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welcome back to off world the show where
we talk about all things space
exploration and pop culture I'm Ariel
Waldman and I'm norm Chan and on today's
episode we are talking about a trope and
a topic that you may have heard about
black holes yeah objects of mysterious
what who knows what people imagine all
sorts of wackadoodle things about black
holes about things that you can sort of
pop into things where you might be
destroyed wormholes it's been a source
of inspiration I think it's safe to say
for science fiction writers and
filmmakers for a very long time and in
popular media one of the first films to
bring the idea of black holes into
mainstream consciousness was the black
hole a Disney live-action film from 1979
yeah it was one of the last films to
really do everything I think in manual
effects so the visualizations of it I
personally loved it it's that right it
strikes that right balance of like
cheesy cheesy old movie but really has
some adorable bits with robots and the
way they visualize spaceships and
spaceship interfaces I thought it was
personally pretty cool
and of course a depiction of a black
hole yeah which gets really trippy at
the end as you would imagine in 1979 so
today we're talking about both the black
hole the 1979 movie we're also talking
about more modern depictions such as
interstellar which is less trippy and
more I guess I don't know a lot of time
dilation a lot of Matthew McConaughey a
lot of love as an extra dimension a
little bit different I don't know I'm
not sure scientists have that pin down
quite yet
yeah well to help demystify some of that
we have a great guest so let's just jump
to the conversation
so we're talking about black holes today
and we have a really really awesome
guest please introduce yourself and what
it is exactly that you do hi should I
introduce myself to you or to the camera
either one I'm faster abdomen I'm a
third year grad student at UC Berkeley
in the Astronomy Department and I study
black holes yeah like so we're talking
about black holes today Norma are you
excited for this one yeah especially in
since black holes have been portrayed in
popular media movies and TVs in all
sorts of ways I'm really curious about
the accuracies of those depictions and
like what people don't know about black
holes yeah so we're at tonight if you
could actually explain what it is a
black hole is for people who are not
familiar or are a little rusty on what
black holes are so the basic thing I
would use to define a black hole is it
kind of needs a backup definition of an
escape velocity so the reason a
rocketship can leave the Earth's
gravitational pull but I can't if I'm
jumping is that the rocket ship has a
velocity high enough to surpass some
threshold set by the Earth's gravity and
escape velocity so anything traveling
above this velocity can leave there as
gravitational field and that velocity is
determined by basically how massive how
much mass and how big an object is so a
black hole is an object for which the
escape velocity surpasses the speed of
light and the speed of light is kind of
the universal speed limit on everything
nothing can travel faster than light in
a vacuum so if the escape velocity of
this object is larger than the speed of
light nothing can leave it once it
enters so what do you call it a
singularity so a singularity is kind of
what the term we use to describe the
center of a black hole structurally you
can kind of give it two parts so there's
the event horizon which is an imaginary
shell that defines the distance from the
center at which the escape velocity is
the speed of light so that's like the
boundary the the point of no return so I
anything past the event horizon can't
get back out and then the singularity is
the center of the black hole the point
of infinite density that's a super super
cool that like the the consequence of
these definitions are then these like
the things that we can visualize we
mention that event horizon
like the way that black holes I've seen
depicted in film almost like a disc
right but the you said a shell so it's
more it's a sphere yeah it would be a
radially or spherically symmetric object
just for the same reasons that most
things in space planets stars black
holes they're all spheres right just a
result of the fact that gravity is
symmetric and how things collapse just
gives you lots of spheres
yeah and it's it's essentially so dead
stars of a certain mass can create black
holes so that is one formation track I
suppose you could say for one type of
black hole and that's exactly about that
the most massive stars when they run
through all of their fuel and no longer
have energy to support the to push back
against the gravity that's been pulling
down towards their centers they
eventually can collapse into a black
hole okay and so where the what are the
other types of black holes so that the
the star dying is a stellar mass black
hole because it tends to have masses
similar to the masses of stars but you
can also have supermassive black holes
which tend to reside in the Centers of
galaxies and these can be over millions
of times the mass of the Sun also I've
been saying solar masses that means one
Sun mass just in case too much jargon I
don't know this has been great I feel
like this is a good like refresher for
everyone some people are more familiar
with black holes than others but I feel
like there's always new research and new
things coming out about black holes
which actually brings me to like how
long have we known about black holes so
the earliest kind of real idea of a
