[Music]
[Applause]
so whatever I first got started in
gravitational waves the experts tried to
make it easy for me and he said a
gravitational wave it’s just a ripple on
space-time you got that three oh yeah I
didn’t get it so what does space-time
space-time is the universe and the
universe is made up of the three
dimensions that we lived in everyday the
X direction the Y direction and the Z
direction so those axes that we were all
taught about in school
however those three dimensions are also
fully United with time it’s inseparable
time is not as constant as you think it
is so in order to make the idea of
space-time easier to understand we often
represent it like a trampoline that has
three lines drawn on it whenever mass is
present in space-time it’s going to make
a depression in that space-time so in
the example I have up on the slide here
you see that the Sun is making a deeper
depression in space-time than the earth
is and that’s because the Sun is more
massive than the earth as’ imagine
rolling a ball on this trampoline
example of space-time if the ball passes
meter or one of those depressions the
ball path at the wall is going to
elected just like if the ball was being
attracted to the mess that’s making the
depression now imagine that you have two
masses moving around as those masses
move around you’re going to have a
change in the curvature of space-time
and those changes are going to ripple
away from the source just like a little
pond and that ripple is going to
decrease in size the farther away it
gets from the source just like a
rippling upon this is one of gravitation
away this gravitational wave very simply
is a change in gravity traveling
throughout the universe that’s what the
experts were trying to simplify for me
whenever they said gravitational waves
are ripples on space-time so this is
really profound you and I we have max
the scale tells us so some of us think
have more masculine we would like but
either way we have mass and we happen to
be in the universe and the universe is
space-time that every single one of us
are making as oppression in space-time
so how does a gravitational wave affect
space as it passes through it if we want
to detect a gravitational wave we need
you know how is a gravitational wave
going to feel well as a gravitational
wave passes through space it’s going to
compress space in one direction based on
the side and expand it in the other
direction say up in there and as the
gravitational wave passes by this
expanding and contracting is going to
ultra naté back and forth so
invitation-only it has the effect of
squishing and expanding and then
changing the direction of that pushing
and expanding as a matter of fact if you
were close enough to a very strong
source of gravitational waves this would
hurt this would hurt so much that you
could be ripped to shreds and this has a
real scientific term associated with it
and it’s called spaghettification why is
it called spaghettification because you
could be stretched so far up and down
while you are squished side-to-side that
you’ll be stretched out when the into a
noodle until you’re ripped apart so
instead of finding gravitational waves
from here on earth we look out into the
universe for some of the most massive by
man energetic events that happened out
there in the universe luckily none of
those are next door to us you do not
have to worry about getting
spaghettified by a gravitational wave
however back cavitation away from the
universes travel vast distances by the
time that it gets to us and it’s getting
weaker all along the way so you will not
be able to feel gravitational wave so we
need to build a detector that can feel a
gravitational wave for us that detector
that we’ve built is called LIGO and the
National Science Foundation has made it
possible for us to make this a reality
so actually talking about this weird
word that is not in the dictionary
called black it’s an acronym so every
letter stands for something that’s break
it down first is the L it stands for
laser we use laser light to make the
measurements to look for gravitational
waves both next one I has a little bit
harder it’s a big word it’s both
interferometer and you can think apart
this word very much in the same way that
you pick apart the word thermometer so
all lammeter
means that this is an instrument to
measure something firm refers to heat or
temperature so a thermometer measures
temperature an interferometer so we see
a monitor in there it’s measuring
something we’re referring for measuring
device the inter curve refers to what is
it that
measuring welcome measuring is how light
three combines with itself how the laser
light in the l3 combines with itself
that is the main function of our
detector to measure the recombination of
life to look for gravitational waves
next is the most important letter and
that is Observatory LIGO is a new kind
of observatory we are not about making
one detection calling in its success and
then go to the home instead we wanted to
make many observations to learn more
about the universe that we live in
oftentimes whenever I talk to people and
I talk about learning about the universe
they say who cares I live here on earth
earth is part of the universe you are
part of the dreamers learn more about
the universe can actually have
implications for us in our everyday
science and what we are doing is this is
an observatory for gravitational wave
astronomy we are not looking
the universe with telescopes we are not
looking at the universe in any form of
