are right, and if we can't,
then it means more likely the equations are wrong. And
we keep finding these weird predictions of general relativity that
turn out to be true. Black holes, gravitational waves, so
(21:21):
when you say connects two points together in space, like
like a shortcut, is it only a point or is
it Could it be like a region of space is
connected to another regional space or does it only work
for little, tiny points. That's a great question. There's a
few different varieties of wormholes. Most of them the opening
is super duper tiny, and so if anything could even
(21:42):
go through it, it would have to be like a
single particle or a single photon or something. But there
are some theories of wormholes where it could be bigger,
you know, big enough for you to pass through or
drive your car through, so you wouldn't have to sit
on the four or five in traffic. Right. Well, what's
the difference between these two types of theories? Like how
can one predict a whole big tunnel? Well, and a
lot of conceptions. A wormhole is sort of like a
(22:03):
hole in space. It's like a If you actually found one,
it would be like a three D object, right, not
not a two D object. Would be like a sphere, okay,
And if you went into that sphere, then you would
appear in another place in space where you would space
is connected through that sphere, right, So it would be
like a really strange door, right, and you look at
(22:24):
the sphere, you can see what's in that other part
of space, and so it's more than just a point
that can be larger. And so in theory you could
you know, go through them. But as we can talk
about that in a moment about the practicalities of making
a wormhole and and and the limitations of them. So
wormholes are theoretically possible, that's right. So there's nothing the
(22:45):
loss of physics to say wormholes cannot exist. And that's
just because space can do these weird things, right. It
can do all these It can twist, it can bend,
it can be strangely connected. You can only have a
wormhole where spaces can of bent around and into itself, right.
And then when these when the space kind of touches
itself again, that's where the wormhole can happen. It's not
like an actual tunnel that goes from one part of
(23:08):
the toilet paper to another part of the toilet paper.
It's like it's when space kind of touches itself again, right,
that's right, you'd be traveling no distance. Right. One side
of the wormhole is exactly the same as the other
side of the wormhole. You know, there's not like a
tunnel where like flashing lights and crazy stuff is happening. Um,
it would be as you pass through, you're on one
side of it and instantly you're on the other side.
(23:29):
It's like zero length. Well, boy, that sounds great. So
you don't have to pack any snacks? That was that?
Was that the goal of your question? You have just
in case you need to go fishing on the other side.
That might be helpful. But yeah, they sound great. They
sound like like it would cut down or travel time
to other stars and like like you could just step
(23:51):
through it and you wouldn't need to pack a lot
or you have a lot of protection to in a
space suit or spaceship. Right, it sounds pretty good. It
does sound pretty good. And so for those folks out
there who are now like googling how to travel to
wormholes or you know, looking on kayak to book your
wormhole ticket, maybe we should bring them down a notch
and then talk about weather wormholes, Um, how wormholes work
(24:13):
in reality? Alright, So unfortunately I have a long list
of reasons here why you will never go through a wormhole.
Wait me in particular or in particular I'm focusing on you, Horror.
Everything I do is about you. I'm just I'm not
skinny enough to fit through what You've been eaten too
(24:35):
many bananas, I've noticed. Um. No, Problem number one is
that nobody's ever found a wormhole, right, so we don't
know if there are any out there. Um. And problem
number one A is that even if wormholes are theoretically possible,
we don't know how to make one, right. I mean,
option one is find a wormhole and go in and
see where you end up. Right. That's sort of like
(24:56):
just getting on a random plane at the airport and
having no idea if you're going to win us Iris
or you know, Singapore. Right. Well, I guess the question
is how would you find one? Like? What what would
what would you look for? Yeah? So, well, how would
you find a wormhole? It would be pretty tough, right.
You'd need to sort of spotted the way we spotted
black holes. Right. We spotted black holes by noticing that
(25:16):
there was this black spot in space where if something
passed behind it, it would disappear and no light was
coming out from it. So for a wormhole, you need
to see things going into it, right, But then it
might just look like a black hole. So you need
to see the other side also, and you need to
see something coming out of it. So you need to
see like particle a going in and then that same
particle coming out the other side. That would be pretty tricky.
(25:39):
You might find one edge of a wormhole and just
think it's a black hole. Oh, until you found the
other side. The one side of the wormhole just looks
like a black hole. That's right. In fact, a lot
of the theories of wormholes start from black holes. They
say that, I am because a wormhole in a black
hole are very similar, right. They both suck things in
and then they constrict space down to a very narrow spot.
(26:03):
The space is very dense inside them. Um, And so
one side of a wormhole could just look like a
black hole. Oh. Wormholes do the same thing as black holes.
They look like a little like a pinch They pinched
space around them, like they contract space leading up to
exactly exactly. And you can think of a wormhole sort
of like imagine whatever visualization you're using for a black
hole in your head. Now, put two of those together
(26:26):
with a little pinchy parts touch, and you had a
sort of flares it like zooms in and then flares
out again and sort of and on one side you
have a black hole. On the other side you have
this thing called a white hole move which is sort
of the opposite of a black hole. And we should
do like a whole podcast episode on white holes. But
what you should know about white holes is that you
(26:46):
can't enter a white hole, but stuff can leave, So
it's sort of the opposite of a black hole in
that sense. Now, no white hole has ever been seen.
It's just a theoretical concept. But if a wormhole really
did exist, it would be a black hole pair to
the white hole. Oh, it's one directional. You can't use
a wormhole two ways, not that we're aware of, right,
So that's that's Problem number two is that wormholes are
(27:07):
a one way trip, and so you might go into it,
come out in Alpha centauri and be like, wow, I
forgot to pack my underwear, and now it's too late.
It's too late. You're going commanded for the rest of
your galactic existence. That's right, um, But there are deeper
problems with wormholes. Um. Problem number three is that wormholes,
as far as we theoretically understand them, are very short lived.