black hole people had proposed objects
from which light can't escape maybe as
early as the 1700s but it really came to
a head with Einstein's
theory of relativity where he proposed
this completely radical way of thinking
about gravity and there are many many
different things that kind of popped out
of this theory one of which or black
holes and so that was in the early like
the early part of the 20th century and
there has been plenty of work between
then and now in the theory of black
holes and it wasn't until way closer to
the end of the last century that we
actually started detecting things that
we would now consider black holes yeah
so I about the detecting you know one of
the movies we watched to sort of dive
into how black holes are depicted in pop
culture was the black hole from 1979 the
Disney movie you know was there anything
you think around the 70s that may have
like been a catalyst for Disney wanting
to make a movie around black holes where
they're just more scientific papers
coming out or review is just right after
the space race
you know everybody lots of national
pride in going to space and it's the
final frontier and lots of excitement
about this new unknown thing that we
were finally starting to go into
physically instead of just thinking
about and looking at I imagine that
could have had a lot to do with it yeah
I mean for me it feels like black holes
or something that even though I don't
know how much we know about it now
versus the 70s but there still feels
like there's so much unknowable oh
there's some everything right everything
but a lot of it is pretty unknown and
that makes it really ripe for science
fiction because to know to infer that
something can exist and have these
properties based on these theories but
then still not know so much then makes
it a fun thing to speculate about
especially when I have something this
massive that you can easily say oh it is
a like a black sphere that no one can
never know what's on the other side
that's fun yeah well like in the movie
they I think they were saying in the
black hole movie they were talking about
how space and time no longer exists
inside but do we actually know if okay
so okay so here's the the problem with
studying black holes and trying to say
anything about them particularly
internal to the event horizon so as I
said already a black hole as a thing
from which light cannot escape light
that is captured from something else or
if it is you know
it's own light it couldn't escape from
it right so it is inherently dark right
and in astronomy the way we learn about
things is by looking at light right when
you look at the sky all you see is the
the pinpricks of light from stars we
look at that light in great detail the
amount of light what color the light is
how it's moving how it's changing but
ultimately we need light to understand
things now there are a couple exceptions
to this things like neutrinos and more
recently gravitational waves which I'm
sure we'll get into in due time but the
vast majority of astronomical
information is gathered through looking
a light so how do you understand a thing
that doesn't have light right it just
isn't giving us any information there's
a boundary to the information we can
possibly extract from this which means
that screenwriters and novelists can
kind of say whatever they want and
nobody can really say they're wrong it's
this interesting like realm of total
creativity where there's I mean there's
there's speculations about you know
wormholes and and all of these exotic
ideas but something to realize maybe is
that there's the category of information
we have a black hole about black holes
that we can kind of verify and then
there's the theories and and all of the
things that you see past entry into
black holes fall into the theories and
there are some theories that are more
scientifically based than others but
definitely all still just definitively
within the realm of speculation right
well and you know something in which I
see black holes get depicted a lot
whether it's movies or TV or
what-have-you is that they get a very
bad rap or they're very evil or it's
like the most destructive force in the
universe and they're going to kill
everything in their path and maybe the
entire universe is going to get sucked
into a black hole you know but you know
I've seen some stuff around black holes
around how they might you know actually
help create things or they might
actually be healthy for galaxies to have
since there's a supermassive black hole
and most galaxies
things of that nature are there ways in
which you think black holes are actually
a healthy part of galaxies or well
before getting to healthiness just to
debunk some of the ideas that they just
go around gobbling up everything right I
think one of the the little facts I
always pull out that surprised people is
that if right now our Sun that we're
orbiting turned into a black hole of the
same mass we would keep going around it
the way we are now it would be pretty
dark and we'd probably die from the lack
of energy that we're receiving that
we're very reliant on pretty soon but in
terms of the Earth's motion it wouldn't
immediately get sucked in it would
continue orbiting this newly created a
hypothetical black hole because even
though black holes have this these
extreme gravitational properties when
you get close into them at a distance
they still behave like any other object
with mass so planets orbit stars and a
stars orbit each other and sometimes you
can have a star in a black hole orbiting
each other and that's a completely maybe
not super common but not a surprising