light we have no pretty pictures like
the Hubble Space Telescope produces we
instead are recording how the universe
feels and that is a gravitational wave
astronomy have to build a detector to
feel these gravitational waves we know
how the gravitational wave is going to
feel it’s going to squish in one
direction expand any other go back and
forth like that so we built an L shape
detector to take advantage of this
squashing and stretching we built a very
large l-shaped detector each side of
malaya it’s four kilometers long and in
our everyday experience that’s a almost
two and a half miles walk so what does
my day look like this is the LIGO that’s
in your back yard so if you take a good
look at it you see lots a beautiful lush
green forest surrounding it we have
another logo in the United States and
it’s in the high desert of Hanford
Washington so you look at this one you
see a very similar detector but a very
different environment instead of lush
green you see brown and desert even
though the environment surrounding our
detectors are
different what’s inside our detector is
almost exactly the same so let’s take a
peek inside of how one of our
interferometers work so we filled the
interferometer roof laser like if the
arms change length the output at our
detector changes the brightness of the
light changes if we take a closer look
the laser light goes into the corner
where it’s split into two equal pieces
it travels four kilometers down on each
arm is reflected by there and it’s
recombined at the corner at the
instrument we call the beam splitter and
that recombination is what we measure at
the output
now if the arms are changing length the
way the light recombines changes if we
take a closer look at the output we can
see that whenever the light is in sync
with the light from the other arm then
we get a nice bright spot coming out of
Hart detector if the leg is out of sync
with the light from the other arm we get
a good spot this is what interference
means this is the direct addition of
laser light together or any kind of
light together and if it’s out of stick
if you add a plus 1 and a minus 1 you
get 0 if you add two plus ones you get 2
and so the two are a bright spot and we
fear
would be our thin spot we measure the
changing brightness of light that comes
out of our detector that tells us about
how the length of our arms have changed
compared to each other and in our the
length of our arms change compared with
each other that means that a
gravitational wave may be present this
is how an interferometer works so we
took a lot of time we spent years
operating our very first detector and
that detector wasn’t sensitive enough to
find gravitational waves then we didn’t
expect it to be sensitive enough to
pucker occupational waves instead this
was a learning experience for us to
figure out how to make a better more
sensitive interferometer once we took
those lessons we built a new detector we
took everything out of what was inside
of Lego and really replace it with new
more sensitive equipment we now call
ourselves advanced LIGO
and on the very first day of using
advanced LIGO to look for gravitational
waves in the very early morning hours so
tense Hill 5:00 in the morning
this signal came through the LIGO Living
detective and we saw the same signal and
the LIGO Hanford detector you can tell
here that there is something special
going on this looks the same this is the
very first direct detection of
gravitational waves ever made the
biggest change in this graph so the
biggest up-and-down change it looks big
but it only changed the length of our
four kilometer long arms remember four
kilometers is about two and a half
months it only changed the length of our
two and a half mile long arms one 1000
the diameter of a proton so less than a
bit of matter that makes a part of an
atomic nucleus we are making the
smallest length measurements humans have
ever made
just look for gravitational waves and if
you take this signal and you put it
through a speaker you can hear it with
your ears so gravitational waves do not
make sound but if you take their signal
you can make it so you can hear it so
this one fifth of a second signal this
one fifth of a second sound you’re about
to hear change everything for us
that low roar that you hear in the
background is the noise that we are
always collecting with our detector that
so was the gravitational wave and you
can’t hear a lot of detail out of that
so so what we did is we increase the
pitch of our gravitational wave so that
you can hear more detail and remember
this gravitational wave only happened
once we’re playing it three times for
you so you can listen to different parts
of it so let’s listen to it again with
its pitch shifted up this was incredibly
exciting so we spent the next five
months playing devil’s advocate we tried
to prove that this isn’t a real
gravitational wave in those five months
we measured our confidence if this is a
real gravitational wave we extracted
science from this signal and we
published our results so what did we
find first of all the shape of this
signal which translates into that sound
that you heard that is a signature of
two bodies going around with each other
and as they get closer and closer
together they orbit each other faster
and faster and faster until they merge
into each other this is the same effect
as whenever a figure skater starts
spinning with their arms out and then
they spend faster and faster as they
pull their arms into their Sun it’s the