(27:29):
So if a wormhole is created, the equations of general
relativity tell us that that pinching point would last very
very briefly, and then they would snap, and then you
just end up with a black hole in a white
hole separated. What wouldn't be connected that general relativity doesn't
like having a It's not a stable solution, all right.
It's not something which can exist and and not change
(27:51):
through time. The equations of general relativity say that um
space space what doesn't like to be connected that way
for very long. It's not the low energy configuration. And
so if a wormhole is created by whatever means, then
a space would relax by separating back into a black
hole and in a white hole. Wait, so wormholes are
not permanent like the curvature. You're talking about a space
(28:14):
and space looping your on itself. It's constantly moving and changing.
That's right. It's like a gravitational wave, right. It's not
a permanent fixture in space. It's a wiggle. And so
wormholes are like that. Wormholes can be created, though we
don't know how, but they can be described by the
equation of general relativity. But they don't last very long.
They're very short lived. They're like, you know, momentarily existing.
(28:36):
Oh boy, yeah, that's a problem. So we we can't
find them and they don't last for very long. That's right,
But some clever physicists thought up a way to maybe
make wormholes last a little longer. I have so many
questions for you, but before we dive in, let's take
a short break. First of all, can we make wormholes?
(29:07):
Is that theoretically possible? Like, can we build something that
would make one? We have no idea. I mean, we
know that the equations of general relativity allow them, but
we don't know how to make a wormhole. Um. But
if we did find a wormhole before it collapsed, some
physicists worked out a way too to make it last longer.
For it to be stable, all you need to do
(29:29):
is stuff it filled with a huge amount of exotic matter,
which is something we've never seen before and don't know
if it exists. But if you could create a huge
amount of it and stuff it inside a wormhole, then
theoretically you might be able to stabilize the wormhole. Now,
exotic matter is this weird stuff that has negative mass,
and you need something with negative mass because it would
(29:50):
have sort of the opposite gravitational effect of normal mass.
Normal mass pull stuff together, negative mass would be pushing
stuff apart. So you stuff that inside the wormhole, it
was sort of hold it open. So if you could
find this special impossible mass, and you could also find
a wormhole and you could throw it in there, it
might keep the wormhole open for more than that's right,
(30:13):
But I wouldn't go in there with your kids. On
the guessing of a bunch of businesses. You could throw
some bananas in there first, that's right. And you know
the other problem with wormholes is they might be super
duper small, right, Even these wormholes were talking about could
be like plank length size, like ten to the minus
thirty five wide. Wait, do you mean like the size
(30:34):
of something that would fit in a wormhole? Is that small?
That's right. We don't really know, but some theories say
that wormholes would have to be super duper tiny if
they exist at all. Right, So that's another disappointing fact.
And and also the the idea about stuffing it full
of exotic matter. That would hold the wormhole open, but
it would also mean you can't go through it, because
as soon as any sort of normal matter went through
(30:56):
it, it it would disrupt it, and then the wormhole would collapse.
So it might be that the wormholes exist, and it
might be that you can hold them open with exotic matter,
but then you couldn't go through them, which makes them
sort of pointless because as soon as you go in
it would close, or yeah, exactly as soon as you
go in then it would collapse. So like totally might
make it through, but then it'll collapse, and then you
(31:17):
don't have any that's right, And then we haven't even
talked about like the dangers of approaching anything that looks
like a black hole. I mean, the gravitational forces are tremendous.
You get anywhere close to a black hole, you're not
going to get into it. You're gonna get shredded by
the title forces before you get very close. So there's
a lot of practical problems with using a wormhole, but
(31:38):
so weird wire wormholes one directional. That's one thing I
didn't quite yet. How does the universe decide which ways
in and which ways out? Well, um, that's a good question.
I don't know. We don't know how to make them,
so we don't know what process determines their directionality. Yeah,
it's a good question. But the but the physics say
the mass says that they are one direction. That's right,
And so let me add an important qualifier. We've been
(31:59):
saying this whole time that they are theoretically possible. That's
true according to general relativity. General relativity, as far as
we note, is true. But we also know that general
relativity is not quantum mechanical, right, that it cannot describe
microscopic things very well, things where the quantum description of
the universe takes over, where particles have fixed amounts of
(32:21):
energy and are divided up into concrete chunks. Right, general
relativity thinks of the universe is continuous and infinitely divisible,
but we know it's not that. Most of the time,
that's not a big deal because we're dealing with macroscopic objects.
But when you're talking about the inside of black holes
or the inside of wormholes, we're pretty sure that quantum
effects are going to be important, which means that if
you're gonna go inside a wormhole, you shouldn't just check
(32:43):
with general relativity. You need to check with quantum gravity,
which is the theory we don't even have. So I
would be very wary of going inside a wormhole, even
if you found one, even if you stabilized it, because
we don't really know what the rules are of quantum gravity, right,
and the hardest part seems to be to stand quantum physics.
It's pretty tricky. Yeah, you gotta be pretty smart to
(33:04):
understand quantum physics, I'll admit. Okay, So to answer the question,
can we use a wormhole to get to another star galaxy?
The answer is maybe, probably not theoretically possible, but it
seems practically impossible. I would be super impressed with the
(33:25):
next generation of engineers if we managed to build useful
wormholes in the next hundred years or so, I would
be very, very deeply impressed. Good job, guys, I think
you'd probably be dead. They'll probably send me as an
experimental subject through the first wormhole just to prove them wrong. Um. Yes,
so I would say. The takeaway is wormholes theoretically possible
(33:47):
but never been seen, and also very impractical. Right. But
let's carry the fantasy a little bit longer here, because
I heard I read that they wormholes might not just
connect space, but they could also connect space and time.
