I’m interested in gravity because it shapes the most extreme objects in the
shapes the most extreme objects in the
shapes the most extreme objects in the universe and I spent most of my career
universe and I spent most of my career
universe and I spent most of my career working with a large international team
working with a large international team
working with a large international team on a project that if you think a little
on a project that if you think a little
on a project that if you think a little bit about it doesn’t make any sense I
bit about it doesn’t make any sense I
bit about it doesn’t make any sense I mean it’s crazy can’t possibly work so
mean it’s crazy can’t possibly work so
mean it’s crazy can’t possibly work so in a nutshell it consists of doing the
in a nutshell it consists of doing the
in a nutshell it consists of doing the following experiment place two chunks of
following experiment place two chunks of
following experiment place two chunks of glass let’s say a kilometer apart place
glass let’s say a kilometer apart place
glass let’s say a kilometer apart place another chunk of glass at 90 degrees
another chunk of glass at 90 degrees
another chunk of glass at 90 degrees engineer the system in such a way that
engineer the system in such a way that
engineer the system in such a way that they can move freely as freely as
they can move freely as freely as
they can move freely as freely as possible and then try to measure the
possible and then try to measure the
possible and then try to measure the relative separation between this object
relative separation between this object
relative separation between this object it’s a very simple experiment and I’m
it’s a very simple experiment and I’m
it’s a very simple experiment and I’m sure you’ll think well it’s very dull
sure you’ll think well it’s very dull
sure you’ll think well it’s very dull but what we want to do is to measure
but what we want to do is to measure
but what we want to do is to measure this to a precision of better than a
this to a precision of better than a
this to a precision of better than a thousandth of the size of a proton if
thousandth of the size of a proton if
thousandth of the size of a proton if you do not know what this number is well
you do not know what this number is well
you do not know what this number is well let’s just say that is a very very small
let’s just say that is a very very small
let’s just say that is a very very small number and here it goes
number and here it goes
number and here it goes so it’s crazy it can’t work you may also
so it’s crazy it can’t work you may also
so it’s crazy it can’t work you may also wonder why should we do this and the
wonder why should we do this and the
wonder why should we do this and the reason is that this is a method that
reason is that this is a method that
reason is that this is a method that could allow you to discover some of the
could allow you to discover some of the
could allow you to discover some of the most extreme objects in the universe
most extreme objects in the universe
most extreme objects in the universe objects that we cannot see that nobody
objects that we cannot see that nobody
objects that we cannot see that nobody has seen that nobody will ever see so
has seen that nobody will ever see so
has seen that nobody will ever see so I’ve asked myself many times why I ended
I’ve asked myself many times why I ended
I’ve asked myself many times why I ended up doing this and the true answer is
up doing this and the true answer is
up doing this and the true answer is that I really don’t know okay I think
that I really don’t know okay I think
that I really don’t know okay I think the only viable explanation I have goes
the only viable explanation I have goes
the only viable explanation I have goes back to memories of my childhood and
back to memories of my childhood and
back to memories of my childhood and adolescence and I had a huge admiration
adolescence and I had a huge admiration
adolescence and I had a huge admiration for people that would try to challenge
for people that would try to challenge
for people that would try to challenge limits try to break boundaries and I’m
limits try to break boundaries and I’m
limits try to break boundaries and I’m not talking about science or science
not talking about science or science
not talking about science or science wasn’t on my mind I’m talking about
wasn’t on my mind I’m talking about
wasn’t on my mind I’m talking about pretty much on anything
pretty much on anything
pretty much on anything I’m your sport is what I wanted to do
I’m your sport is what I wanted to do
I’m your sport is what I wanted to do but you know through some very
but you know through some very
but you know through some very complicated paths
complicated paths
complicated paths that only maybe now starts to make sense
that only maybe now starts to make sense
that only maybe now starts to make sense I tried to find a job in which in my
I tried to find a job in which in my
I tried to find a job in which in my little world with my very limited
little world with my very limited
little world with my very limited abilities everyday I could try to push
abilities everyday I could try to push
abilities everyday I could try to push the limit a little bit more and I was
the limit a little bit more and I was