thing to see at all so they're they're
not as aggressively violence as people
tend to think where they're going out of
their way they kind of just sit where
they are and interact in in ways that
other objects tend to in some cases now
like you were saying about supermassive
black holes in the center of galaxies so
for those of you who are not familiar
this class of a supermassive black hole
is that way millions or hundreds of
millions of or even billions of times
the mass of the Sun reside in the center
of most galaxies and you can imagine
again this thing's orbiting each other
all the stars in a galaxy orbit around
this central supermassive black hole but
in addition to stars orbiting the black
hole you can often have other materials
so like gas dust that accumulates in
galaxies also orbiting these black holes
and what's called an accretion disk an
accretion disk is basically if you had a
black hole right here you can imagine
kind of
a drain everything swirling into it on a
disk and this is just the stream of gas
and dust and other particles coming in
really really really fast one thing to
keep in mind is just like the escape
velocity of a black hole is a speed of
light that means that things falling
into it will be traveling close to that
speed once they come in so you have all
these really rapidly moving particles
generating lots of heat emitting lots of
radiation and this radiation actually
does a lot to power processes in the
galaxies such as star formation and the
things happen right outside the event
horizon things we can observe how much
of that informs what we think or what we
know about oh it informs alive so one of
the ways in which people can point to a
galaxy a galaxy that might just be a few
pixels in your little images that you're
trying to look at it and say something
meaningful about even if you can't see
this supermassive black hole because
obviously we as I said before you can't
see the black hole you look at the
effects that it has on things around it
so you can look at the the orbital
dynamics of everything else in the
galaxy and see maybe you might look at
as a function of how close you are to
the center how quickly our star is
moving and that can tell you the mass of
the thing that they must be orbiting so
by looking at dynamics and galaxies
people can say okay that galaxy has a
supermassive black hole at its center
with a mass of blah blah blah yeah so
well I have to ask you you know we're
going a bit into the science of black
holes but so what were your thoughts on
how it was depicted in the 1979 film of
you know they go into the black hole and
well before they go I call when I talk
about you know this ship with
anti-gravity field yes being able to
outrun the black hole's pool and right
so anti-gravity field statically I'm not
sure how that works the idea that I
think that if I'm getting this correct
from the movie is that they're pushing
against it so they're like constantly
running away from it or at least I maybe
I'm being generous that's what I think
they would want to try so just like we
had established the idea of
velocity right at the event horizon it
would be close it would be the speed of
light a little bit far away from it it
would be very very high but maybe
something that in the sci-fi world is an
attainable speed like 90% the speed of
light or something like that depending
on how far away they are so I guess what
they're doing in the movie is saying
here's the black hole and here's us and
we're traveling that way fast enough to
be pulling against or
counteracting the pull of the black hole
which is fine it's a it's it's an it's
an ambitious technological feat but
there's nothing to say that if you had
the capacity to reach speeds like that
that you couldn't do that though
realistically other things might come in
your way before even crossing the event
horizon before we continue on with this
week's episode I want you know that
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ort a TV now back to the conversation
right well so we also have you know just
the depictions generally of black holes
over time so in this 79 film you know it
sort of looks like a swirling galaxy but
then you've you know you jump several
years and decades ahead to interstellar
which like put a lot of effort and and
science advising into what a black hole
might look like if you get up close to
it and so you see mortis or the
accretion disk that you're talking about
in front of it do you think that we're
getting closer to depicting what might
be going on in a black hole do you think
sci-fi is paying more attention to the
actual physics involved or do you think
we're still kind of far often and how we
depict it so interstellar was a really
cool case so as I'm sure you know Kip
Thorne was the like science consultant
and he I think he and somebody else had
originally written the movie in a form
that isn't what it became but it would
initially they were trying really really
hard to keep it true to what is
physically possible
maybe not technologically possible
currently but within the realms of what
physics allows right and so this was
really interesting he wrote a whole book
on the science of interstellar and I
read it back in the movie came out and
one of the things that really struck me
was that the depictions like visually of
the black hole in the in the case of the
movie it's a it's a wormhole right so
the idea is that you enter the black
hole next to Jupiter to get into the
wormhole on one side and pop out
somewhere else and there's something
else on that other side it's like a
different point in space not some other