exact thing that is going on so the fact
that we heard this move sound we knew
with two bodies
and merging into one further data
analysis revealed that this was two
black holes each 30 times as massive as
our Sun but the size of cities and a
billion light years away from us as they
were going around each other in this
signal they were orbiting each other
over a hundred times a second imagine
that something that is each 30 times the
mass of the Sun going around each other
30 times every second and just before
they collide it fit light at the speed
that was a little bit more than half the
speed of light and in just this one bit
of a second signal more energy was
released in gravitational waves than in
all of the light from 500 billion Milky
Way galaxies well after this detection
we went on to make two more defections
what was on Christmas night of 2015 that
would be awesome Christmas present the
other one was announced just two days
ago I’m very excited that the press
conference happened before this talk
otherwise I will be allowed to tell you
anything about and be certain so on
January 4th of this year we detected
another gravitational wave and all of
these gravitational waves have been from
black holes merging together to form a
bigger black hole so what are the
accomplishments for making these
detections business the very first time
that we have directly observed a black
hole before this we were able to infer
the presence of black holes from X
produced by gas and dust being
compressed and heated up as they
approach at enter a black hole that’s
what all of those purple black culture
in looking at are those are the black
holes we observed with x-rays and now
with gravitational waves and those are
the black holes that are blue on this
chart those are the very first black
holes that we have directly observe this
is also the very first time we’ve seen
black holes coming in pairs and this is
also the first time we’ve seen a pair of
black balls merging into one after they
merge into one
these have produced the largest known
black holes of their class and this
class is called stellar-mass black holes
stellar-mass means that these are the
corpses of the most massive stars that
whenever they die they collapse into a
black hole and these are the largest
known stellar-mass black holes every
time humans have looked at the universe
in a new way we’ve found something we
never imagined to look for and that new
thing that unexpected thing usually
revolutionize our understanding of the
universe and I want to be a part of that
revolution what secrets will the
universe revealed to us in gravitational
waves I don’t know but I do know that
going to happen in your back
[Music]
[Applause]
[Music]
you
[Applause]
[Applause]
so whatever I first got started in
gravitational waves the experts tried to
make it easy for me and he said a
gravitational wave it’s just a ripple on
space-time you got that three oh yeah I
didn’t get it so what does space-time
space-time is the universe and the
universe is made up of the three
dimensions that we lived in everyday the
X direction the Y direction and the Z
direction so those axes that we were all
taught about in school
however those three dimensions are also
fully United with time it’s inseparable
time is not as constant as you think it
is so in order to make the idea of
space-time easier to understand we often
represent it like a trampoline that has
three lines drawn on it whenever mass is
present in space-time it’s going to make
a depression in that space-time so in
the example I have up on the slide here
you see that the Sun is making a deeper
depression in space-time than the earth
is and that’s because the Sun is more
massive than the earth as’ imagine
rolling a ball on this trampoline
example of space-time if the ball passes
meter or one of those depressions the
ball path at the wall is going to
elected just like if the ball was being
attracted to the mess that’s making the
depression now imagine that you have two
masses moving around as those masses
move around you’re going to have a
change in the curvature of space-time
and those changes are going to ripple
away from the source just like a little
pond and that ripple is going to
decrease in size the farther away it
gets from the source just like a
rippling upon this is one of gravitation
away this gravitational wave very simply
is a change in gravity traveling
throughout the universe that’s what the
experts were trying to simplify for me
whenever they said gravitational waves
are ripples on space-time so this is
really profound you and I we have max
the scale tells us so some of us think
have more masculine we would like but
either way we have mass and we happen to
be in the universe and the universe is
space-time that every single one of us
are making as oppression in space-time
so how does a gravitational wave affect
space as it passes through it if we want
to detect a gravitational wave we need
you know how is a gravitational wave
going to feel well as a gravitational
wave passes through space it’s going to
compress space in one direction based on
the side and expand it in the other
direction say up in there and as the
gravitational wave passes by this
expanding and contracting is going to
ultra naté back and forth so
invitation-only it has the effect of
squishing and expanding and then
changing the direction of that pushing
and expanding as a matter of fact if you
were close enough to a very strong
source of gravitational waves this would