the limit a little bit more and I was lucky to end up working on one of the
lucky to end up working on one of the
lucky to end up working on one of the most ambitious science projects of
most ambitious science projects of
most ambitious science projects of recent years so the story I want to tell
recent years so the story I want to tell
recent years so the story I want to tell you last over a century and decades
you last over a century and decades
you last over a century and decades after decades is a story of challenging
after decades is a story of challenging
after decades is a story of challenging limits common wisdoms
limits common wisdoms
limits common wisdoms and pushing boundaries I think you know
and pushing boundaries I think you know
and pushing boundaries I think you know all know Isaac Newton is one of the you
all know Isaac Newton is one of the you
all know Isaac Newton is one of the you know Giants of physics his theory of
know Giants of physics his theory of
know Giants of physics his theory of gravity was the theory of gravity and we
gravity was the theory of gravity and we
gravity was the theory of gravity and we all sweat blood at school learning it
all sweat blood at school learning it
all sweat blood at school learning it however a century ago a younger
however a century ago a younger
however a century ago a younger physicist Albert Einstein came along
physicist Albert Einstein came along
physicist Albert Einstein came along looked at the theory with fresh eyes and
looked at the theory with fresh eyes and
looked at the theory with fresh eyes and realized that things didn’t quite add up
realized that things didn’t quite add up
realized that things didn’t quite add up if ever so slightly now challenging
if ever so slightly now challenging
if ever so slightly now challenging Newton’s idea was unimaginable okay but
Newton’s idea was unimaginable okay but
Newton’s idea was unimaginable okay but now we know that Newton’s theory is just
now we know that Newton’s theory is just
now we know that Newton’s theory is just an approximation of a more general
an approximation of a more general
an approximation of a more general theory that we call an since theory of
theory that we call an since theory of
theory that we call an since theory of general relativity and one of the great
general relativity and one of the great
general relativity and one of the great revolutions that that the theory brought
revolutions that that the theory brought
revolutions that that the theory brought was the realization that gravity has its
was the realization that gravity has its
was the realization that gravity has its own language its own broadcasting
own language its own broadcasting
own language its own broadcasting channel through a form of radiation that
channel through a form of radiation that
channel through a form of radiation that is called gravitational waves now every
is called gravitational waves now every
is called gravitational waves now every object that moves my arms here or
object that moves my arms here or
object that moves my arms here or objects in the distant universe they
objects in the distant universe they
objects in the distant universe they creator they radiate little ripples in
creator they radiate little ripples in
creator they radiate little ripples in the fabric of space and time that
the fabric of space and time that
the fabric of space and time that propagates at the speed of light through
propagates at the speed of light through
propagates at the speed of light through the entire universe and they carry a
the entire universe and they carry a
the entire universe and they carry a full message about the source that
full message about the source that
full message about the source that generated them this is the fundamental
generated them this is the fundamental
generated them this is the fundamental prediction of Einstein’s theory however
prediction of Einstein’s theory however
prediction of Einstein’s theory however Einstein famously said well forget about
Einstein famously said well forget about
Einstein famously said well forget about gravitation
gravitation
gravitation okay you will never be able to detect
okay you will never be able to detect
okay you will never be able to detect them they are way too weak but during
them they are way too weak but during
them they are way too weak but during the different centuries people of the
the different centuries people of the
the different centuries people of the different decades people started really
different decades people started really
different decades people started really to think about finding methods of
to think about finding methods of
to think about finding methods of detecting gravitational waves and the
detecting gravitational waves and the
detecting gravitational waves and the reason is twofold first one if you
reason is twofold first one if you
reason is twofold first one if you detect gravitational waves you provide a
detect gravitational waves you provide a
detect gravitational waves you provide a confirmation of a fundamental prediction
confirmation of a fundamental prediction
confirmation of a fundamental prediction of a theory that is a pillar of modern
of a theory that is a pillar of modern
of a theory that is a pillar of modern physics second and possibly most
physics second and possibly most
physics second and possibly most importantly or more importantly you have
