so time travel has really captures our imagination I have some examples here on
imagination I have some examples here on
imagination I have some examples here on my title slide we’ve got the poster from
my title slide we’ve got the poster from
my title slide we’ve got the poster from Back to the Future this interesting
Back to the Future this interesting
Back to the Future this interesting painting by Salvador Dali and Marcel
painting by Salvador Dali and Marcel
painting by Salvador Dali and Marcel Duchamp and of course there’s a Star
Duchamp and of course there’s a Star
Duchamp and of course there’s a Star Trek in countless science fiction media
Trek in countless science fiction media
Trek in countless science fiction media now I always in all my talks on time
now I always in all my talks on time
now I always in all my talks on time travel point out this quote or something
travel point out this quote or something
travel point out this quote or something like it this is from Simon Newcomb
like it this is from Simon Newcomb
like it this is from Simon Newcomb aerial flight is one of the classic
aerial flight is one of the classic
aerial flight is one of the classic problems with which men will never have
problems with which men will never have
problems with which men will never have to cope I didn’t include it in my talk
to cope I didn’t include it in my talk
to cope I didn’t include it in my talk but the New York Times in July of 1969
but the New York Times in July of 1969
but the New York Times in July of 1969 you’ll probably figure out why that’s a
you’ll probably figure out why that’s a
you’ll probably figure out why that’s a significant date had to retract a
significant date had to retract a
significant date had to retract a statement they wrote in 1920 saying that
statement they wrote in 1920 saying that
statement they wrote in 1920 saying that a rocket will never leave the Earth’s
a rocket will never leave the Earth’s
a rocket will never leave the Earth’s atmosphere because it has nothing to
atmosphere because it has nothing to
atmosphere because it has nothing to push against oops so my point here is is
push against oops so my point here is is
push against oops so my point here is is that even though as we’ll see today that
that even though as we’ll see today that
that even though as we’ll see today that even if time travel is most likely
even if time travel is most likely
even if time travel is most likely impossible due to our best understanding
impossible due to our best understanding
impossible due to our best understanding of physics our best understanding has
of physics our best understanding has
of physics our best understanding has has been wrong so it’s not just that a
has been wrong so it’s not just that a
has been wrong so it’s not just that a non-scientist writing article in The New
non-scientist writing article in The New
non-scientist writing article in The New York Times for example has been wrong
York Times for example has been wrong
York Times for example has been wrong but also experts have been wrong on the
but also experts have been wrong on the
but also experts have been wrong on the feasibility of air travel and the
feasibility of air travel and the
feasibility of air travel and the feasibility of space travel and I could
feasibility of space travel and I could
feasibility of space travel and I could have an entire talk on quotes of of
have an entire talk on quotes of of
have an entire talk on quotes of of famous astronomers saying how space
famous astronomers saying how space
famous astronomers saying how space travel was nonsense and will never and
travel was nonsense and will never and
travel was nonsense and will never and will never leave the Earth’s gravity so
will never leave the Earth’s gravity so
will never leave the Earth’s gravity so no a talk on time travel really needs to
no a talk on time travel really needs to
no a talk on time travel really needs to start with Einstein’s theory of special
start with Einstein’s theory of special
start with Einstein’s theory of special relativity so Einstein solved of the
relativity so Einstein solved of the
relativity so Einstein solved of the many epiphanies he had and many problems
many epiphanies he had and many problems
many epiphanies he had and many problems he was able to solve
he was able to solve
he was able to solve he saw the the an issue between
he saw the the an issue between
he saw the the an issue between classical physics of mechanics and
classical physics of mechanics and
classical physics of mechanics and electromagnetism and he was able to we
electromagnetism and he was able to we
electromagnetism and he was able to we don’t have time of course brief time
don’t have time of course brief time
don’t have time of course brief time together today to go through all the
together today to go through all the
together today to go through all the details but he was able to solve and
details but he was able to solve and
details but he was able to solve and reconcile
reconcile
reconcile some contradictory models and parts of
some contradictory models and parts of
some contradictory models and parts of physics by postulating that the speed of
physics by postulating that the speed of
physics by postulating that the speed of light is constant in all frames of
light is constant in all frames of
light is constant in all frames of reference and we especially in science
reference and we especially in science
reference and we especially in science fiction like to think of that as a
fiction like to think of that as a
fiction like to think of that as a limitation all speed of light is not
limitation all speed of light is not
limitation all speed of light is not that fast when you think of
that fast when you think of
that fast when you think of intergalactic skills but is it results
intergalactic skills but is it results
intergalactic skills but is it results in some incredibly interesting and
in some incredibly interesting and
in some incredibly interesting and important mathematical consequences and
important mathematical consequences and
important mathematical consequences and one of them is the twin paradox which
one of them is the twin paradox which
one of them is the twin paradox which isn’t really a paradox oh it’s a
isn’t really a paradox oh it’s a
isn’t really a paradox oh it’s a terrible name for it because it’s a real
terrible name for it because it’s a real
terrible name for it because it’s a real effect and in fact even though I’m
effect and in fact even though I’m
effect and in fact even though I’m illustrating with a cartoon with
illustrating with a cartoon with
illustrating with a cartoon with interstellar travel that we’re not
interstellar travel that we’re not
interstellar travel that we’re not capable of yet as a species on the on
capable of yet as a species on the on
capable of yet as a species on the on this on small scales especially at the
this on small scales especially at the
this on small scales especially at the subatomic level we know that the the
subatomic level we know that the the
subatomic level we know that the the twin effect is I prefer to call it is
twin effect is I prefer to call it is
twin effect is I prefer to call it is real so the so Harold Lyons who’s the
real so the so Harold Lyons who’s the
real so the so Harold Lyons who’s the father of sherry lines who’s one of our
father of sherry lines who’s one of our
father of sherry lines who’s one of our organizers today actually invented the
organizers today actually invented the
organizers today actually invented the first atomic clock you can see post an
first atomic clock you can see post an
first atomic clock you can see post an atomic clock there and a photo of Harold
atomic clock there and a photo of Harold
atomic clock there and a photo of Harold Lyons over there was a the atomic clock
