if crawling around those caves made you feel claustrophobic and you might like
feel claustrophobic and you might like
feel claustrophobic and you might like space more it’s expanding I’m going to
space more it’s expanding I’m going to
space more it’s expanding I’m going to talk about tell you a little bit about
talk about tell you a little bit about
talk about tell you a little bit about how observations of exploding stars
how observations of exploding stars
how observations of exploding stars called supernovae have revealed that we
called supernovae have revealed that we
called supernovae have revealed that we live in a universe that is not just
live in a universe that is not just
live in a universe that is not just expanding but actually expanding faster
expanding but actually expanding faster
expanding but actually expanding faster and faster propelled by a mysterious
and faster propelled by a mysterious
and faster propelled by a mysterious newly discovered component of the
newly discovered component of the
newly discovered component of the universe called dark energy so when we
universe called dark energy so when we
universe called dark energy so when we look out at the universe it looks like
look out at the universe it looks like
look out at the universe it looks like it’s expanding around us the universe
it’s expanding around us the universe
it’s expanding around us the universe acts like it received a big kick that we
acts like it received a big kick that we
acts like it received a big kick that we call the Big Bang and now the galaxies
call the Big Bang and now the galaxies
call the Big Bang and now the galaxies are rushing apart you could think of
are rushing apart you could think of
are rushing apart you could think of this like a giant loaf of raisin bread
this like a giant loaf of raisin bread
this like a giant loaf of raisin bread rising in the oven the galaxies would be
rising in the oven the galaxies would be
rising in the oven the galaxies would be like the raisins and as it gets bigger
like the raisins and as it gets bigger
like the raisins and as it gets bigger there’s more space between more distant
there’s more space between more distant
there’s more space between more distant raisins they appear to rush apart even
raisins they appear to rush apart even
raisins they appear to rush apart even faster so how do we actually know this
faster so how do we actually know this
faster so how do we actually know this about our universe how do we figure this
about our universe how do we figure this
about our universe how do we figure this out well as you saw in that animation we
out well as you saw in that animation we
out well as you saw in that animation we would have to measure how far away the
would have to measure how far away the
would have to measure how far away the galaxies are around us and we’d have to
galaxies are around us and we’d have to
galaxies are around us and we’d have to measure how fast they appear to be
measure how fast they appear to be
measure how fast they appear to be moving away from us to learn this about
moving away from us to learn this about
moving away from us to learn this about the universe so it turns out the first
the universe so it turns out the first
the universe so it turns out the first of those figuring out how far away
of those figuring out how far away
of those figuring out how far away galaxies are is very hard to give you
galaxies are is very hard to give you
galaxies are is very hard to give you some understanding of how you measure
some understanding of how you measure
some understanding of how you measure distances in space let me first remind
distances in space let me first remind
distances in space let me first remind you of how you measure distances here on
you of how you measure distances here on
you of how you measure distances here on earth on earth we use all kinds of tools
earth on earth we use all kinds of tools
earth on earth we use all kinds of tools for example if you want to know the
for example if you want to know the
for example if you want to know the distance to a tree
distance to a tree
distance to a tree surveyors determine they might look at
surveyors determine they might look at
surveyors determine they might look at that tree compared to a distant mountain
that tree compared to a distant mountain
that tree compared to a distant mountain and then they would move their equipment
and then they would move their equipment
and then they would move their equipment over and see how the position of that
over and see how the position of that
over and see how the position of that tree has changed through what angle
tree has changed through what angle
tree has changed through what angle relative to the distant mountain by
relative to the distant mountain by
relative to the distant mountain by setting up some triangles some simple
setting up some triangles some simple
setting up some triangles some simple geometry you could determine the
geometry you could determine the
geometry you could determine the distance to the tree a more natural
distance to the tree a more natural
distance to the tree a more natural means is a lighthouse if you’re a ship
means is a lighthouse if you’re a ship
means is a lighthouse if you’re a ship captain you have an understanding of how
captain you have an understanding of how
captain you have an understanding of how luminous a lighthouse is so when you see
luminous a lighthouse is so when you see
luminous a lighthouse is so when you see one looking very faint you could judge
one looking very faint you could judge
one looking very faint you could judge approximate
approximate
approximate how far away you are from that
how far away you are from that