universe but just the other side of this
universe you know and so what they did
to depict the black hole was they're
like okay so here's the view you would
see on the other side now let's warp
that view like take that picture that
you would have seen on the other side of
the wormhole and distorted in a
mathematically rigorous way based on I'm
Stein's equations of relativity and how
grab how or all these since developed
theories on how wormholes would function
and you know meticulously calculate what
that would look like on the other side
so what you see when you look at the
black hole in interstellar is a
projection of what would be on the other
side through a wormhole which is
honestly the fact that not even that but
specifically through a wormhole and then
into an IMAX cam
to account the optics of the camera
itself and things like lens flares and
all that lens glares lens flares I don't
know things about cameras but yeah so
they so they go into all that detail
just for the visual of the black hole
not even like that the story or what it
does or the time dilation and all that
but just for the image they were like
building these like ray tracing programs
that's just really really elaborate so
I'm pretty impressed yeah well I'm glad
to hear it because I've seen it sort of
copied I think like a recent episode of
Star Trek discovery actually had a black
hole that looked very similar to
interstellar version of black holes so
I'm hoping like all that hard work will
like go into like paying off or like
having more accurate movies and TV shows
in the future until the next big
ambitious movie wants to crunch the math
again and and show their portrayal you
mentioned um time dilation and it's
something that's I've always wondered as
you get closer to so the event horizon
you're moving closer to the speed of
light so relatively speaking the way you
experience time there would be
essentially different than people
further away yeah how does that work and
what does that I mean I've heard the
theory that you know as you get close
you see the end of the universe because
everything else is moving right so much
slower for you basically there's a
effects on sensory relativity that says
that when you're in very very very
strong gravitational fields the way time
flows can be distorted right so the the
idea here is that if you are close to a
black hole for you the passage of time
goes more slowly so this is why in the
movie Matthew McConaughey's character
comes towards you know he goes to that
planet that's near the black hole and
then he when they go back everybody is
much older time has passed so for
everybody on board that ship that came
close to the black hole time just slowed
down because of the present you know
their proximity
to the black hole and it seems pretty
outlandish but that's actually a very
rigorously tested theoretically
supported idea that we we kind of
classify as true at this point so the
time dilation has seen an interstellar
is that sort of was the time differences
kind of just convenient for moviemaking
purposes or were they on the order of
the actual time dilation that you might
have around a black hole I don't know if
anything into two mice so it's no it's
actually apparently if you had a black
hole of whatever mass it wasn't the
movie and you you calibrated its spin
just correctly I think that was a
critical thing and getting that to be
realistic that it would have to be a
rotating black hole then you could have
a planet nearby it that was in a stable
orbit that experienced that amount of
time dilation apparently it was a point
of contention between Christopher Nolan
and Kip Thorne where he's like I want it
to be seven years for one hour I was
like no that doesn't work and he's like
go do the calculations and he did it was
like okay I just need to make it spin
mathematically very cool so we have
these kind of bookends in the
pop-culture portrayals right from 1979
to so our seller was at 28 2014 right is
there a renewed interest or more
information about black holes so one of
the most notable discoveries in physics
at least in this century so far is the
detection of gravitational waves so I'll
probably get into the details of this
but baseline when two black holes are
rotating around each other and they
eventually collide in right before when
they're in spiraling they release
gravitational waves which are like
ripples through space and time itself
that we measured in 2015 for the first
time ya know I was so extremely
extremely excited so just a year after
interstellar came out all this
excitement about a black hole in a movie
we had this completely groundbreaking
revolutionary discovery in physics that
is fundamentally changing the way we can
start to study black holes that Einstein
predicted a hundred years ago that were
only now seeing for the first time and
since that first gravitational wave
detection of that first black hole
mergers I think there have been a
handful more that have been discovered
and people are building more and more of
these specific types of instruments that
can detect these gravitational waves and
so this is there's no way to under 200
vs. how much of a change this is in the
way astronomy is done because just like
I was saying light earlier is the only
way and we know everything more yeah
exactly we have a it's like we could see
before and now we could hear so it's
it's really going to change the game
alone yeah I
endlessly fascinated with how we
actually detect gravitational waves and
it's essentially like with like oh and
the other detectors is like all we do is
we put very careful measuring tape and
we just wait around for a wave to kind