Lyons over there was a the atomic clock
Lyons over there was a the atomic clock which is our most precise timekeeping
which is our most precise timekeeping
which is our most precise timekeeping device was able to demonstrate that what
device was able to demonstrate that what
device was able to demonstrate that what I’m about to tell you is an actual real
I’m about to tell you is an actual real
I’m about to tell you is an actual real fact so the classic example of the twin
fact so the classic example of the twin
fact so the classic example of the twin paradox is that you have you have two
paradox is that you have you have two
paradox is that you have you have two twins and one takes an interstellar
twins and one takes an interstellar
twins and one takes an interstellar journey to some distant star planet
journey to some distant star planet
journey to some distant star planet closest speed of light turns around and
closest speed of light turns around and
closest speed of light turns around and comes back and the the the twin who took
comes back and the the the twin who took
comes back and the the the twin who took the journey it is one that when he
the journey it is one that when he
the journey it is one that when he returns earth is significantly younger
returns earth is significantly younger
returns earth is significantly younger than his brother or sister and this is
than his brother or sister and this is
than his brother or sister and this is this is a real effect that we cannot do
this is a real effect that we cannot do
this is a real effect that we cannot do on these large scales yet but the thanks
on these large scales yet but the thanks
on these large scales yet but the thanks to atomic clocks and very fast planes we
to atomic clocks and very fast planes we
to atomic clocks and very fast planes we can show that indeed this is a real
can show that indeed this is a real
can show that indeed this is a real effect and that time is plastic we
effect and that time is plastic we
effect and that time is plastic we talked a lot about we talked about
talked a lot about we talked about
talked a lot about we talked about neuroplasticity today we all have this
neuroplasticity today we all have this
neuroplasticity today we all have this intuition that time is absolute but that
intuition that time is absolute but that
intuition that time is absolute but that is shattered by Einstein in relativity
is shattered by Einstein in relativity
is shattered by Einstein in relativity time is not absolute and your time and
time is not absolute and your time and
time is not absolute and your time and my time do not
my time do not
my time do not floo at the exact same rate it’s not
floo at the exact same rate it’s not
floo at the exact same rate it’s not like the universe has a universal
like the universe has a universal
like the universe has a universal timepiece and every star in Planet has a
timepiece and every star in Planet has a
timepiece and every star in Planet has a clock ticking at some at the same rate
clock ticking at some at the same rate
clock ticking at some at the same rate so if we take this now and so if this is
so if we take this now and so if this is
so if we take this now and so if this is a question now of Engineering and
a question now of Engineering and
a question now of Engineering and Technology not of physics so this is if
Technology not of physics so this is if
Technology not of physics so this is if we had the fuel probably something
we had the fuel probably something
we had the fuel probably something better than fossil fuels to do
better than fossil fuels to do
better than fossil fuels to do interstellar travel this is guaranteed
interstellar travel this is guaranteed
interstellar travel this is guaranteed to work but now this is maybe not as
to work but now this is maybe not as
to work but now this is maybe not as satisfying this is time travel to the
satisfying this is time travel to the
satisfying this is time travel to the future one way because your your your
future one way because your your your
future one way because your your your your contemporary friends or your this
your contemporary friends or your this
your contemporary friends or your this you may outlive your descendants by
you may outlive your descendants by
you may outlive your descendants by taking an interstellar trip coming back
taking an interstellar trip coming back
taking an interstellar trip coming back to earth but that’s a one-way trip to
to earth but that’s a one-way trip to
to earth but that’s a one-way trip to the future now let’s try to if we try to
the future now let’s try to if we try to
the future now let’s try to if we try to do some mathematical extrapolations in
do some mathematical extrapolations in
do some mathematical extrapolations in relativity to see well what can we do to
relativity to see well what can we do to
relativity to see well what can we do to get to the past so if we mathematically
get to the past so if we mathematically
get to the past so if we mathematically extrapolate that as you approach the
extrapolate that as you approach the
extrapolate that as you approach the speed of light we know that time slows
speed of light we know that time slows
speed of light we know that time slows down in some sort of it’s an ill-defined
down in some sort of it’s an ill-defined
down in some sort of it’s an ill-defined sense but at the speed of light time
sense but at the speed of light time
sense but at the speed of light time stops then if we extrapolate that ah
stops then if we extrapolate that ah
stops then if we extrapolate that ah faster than the speed of light should
faster than the speed of light should
faster than the speed of light should mean time goes in Reverse unfortunately
mean time goes in Reverse unfortunately
mean time goes in Reverse unfortunately though you would meet an infinite amount
though you would meet an infinite amount
though you would meet an infinite amount of energy to push anything with nonzero
of energy to push anything with nonzero
of energy to push anything with nonzero mass to the speed of light itself let
mass to the speed of light itself let
mass to the speed of light itself let alone to exceed it so that doesn’t seem
alone to exceed it so that doesn’t seem
alone to exceed it so that doesn’t seem to be something practical or realistic
to be something practical or realistic
to be something practical or realistic in any way so now let’s expand though
in any way so now let’s expand though
in any way so now let’s expand though from special relativity to Einstein’s
from special relativity to Einstein’s
from special relativity to Einstein’s other great epiphany which was general
other great epiphany which was general
other great epiphany which was general relativity where he essentially rewrote
relativity where he essentially rewrote
relativity where he essentially rewrote Newton’s theory of gravity to have a
Newton’s theory of gravity to have a
Newton’s theory of gravity to have a just Co come up with a completely
just Co come up with a completely
just Co come up with a completely different theory of gravity that
different theory of gravity that
different theory of gravity that explains gravity in a different way
explains gravity in a different way
explains gravity in a different way through gravity being the geometry of
through gravity being the geometry of
through gravity being the geometry of space-time and not just some mysterious
space-time and not just some mysterious
space-time and not just some mysterious force and recently this year’s you know
force and recently this year’s you know
force and recently this year’s you know Nobel Prize in Physics was awarded for
Nobel Prize in Physics was awarded for
Nobel Prize in Physics was awarded for the discovery of gravitational waves
the discovery of gravitational waves