That's right, Space is part of this constructor called space
time right where time is sort of the fourth dimension.
And um, people have crazy ideas with what you could
(34:09):
do with wormholes if you found them. If you take
one end of the wormhole and you accelerated to really
really high speeds, then you can take advantage of time dilation. Right,
that's moving clocks run more slowly. Um. But if you're connected,
if you have a stationary point connected to the fast
moving point, that you can play all sorts of tricks
with special relativity and maybe even go back in time.
(34:32):
But Stephen Hawking says that's impossible. He says that if
you send anything through the wormhole that the wormhole will collapse.
And so they called this the chronological protection conjecture, with
the universes like conspired to make the laws of physics
impossible to do time travel. And I said, I took
a stand on our time travel episode. I said time
travel is impossible, and I stick by that because I
(34:55):
think that this concept of using wormholes and trail back
in time is absurd, not just impractical, but absurd and illogical. Okay,
so sorry to rain on your parade, to to to
prick your fantasy there, Jorge, let me throughout my idea
for a sci fi novel right here. I'm just gonna
I'm just gonna crush that out and put it in
the trash here. No, no, science fiction is totally allowed, totally.
You let in your universe. You can make up whatever
(35:17):
rules you want as long as you follow them, so
we can have that in your science fiction universe, no problem.
All right, I guess until then we have to sit
in traffic until the engineers figure out the wormhole. That's right,
And so we hope you enjoyed this episode of Daniel
and Jorge and um explain the universe and Daniel moorehe
shoot down your sci fi idea. That's right, and try
(35:38):
send me your sci fi idea through the wormhole of
the internet, and I'll tell you why it's wrong, but
in a very cheerful tone. That's right. Warm your way
into Daniel's inbox. All right. Thanks to everyone, have a
good one, see you next time. If you still have
(36:01):
a question after listening to all these explanations, please drop
us a line. We'd love to hear from you. You
can find us at Facebook, Twitter, and Instagram at Daniel
and Jorge as one Word, or email us at Feedback
at Daniel and Jorge dot com,
Hey, Daniel. So we did an episode about teleportation, whether
it's possible to go from one point in space to
another point in space instantly, that's right, without actually moving
through space. And the episode was very popular, but we
got a ton of comments on Twitter and the Facebook's
about something we may have missed. That's right. A lot
(00:28):
of people commented that we didn't talk about one possible way,
one important possible way to move to another part of
the universe very rapidly. Yeah, like there's a loophole in
the laws of the universe. Perhaps I don't think this
counts as a loophole. I don't think it counts as teleportation,
but we'll dig into it. Him and I'm Daniel. Welcome
(01:08):
to our podcast. Daniel and Jorge explain the Universe, in
which a physicist and a cartoonist try to take the
universe apart, break it into pieces you can understand, and
download them one at a time into your brain. Today
on the episode, we're going to talk about possible loophole
in the laws of physics worm more molds. A lot
(01:34):
of people commented when we talked about teleportation that wormholes
might be another way to get from one place in
space to another place in space without actually moving through space.
And I'm going to take issue with that that. Yeah,
wormholes might let you move um rapidly from one place
in space to another, but it's not technically teleportation. But
(01:56):
we'll dig into that in a moment. So, yeah, wormholes,
they're they're kind of the basis of one of my
favorite movie sci fi movies, which is Okay, good Contact interest,
Why is Contact your favorite movie? It's one of my
favorite movies just it's such a great, well me made movie.
The storyline is is great, and it's just kind of
this great character portrait of Jodie Foster's character kind of
(02:19):
searching for answers out there in the universe. Yeah, it's
also one of my favorite movies because it touches on
a bunch of really interesting themes. First of all, of course,
it's fascinating to have to potentially get a message from
outer space that's like everybody's dream, right. But the other
thing I really like about that movie is that it
shows the process that a lot of the excitement of
the plot is in unraveling the message. Right. You don't
(02:40):
just get the message and boom you understand it. It's
like in English, and it makes perfect sense. It's a
puzzle and they have to figure it out and think
about it, and then it clicks into place and all
of a sudden, this gibberish turns into into physics and math.
And to me, that was really exciting to see that
process played out. Yeah, and I liked how you Know
is based on a book written by Carl Sagan. Do
of that, yes, Yeah, And so he really thought about
(03:02):
the whole process of like, if we had to build
this giant machine from a message from aliens, have would
that happen? You know, what sort of international cooperations or
organizations and how how would the engineering be done? And
he really thought through all these kind of interesting political details. Yeah.
I think Carl Sagon probably spent a lot of time
(03:22):
thinking about how to talk to aliens and how to
respond if they talk to us, and all sorts of stuff.
I bet that dude smoked a lot of banana peals
and had a lot of deep thoughts on the topic.
Ate a lot of banana, right, probably ate a lot
of bananas as well. That's why I don't think that
puts you in the same frame of mind is smoking
the peels. But it's probably helpful. Yeah, but anyways, in
that movie, Jodie Foster's character goes to another galaxy through
(03:48):
a wormhole. Like that's what. Sorry, I may have spoiled
the plot, but they build a machine and it takes
her through a wormhole and she travels to another part
of the universe with through it. I think it's okay
to spoil the plot twenty year old movies at this point,
or Hey, you don't need to never talk about that movie.
I think it's all right. Yeah, um, yeah, they in
that movie they have like this intergalactic network. It's like
(04:09):
a subway system where you can like zip from one
place to the other um in order to get around
and and it's a sort of a common trope that's
like the thinking of humans as new on the scene
and then maybe somebody else in the galaxy has already
built this incredible infrastructure. And it's a common way that
science fiction writers approached this problem of we're so isolated,
we're so far from everybody else. How could we possibly
(04:31):
have either an interstellar civilization of just humans or interact
with and and live with and develop with and talk
to communicate with aliens and other star systems When everything
is so dang far apart. Yeah, so warmholes is kind
of one way you could do it, at least in
science fiction, is have these tunnels through space that connect
really far away points. That's right. Typically you do either
(04:54):
fasten the light travel or warp speed or wormholes. Right,
and so we've covered two of those already, So it's
time to dig into wormholes. Try to jump into the hole.