importantly or more importantly you have
importantly or more importantly you have a new way of discovering objects that
a new way of discovering objects that
a new way of discovering objects that you cannot see now think about how we
you cannot see now think about how we
you cannot see now think about how we know what we know about the universe we
know what we know about the universe we
know what we know about the universe we look admittedly with very powerful
look admittedly with very powerful
look admittedly with very powerful instruments telescopes but we just look
instruments telescopes but we just look
instruments telescopes but we just look what if there is stuff out there and we
what if there is stuff out there and we
what if there is stuff out there and we know there is there must be that doesn’t
know there is there must be that doesn’t
know there is there must be that doesn’t emit any light contrast that with the
emit any light contrast that with the
emit any light contrast that with the way in which we have learned everything
way in which we have learned everything
way in which we have learned everything about around us so we look we hear we
about around us so we look we hear we
about around us so we look we hear we taste we touch we smell we have a sense
taste we touch we smell we have a sense
taste we touch we smell we have a sense for every channel of information think
for every channel of information think
for every channel of information think about going to a wonderful three-star
about going to a wonderful three-star
about going to a wonderful three-star Michelin restaurant and enjoying the
Michelin restaurant and enjoying the
Michelin restaurant and enjoying the delicious food by watching it or going
delicious food by watching it or going
delicious food by watching it or going to an Adele’s concert not being able to
to an Adele’s concert not being able to
to an Adele’s concert not being able to hear her song just looking at her
hear her song just looking at her
hear her song just looking at her what would we miss so what are we
what would we miss so what are we
what would we miss so what are we missing by just looking at the universe
missing by just looking at the universe
missing by just looking at the universe and not not being able to you know tune
and not not being able to you know tune
and not not being able to you know tune on a new broadcasting channel so how
on a new broadcasting channel so how
on a new broadcasting channel so how could we observe gravitational waves
could we observe gravitational waves
could we observe gravitational waves now gravitation waves that travel
now gravitation waves that travel
now gravitation waves that travel through this hole when I move my arms
through this hole when I move my arms
through this hole when I move my arms for example okay they stretch and
for example okay they stretch and
for example okay they stretch and squeeze space and time your body’s
squeeze space and time your body’s
squeeze space and time your body’s really been stretched and squashed by
really been stretched and squashed by
really been stretched and squashed by gravitational waves but you don’t feel
gravitational waves but you don’t feel
gravitational waves but you don’t feel it you don’t build because it’s so such
it you don’t build because it’s so such
it you don’t build because it’s so such a tiny tiny tiny effect but in order to
a tiny tiny tiny effect but in order to
a tiny tiny tiny effect but in order to observe them what we need is a measuring
observe them what we need is a measuring
observe them what we need is a measuring device that measures displacement okay
device that measures displacement okay
device that measures displacement okay so we need a ruler but not any ruler of
so we need a ruler but not any ruler of
so we need a ruler but not any ruler of super ruler now maybe those chunks of
super ruler now maybe those chunks of
super ruler now maybe those chunks of glass starts to make sense and
glass starts to make sense and
glass starts to make sense and remarkably NAFA we’ve been able to
remarkably NAFA we’ve been able to
remarkably NAFA we’ve been able to design such a ruler it’s called a laser
design such a ruler it’s called a laser
design such a ruler it’s called a laser interferometers it uses light as a ruler
interferometers it uses light as a ruler
interferometers it uses light as a ruler so this is like oh the laser
so this is like oh the laser
so this is like oh the laser interferometer gravitational-wave
interferometer gravitational-wave
interferometer gravitational-wave Observatory it actually consists of two
Observatory it actually consists of two
Observatory it actually consists of two identical instruments one in the swamp
identical instruments one in the swamp
identical instruments one in the swamp of Louisiana and Livingstone in the
of Louisiana and Livingstone in the
of Louisiana and Livingstone in the other one in the desert of Washington
other one in the desert of Washington
other one in the desert of Washington State at Hanford a laser beam shines
State at Hanford a laser beam shines
State at Hanford a laser beam shines through up a piece of glass the beam
through up a piece of glass the beam
through up a piece of glass the beam splitter it’s divided up into two arms
splitter it’s divided up into two arms