how far away you are from that lighthouse at night now if it were a
lighthouse at night now if it were a
lighthouse at night now if it were a foggy night that lighthouse could look
foggy night that lighthouse could look
foggy night that lighthouse could look faint and fooling you into thinking it’s
faint and fooling you into thinking it’s
faint and fooling you into thinking it’s further away than it really is so we
further away than it really is so we
further away than it really is so we have tools called fog horns that work by
have tools called fog horns that work by
have tools called fog horns that work by the same principle the attenuation or
the same principle the attenuation or
the same principle the attenuation or reduction of the sound instead of the
reduction of the sound instead of the
reduction of the sound instead of the light over the distance hearing a
light over the distance hearing a
light over the distance hearing a foghorn sound very quiet tells you it’s
foghorn sound very quiet tells you it’s
foghorn sound very quiet tells you it’s far away another tool that we all use
far away another tool that we all use
far away another tool that we all use without even thinking is an
without even thinking is an
without even thinking is an understanding of the true physical size
understanding of the true physical size
understanding of the true physical size of an object so that when it appears
of an object so that when it appears
of an object so that when it appears small we can judge how far away it is so
small we can judge how far away it is so
small we can judge how far away it is so in the case of these airplanes we
in the case of these airplanes we
in the case of these airplanes we understand that the very small airplanes
understand that the very small airplanes
understand that the very small airplanes are the same thing just in the
are the same thing just in the
are the same thing just in the background they are not for example baby
background they are not for example baby
background they are not for example baby airplanes that were birthed by these
airplanes that were birthed by these
airplanes that were birthed by these larger airplanes that’s just something
larger airplanes that’s just something
larger airplanes that’s just something that we intuitively understand now all
that we intuitively understand now all
that we intuitively understand now all of these are human-made objects and so
of these are human-made objects and so
of these are human-made objects and so we don’t have the use of those in space
we don’t have the use of those in space
we don’t have the use of those in space so we have to use telescopes and what
so we have to use telescopes and what
so we have to use telescopes and what nature provides and what nature provides
nature provides and what nature provides
nature provides and what nature provides to us is something very similar to the
to us is something very similar to the
to us is something very similar to the lighthouse naturally-occurring
lighthouse naturally-occurring
lighthouse naturally-occurring lighthouses that we call standard
lighthouses that we call standard
lighthouses that we call standard candles and our favorite standard candle
candles and our favorite standard candle
candles and our favorite standard candle occurs when there’s a galaxy like the
occurs when there’s a galaxy like the
occurs when there’s a galaxy like the one you see here that might have ten or
one you see here that might have ten or
one you see here that might have ten or a hundred billion stars in it but at
a hundred billion stars in it but at
a hundred billion stars in it but at some point in time one of those stars
some point in time one of those stars
some point in time one of those stars may explode in what we call a supernova
may explode in what we call a supernova
may explode in what we call a supernova explosion when it’s as bright as about
explosion when it’s as bright as about
explosion when it’s as bright as about four billion times the brightness of the
four billion times the brightness of the
four billion times the brightness of the Sun and provides an excellent standard
Sun and provides an excellent standard
Sun and provides an excellent standard candle if you could start the animation
candle if you could start the animation
candle if you could start the animation for that I think a supernova is gonna go
for that I think a supernova is gonna go
for that I think a supernova is gonna go off there it is and so as you place that
off there it is and so as you place that
off there it is and so as you place that supernova further away like the
supernova further away like the
supernova further away like the lighthouse we can judge its distance
lighthouse we can judge its distance
lighthouse we can judge its distance from its brightness we use what’s called
from its brightness we use what’s called
from its brightness we use what’s called the inverse square law that the
the inverse square law that the
the inverse square law that the brightness will decline as one over the
brightness will decline as one over the
brightness will decline as one over the distance squared as the light going out
distance squared as the light going out
distance squared as the light going out has to paint the surface of a larger and
has to paint the surface of a larger and
has to paint the surface of a larger and larger sphere so if one of these
larger sphere so if one of these
larger sphere so if one of these supernovae is twice as far away it’ll
supernovae is twice as far away it’ll
supernovae is twice as far away it’ll appear four times as faint if it’s three
appear four times as faint if it’s three
appear four times as faint if it’s three times as far away it’ll appear nine