It's worm our way into this holy topic. Well, as usually,
we were wondering how many of you out there knew
what a wormhole was and whether or not they're real,
(05:15):
that's right. So I walked around and I asked a
bunch of random people, one of whom was my wife,
if they knew what wormholes were and if they thought
they were a real thing out there in space or
just sort of an idea and a head of science
fiction authors, So does have you listening think about it
for a second. Do you think wormholes are real? And
do you know what they are? Here's what people had
to say. Um, and the question was if that would
(05:38):
be possible. It's a real thing, like it's out there,
it's pretty somewhere. I don't think so. No, Yeah, that
seems something like I would see like in a scientific
or like a sci fi movie. But yeah, I don't.
I don't think they're a real thing. I think so,
I'm pretty sure, all right, I believe it's a distinct possibility.
I don't. I will not say for sure that it
(05:59):
is or it isn't, but I do believe the possibility
remains open that there is ways to traverse through space. No,
why not? I don't know. They just have this sci
fi sheen about them. Probably maybe I don't know. I'm
a chemical engineer, so it was not really my field,
but it's possible. Yeah, in this case, I think a
(06:20):
lot of people seem to have heard about wormholes, Like
almost nobody has said what what the wormhole um? And
a lot of people believe that they exist and and
a lot of people believe that scientists will be able
to make them. Yeah, a lot of people seem to
know them from science fiction. Like it's kind of a
well known science fiction idea and used a lot in
science fiction. Yeah, it's a common trop um to solve
(06:43):
that problem with with your your plot having people spread
all over the galaxy. And so it's definitely something we
should talk about because it's something that's out there. So
I wonder if if that's a thing, like, if you
show it enough in science fiction, eventually people will think
it's just an engineering problem. I thought you were gonna
say something else. If it's an if it appears in
science fiction oft enough, does it become real? That would
(07:06):
be pretty cool, right if if things that were right
into novels eventually turned out to be reality because they
were written into novels, that would be a cool sci
fi novel right there. Yeah, well, sort of in a way.
I mean, it's sort of becomes possible in the minds
of people, and so engineers then go like, hey, what
what will we need to make this happen? And so
then um, yeah, you kind of have to believe that
(07:28):
it's possible before you can try to do it, right,
That's right. It might seem like a bit of a stretch,
but I definitely include science fiction authors in the sort
of spectrum of intellectuals who are responsible for creating the future.
You know, in my mind, he goes from science fiction
authors who do whatever they need to do to get
inspired and think of crazy ways that that technology might
change our society, to physicists who think is that at
(07:51):
all possible, like even technically that could even ever happen,
And once physicists sign off on it, then yeah, it
gets dumped on the engineers like make it so. Yeah.
But science fiction authors also have to know the science right,
Like they can't just say like, hey, here, here is
a pink unicorn that make helps you travel through space.
Oh man, I don't know how much science fiction. I
(08:13):
read a lot of science fiction, and a lot of
it doesn't sound science at all. I just said they
have to read signs, not understand signs. So what is
a wormhole? A wormhole is a connection between two parts
of space that otherwise seem very distant. Okay, And it's
(08:38):
not a teleportation. It's not like I'm here in Los
Angeles and I want to go to New York and
I disappear from Los Angeles and then I appear in
New York. That's teleportation with you, you appear in another
place in space without actually moving through space. A wormhole
is a very different solution. A wormhole says, can we
create a connection between l A and New York? And
(08:59):
I'm not talking about elon Musk underground tunnels or anything crazy.
I'm saying, can you bring those two parts of space
close together. Can you connect them so that you are
still moving through space? But that the distance is very short? Right?
So what does it mean to connect two points that
are distant to each other? Meaning like, I'm here in
Pasadena and next to me is another point in space,
(09:22):
so I can move to that point in space. But
you're saying that my point in space that I'm in
right now could also potentially be connected to another point
far away from here. That's right, And to understand this
you need to relax a little bit your concept of
what space is. Right, If you're thinking of space as
like emptiness, like the backdrop, the stage on which the
theater of the universe takes place, that's an old idea
(09:45):
and it makes a lot of sense based on your experience, right,
that's what how it seems to work. But that's but
we have a more modern idea of space. Now. Space
can do all sorts of weird things that that nothingness
or emptiness or backdrop can't do, right, and most importantly,
space can bend. Space has a shape. Okay, you know
this is a very confusing topic for a lot of
(10:05):
people to get their minds around, meaning that space is
not rigid, you know, like a big empty warehouse that
just it's it's there and it's fixed and it's square.
You're saying space is more like I think the idea
is more like spaces like like the ocean, you know,
like it's like like we're swimming in water and this
thing can kind of squish and bend and flow and
(10:26):
and and push you in different directions. That's right. The
ocean is a useful analogy because it tells you that
this space can do all sorts of interesting things, and
that we're embedded in it. And it's not an emptiness,
it's a thing. It's a physical thing with behaviors. Right.