splitter it’s divided up into two arms it travels four kilometers it reaches to
it travels four kilometers it reaches to
it travels four kilometers it reaches to other chunks of glass the end mirrors it
other chunks of glass the end mirrors it
other chunks of glass the end mirrors it bounces off it comes back then gets
bounces off it comes back then gets
bounces off it comes back then gets recombined at the beam splitter and by
recombined at the beam splitter and by
recombined at the beam splitter and by watching the change in the intensity of
watching the change in the intensity of
watching the change in the intensity of light we can measure this very very
light we can measure this very very
light we can measure this very very minut changes in distances in the arms
minut changes in distances in the arms
minut changes in distances in the arms to better than no one thousandth of the
to better than no one thousandth of the
to better than no one thousandth of the size of a proton so like all um was
size of a proton so like all um was
size of a proton so like all um was conceived many years ago and it took her
conceived many years ago and it took her
conceived many years ago and it took her over thirty years really to conceive
over thirty years really to conceive
over thirty years really to conceive design build and now operate this
design build and now operate this
design build and now operate this instrument and the effort of over a
instrument and the effort of over a
instrument and the effort of over a thousand scientists and engineers
and LIGO was completed about a year and
and LIGO was completed about a year and a half ago and it started to observe the
a half ago and it started to observe the
a half ago and it started to observe the Saturday the 12th of September 2015 it
Saturday the 12th of September 2015 it
Saturday the 12th of September 2015 it monitors the old sky and we didn’t know
monitors the old sky and we didn’t know
monitors the old sky and we didn’t know how long we would have to wait to detect
how long we would have to wait to detect
how long we would have to wait to detect gravitational waves maybe forever two
gravitational waves maybe forever two
gravitational waves maybe forever two days later it’s Monday September 14th
days later it’s Monday September 14th
days later it’s Monday September 14th this is what shows up on our computer
this is what shows up on our computer
this is what shows up on our computer screens is the same signal that arrives
screens is the same signal that arrives
screens is the same signal that arrives first at livingstone seven milliseconds
first at livingstone seven milliseconds
first at livingstone seven milliseconds later arrives at Hanford it has a very
later arrives at Hanford it has a very
later arrives at Hanford it has a very peculiar structure of a signal that
peculiar structure of a signal that
peculiar structure of a signal that increases in frequency and in amplitude
increases in frequency and in amplitude
increases in frequency and in amplitude and then disappears he is a signal that
and then disappears he is a signal that
and then disappears he is a signal that you would expect from gravitation waves
you would expect from gravitation waves
you would expect from gravitation waves from a binary system in the reaction by
from a binary system in the reaction by
from a binary system in the reaction by me and everybody on the analysis team
me and everybody on the analysis team
me and everybody on the analysis team was this is a joke
was this is a joke
was this is a joke okay this just can’t be real something
okay this just can’t be real something
okay this just can’t be real something is wrong and the name of the game became
is wrong and the name of the game became
is wrong and the name of the game became to try to figure out what is the source
to try to figure out what is the source
to try to figure out what is the source may be local man-made or around us that
may be local man-made or around us that
may be local man-made or around us that has produced this the signal and it took
has produced this the signal and it took
has produced this the signal and it took months to figure it out and as Arthur
months to figure it out and as Arthur
months to figure it out and as Arthur Conan Doyle said you know when you have
Conan Doyle said you know when you have
Conan Doyle said you know when you have a limiting it eliminated the impossible
a limiting it eliminated the impossible
a limiting it eliminated the impossible whatever remains however implausible
whatever remains however implausible
whatever remains however implausible must be the truth and what remained
must be the truth and what remained
must be the truth and what remained there was the only explanation that this
there was the only explanation that this
there was the only explanation that this signal was really due to the two
signal was really due to the two
signal was really due to the two gravitational waves that wiggled the
gravitational waves that wiggled the
gravitational waves that wiggled the like mirrors from an Astrophysical
like mirrors from an Astrophysical
like mirrors from an Astrophysical source and water source so about a
source and water source so about a
source and water source so about a billion years ago two black holes the
billion years ago two black holes the