the discovery of gravitational waves which is an astounding additional upon
which is an astounding additional upon
which is an astounding additional upon other existing mountains of evidence of
other existing mountains of evidence of
other existing mountains of evidence of the of the predictive power
the of the predictive power
the of the predictive power of general relativity and how it
of general relativity and how it
of general relativity and how it accurately explains the world around us
accurately explains the world around us
accurately explains the world around us if we look at general relativity you can
if we look at general relativity you can
if we look at general relativity you can come up with something known as a
come up with something known as a
come up with something known as a tippler cylinder so this is another
tippler cylinder so this is another
tippler cylinder so this is another attempt at trying to get some something
attempt at trying to get some something
attempt at trying to get some something that gets us time travel to the past and
that gets us time travel to the past and
that gets us time travel to the past and the idea here is is you have a very
the idea here is is you have a very
the idea here is is you have a very dense material and that if it’s rotating
dense material and that if it’s rotating
dense material and that if it’s rotating fast enough and the materials dense
fast enough and the materials dense
fast enough and the materials dense enough this twist spacetime in a way
enough this twist spacetime in a way
enough this twist spacetime in a way that traveling around the cylinder in
that traveling around the cylinder in
that traveling around the cylinder in space should get get you back in time
space should get get you back in time
space should get get you back in time you can think of this a good analogy is
you can think of this a good analogy is
you can think of this a good analogy is a spiral staircase so we’re all taught
a spiral staircase so we’re all taught
a spiral staircase so we’re all taught that if you if you walk around 360
that if you if you walk around 360
that if you if you walk around 360 degrees you return to the same point try
degrees you return to the same point try
degrees you return to the same point try that on a spiral staircase you do not
that on a spiral staircase you do not
that on a spiral staircase you do not return to the same point the idea here
return to the same point the idea here
return to the same point the idea here is is that with a spinning cylinder with
is is that with a spinning cylinder with
is is that with a spinning cylinder with you can set up the right space-time
you can set up the right space-time
you can set up the right space-time geometry that gets space-time twisting
geometry that gets space-time twisting
geometry that gets space-time twisting such that if you execute 360 degrees
such that if you execute 360 degrees
such that if you execute 360 degrees spatially you return to a different
spatially you return to a different
spatially you return to a different point in time including the past the
point in time including the past the
point in time including the past the problem with this is is well how would
problem with this is is well how would
problem with this is is well how would you get a material that’s dense enough
you get a material that’s dense enough
you get a material that’s dense enough and one of the main issues pointed out
and one of the main issues pointed out
and one of the main issues pointed out by Stephen Hawking is that for any of
by Stephen Hawking is that for any of
by Stephen Hawking is that for any of these types of ideas you would need
these types of ideas you would need
these types of ideas you would need either an infinitely long cylinder or
either an infinitely long cylinder or
either an infinitely long cylinder or you’d need something called negative
you’d need something called negative
you’d need something called negative energy basically matter that would have
energy basically matter that would have
energy basically matter that would have a would have negative mass instead of
a would have negative mass instead of
a would have negative mass instead of positive which I’ll come back to later
positive which I’ll come back to later
positive which I’ll come back to later so it doesn’t look like warping
so it doesn’t look like warping
so it doesn’t look like warping space-time is gonna work we have these
space-time is gonna work we have these
space-time is gonna work we have these infeasible obstacles infinite length how
infeasible obstacles infinite length how
infeasible obstacles infinite length how you gonna make something infinitely long
you gonna make something infinitely long
you gonna make something infinitely long although I think the size of the
although I think the size of the
although I think the size of the universe would would work too so if the
universe would would work too so if the
universe would would work too so if the universe isn’t infinite you can get
universe isn’t infinite you can get
universe isn’t infinite you can get around this what if instead of trying to
around this what if instead of trying to
around this what if instead of trying to twist space-time you try to punch a hole
twist space-time you try to punch a hole
twist space-time you try to punch a hole through it so this is the very classic
through it so this is the very classic
through it so this is the very classic here’s a picture of the the idea of a
here’s a picture of the the idea of a
here’s a picture of the the idea of a wormhole where you can punch a hole
wormhole where you can punch a hole
wormhole where you can punch a hole through space-time and you get from one
through space-time and you get from one
through space-time and you get from one distant location to another or even
distant location to another or even
distant location to another or even another universe or hopefully even
another universe or hopefully even
another universe or hopefully even better to a point in the past or future
better to a point in the past or future
better to a point in the past or future and the this is just a car
and the this is just a car
and the this is just a car tune the class example of this is you
tune the class example of this is you
tune the class example of this is you take a sheet of paper or you poke a hole
take a sheet of paper or you poke a hole
take a sheet of paper or you poke a hole through it to point out how what if you
through it to point out how what if you
through it to point out how what if you can have a shortcut through space-time I
can have a shortcut through space-time I
can have a shortcut through space-time I should point out this is only a cartoons
should point out this is only a cartoons
should point out this is only a cartoons and so we have three spatial dimensions
and so we have three spatial dimensions
and so we have three spatial dimensions they got this right in the movie
they got this right in the movie
they got this right in the movie interstellar a wormhole would actually
interstellar a wormhole would actually
interstellar a wormhole would actually be a sphere not a 2d hole like we’re
be a sphere not a 2d hole like we’re
be a sphere not a 2d hole like we’re used to in in the book so this is just
used to in in the book so this is just
used to in in the book so this is just an analogy because I can’t give you a
an analogy because I can’t give you a
an analogy because I can’t give you a four dimensional projection and
four dimensional projection and
four dimensional projection and PowerPoint that that’ll be in a future
PowerPoint that that’ll be in a future
PowerPoint that that’ll be in a future version so and there’s a the problem
version so and there’s a the problem
version so and there’s a the problem with wormholes this is a great idea and