And a very common way to think about the bending
of space is to think about the bending of space
in a higher dimension, and typically people use a two
(10:48):
dimensional analogy. Now this analogy is flawed for one very
important reason, which I'll tell you after we're done with
the analogy, but it is still helpful in thinking about
how space can move. So typically people think about space
and two to pensions so that then they can then
they can think about the bending of space and three dimensions,
because it's really hard to think in four dimensions, right,
bending of three dimensional space and four dimensions is hard,
(11:09):
so let's just start with two. So you imagine your
typical notion of two dimensional space might be like a
rubber sheet, okay, and then we think about the bending
of that spaces that bending in the third dimension, Like
you put a heavy ball on the rubber sheet. What
happens while the sheet bends right? Where you can imagine
twisting a rubber sheet or or folding a rubber sheet over. Right,
(11:30):
If you fold a rubber sheet over, then two parts
which would be far apart if you moved along the sheet,
could be very close to each other in that third dimension, right,
Or if you roll it up right, imagine rolling up
a two dimensional um sheet of space, then you have
like a toilet paper roll or a toilet paper universe
in which parts of the sheet are touching other parts
(11:51):
of the sheet that are outside or inside on the roll,
and then they're actually very close to each other. Oh
you mean, like I can walk forward for a long
time and I think I'm going straight, but really I'm
going around and around this toilet paper. That's right. And
a wormhole would be a connection that's not along the paper.
It would be a more complex connection to be a
connection from one um one roll around to the next roll,
(12:15):
or to the to the inner roll, or to the
more outer roll. Or if you imagine just a simple
simple rubber sheet where you're folding it like a taco,
it would be a connection between the two sides of
the taco, and you can go the long way around
by moving along the sheet. But a wormhole would be
a more unusual connection, would be a connection that sort
of shortcuts. And space can do these things, right. We
know that space is more complicated than just emptiness, and
(12:38):
it has a shape, and that shape can be complicated. Right.
It can bend, it can stretch, you can wiggle, it
can ripple. They could also just have strange connections to it. Right,
you can connect two parts of space that are distant
along one path, and you can make them very close
together on other paths. Right. I thought of a great analogy.
You know, how you when you're an how to do
(12:58):
with the banana most it's yellow? Um, you know when
you're in ikea and you're walking along and you're you know,
watching all the furnit turn and stuff, and then suddenly
you come upon like a here, here's a shortgut to
betting or here's her shortgut to kitchen, and it's like,
you're like, what what's going on? It's like the Ikea.
It takes you in a path that curves around every
(13:18):
every once in a while you can cut through some
of these folds of your path. That's sort of like
what a worm hall is, right, that's exactly right. And uh,
some hot times when I'm in Ikea, I really wish
I had a wormhole to just get me out of
here immediately and send me home. Oh my god. Well,
they really do kind of distort your spacetime in there
that you never leave. It's like a casino. There's no
(13:39):
outside windows. You can't tell if you've been there for
ten minutes or ten hours. It's sort of a nightmare. Now,
that's a that's a perfect analogy, um, And it shows
you how there can be two paths to get to
the same place, right, a long one and a short one.
And the thing that's tricky for people to understand is
how this space can be bent. And the problem with
the analogy we talked about earlier bending of two dimensional
space in the third dimension, right, it's that third dimension
(14:02):
that helps you get from one place to the other
because the bending is in that third dimension. So you
have to be able to move in that third dimension
or connect space in that third dimension. The problem with
that analogy is that we don't think our three dimensional
space is embedded in some four dimensional space. Right. The
bending of space is not in some other higher fourth dimension.
(14:23):
It's intrinsic, okay, rather than extrinsic. It's intrinsic. It's the
relationship between points in space. It's not that the space
itself is embedded in some four dimensional space that's twisting
it like a three D rubber sheet. Right. It's all
about the relationship between points in space. Right. But I
guess the weird thing is to think about these forks
(14:43):
in the road, right, like an I key, I'm walking around,
walking forward, and suddenly I have two options. I can
keep going on the loopy path, or I can take
the shortcut to the next loop. Right, that's right? And
so what does it mean to connect something in space
for us? You know? Like, does that mean that I
can either move to the side of myself or I
can move a bazillion light years away if I move
(15:07):
in a special direction. What does that mean to have
two points connected? That are actually far away. It just
means that there's two different paths with two different lengths
to the same place. Right when you say that other
point is a Brazilian light year was away, Yeah, it's
a bazilion light years the way if you move through
flat space, right, if you sort of like point yourself
in that direction and go right. But um, there can
(15:28):
be another path that's shorter. Right, But how do I
choose those paths? Like, how do I choose to take
the shortcut or not the shortcut? Well, there has to
be a connection there, and that's where the wormhole is, right.
A wormhole is that kind of connection. It's a connection
between two parts of space which otherwise are far apart,
to make them actually closer. And that's why earlier I
was saying it's not teleportation. You're still just moving through space.
(15:50):
If we define teleportation as moving to another location without
moving through space, then a wormhole is not teleportation because
you're still moving through space. You've just shrunk the distance
you have to travel by bringing those two things closer together,
by creating a path between them that's short. And the
only way this is possible is if space can do
these weird things. If space can twist and bend and
(16:12):
and have bizarre shapes to it. M always see you're saying,
teleportation is more like you disappear from here and you
appear over there. But traveling through a warm hole is
basically just um, just still traveling. You're still moving. It
just so happens to be a shortcut, that's right. It's like,
you know if you say, hey, can you teleport something
from the fridge to the couch, and I like, you know,
(16:35):
make a lasso, and I dragged the fridge over to
the couch, and I'm like, hey, look, I don't have
to get off the couch to get something out of
the fridge anymore. That's not really teleportation, right, I've just
brought the destination closer to me so that I can
reach it without getting off the couch. Right, Although for
me either way, you did it for me, so I'm happy.