billion years ago two black holes the size of about 200 kilometers is the size
size of about 200 kilometers is the size
size of about 200 kilometers is the size between work and in London roughly one
between work and in London roughly one
between work and in London roughly one packed with 29 times the mass of the Sun
packed with 29 times the mass of the Sun
packed with 29 times the mass of the Sun the other one packed with 35 times the
the other one packed with 35 times the
the other one packed with 35 times the mass of the Sun where
mass of the Sun where
mass of the Sun where orbiting around each other at half of
orbiting around each other at half of
orbiting around each other at half of the speed of light 150 million
the speed of light 150 million
the speed of light 150 million kilometers per second okay their
kilometers per second okay their
kilometers per second okay their separation was about the size of the UK
separation was about the size of the UK
separation was about the size of the UK a bit more so if you have troubles in
a bit more so if you have troubles in
a bit more so if you have troubles in picturing this think about this so these
picturing this think about this so these
picturing this think about this so these two black holes were orbiting around
two black holes were orbiting around
two black holes were orbiting around each other with a frequency of a kitchen
each other with a frequency of a kitchen
each other with a frequency of a kitchen mixer okay
mixer okay
mixer okay 5,200 times per second legal so the
5,200 times per second legal so the
5,200 times per second legal so the final quarter of a second of this motion
final quarter of a second of this motion
final quarter of a second of this motion five orbits the system lost more and
five orbits the system lost more and
five orbits the system lost more and more energy and then they smashed into
more energy and then they smashed into
more energy and then they smashed into each other in this process they release
each other in this process they release
each other in this process they release the the equivalent of three times the
the the equivalent of three times the
the the equivalent of three times the mass of the Sun into energy how much is
mass of the Sun into energy how much is
mass of the Sun into energy how much is this it’s enormous
this it’s enormous
this it’s enormous okay is for a fraction of a second they
okay is for a fraction of a second they
okay is for a fraction of a second they emitted more energy that all the
emitted more energy that all the
emitted more energy that all the energies that goes in light from all the
energies that goes in light from all the
energies that goes in light from all the stars of all the galaxies in the entire
stars of all the galaxies in the entire
stars of all the galaxies in the entire universe the nobody saw a flash of light
universe the nobody saw a flash of light
universe the nobody saw a flash of light because all the energy got pumped into
because all the energy got pumped into
because all the energy got pumped into gravitational waves and the fabric of
gravitational waves and the fabric of
gravitational waves and the fabric of space-time it traveled a billion years
space-time it traveled a billion years
space-time it traveled a billion years it arrived here on that Monday morning
it arrived here on that Monday morning
it arrived here on that Monday morning and wiggled the LIGO mirrors so this
and wiggled the LIGO mirrors so this
and wiggled the LIGO mirrors so this very unremarkable wiggle is the
very unremarkable wiggle is the
very unremarkable wiggle is the fingerprint of the last quarter of a
fingerprint of the last quarter of a
fingerprint of the last quarter of a second of the swan song of a binary
second of the swan song of a binary
second of the swan song of a binary black hole merging and forming you know
black hole merging and forming you know
black hole merging and forming you know the first cry of a newborn black hole
the first cry of a newborn black hole
the first cry of a newborn black hole this is three discovers in one is the
this is three discovers in one is the
this is three discovers in one is the detection of gravitational waves a
detection of gravitational waves a
detection of gravitational waves a hundred years after Einstein predicted
hundred years after Einstein predicted
hundred years after Einstein predicted them it’s the discovery of objects we
them it’s the discovery of objects we
them it’s the discovery of objects we never saw before binary black holes it
never saw before binary black holes it
never saw before binary black holes it is the best evidence we have today that
is the best evidence we have today that
is the best evidence we have today that this object black holes that are
this object black holes that are
this object black holes that are objects of the theory objects of
objects of the theory objects of
objects of the theory objects of mathematics actually are produced by
mathematics actually are produced by
mathematics actually are produced by nature but this the story repeated
nature but this the story repeated
nature but this the story repeated itself so we didn’t see only one in
itself so we didn’t see only one in
itself so we didn’t see only one in October October 12th we saw another
October October 12th we saw another