hurt this would hurt so much that you
could be ripped to shreds and this has a
real scientific term associated with it
and it’s called spaghettification why is
it called spaghettification because you
could be stretched so far up and down
while you are squished side-to-side that
you’ll be stretched out when the into a
noodle until you’re ripped apart so
instead of finding gravitational waves
from here on earth we look out into the
universe for some of the most massive by
man energetic events that happened out
there in the universe luckily none of
those are next door to us you do not
have to worry about getting
spaghettified by a gravitational wave
however back cavitation away from the
universes travel vast distances by the
time that it gets to us and it’s getting
weaker all along the way so you will not
be able to feel gravitational wave so we
need to build a detector that can feel a
gravitational wave for us that detector
that we’ve built is called LIGO and the
National Science Foundation has made it
possible for us to make this a reality
so actually talking about this weird
word that is not in the dictionary
called black it’s an acronym so every
letter stands for something that’s break
it down first is the L it stands for
laser we use laser light to make the
measurements to look for gravitational
waves both next one I has a little bit
harder it’s a big word it’s both
interferometer and you can think apart
this word very much in the same way that
you pick apart the word thermometer so
all lammeter
means that this is an instrument to
measure something firm refers to heat or
temperature so a thermometer measures
temperature an interferometer so we see
a monitor in there it’s measuring
something we’re referring for measuring
device the inter curve refers to what is
it that
measuring welcome measuring is how light
three combines with itself how the laser
light in the l3 combines with itself
that is the main function of our
detector to measure the recombination of
life to look for gravitational waves
next is the most important letter and
that is Observatory LIGO is a new kind
of observatory we are not about making
one detection calling in its success and
then go to the home instead we wanted to
make many observations to learn more
about the universe that we live in
oftentimes whenever I talk to people and
I talk about learning about the universe
they say who cares I live here on earth
earth is part of the universe you are
part of the dreamers learn more about
the universe can actually have
implications for us in our everyday
science and what we are doing is this is
an observatory for gravitational wave
astronomy we are not looking
the universe with telescopes we are not
looking at the universe in any form of
light we have no pretty pictures like
the Hubble Space Telescope produces we
instead are recording how the universe
feels and that is a gravitational wave
astronomy have to build a detector to
feel these gravitational waves we know
how the gravitational wave is going to
feel it’s going to squish in one
direction expand any other go back and
forth like that so we built an L shape
detector to take advantage of this
squashing and stretching we built a very
large l-shaped detector each side of
malaya it’s four kilometers long and in
our everyday experience that’s a almost
two and a half miles walk so what does
my day look like this is the LIGO that’s
in your back yard so if you take a good
look at it you see lots a beautiful lush
green forest surrounding it we have
another logo in the United States and
it’s in the high desert of Hanford
Washington so you look at this one you
see a very similar detector but a very
different environment instead of lush
green you see brown and desert even
though the environment surrounding our
detectors are
different what’s inside our detector is
almost exactly the same so let’s take a
peek inside of how one of our
interferometers work so we filled the
interferometer roof laser like if the
arms change length the output at our
detector changes the brightness of the
light changes if we take a closer look
the laser light goes into the corner
where it’s split into two equal pieces
it travels four kilometers down on each
arm is reflected by there and it’s
recombined at the corner at the
instrument we call the beam splitter and
that recombination is what we measure at
the output
now if the arms are changing length the
way the light recombines changes if we
take a closer look at the output we can
see that whenever the light is in sync
with the light from the other arm then
we get a nice bright spot coming out of
Hart detector if the leg is out of sync
with the light from the other arm we get
a good spot this is what interference
means this is the direct addition of
laser light together or any kind of
light together and if it’s out of stick
if you add a plus 1 and a minus 1 you
get 0 if you add two plus ones you get 2
and so the two are a bright spot and we
fear
would be our thin spot we measure the
changing brightness of light that comes
out of our detector that tells us about
how the length of our arms have changed
compared to each other and in our the
length of our arms change compared with
each other that means that a
gravitational wave may be present this
is how an interferometer works so we
took a lot of time we spent years
operating our very first detector and
that detector wasn’t sensitive enough to
find gravitational waves then we didn’t
expect it to be sensitive enough to
pucker occupational waves instead this