You're like, I don't care about the details. Just get
me that drink, my next banana, right, I don't pay
(16:58):
you to bother me with the details. Um. Yeah, And
so it's a semantic distinction. I only I don't really
usually care about semantic distinctions, but a lot of people
were curious about why we didn't talk about wormholes in
the teleportation episode. And that's why because in my mind,
it's not really teleportation. Also, it's actually maybe possible, whereas
teleportation is, like, you know, much more difficult. You're being
a physics lawyer, Yes, I was being a physicist. That's
(17:21):
sort of my job, is his lawyer. Before we keep going,
let's take a short break. So, yeah, so that's a wormhole.
(17:42):
It's connect It's like when you short circuit two point
in space. That's right, Yeah, you bring them, you make
you create a path between them. Um, a short path
between two points that are otherwise really far apart. That's
where a wormhole is. Yeah. So this seems to really fantastical.
Is this real? Is this actually based on the laws
of physics? That this is possible? It's an amazing idea, right,
(18:05):
And the craziest thing about it is that it does
follow the laws of physics. If you brought this concept
to the International or the Intergalactic or the Universal Court
of Physics, they would say, yeah, that's allowed. WHOA, what
does that mean? How kind of how can the laws
of physics allowed? Is? Well, you know, um, it violates
our intuition and it seems really odd. But a lot
(18:27):
of things in the universe violate our intuition and seem odd.
And those are the most fun things, right, Those are
the things that make physics so interesting. Um. But we
say that it's theoretically allowed because we figured out some
rules of the universe. Right. We watch the universe, We
watch apples fall off trees, we see balls moving through
the air, we watch planets go around suns, and we
observes various things, and then we develop laws that describe them. Right.
(18:49):
So in this case, we're talking about general relativity, right
Einstein's field equations. That's say, here are the rules of
how space can be bent. I remember general relativity described gravity,
and gravity is not a force like other forces, and
that we have like a quantum mechanical description of little
particles being sent back and forth to transmit the force.
As far as we know, gravity is a bending of space.
(19:11):
And so general relativity tells us what are the rules
for bending space? And there's a list of rules. Right,
space can do this basically do that's basically do the
other thing. So when we say is something theoretically allowed,
what we mean is does it follow those rules, Right,
And so the rules say that you can bend space
so much that it comes around and kind of touches itself. Again,
(19:33):
that's right, wormholes satisfy those equations. According to those equations,
wormholes are allowed. And that that doesn't mean that wormsholes exist, right,
It means that they are allowed. It's like saying, you know,
before anybody had ever build a tesla, you might say,
we'll do the laws of physics prevent anyone from building
this awesome car. They can go two miles an hour
and looks really cool. You might say, yeah, the laws
(19:55):
of physics allow it, but nobody has ever built a
tesla before. Right, In the same way, worm holes are
allowed by the laws of physics. But that doesn't mean
necessarily that there are any, right. And then, and black
holes were also in this category for a long time, right, Like,
we thought black holes were possible, but we had never
absorved one or seen evidence of one. That's right. Black
(20:16):
holes were just theoretical for a long time. And it
came about exactly the same way. People were playing with
the Einstein equations and saying, well, what's the weirdest thing
we can get space to do? Right? One, can you
can you do this, can do that, can do this
other thing? And they found all these solutions to the equations. Right,
a solution of the equation is a description of space
that follows all those rules. And from the case of
black holes, they figured out if you have a really,
(20:38):
really dense object and you get this bizarre thing in
space called a black hole. And it was decades before
anybody actually observed one. It was for a long time
people didn't know is this just theoretical, I mean, this
is right, or is it something that's actually real, or
is it just you know, is it proof that the
equations are wrong? Right? It sort It seems like a bizarre,
nonsensical prediction of the equations. And that's the kind thing
(21:00):
we're always doing in physics. We're saying, let's take the
equations we have, let's see what they predict, and let's
go out and look to see if we can spot that.
Because if you can spot it, it means probably more
likely that the equations are right, and if we can't,
then it means more likely the equations are wrong. And
we keep finding these weird predictions of general relativity that
turn out to be true. Black holes, gravitational waves, so
(21:21):
when you say connects two points together in space, like
like a shortcut, is it only a point or is
it Could it be like a region of space is
connected to another regional space or does it only work
for little, tiny points. That's a great question. There's a
few different varieties of wormholes. Most of them the opening
is super duper tiny, and so if anything could even
(21:42):
go through it, it would have to be like a
single particle or a single photon or something. But there
are some theories of wormholes where it could be bigger,
you know, big enough for you to pass through or
drive your car through, so you wouldn't have to sit
on the four or five in traffic. Right. Well, what's
the difference between these two types of theories? Like how
can one predict a whole big tunnel? Well, and a
lot of conceptions. A wormhole is sort of like a
(22:03):
hole in space. It's like a If you actually found one,
it would be like a three D object, right, not
not a two D object. Would be like a sphere, okay,
And if you went into that sphere, then you would
appear in another place in space where you would space
is connected through that sphere, right, So it would be
like a really strange door, right, and you look at
(22:24):
the sphere, you can see what's in that other part
of space, and so it's more than just a point
that can be larger. And so in theory you could
you know, go through them. But as we can talk
about that in a moment about the practicalities of making
a wormhole and and and the limitations of them. So
wormholes are theoretically possible, that's right. So there's nothing the
(22:45):
loss of physics to say wormholes cannot exist. And that's
just because space can do these weird things, right. It
can do all these It can twist, it can bend,
it can be strangely connected. You can only have a
wormhole where spaces can of bent around and into itself, right.
And then when these when the space kind of touches
itself again, that's where the wormhole can happen. It's not
like an actual tunnel that goes from one part of
(23:08):
the toilet paper to another part of the toilet paper.
It's like it's when space kind of touches itself again, right,
that's right, you'd be traveling no distance. Right. One side
of the wormhole is exactly the same as the other
side of the wormhole. You know, there's not like a
tunnel where like flashing lights and crazy stuff is happening. Um,
it would be as you pass through, you're on one
side of it and instantly you're on the other side.