times as far away it’ll appear nine
times as far away it’ll appear nine times as faint so we look for the
times as faint so we look for the
times as faint so we look for the supernovae and they allow us to measure
supernovae and they allow us to measure
supernovae and they allow us to measure the distances to the galaxies in which
the distances to the galaxies in which
the distances to the galaxies in which they reside so how do we measure that
they reside so how do we measure that
they reside so how do we measure that other aspect of
other aspect of
other aspect of the the fact that it looks like
the the fact that it looks like
the the fact that it looks like everything is moving away from
everything is moving away from
everything is moving away from everything else well we can also
everything else well we can also
everything else well we can also determine that from the light of the
determine that from the light of the
determine that from the light of the supernova in a different way that light
supernova in a different way that light
supernova in a different way that light is emitted at a certain wavelength
is emitted at a certain wavelength
is emitted at a certain wavelength these are wavelengths that we can
these are wavelengths that we can
these are wavelengths that we can determine in the laboratory but as that
determine in the laboratory but as that
determine in the laboratory but as that light travels to our telescopes the
light travels to our telescopes the
light travels to our telescopes the expansion of space stretches the
expansion of space stretches the
expansion of space stretches the wavelengths of light it makes that light
wavelengths of light it makes that light
wavelengths of light it makes that light longer wavelength that is tilted toward
longer wavelength that is tilted toward
longer wavelength that is tilted toward the red end of the spectrum and so we
the red end of the spectrum and so we
the red end of the spectrum and so we see a redshift of the light so this is
see a redshift of the light so this is
see a redshift of the light so this is what it would look like if you had a
what it would look like if you had a
what it would look like if you had a distant supernova emitting some blue
distant supernova emitting some blue
distant supernova emitting some blue light and while the light is traveling
light and while the light is traveling
light and while the light is traveling space expands and it reaches our
space expands and it reaches our
space expands and it reaches our observatory it is already stretched or
observatory it is already stretched or
observatory it is already stretched or shifted to the red and so we can measure
shifted to the red and so we can measure
shifted to the red and so we can measure that redshift and so every time we see
that redshift and so every time we see
that redshift and so every time we see one of these supernovae these standard
one of these supernovae these standard
one of these supernovae these standard candles we can determine how far away it
candles we can determine how far away it
candles we can determine how far away it is and how fast that galaxy is moving
is and how fast that galaxy is moving
is and how fast that galaxy is moving away from us so you might wonder ok so
away from us so you might wonder ok so
away from us so you might wonder ok so the universe is expanding but what
the universe is expanding but what
the universe is expanding but what happens after that what’s next in this
happens after that what’s next in this
happens after that what’s next in this story it’s a little bit like asking what
story it’s a little bit like asking what
story it’s a little bit like asking what happens to a cannonball when it’s fired
happens to a cannonball when it’s fired
happens to a cannonball when it’s fired from the top of a tall mountain on the
from the top of a tall mountain on the
from the top of a tall mountain on the surface of the earth and the answer is
surface of the earth and the answer is
surface of the earth and the answer is it depends how fast you fire that
it depends how fast you fire that
it depends how fast you fire that cannonball it depends also relative to
cannonball it depends also relative to
cannonball it depends also relative to how massive the earth is if the earth is
how massive the earth is if the earth is
how massive the earth is if the earth is not very massive or you fire the
not very massive or you fire the
not very massive or you fire the cannonball very fast the cannonball will
cannonball very fast the cannonball will
cannonball very fast the cannonball will escape the Earth’s gravitational pull it
escape the Earth’s gravitational pull it
escape the Earth’s gravitational pull it will go out into space if the cannonball
will go out into space if the cannonball
will go out into space if the cannonball is not fired very fast or the earth is
is not fired very fast or the earth is
is not fired very fast or the earth is very heavy it will fall back down and in
very heavy it will fall back down and in
very heavy it will fall back down and in both cases although the cannonball was
both cases although the cannonball was
both cases although the cannonball was slowing down the specific velocity needs
slowing down the specific velocity needs
slowing down the specific velocity needs to be determined to know whether it is
to be determined to know whether it is
to be determined to know whether it is what we call the escape velocity that
what we call the escape velocity that
what we call the escape velocity that that knife-edge case between the
that knife-edge case between the
that knife-edge case between the cannonball that will go out forever or
cannonball that will go out forever or