with wormholes this is a great idea and
with wormholes this is a great idea and you can write down the equations for
you can write down the equations for
you can write down the equations for this in general relativity and as I said
this in general relativity and as I said
this in general relativity and as I said before we believe in relativity we
before we believe in relativity we
before we believe in relativity we discovered gravitational waves we saw
discovered gravitational waves we saw
discovered gravitational waves we saw war this week and your your GPS needs
war this week and your your GPS needs
war this week and your your GPS needs relativistic Corrections we’re both
relativistic Corrections we’re both
relativistic Corrections we’re both special and general relativity as we
special and general relativity as we
special and general relativity as we communicate with satellites they’re
communicate with satellites they’re
communicate with satellites they’re traveling fast and are far from the US
traveling fast and are far from the US
traveling fast and are far from the US gravitational field but these the
gravitational field but these the
gravitational field but these the equations of general relativity tell us
equations of general relativity tell us
equations of general relativity tell us that unfortunately a wormhole would be
that unfortunately a wormhole would be
that unfortunately a wormhole would be unstable even a laser pointer even light
unstable even a laser pointer even light
unstable even a laser pointer even light attempting to traverse the wormhole
attempting to traverse the wormhole
attempting to traverse the wormhole would collapse it you need something
would collapse it you need something
would collapse it you need something with negative mass or at least negative
with negative mass or at least negative
with negative mass or at least negative mass squared to go through what just
mass squared to go through what just
mass squared to go through what just knows the the tachyon particle the
knows the the tachyon particle the
knows the the tachyon particle the hypothetical particle that’s always
hypothetical particle that’s always
hypothetical particle that’s always traveling faster than the speed of light
traveling faster than the speed of light
traveling faster than the speed of light and so this again runs into this issue
and so this again runs into this issue
and so this again runs into this issue of negative mass seems to be a running
of negative mass seems to be a running
of negative mass seems to be a running theme of something we need for time
theme of something we need for time
theme of something we need for time travel and I’m going to now explain why
travel and I’m going to now explain why
travel and I’m going to now explain why that appears to be the case so this is a
that appears to be the case so this is a
that appears to be the case so this is a classic a cartoon that’s used to
classic a cartoon that’s used to
classic a cartoon that’s used to illustrate it with a 2d analogy of our
illustrate it with a 2d analogy of our
illustrate it with a 2d analogy of our of our three dimensions of space what
of our three dimensions of space what
of our three dimensions of space what the how general relativity describes
the how general relativity describes
the how general relativity describes gravity in the universe so bodies with
gravity in the universe so bodies with
gravity in the universe so bodies with mass the earth the Sun will make dents
mass the earth the Sun will make dents
mass the earth the Sun will make dents in space-time the more massive an object
in space-time the more massive an object
in space-time the more massive an object is though the more significant the dent
is though the more significant the dent
is though the more significant the dent so our the Earth orbits the Sun not
so our the Earth orbits the Sun not
so our the Earth orbits the Sun not because there’s this as there’s this
because there’s this as there’s this
because there’s this as there’s this mysterious action at a distance that
mysterious action at a distance that
mysterious action at a distance that Isaac Newton would call it but because
Isaac Newton would call it but because
Isaac Newton would call it but because there’s this invisible manifold of
there’s this invisible manifold of
there’s this invisible manifold of space-time that’s being warped and if
space-time that’s being warped and if
space-time that’s being warped and if you have enough a velocity you
you have enough a velocity you
you have enough a velocity you all around something instead of into it
all around something instead of into it
all around something instead of into it but if we keep extrapolating and
but if we keep extrapolating and
but if we keep extrapolating and extrapolating we get from the earth to
extrapolating we get from the earth to
extrapolating we get from the earth to the Sun to entire clusters of galaxies
the Sun to entire clusters of galaxies
the Sun to entire clusters of galaxies which are have enough gravitational
which are have enough gravitational
which are have enough gravitational field to actually bend light the Sun
field to actually bend light the Sun
field to actually bend light the Sun does is well of course and even the
does is well of course and even the
does is well of course and even the earth emits a much smaller effect but if
earth emits a much smaller effect but if
earth emits a much smaller effect but if we keep going to black holes this is a
we keep going to black holes this is a
we keep going to black holes this is a picture from the movie interstellar then
picture from the movie interstellar then
picture from the movie interstellar then if we keep extrapolating in the
if we keep extrapolating in the
if we keep extrapolating in the classical theory of general relativity
classical theory of general relativity
classical theory of general relativity there comes a point where at me at the
there comes a point where at me at the
there comes a point where at me at the event horizon of a black hole the point
event horizon of a black hole the point
event horizon of a black hole the point of no-return beyond which even light
of no-return beyond which even light
of no-return beyond which even light can’t escape if you if you throw
can’t escape if you if you throw
can’t escape if you if you throw something into a black hole to an
something into a black hole to an
something into a black hole to an external observer it would be as if time
external observer it would be as if time
external observer it would be as if time had stopped so the extrapolation here
had stopped so the extrapolation here
had stopped so the extrapolation here similarly to the extrapolation with
similarly to the extrapolation with
similarly to the extrapolation with speed as you approach the speed of light
speed as you approach the speed of light
speed as you approach the speed of light time slows down and stops if we do this
time slows down and stops if we do this
time slows down and stops if we do this with gravity in general and says special
with gravity in general and says special
with gravity in general and says special relativity as gravity goes to infinity
relativity as gravity goes to infinity
relativity as gravity goes to infinity time slows down to the point of stopping
time slows down to the point of stopping
time slows down to the point of stopping now again though time is relative if
now again though time is relative if
now again though time is relative if you’re falling into the black hole you
you’re falling into the black hole you
you’re falling into the black hole you don’t freeze at the border you fall in
don’t freeze at the border you fall in
don’t freeze at the border you fall in and die okay so this is the external
and die okay so this is the external