was a learning experience for us to
figure out how to make a better more
sensitive interferometer once we took
those lessons we built a new detector we
took everything out of what was inside
of Lego and really replace it with new
more sensitive equipment we now call
ourselves advanced LIGO
and on the very first day of using
advanced LIGO to look for gravitational
waves in the very early morning hours so
tense Hill 5:00 in the morning
this signal came through the LIGO Living
detective and we saw the same signal and
the LIGO Hanford detector you can tell
here that there is something special
going on this looks the same this is the
very first direct detection of
gravitational waves ever made the
biggest change in this graph so the
biggest up-and-down change it looks big
but it only changed the length of our
four kilometer long arms remember four
kilometers is about two and a half
months it only changed the length of our
two and a half mile long arms one 1000
the diameter of a proton so less than a
bit of matter that makes a part of an
atomic nucleus we are making the
smallest length measurements humans have
ever made
just look for gravitational waves and if
you take this signal and you put it
through a speaker you can hear it with
your ears so gravitational waves do not
make sound but if you take their signal
you can make it so you can hear it so
this one fifth of a second signal this
one fifth of a second sound you’re about
to hear change everything for us
that low roar that you hear in the
background is the noise that we are
always collecting with our detector that
so was the gravitational wave and you
can’t hear a lot of detail out of that
so so what we did is we increase the
pitch of our gravitational wave so that
you can hear more detail and remember
this gravitational wave only happened
once we’re playing it three times for
you so you can listen to different parts
of it so let’s listen to it again with
its pitch shifted up this was incredibly
exciting so we spent the next five
months playing devil’s advocate we tried
to prove that this isn’t a real
gravitational wave in those five months
we measured our confidence if this is a
real gravitational wave we extracted
science from this signal and we
published our results so what did we
find first of all the shape of this
signal which translates into that sound
that you heard that is a signature of
two bodies going around with each other
and as they get closer and closer
together they orbit each other faster
and faster and faster until they merge
into each other this is the same effect
as whenever a figure skater starts
spinning with their arms out and then
they spend faster and faster as they
pull their arms into their Sun it’s the
exact thing that is going on so the fact
that we heard this move sound we knew
with two bodies
and merging into one further data
analysis revealed that this was two
black holes each 30 times as massive as
our Sun but the size of cities and a
billion light years away from us as they
were going around each other in this
signal they were orbiting each other
over a hundred times a second imagine
that something that is each 30 times the
mass of the Sun going around each other
30 times every second and just before
they collide it fit light at the speed
that was a little bit more than half the
speed of light and in just this one bit
of a second signal more energy was
released in gravitational waves than in
all of the light from 500 billion Milky
Way galaxies well after this detection
we went on to make two more defections
what was on Christmas night of 2015 that
would be awesome Christmas present the
other one was announced just two days
ago I’m very excited that the press
conference happened before this talk
otherwise I will be allowed to tell you
anything about and be certain so on
January 4th of this year we detected
another gravitational wave and all of
these gravitational waves have been from
black holes merging together to form a
bigger black hole so what are the
accomplishments for making these
detections business the very first time
that we have directly observed a black
hole before this we were able to infer
the presence of black holes from X
produced by gas and dust being
compressed and heated up as they
approach at enter a black hole that’s
what all of those purple black culture
in looking at are those are the black
holes we observed with x-rays and now
with gravitational waves and those are
the black holes that are blue on this
chart those are the very first black
holes that we have directly observe this
is also the very first time we’ve seen
black holes coming in pairs and this is
also the first time we’ve seen a pair of
black balls merging into one after they
merge into one
these have produced the largest known
black holes of their class and this
class is called stellar-mass black holes
stellar-mass means that these are the
corpses of the most massive stars that
whenever they die they collapse into a
black hole and these are the largest
known stellar-mass black holes every
time humans have looked at the universe
in a new way we’ve found something we
never imagined to look for and that new
thing that unexpected thing usually
revolutionize our understanding of the
universe and I want to be a part of that
revolution what secrets will the
universe revealed to us in gravitational
waves I don’t know but I do know that
going to happen in your back
[Music]
[Applause]
[Music]
you
[Applause]
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