cannonball that will go out forever or the one that will fall down so this is
the one that will fall down so this is
the one that will fall down so this is what we expected after discovering that
what we expected after discovering that
what we expected after discovering that the universe was expanding when that was
the universe was expanding when that was
the universe was expanding when that was discovered by Edwin Hubble in 1930 that
discovered by Edwin Hubble in 1930 that
discovered by Edwin Hubble in 1930 that although expanding the expansion would
although expanding the expansion would
although expanding the expansion would be slowing down now that wasn’t always
be slowing down now that wasn’t always
be slowing down now that wasn’t always the understanding though even before
the understanding though even before
the understanding though even before Hubble observed that the universe was
Hubble observed that the universe was
Hubble observed that the universe was expanding back in 1916 Einstein was
expanding back in 1916 Einstein was
expanding back in 1916 Einstein was thinking about the universe he was
thinking about the universe he was
thinking about the universe he was thinking about it in the context of a
thinking about it in the context of a
thinking about it in the context of a new
new
new theory he had of gravity called general
theory he had of gravity called general
theory he had of gravity called general relativity and Einstein made one of his
relativity and Einstein made one of his
relativity and Einstein made one of his few mistakes he was under the mistaken
few mistakes he was under the mistaken
few mistakes he was under the mistaken impression that the universe was static
impression that the universe was static
impression that the universe was static that it was immutable that it wasn’t
that it was immutable that it wasn’t
that it was immutable that it wasn’t getting bigger or getting smaller but he
getting bigger or getting smaller but he
getting bigger or getting smaller but he realized that if the universe were in
realized that if the universe were in
realized that if the universe were in that state then all the attractive
that state then all the attractive
that state then all the attractive gravity from all the stuff in the
gravity from all the stuff in the
gravity from all the stuff in the universe would cause the universe to
universe would cause the universe to
universe would cause the universe to start to collapse again so he didn’t
start to collapse again so he didn’t
start to collapse again so he didn’t know how to keep the universe in that
know how to keep the universe in that
know how to keep the universe in that static situation and he made an amazing
static situation and he made an amazing
static situation and he made an amazing discovery enabled by his new theory his
discovery enabled by his new theory his
discovery enabled by his new theory his amazing discovery was although the
amazing discovery was although the
amazing discovery was although the gravity of the objects in the universe
gravity of the objects in the universe
gravity of the objects in the universe is attractive the gravity of the empty
is attractive the gravity of the empty
is attractive the gravity of the empty space between the objects could be
space between the objects could be
space between the objects could be repulsive and this kind of repulsive
repulsive and this kind of repulsive
repulsive and this kind of repulsive gravity could balance the attractive
gravity could balance the attractive
gravity could balance the attractive gravity keep the universe static now he
gravity keep the universe static now he
gravity keep the universe static now he called that repulsive gravity the
called that repulsive gravity the
called that repulsive gravity the cosmological constant and today we would
cosmological constant and today we would
cosmological constant and today we would call it dark energy now when Einstein
call it dark energy now when Einstein
call it dark energy now when Einstein saw that the universe was expanding when
saw that the universe was expanding when
saw that the universe was expanding when that was shown to him he then called
that was shown to him he then called
that was shown to him he then called this the biggest blunder of his career
this the biggest blunder of his career
this the biggest blunder of his career that he had made that to invent this
that he had made that to invent this
that he had made that to invent this idea of this dark energy when it wasn’t
idea of this dark energy when it wasn’t
idea of this dark energy when it wasn’t needed so how do we actually measure
needed so how do we actually measure
needed so how do we actually measure then if the expansion is slowing down
then if the expansion is slowing down
then if the expansion is slowing down and if so by how much well when I told
and if so by how much well when I told
and if so by how much well when I told you how we measure the expansion of the
you how we measure the expansion of the
you how we measure the expansion of the universe I left one crucial piece of
universe I left one crucial piece of
universe I left one crucial piece of information out which is that when we
information out which is that when we
information out which is that when we observe these distant supernovae these
observe these distant supernovae these
observe these distant supernovae these exploding stars and when they carry this
exploding stars and when they carry this
exploding stars and when they carry this information to us how far away they are
information to us how far away they are
information to us how far away they are how fast or how much redshift has been
how fast or how much redshift has been