and die okay so this is the external observer so some day I think it will be
observer so some day I think it will be
observer so some day I think it will be a lot of fun to just park next to a
a lot of fun to just park next to a
a lot of fun to just park next to a black hole and throw stuff at it and
black hole and throw stuff at it and
black hole and throw stuff at it and create this ring of frozen objects that
create this ring of frozen objects that
create this ring of frozen objects that appear frozen in time again though from
appear frozen in time again though from
appear frozen in time again though from the objects perspective it falls in and
the objects perspective it falls in and
the objects perspective it falls in and an is crushed in the singularity most
an is crushed in the singularity most
an is crushed in the singularity most likely according to our current best
likely according to our current best
likely according to our current best understanding now let’s let’s look at a
understanding now let’s let’s look at a
understanding now let’s let’s look at a more recent so we’ve we talked about the
more recent so we’ve we talked about the
more recent so we’ve we talked about the Tipler cylinder and the and the twin
Tipler cylinder and the and the twin
Tipler cylinder and the and the twin paradox these are all go back decades I
paradox these are all go back decades I
paradox these are all go back decades I want to talk about a more recent
want to talk about a more recent
want to talk about a more recent thinking on this topic going in a
thinking on this topic going in a
thinking on this topic going in a different direction although still
different direction although still
different direction although still following one of the earlier themes of
following one of the earlier themes of
following one of the earlier themes of rotation one was negative energy and the
rotation one was negative energy and the
rotation one was negative energy and the other was in each force somehow twisting
other was in each force somehow twisting
other was in each force somehow twisting space-time and so a colleague of mine
space-time and so a colleague of mine
space-time and so a colleague of mine professor Ron mallet at University of
professor Ron mallet at University of
professor Ron mallet at University of Connecticut stores whom I met when I was
Connecticut stores whom I met when I was
Connecticut stores whom I met when I was giving a colloquy
giving a colloquy
giving a colloquy at at University of Connecticut on my
at at University of Connecticut on my
at at University of Connecticut on my research into on my research into Dark
research into on my research into Dark
research into on my research into Dark Matter he’s actually the only real-life
Matter he’s actually the only real-life
Matter he’s actually the only real-life experimental physicist who’s not a
experimental physicist who’s not a
experimental physicist who’s not a crackpot real tenured professor although
crackpot real tenured professor although
crackpot real tenured professor although my um my colleagues always say being a
my um my colleagues always say being a
my um my colleagues always say being a professor of patient he does not
professor of patient he does not
professor of patient he does not guarantee you’re not a crackpot but he’s
guarantee you’re not a crackpot but he’s
guarantee you’re not a crackpot but he’s he’s a real deal and he’s got a new idea
he’s a real deal and he’s got a new idea
he’s a real deal and he’s got a new idea that he came up with only I believe it
that he came up with only I believe it
that he came up with only I believe it was a decade ago now to to create a a
was a decade ago now to to create a a
was a decade ago now to to create a a time to create an effect by which you
time to create an effect by which you
time to create an effect by which you could travel to the past using he has a
could travel to the past using he has a
could travel to the past using he has a completely new idea of how to attack
completely new idea of how to attack
completely new idea of how to attack this problem this is a photo of him with
this problem this is a photo of him with
this problem this is a photo of him with one of his prototypes is not
one of his prototypes is not
one of his prototypes is not photoshopped it’s a real device it
photoshopped it’s a real device it
photoshopped it’s a real device it doesn’t take you to the past yet but but
doesn’t take you to the past yet but but
doesn’t take you to the past yet but but this is a real device that I might
this is a real device that I might
this is a real device that I might explain to you how this works the idea
explain to you how this works the idea
explain to you how this works the idea of dr. mallets idea is that you produce
of dr. mallets idea is that you produce
of dr. mallets idea is that you produce a cylinder of laser light and the you
a cylinder of laser light and the you
a cylinder of laser light and the you use mirrors or something like that you
use mirrors or something like that you
use mirrors or something like that you know that create a circulating laser so
know that create a circulating laser so
know that create a circulating laser so that’s confined to to a spiral
that’s confined to to a spiral
that’s confined to to a spiral essentially along a cylinder and the
essentially along a cylinder and the
essentially along a cylinder and the idea is is that if the laser is strong
idea is is that if the laser is strong
idea is is that if the laser is strong enough you should be able to send
enough you should be able to send
enough you should be able to send something in on one side send a particle
something in on one side send a particle
something in on one side send a particle in on one side and emerges on the other
in on one side and emerges on the other
in on one side and emerges on the other side the cylinder in the past because if
side the cylinder in the past because if
side the cylinder in the past because if the laser light is strong enough it’s
the laser light is strong enough it’s
the laser light is strong enough it’s like it’s like this animation here of
like it’s like this animation here of
like it’s like this animation here of swirling a cup of coffee space and time
swirling a cup of coffee space and time
swirling a cup of coffee space and time itself is rotated and on a small scale
itself is rotated and on a small scale
itself is rotated and on a small scale this also just like the twin effect and
this also just like the twin effect and
this also just like the twin effect and the gravitational slowing of time this
the gravitational slowing of time this
the gravitational slowing of time this is a real effect we’ve that we’ve
is a real effect we’ve that we’ve
is a real effect we’ve that we’ve measured we’ve measured it’s called
measured we’ve measured it’s called
measured we’ve measured it’s called frame dragging from the earth this is
frame dragging from the earth this is
frame dragging from the earth this is just extrapolating this on steroids now
just extrapolating this on steroids now
just extrapolating this on steroids now it remains to be seen
it remains to be seen
it remains to be seen does this really they’re a document of
does this really they’re a document of
does this really they’re a document of course about arguing with is discussing
course about arguing with is discussing
course about arguing with is discussing with his colleagues would it need to be
with his colleagues would it need to be
with his colleagues would it need to be infinitely long to work does this still
infinitely long to work does this still
infinitely long to work does this still need does it need negative energy so the
need does it need negative energy so the
need does it need negative energy so the last topic I’m going to hit so these are