October October 12th we saw another characteristic signal this time from two
characteristic signal this time from two
characteristic signal this time from two black holes one of 23 and the other one
black holes one of 23 and the other one
black holes one of 23 and the other one of 13 solar masses is not as strong we
of 13 solar masses is not as strong we
of 13 solar masses is not as strong we cannot be as sure as the first one but
cannot be as sure as the first one but
cannot be as sure as the first one but most likely it is from a binary black
most likely it is from a binary black
most likely it is from a binary black holes and then we had a late Christmas
holes and then we had a late Christmas
holes and then we had a late Christmas present on Boxing Day you cannot see on
present on Boxing Day you cannot see on
present on Boxing Day you cannot see on the plot because it’s too weak and you
the plot because it’s too weak and you
the plot because it’s too weak and you need to use all the sophisticated
need to use all the sophisticated
need to use all the sophisticated analysis techniques to pull it out from
analysis techniques to pull it out from
analysis techniques to pull it out from the data we detected gravitational waves
the data we detected gravitational waves
the data we detected gravitational waves from a 15 and a 7 solar mass black holes
from a 15 and a 7 solar mass black holes
from a 15 and a 7 solar mass black holes guess what the universe is full of
guess what the universe is full of
guess what the universe is full of binary black holes smashing into each
binary black holes smashing into each
binary black holes smashing into each other we didn’t know it seems that every
other we didn’t know it seems that every
other we didn’t know it seems that every we can estimate every 15 minutes or so
we can estimate every 15 minutes or so
we can estimate every 15 minutes or so there are binary black holes that
there are binary black holes that
there are binary black holes that collide in the universe and so far we
collide in the universe and so far we
collide in the universe and so far we are able to see gravitation waves only
are able to see gravitation waves only
are able to see gravitation waves only from the most from the closest objects
from the most from the closest objects
from the most from the closest objects we have and in the future as the
we have and in the future as the
we have and in the future as the instrument becomes better more
instrument becomes better more
instrument becomes better more instruments joints this network of
instruments joints this network of
instruments joints this network of interferometers would see more and more
interferometers would see more and more
interferometers would see more and more so you see this is really in the moment
so you see this is really in the moment
so you see this is really in the moment when LIGO
when LIGO
when LIGO started to operate the moment where we
started to operate the moment where we
started to operate the moment where we had a device sensitive enough to tune on
had a device sensitive enough to tune on
had a device sensitive enough to tune on this new broadcast we started to
this new broadcast we started to
this new broadcast we started to discover new things it’s a new year of
discover new things it’s a new year of
discover new things it’s a new year of cosmic exploration is like their very
cosmic exploration is like their very
cosmic exploration is like their very first explorers who sailed the oceans
first explorers who sailed the oceans
first explorers who sailed the oceans and as they venture past the Pillars of
and as they venture past the Pillars of
and as they venture past the Pillars of Hercules they discover new land who
Hercules they discover new land who
Hercules they discover new land who knows what we are going to discover next
so one day maybe a distant day a day
so one day maybe a distant day a day that I won’t see we will take the
that I won’t see we will take the
that I won’t see we will take the ultimate lamp of the place we live in
ultimate lamp of the place we live in
ultimate lamp of the place we live in a map of the universe our universe when
a map of the universe our universe when
a map of the universe our universe when it was only a fraction of a second old
it was only a fraction of a second old
it was only a fraction of a second old and that baby universe has got only one
and that baby universe has got only one
and that baby universe has got only one way of talking to us and that’s very
way of talking to us and that’s very
way of talking to us and that’s very different waves nothing else of course
different waves nothing else of course
different waves nothing else of course you know this is uncharted territory and
you know this is uncharted territory and
you know this is uncharted territory and I would be a fool and an arrogant to say
I would be a fool and an arrogant to say
I would be a fool and an arrogant to say what we are going to discover next I
what we are going to discover next I
what we are going to discover next I don’t know I cannot know I just told to
don’t know I cannot know I just told to
don’t know I cannot know I just told to be surprised over and over again thank
be surprised over and over again thank
be surprised over and over again thank you
you
you [Applause]
”
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