how fast or how much redshift has been caused by the expansion of space there’s
caused by the expansion of space there’s
caused by the expansion of space there’s a large delay built-in I like to say
a large delay built-in I like to say
a large delay built-in I like to say that the universe does not instant
that the universe does not instant
that the universe does not instant message so when you send an instant
message so when you send an instant
message so when you send an instant message on your phone you think of it as
message on your phone you think of it as
message on your phone you think of it as getting there right away of course you
getting there right away of course you
getting there right away of course you know it requires at least the time that
know it requires at least the time that
know it requires at least the time that it takes the speed of light to reach
it takes the speed of light to reach
it takes the speed of light to reach your friend but that’s a trivial amount
your friend but that’s a trivial amount
your friend but that’s a trivial amount it’s not so trivial for the universe
it’s not so trivial for the universe
it’s not so trivial for the universe when you are looking at objects that are
when you are looking at objects that are
when you are looking at objects that are billions of light years away it takes
billions of light years away it takes
billions of light years away it takes billions of years for the light from
billions of years for the light from
billions of years for the light from them to reach us which means that we are
them to reach us which means that we are
them to reach us which means that we are learning about the universe as it was
learning about the universe as it was
learning about the universe as it was expanding billions of years ago so when
expanding billions of years ago so when
expanding billions of years ago so when we look at a nearby supernova that might
we look at a nearby supernova that might
we look at a nearby supernova that might tell us how fast the universe was
tell us how fast the universe was
tell us how fast the universe was expanding a billion years ago one
expanding a billion years ago one
expanding a billion years ago one further away might tell us how fast the
further away might tell us how fast the
further away might tell us how fast the universe is expanding two billion years
universe is expanding two billion years
universe is expanding two billion years ago further 3 billion years ago so what
ago further 3 billion years ago so what
ago further 3 billion years ago so what seems annoying is actually incredibly
seems annoying is actually incredibly
seems annoying is actually incredibly valuable to us these supernovae carry
valuable to us these supernovae carry
valuable to us these supernovae carry information about the past by looking
information about the past by looking
information about the past by looking further away and allow us to see how
further away and allow us to see how
further away and allow us to see how that expansion rate of the universe has
that expansion rate of the universe has
that expansion rate of the universe has been changing over time so about 15
been changing over time so about 15
been changing over time so about 15 years ago when I got involved in this
years ago when I got involved in this
years ago when I got involved in this work when I was a graduate student in a
work when I was a graduate student in a
work when I was a graduate student in a postdoc the expectation was that the
postdoc the expectation was that the
postdoc the expectation was that the universe was either slowing down a great
universe was either slowing down a great
universe was either slowing down a great deal like the universe model on the left
deal like the universe model on the left
deal like the universe model on the left a very heavyweight universe full of
a very heavyweight universe full of
a very heavyweight universe full of matter that was quickly slowing down the
matter that was quickly slowing down the
matter that was quickly slowing down the expansion eventually the expansion would
expansion eventually the expansion would
expansion eventually the expansion would halt and then it would start to contract
halt and then it would start to contract
halt and then it would start to contract and the universe would end any kind of
and the universe would end any kind of
and the universe would end any kind of Big Crunch the inverse of the Big Bang
Big Crunch the inverse of the Big Bang
Big Crunch the inverse of the Big Bang or we lived in a lightweight universe I
or we lived in a lightweight universe I
or we lived in a lightweight universe I heard some people I don’t know if they
heard some people I don’t know if they
heard some people I don’t know if they were sounded nervous about this Big
were sounded nervous about this Big
were sounded nervous about this Big Crunch it’s even in the worst case it
Crunch it’s even in the worst case it
Crunch it’s even in the worst case it would be about 30 billion years from now
would be about 30 billion years from now
would be about 30 billion years from now but it could have been that we lived in
but it could have been that we lived in
but it could have been that we lived in a lightweight universe one with very
a lightweight universe one with very
a lightweight universe one with very little matter in it and so the universe
little matter in it and so the universe
little matter in it and so the universe would expand forever that is like the
would expand forever that is like the
would expand forever that is like the cannon ball the universe would have
cannon ball the universe would have
cannon ball the universe would have escape velocity from itself and so our
escape velocity from itself and so our