last topic I’m going to hit so these are
last topic I’m going to hit so these are all the examples of ideas of what we can
all the examples of ideas of what we can
all the examples of ideas of what we can do and a lot of these are from
do and a lot of these are from
do and a lot of these are from relativity but let’s think also about
relativity but let’s think also about
relativity but let’s think also about quantum mechanics which is so relativity
quantum mechanics which is so relativity
quantum mechanics which is so relativity tells us about gravity and about speed
tells us about gravity and about speed
tells us about gravity and about speed with the speed of light but there’s also
with the speed of light but there’s also
with the speed of light but there’s also a whole other area of physics explains
a whole other area of physics explains
a whole other area of physics explains the world of the very small that
the world of the very small that
the world of the very small that explains particle physics and that’s
explains particle physics and that’s
explains particle physics and that’s quantum mechanics in quantum mechanics
quantum mechanics in quantum mechanics
quantum mechanics in quantum mechanics we can try to attack the question of
we can try to attack the question of
we can try to attack the question of whether time travel is possible
whether time travel is possible
whether time travel is possible looking at particles proton and electron
looking at particles proton and electron
looking at particles proton and electron or a photon traveling what if it
or a photon traveling what if it
or a photon traveling what if it interacts with itself in the past what
interacts with itself in the past what
interacts with itself in the past what does that even mean if it prevents its
does that even mean if it prevents its
does that even mean if it prevents its own trajectory through a wormhole for
own trajectory through a wormhole for
own trajectory through a wormhole for example and that’s a variation on things
example and that’s a variation on things
example and that’s a variation on things like the grandfather a paradox about
like the grandfather a paradox about
like the grandfather a paradox about breaking it down into into subatomic
breaking it down into into subatomic
breaking it down into into subatomic particles so time travel if it is
particles so time travel if it is
particles so time travel if it is allowed we would need to under we need a
allowed we would need to under we need a
allowed we would need to under we need a full fury of physics combining our
full fury of physics combining our
full fury of physics combining our understanding of quantum mechanics and
understanding of quantum mechanics and
understanding of quantum mechanics and relativity to get a full answer as to
relativity to get a full answer as to
relativity to get a full answer as to whether it’s possible or not right now
whether it’s possible or not right now
whether it’s possible or not right now we don’t have we we don’t have one
we don’t have we we don’t have one
we don’t have we we don’t have one simple set of equations we can write
simple set of equations we can write
simple set of equations we can write down that explains the entire universe
down that explains the entire universe
down that explains the entire universe including gravity and particle physics
including gravity and particle physics
including gravity and particle physics all at once there are if time travel is
all at once there are if time travel is
all at once there are if time travel is possible I can’t give a talk on on that
possible I can’t give a talk on on that
possible I can’t give a talk on on that topic without mentioning paradoxes my
topic without mentioning paradoxes my
topic without mentioning paradoxes my favorite though is I think even more
favorite though is I think even more
favorite though is I think even more complicated than you know killing one of
complicated than you know killing one of
complicated than you know killing one of your ancestors or a particle bumping
your ancestors or a particle bumping
your ancestors or a particle bumping into itself in the past but there’s the
into itself in the past but there’s the
into itself in the past but there’s the ontological paradox so here we see
ontological paradox so here we see
ontological paradox so here we see Calvin trying to steal his homework from
Calvin trying to steal his homework from
Calvin trying to steal his homework from himself so he doesn’t have to do it so
himself so he doesn’t have to do it so
himself so he doesn’t have to do it so if time travel is possible it leads to
if time travel is possible it leads to
if time travel is possible it leads to this serious issue of information
this serious issue of information
this serious issue of information without a source which in quantum
without a source which in quantum
without a source which in quantum mechanics is a very serious problem we
mechanics is a very serious problem we
mechanics is a very serious problem we how can we if if time travel is real
how can we if if time travel is real
how can we if if time travel is real forget about the paradoxes of you know
forget about the paradoxes of you know
forget about the paradoxes of you know killing you’re of killing one of your
killing you’re of killing one of your
killing you’re of killing one of your ancestors either by accident or on
ancestors either by accident or on
ancestors either by accident or on purpose but because what happens if you
purpose but because what happens if you
purpose but because what happens if you have objects or ideas without an origin
have objects or ideas without an origin
have objects or ideas without an origin that are essentially closed loops so
that are essentially closed loops so
that are essentially closed loops so this is very very very very bizarre so
this is very very very very bizarre so
this is very very very very bizarre so one solution by a physicist David
one solution by a physicist David
one solution by a physicist David Deutsch is that you’ve probably heard of
Deutsch is that you’ve probably heard of
Deutsch is that you’ve probably heard of the solution of parallel universes
the solution of parallel universes
the solution of parallel universes oh it’s no time there are no paradoxes
oh it’s no time there are no paradoxes
oh it’s no time there are no paradoxes you just make another timeline another
you just make another timeline another
you just make another timeline another explanation is predestination if you try
explanation is predestination if you try
explanation is predestination if you try to assassinate Hitler your gun will
to assassinate Hitler your gun will
to assassinate Hitler your gun will always Jam personally I think that’s a
always Jam personally I think that’s a
always Jam personally I think that’s a lousy explanation it’s not
lousy explanation it’s not
lousy explanation it’s not intellectually satisfying then there’s a
intellectually satisfying then there’s a
intellectually satisfying then there’s a third explanation that’s not explored
third explanation that’s not explored
third explanation that’s not explored very often not even in fiction because
very often not even in fiction because
very often not even in fiction because it’s so bizarre and that is the idea
it’s so bizarre and that is the idea
it’s so bizarre and that is the idea that if you did if you did try to create
that if you did if you did try to create
that if you did if you did try to create a paradox the universe becomes a mobius
a paradox the universe becomes a mobius
a paradox the universe becomes a mobius strip and you have two timelines
strip and you have two timelines
strip and you have two timelines existing simultaneously and so if you go
existing simultaneously and so if you go