of pass through and then we see
basically we see the measuring tape like
if we're measuring a room we see that
room grow by like white like a quarter
of a neutron or softening or something
like that
it's amazing that we're like actually
detecting it just by detecting like yeah
there's it's really cool so is that you
know I know that's like an extremely
exciting area of black hole research and
and really opens up a lot is there
anything that you're looking at now
that's really exciting you now that
we've detected gravitational waves so my
like my in the research sense my
research is pretty far removed from that
type of black hole detection I do a
completely different thing in order to
look for black holes however I will say
that I've spent a lot of time since then
sitting around with friends saying okay
gravitational waves are a thing how can
we use them what are they become become
like I feel like this is such a ripe
area for sci-fi in the future just
because it's a it's a whole other thing
that we've just not really considered
before like what does
what happens when a civilization could
create gravitational waves and could you
you know use them as the basis for
technology like think of how much of
modern technology is kind of being able
to manipulate electromagnetic fields
what if we could manipulate
gravitational fields like it's it just
for a mental exercise fun thought
experiment perspective it's something I
like to think about a lot but uh it's
unfortunately not very related to the
the actual work I do oh but it's fun to
think about and I feel like that
creativity will ultimately inspire you
to sort of think about new ways of
looking at things and I think that's
what's really awesome about science
fiction and and having black holes in
science fiction is because even as we
discover more about them there's just so
much left that we don't know right
that's the exciting part it is exciting
thirty years later we could look back at
interstellar in the same way we're
looking back black hole exactly are
there other things that you just kind of
we're done with in terms of depictions
of black hole in science fiction let's
no longer talk about them as wormholes
or things that you really want to see in
the spacefaring aspect I mean so I feel
like wormholes were cool for sci-fi
because it's just such an interesting
plot device the same way time-travel is
such an interesting plot device even
though neither are things that are like
very feasible but I think there are
areas of research that could kind of be
interesting to people developing sci-fi
like I was I was at a conference
recently where me and a couple other
people who were attended who also
presented their research on literally a
table of people who look for black holes
right and we were just sitting around
thinking like okay if we were on tour
like write a book describing the thing
that we I studied basically it's called
gravitational lensing it's when it's
another gravitational effect not time
dilation anything like that but black
holes can warp light traveling around
them and I basically look for that
warped light so we're sitting around
saying okay there's this there's this
thing we all study how could we like
what
angle could we use to make it
interesting like could you make a weapon
that's a gravitational lens could you
like have a civilization like
artificially making lens situations in
order to achieve some technological goal
could you so it's it's it's again just
that kind of head in there speculation
like huh that would be interesting but
yeah I feel like I'm forgetting what the
actual question anymore filmmakers yeah
the people know exactly with new ideas
more interesting stories endlessly just
fascinating area well thank you so much
for being on the show today having me it
was super fun I don't know if it shows
but I basically love talking about this
stuff to anybody who will listen
it makes all my friends and family
pretty annoyed probably but we love it
I'm glad this is the right place for me
yeah we're all geeks here great I love
it ok so we drove into a lot of
different aspects of black holes time
dilation we jumped into whether or not
there are worlds inside black holes why
people even imagined in the first place
that there's worlds inside black holes
and it just comes down to the fact that
we don't know a whole lot but what's
really exciting is gravitational waves
and all this stuff that's going to be
bringing through just way more
information about black holes over the
coming decades so it's kind of the
Renaissance of what we could imagine
black holes are or what they're like if
we were to encounter them in outer space
and we ended with you know how can
storyteller is really make use of that
and that's really the big question right
we have these kind of tried and true
depictions and plot devices using black
holes but I think going forward everyone
from researchers to pop culture fans
included would love to see this
mysterious object and an idea of being
taken in different directions yeah
actually I in the comments I'd be
interested to hear all of you what you
have to say about what you would like to
see depicted in films or TV or even
books about I don't know why it would be
like to interact with black holes or how
we could have more interesting stories
around black holes in the future or if
you know of a great story that does
involve a black hole we'd love to hear
that suggestion as well you can catch
offworld as a video on YouTube but also
as audio only on as a podcast that
tested comm / off world and we'll be
back next time with another episode
you