escape velocity from itself and so our expectation was we can measure this rate
expectation was we can measure this rate
expectation was we can measure this rate of slowing like we couldn’t measure the
of slowing like we couldn’t measure the
of slowing like we couldn’t measure the slowing of the Cannonball and figure out
slowing of the Cannonball and figure out
slowing of the Cannonball and figure out what the ultimate fate was of the
what the ultimate fate was of the
what the ultimate fate was of the universe now the way we sought to do
universe now the way we sought to do
universe now the way we sought to do this was to look for some of the most
this was to look for some of the most
this was to look for some of the most distant supernovae we could find and
distant supernovae we could find and
distant supernovae we could find and generally we can find these only with
generally we can find these only with
generally we can find these only with the Hubble Space Telescope and these
the Hubble Space Telescope and these
the Hubble Space Telescope and these very distant supernovae give us
very distant supernovae give us
very distant supernovae give us information from 10 or 11 billion years
information from 10 or 11 billion years
information from 10 or 11 billion years ago when the universe was only one or
ago when the universe was only one or
ago when the universe was only one or two billion years old and so they allow
two billion years old and so they allow
two billion years old and so they allow us to reach way back in the expansion
us to reach way back in the expansion
us to reach way back in the expansion history of the universe so I think of
history of the universe so I think of
history of the universe so I think of the supernovae as sort of natural time
the supernovae as sort of natural time
the supernovae as sort of natural time capsules in the universe and after
capsules in the universe and after
capsules in the universe and after hearing Kenny’s talk I sort of think of
hearing Kenny’s talk I sort of think of
hearing Kenny’s talk I sort of think of them almost like the blue holes of our
them almost like the blue holes of our
them almost like the blue holes of our universe because they’re the places
universe because they’re the places
universe because they’re the places where we can collect this information
where we can collect this information
where we can collect this information that we can’t get anywhere else that
that we can’t get anywhere else that
that we can’t get anywhere else that tells us about the early history of the
tells us about the early history of the
tells us about the early history of the universe and so here are a number
universe and so here are a number
universe and so here are a number pictures showing what a distant galaxy
pictures showing what a distant galaxy
pictures showing what a distant galaxy looks like just before a supernova
looks like just before a supernova
looks like just before a supernova explodes and just after a supernova
explodes and just after a supernova
explodes and just after a supernova explodes people usually ask me how do we
explodes people usually ask me how do we
explodes people usually ask me how do we find these supernovae and I usually
find these supernovae and I usually
find these supernovae and I usually remarked at if you look at the ends of
remarked at if you look at the ends of
remarked at if you look at the ends of the arrows and the pictures usually you
the arrows and the pictures usually you
the arrows and the pictures usually you can find them without too much trouble
can find them without too much trouble
can find them without too much trouble now we had those arrows that afterwards
now we had those arrows that afterwards
now we had those arrows that afterwards actually but anyway so this was one of
actually but anyway so this was one of
actually but anyway so this was one of those really exciting times where both
those really exciting times where both
those really exciting times where both of the prevailing theories were ruled
of the prevailing theories were ruled
of the prevailing theories were ruled out and we ended up with a very
out and we ended up with a very
out and we ended up with a very surprising picture for the universe that
surprising picture for the universe that
surprising picture for the universe that the universe was actually accelerating
the universe was actually accelerating
the universe was actually accelerating and this was the breakthrough of the
and this was the breakthrough of the
and this was the breakthrough of the year for science magazine in 1998
year for science magazine in 1998
year for science magazine in 1998 because you know poor Einstein it’s been
because you know poor Einstein it’s been
because you know poor Einstein it’s been yanked back and forth along this whole
yanked back and forth along this whole
yanked back and forth along this whole story you know the universe is static no
story you know the universe is static no
story you know the universe is static no now we need spark energy no that was a
now we need spark energy no that was a
now we need spark energy no that was a big blunder no now we think it exists
big blunder no now we think it exists
big blunder no now we think it exists after all but that’s sometimes the way
after all but that’s sometimes the way
after all but that’s sometimes the way science goes so we now think the
science goes so we now think the
science goes so we now think the universe is actually dominated by this
universe is actually dominated by this
universe is actually dominated by this dark energy component the energy of
dark energy component the energy of
dark energy component the energy of empty space which causes this repulsive