existing simultaneously and so if you go back in time and kill your grandfather
back in time and kill your grandfather
back in time and kill your grandfather or your mother
or your mother
or your mother you become you’re both dead and alive at
you become you’re both dead and alive at
you become you’re both dead and alive at like Schrodinger’s cat you’re 50% dead
like Schrodinger’s cat you’re 50% dead
like Schrodinger’s cat you’re 50% dead 50% alive what does that even mean
50% alive what does that even mean
50% alive what does that even mean though and that’s that’s a difficult
though and that’s that’s a difficult
though and that’s that’s a difficult question since quantum mechanics is
question since quantum mechanics is
question since quantum mechanics is about particles we are collections of
about particles we are collections of
about particles we are collections of vast numbers of particles tend to a very
vast numbers of particles tend to a very
vast numbers of particles tend to a very large number and so it’s not clear what
large number and so it’s not clear what
large number and so it’s not clear what the what these what the eerie quantum
the what these what the eerie quantum
the what these what the eerie quantum effects mean for large collections of
effects mean for large collections of
effects mean for large collections of atoms like ourselves so all of these
atoms like ourselves so all of these
atoms like ourselves so all of these ideas parallel universes and and this
ideas parallel universes and and this
ideas parallel universes and and this predestination paradox
predestination paradox
predestination paradox are explored in fiction all the time
are explored in fiction all the time
are explored in fiction all the time we’ve got the flash Twilight Zone Star
we’ve got the flash Twilight Zone Star
we’ve got the flash Twilight Zone Star Trek things like that every so often we
Trek things like that every so often we
Trek things like that every so often we have supposedly real-life evidence of
have supposedly real-life evidence of
have supposedly real-life evidence of time travel that’s always really easy to
time travel that’s always really easy to
time travel that’s always really easy to debunk though such as the infamous cell
debunk though such as the infamous cell
debunk though such as the infamous cell phone in the Charlie Chaplin movie the
phone in the Charlie Chaplin movie the
phone in the Charlie Chaplin movie the circus which was very easily explained
circus which was very easily explained
circus which was very easily explained away as a as an earpiece for for the
away as a as an earpiece for for the
away as a as an earpiece for for the hearing-impaired so these are usually
hearing-impaired so these are usually
hearing-impaired so these are usually pretty easy to debunk we don’t have any
pretty easy to debunk we don’t have any
pretty easy to debunk we don’t have any really robust evidence that there are
really robust evidence that there are
really robust evidence that there are time travelers among us except of course
time travelers among us except of course
time travelers among us except of course there’s the composer Gustav Mahler who
there’s the composer Gustav Mahler who
there’s the composer Gustav Mahler who looks exactly like me so I actually in
looks exactly like me so I actually in
looks exactly like me so I actually in fact I filled my wife with that one on
fact I filled my wife with that one on
fact I filled my wife with that one on Facebook she said how did you get a
Facebook she said how did you get a
Facebook she said how did you get a daguerreotype photo of yourself that’s
daguerreotype photo of yourself that’s
daguerreotype photo of yourself that’s amazing
amazing
amazing that was it That’s not me all right so
that was it That’s not me all right so
that was it That’s not me all right so tourists from the future though are
tourists from the future though are
tourists from the future though are always brought up by Stephen Hawking and
always brought up by Stephen Hawking and
always brought up by Stephen Hawking and Neil deGrasse Tyson who I hope see this
Neil deGrasse Tyson who I hope see this
Neil deGrasse Tyson who I hope see this on youtube I hope I can’t to stare
on youtube I hope I can’t to stare
on youtube I hope I can’t to stare attention because I the humble professor
attention because I the humble professor
attention because I the humble professor from UAlbany I’m gonna tell them that
from UAlbany I’m gonna tell them that
from UAlbany I’m gonna tell them that they’re wrong about something very
they’re wrong about something very
they’re wrong about something very important so I’m gonna boldly declare
important so I’m gonna boldly declare
important so I’m gonna boldly declare that time travel is not disproven by a
that time travel is not disproven by a
that time travel is not disproven by a lack of tourists in the future and the
lack of tourists in the future and the
lack of tourists in the future and the reason is easy and in fact since I’m not
reason is easy and in fact since I’m not
reason is easy and in fact since I’m not expert generativity they are they should
expert generativity they are they should
expert generativity they are they should know because in general relativity it’s
know because in general relativity it’s
know because in general relativity it’s very easy to show that for example
very easy to show that for example
very easy to show that for example wormholes this is a classic example this
wormholes this is a classic example this
wormholes this is a classic example this you can’t even if time travel is real
you can’t even if time travel is real
you can’t even if time travel is real you can’t go back
you can’t go back
you can’t go back before you made the machine so if I’d
before you made the machine so if I’d
before you made the machine so if I’d use a wormhole for example time travel
use a wormhole for example time travel
use a wormhole for example time travel the day that I punch the wormhole that’s
the day that I punch the wormhole that’s
the day that I punch the wormhole that’s the first day I can go back to from the
the first day I can go back to from the
the first day I can go back to from the future to that day I can’t go back
future to that day I can’t go back
future to that day I can’t go back further than the past then the moment I
further than the past then the moment I
further than the past then the moment I created the machine or phenomenon there
created the machine or phenomenon there
created the machine or phenomenon there are exceptions of course what if there’s
are exceptions of course what if there’s
are exceptions of course what if there’s naturally occurring wormholes that have
naturally occurring wormholes that have
naturally occurring wormholes that have been around since the big since the
been around since the big since the
been around since the big since the beginning of time things like that but
beginning of time things like that but
beginning of time things like that but in general I’m not worried about the
in general I’m not worried about the
in general I’m not worried about the lack of tourists from the future because
lack of tourists from the future because
lack of tourists from the future because it just means time travel hasn’t been
it just means time travel hasn’t been
it just means time travel hasn’t been invented yet so I don’t see a problem
invented yet so I don’t see a problem
invented yet so I don’t see a problem with that so in conclusion the problems
with that so in conclusion the problems
with that so in conclusion the problems we have with time travel based on our
we have with time travel based on our
we have with time travel based on our current understanding of physics are
current understanding of physics are
current understanding of physics are unfortunately numerous you need to go