(23:29):
It's like zero length. Well, boy, that sounds great. So
you don't have to pack any snacks? That was that?
Was that the goal of your question? You have just
in case you need to go fishing on the other side.
That might be helpful. But yeah, they sound great. They
sound like like it would cut down or travel time
to other stars and like like you could just step
(23:51):
through it and you wouldn't need to pack a lot
or you have a lot of protection to in a
space suit or spaceship. Right, it sounds pretty good. It
does sound pretty good. And so for those folks out
there who are now like googling how to travel to
wormholes or you know, looking on kayak to book your
wormhole ticket, maybe we should bring them down a notch
and then talk about weather wormholes, Um, how wormholes work
(24:13):
in reality? Alright, So unfortunately I have a long list
of reasons here why you will never go through a wormhole.
Wait me in particular or in particular I'm focusing on you, Horror.
Everything I do is about you. I'm just I'm not
skinny enough to fit through what You've been eaten too
(24:35):
many bananas, I've noticed. Um. No, Problem number one is
that nobody's ever found a wormhole, right, so we don't
know if there are any out there. Um. And problem
number one A is that even if wormholes are theoretically possible,
we don't know how to make one, right. I mean,
option one is find a wormhole and go in and
see where you end up. Right. That's sort of like
(24:56):
just getting on a random plane at the airport and
having no idea if you're going to win us Iris
or you know, Singapore. Right. Well, I guess the question
is how would you find one? Like? What what would
what would you look for? Yeah? So, well, how would
you find a wormhole? It would be pretty tough, right.
You'd need to sort of spotted the way we spotted
black holes. Right. We spotted black holes by noticing that
(25:16):
there was this black spot in space where if something
passed behind it, it would disappear and no light was
coming out from it. So for a wormhole, you need
to see things going into it, right, But then it
might just look like a black hole. So you need
to see the other side also, and you need to
see something coming out of it. So you need to
see like particle a going in and then that same
particle coming out the other side. That would be pretty tricky.
(25:39):
You might find one edge of a wormhole and just
think it's a black hole. Oh, until you found the
other side. The one side of the wormhole just looks
like a black hole. That's right. In fact, a lot
of the theories of wormholes start from black holes. They
say that, I am because a wormhole in a black
hole are very similar, right. They both suck things in
and then they constrict space down to a very narrow spot.
(26:03):
The space is very dense inside them. Um, And so
one side of a wormhole could just look like a
black hole. Oh. Wormholes do the same thing as black holes.
They look like a little like a pinch They pinched
space around them, like they contract space leading up to
exactly exactly. And you can think of a wormhole sort
of like imagine whatever visualization you're using for a black
hole in your head. Now, put two of those together
(26:26):
with a little pinchy parts touch, and you had a
sort of flares it like zooms in and then flares
out again and sort of and on one side you
have a black hole. On the other side you have
this thing called a white hole move which is sort
of the opposite of a black hole. And we should
do like a whole podcast episode on white holes. But
what you should know about white holes is that you
(26:46):
can't enter a white hole, but stuff can leave, So
it's sort of the opposite of a black hole in
that sense. Now, no white hole has ever been seen.
It's just a theoretical concept. But if a wormhole really
did exist, it would be a black hole pair to
the white hole. Oh, it's one directional. You can't use
a wormhole two ways, not that we're aware of, right,
So that's that's Problem number two is that wormholes are
(27:07):
a one way trip, and so you might go into it,
come out in Alpha centauri and be like, wow, I
forgot to pack my underwear, and now it's too late.
It's too late. You're going commanded for the rest of
your galactic existence. That's right, um, But there are deeper
problems with wormholes. Um. Problem number three is that wormholes,
as far as we theoretically understand them, are very short lived.
(27:29):
So if a wormhole is created, the equations of general
relativity tell us that that pinching point would last very
very briefly, and then they would snap, and then you
just end up with a black hole in a white
hole separated. What wouldn't be connected that general relativity doesn't
like having a It's not a stable solution, all right.
It's not something which can exist and and not change
(27:51):
through time. The equations of general relativity say that um
space space what doesn't like to be connected that way
for very long. It's not the low energy configuration. And
so if a wormhole is created by whatever means, then
a space would relax by separating back into a black
hole and in a white hole. Wait, so wormholes are
not permanent like the curvature. You're talking about a space
(28:14):
and space looping your on itself. It's constantly moving and changing.
That's right. It's like a gravitational wave, right. It's not
a permanent fixture in space. It's a wiggle. And so
wormholes are like that. Wormholes can be created, though we
don't know how, but they can be described by the
equation of general relativity. But they don't last very long.
They're very short lived. They're like, you know, momentarily existing.
(28:36):
Oh boy, yeah, that's a problem. So we we can't
find them and they don't last for very long. That's right,
But some clever physicists thought up a way to maybe
make wormholes last a little longer. I have so many
questions for you, but before we dive in, let's take
a short break. First of all, can we make wormholes?
(29:07):
Is that theoretically possible? Like, can we build something that
would make one? We have no idea. I mean, we
know that the equations of general relativity allow them, but
we don't know how to make a wormhole. Um. But
if we did find a wormhole before it collapsed, some
physicists worked out a way too to make it last longer.
For it to be stable, all you need to do
(29:29):
is stuff it filled with a huge amount of exotic matter,
which is something we've never seen before and don't know
if it exists. But if you could create a huge
amount of it and stuff it inside a wormhole, then
theoretically you might be able to stabilize the wormhole. Now,
exotic matter is this weird stuff that has negative mass,
and you need something with negative mass because it would
(29:50):
have sort of the opposite gravitational effect of normal mass.