empty space which causes this repulsive
empty space which causes this repulsive gravity which causes the universe to
gravity which causes the universe to
gravity which causes the universe to accelerate so after about a decade
accelerate so after about a decade
accelerate so after about a decade decade in half of working hard on this
decade in half of working hard on this
decade in half of working hard on this we have arrived at what is on the one
we have arrived at what is on the one
we have arrived at what is on the one hand the glasses have full story you
hand the glasses have full story you
hand the glasses have full story you know we’ve made tremendous progress we
know we’ve made tremendous progress we
know we’ve made tremendous progress we now have labeled every part of the
now have labeled every part of the
now have labeled every part of the universe about 0.05 percent of it is in
universe about 0.05 percent of it is in
universe about 0.05 percent of it is in the form of planets another point 5% in
the form of planets another point 5% in
the form of planets another point 5% in the form of stars another 4% in the form
the form of stars another 4% in the form
the form of stars another 4% in the form of gas gas which is made of the elements
of gas gas which is made of the elements
of gas gas which is made of the elements that you see in the periodic table of
that you see in the periodic table of
that you see in the periodic table of elements so about the whole universe
elements so about the whole universe
elements so about the whole universe made of normal stuff the stuff we’re
made of normal stuff the stuff we’re
made of normal stuff the stuff we’re made of is only about 4 and 1/2 percent
made of is only about 4 and 1/2 percent
made of is only about 4 and 1/2 percent of the universe so it’s really quite
of the universe so it’s really quite
of the universe so it’s really quite striking that the the stuff we’re
striking that the the stuff we’re
striking that the the stuff we’re familiar with is really just sort of the
familiar with is really just sort of the
familiar with is really just sort of the frosting on the cake the majority is 23%
frosting on the cake the majority is 23%
frosting on the cake the majority is 23% in the form of another type of matter
in the form of another type of matter
in the form of another type of matter that has attracted gravity but we don’t
that has attracted gravity but we don’t
that has attracted gravity but we don’t understand the kind of particle that it
understand the kind of particle that it
understand the kind of particle that it is made out of but it is not what I
is made out of but it is not what I
is made out of but it is not what I would call normal physics or the kinds
would call normal physics or the kinds
would call normal physics or the kinds of particles that we’re already familiar
of particles that we’re already familiar
of particles that we’re already familiar with and then there’s the even more
with and then there’s the even more
with and then there’s the even more mysterious component to dark energy that
mysterious component to dark energy that
mysterious component to dark energy that makes up now we think about 73% of the
makes up now we think about 73% of the
makes up now we think about 73% of the universe and so the I said
universe and so the I said
universe and so the I said glass-is-half-full part of the story is
glass-is-half-full part of the story is
glass-is-half-full part of the story is we have finally come to terms with the
we have finally come to terms with the
we have finally come to terms with the pie chart of the universe
pie chart of the universe
pie chart of the universe and the part that’s a little frustrating
and the part that’s a little frustrating
and the part that’s a little frustrating is we don’t understand ninety-six
is we don’t understand ninety-six
is we don’t understand ninety-six percent of it so but that as Kenny said
percent of it so but that as Kenny said
percent of it so but that as Kenny said in this case this is our job security is
in this case this is our job security is
in this case this is our job security is you know our vast ignorance but anyway
you know our vast ignorance but anyway
you know our vast ignorance but anyway so I think what we are looking forward
so I think what we are looking forward
so I think what we are looking forward to over the next decade is experiments
to over the next decade is experiments
to over the next decade is experiments and measurements that will help us
and measurements that will help us
and measurements that will help us understand both the nature of the dark
understand both the nature of the dark
understand both the nature of the dark matter the nature of the dark energy and
matter the nature of the dark energy and
matter the nature of the dark energy and in all likelihood from this will come a
in all likelihood from this will come a
in all likelihood from this will come a deeper understanding of gravity and the
deeper understanding of gravity and the
deeper understanding of gravity and the fundamental laws of physics and in the
fundamental laws of physics and in the
fundamental laws of physics and in the past when we have learned more about the
past when we have learned more about the
past when we have learned more about the fundamental laws of physics
fundamental laws of physics
fundamental laws of physics we’ve always learned a great deal in the
we’ve always learned a great deal in the
we’ve always learned a great deal in the realms of science and technology so I
realms of science and technology so I
realms of science and technology so I will end there thank you
”
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