unfortunately numerous you need to go
unfortunately numerous you need to go faster than light build a device of
faster than light build a device of
faster than light build a device of infinite length use negative energy or
infinite length use negative energy or
infinite length use negative energy or infinite energy you would need something
infinite energy you would need something
infinite energy you would need something gravitationally gravitationally
gravitationally gravitationally
gravitationally gravitationally repulsive if we extrapolate as I was
repulsive if we extrapolate as I was
repulsive if we extrapolate as I was talking about how increasing gravity
talking about how increasing gravity
talking about how increasing gravity slows time down and gets you to the
slows time down and gets you to the
slows time down and gets you to the future to get to the past you’d need
future to get to the past you’d need
future to get to the past you’d need something that we we don’t know exists
something that we we don’t know exists
something that we we don’t know exists and we don’t even have a model or
and we don’t even have a model or
and we don’t even have a model or hypothesis that predicts any sort of
hypothesis that predicts any sort of
hypothesis that predicts any sort of particle or material with the requisite
particle or material with the requisite
particle or material with the requisite type of negative energy so I’m gonna
type of negative energy so I’m gonna
type of negative energy so I’m gonna conclude that it’s unlikely that a human
conclude that it’s unlikely that a human
conclude that it’s unlikely that a human will ever travel through time at least
will ever travel through time at least
will ever travel through time at least into the past with a fine tunable
into the past with a fine tunable
into the past with a fine tunable machine with an on/off switch like we
machine with an on/off switch like we
machine with an on/off switch like we want an in fiction
want an in fiction
want an in fiction however I will make the bold optimistic
however I will make the bold optimistic
however I will make the bold optimistic prediction that once we’ve figured out
prediction that once we’ve figured out
prediction that once we’ve figured out how to marry relativity and quantum
how to marry relativity and quantum
how to marry relativity and quantum mechanics and we have a full fury of
mechanics and we have a full fury of
mechanics and we have a full fury of everything that I
everything that I
everything that I think that time travel will be possible
think that time travel will be possible
think that time travel will be possible for subatomic particles so that it’ll be
for subatomic particles so that it’ll be
for subatomic particles so that it’ll be possible to communicate for example have
possible to communicate for example have
possible to communicate for example have some sort of time telephone or telegraph
some sort of time telephone or telegraph
some sort of time telephone or telegraph and I’m gonna boldly predict with no
and I’m gonna boldly predict with no
and I’m gonna boldly predict with no nothing to back this claim up but that
nothing to back this claim up but that
nothing to back this claim up but that within a hundred years we’ll get to the
within a hundred years we’ll get to the
within a hundred years we’ll get to the point where we have the technology to
point where we have the technology to
point where we have the technology to send a subatomic particle a tiny
send a subatomic particle a tiny
send a subatomic particle a tiny fraction of a second into the past not
fraction of a second into the past not
fraction of a second into the past not carrying any useful information
carrying any useful information
carrying any useful information initially now in order for that to be
initially now in order for that to be
initially now in order for that to be feasible though time travel would have
feasible though time travel would have
feasible though time travel would have to be taken seriously which it isn’t and
to be taken seriously which it isn’t and
to be taken seriously which it isn’t and no one would actually be working on it
no one would actually be working on it
no one would actually be working on it other than other than Ron mallet I don’t
other than other than Ron mallet I don’t
other than other than Ron mallet I don’t know of anyone else who’s really taking
know of anyone else who’s really taking
know of anyone else who’s really taking it seriously in terms of experimental
it seriously in terms of experimental
it seriously in terms of experimental physicists there are many theoretical
physicists there are many theoretical
physicists there are many theoretical physicists who do write on papers on it
physicists who do write on papers on it
physicists who do write on papers on it who work on general relativity but I
who work on general relativity but I
who work on general relativity but I don’t know other the other than run mail
don’t know other the other than run mail
don’t know other the other than run mail and I don’t know anyone else who’s
and I don’t know anyone else who’s
and I don’t know anyone else who’s taking it seriously enough to try to
taking it seriously enough to try to
taking it seriously enough to try to build something and I think in order for
build something and I think in order for
build something and I think in order for my optimistic prediction to come true it
my optimistic prediction to come true it
my optimistic prediction to come true it would have to be taken seriously and
would have to be taken seriously and
would have to be taken seriously and pursued by large numbers of the
pursued by large numbers of the
pursued by large numbers of the brightest minds in order for even in a
brightest minds in order for even in a
brightest minds in order for even in a hundred years even for my my this
hundred years even for my my this
hundred years even for my my this prediction is way too optimistic for my
prediction is way too optimistic for my
prediction is way too optimistic for my colleagues but people but in general
colleagues but people but in general
colleagues but people but in general nine nine scientists say no that’s not
nine nine scientists say no that’s not
nine nine scientists say no that’s not good enough what do you mean subatomic
good enough what do you mean subatomic
good enough what do you mean subatomic particles I want to get in the time
particles I want to get in the time
particles I want to get in the time machine and so I’m gonna conclude with
machine and so I’m gonna conclude with
machine and so I’m gonna conclude with this ever a lot of what I talked about
this ever a lot of what I talked about
this ever a lot of what I talked about today wouldn’t be possible obviously
today wouldn’t be possible obviously
today wouldn’t be possible obviously with Einsteins a seminal work and and I
with Einsteins a seminal work and and I
with Einsteins a seminal work and and I always throw out this photo of Einstein
always throw out this photo of Einstein
always throw out this photo of Einstein because we got to remember that he
because we got to remember that he
because we got to remember that he didn’t always have gray hair you know he
didn’t always have gray hair you know he
didn’t always have gray hair you know he was born he was a baby and he there was
was born he was a baby and he there was
was born he was a baby and he there was a point in which he did not have gray
a point in which he did not have gray
a point in which he did not have gray hair yet so I always like throwing out
hair yet so I always like throwing out
hair yet so I always like throwing out that image so that’s all I’ve got thank
that image so that’s all I’ve got thank
that image so that’s all I’ve got thank you
”
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