Normal mass pull stuff together, negative mass would be pushing
stuff apart. So you stuff that inside the wormhole, it
was sort of hold it open. So if you could
find this special impossible mass, and you could also find
a wormhole and you could throw it in there, it
might keep the wormhole open for more than that's right,
(30:13):
But I wouldn't go in there with your kids. On
the guessing of a bunch of businesses. You could throw
some bananas in there first, that's right. And you know
the other problem with wormholes is they might be super
duper small, right, Even these wormholes were talking about could
be like plank length size, like ten to the minus
thirty five wide. Wait, do you mean like the size
(30:34):
of something that would fit in a wormhole? Is that small?
That's right. We don't really know, but some theories say
that wormholes would have to be super duper tiny if
they exist at all. Right, So that's another disappointing fact.
And and also the the idea about stuffing it full
of exotic matter. That would hold the wormhole open, but
it would also mean you can't go through it, because
as soon as any sort of normal matter went through
(30:56):
it, it it would disrupt it, and then the wormhole would collapse.
So it might be that the wormholes exist, and it
might be that you can hold them open with exotic matter,
but then you couldn't go through them, which makes them
sort of pointless because as soon as you go in
it would close, or yeah, exactly as soon as you
go in then it would collapse. So like totally might
make it through, but then it'll collapse, and then you
(31:17):
don't have any that's right, And then we haven't even
talked about like the dangers of approaching anything that looks
like a black hole. I mean, the gravitational forces are tremendous.
You get anywhere close to a black hole, you're not
going to get into it. You're gonna get shredded by
the title forces before you get very close. So there's
a lot of practical problems with using a wormhole, but
(31:38):
so weird wire wormholes one directional. That's one thing I
didn't quite yet. How does the universe decide which ways
in and which ways out? Well, um, that's a good question.
I don't know. We don't know how to make them,
so we don't know what process determines their directionality. Yeah,
it's a good question. But the but the physics say
the mass says that they are one direction. That's right,
And so let me add an important qualifier. We've been
(31:59):
saying this whole time that they are theoretically possible. That's
true according to general relativity. General relativity, as far as
we note, is true. But we also know that general
relativity is not quantum mechanical, right, that it cannot describe
microscopic things very well, things where the quantum description of
the universe takes over, where particles have fixed amounts of
(32:21):
energy and are divided up into concrete chunks. Right, general
relativity thinks of the universe is continuous and infinitely divisible,
but we know it's not that. Most of the time,
that's not a big deal because we're dealing with macroscopic objects.
But when you're talking about the inside of black holes
or the inside of wormholes, we're pretty sure that quantum
effects are going to be important, which means that if
you're gonna go inside a wormhole, you shouldn't just check
(32:43):
with general relativity. You need to check with quantum gravity,
which is the theory we don't even have. So I
would be very wary of going inside a wormhole, even
if you found one, even if you stabilized it, because
we don't really know what the rules are of quantum gravity, right,
and the hardest part seems to be to stand quantum physics.
It's pretty tricky. Yeah, you gotta be pretty smart to
(33:04):
understand quantum physics, I'll admit. Okay, So to answer the question,
can we use a wormhole to get to another star galaxy?
The answer is maybe, probably not theoretically possible, but it
seems practically impossible. I would be super impressed with the
(33:25):
next generation of engineers if we managed to build useful
wormholes in the next hundred years or so, I would
be very, very deeply impressed. Good job, guys, I think
you'd probably be dead. They'll probably send me as an
experimental subject through the first wormhole just to prove them wrong. Um. Yes,
so I would say. The takeaway is wormholes theoretically possible
(33:47):
but never been seen, and also very impractical. Right. But
let's carry the fantasy a little bit longer here, because
I heard I read that they wormholes might not just
connect space, but they could also connect space and time.
That's right, Space is part of this constructor called space
time right where time is sort of the fourth dimension.
And um, people have crazy ideas with what you could
(34:09):
do with wormholes if you found them. If you take
one end of the wormhole and you accelerated to really
really high speeds, then you can take advantage of time dilation. Right,
that's moving clocks run more slowly. Um. But if you're connected,
if you have a stationary point connected to the fast
moving point, that you can play all sorts of tricks
with special relativity and maybe even go back in time.
(34:32):
But Stephen Hawking says that's impossible. He says that if
you send anything through the wormhole that the wormhole will collapse.
And so they called this the chronological protection conjecture, with
the universes like conspired to make the laws of physics
impossible to do time travel. And I said, I took
a stand on our time travel episode. I said time
travel is impossible, and I stick by that because I
(34:55):
think that this concept of using wormholes and trail back
in time is absurd, not just impractical, but absurd and illogical. Okay,
so sorry to rain on your parade, to to to
prick your fantasy there, Jorge, let me throughout my idea
for a sci fi novel right here. I'm just gonna
I'm just gonna crush that out and put it in
the trash here. No, no, science fiction is totally allowed, totally.
You let in your universe. You can make up whatever
(35:17):
rules you want as long as you follow them, so
we can have that in your science fiction universe, no problem.
All right, I guess until then we have to sit
in traffic until the engineers figure out the wormhole. That's right,
And so we hope you enjoyed this episode of Daniel
and Jorge and um explain the universe and Daniel moorehe
shoot down your sci fi idea. That's right, and try
(35:38):
send me your sci fi idea through the wormhole of
the internet, and I'll tell you why it's wrong, but
in a very cheerful tone. That's right. Warm your way
into Daniel's inbox. All right. Thanks to everyone, have a
good one, see you next time. If you still have
(36:01):
a question after listening to all these explanations, please drop
us a line. We'd love to hear from you. You
can find us at Facebook, Twitter, and Instagram at Daniel
and Jorge as one Word, or email us at Feedback
at Daniel and Jorge dot com,
Hosts And Creators
Daniel Whiteson
Kelly Weinersmith
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