Commons here at the University of
Rochester and there was a company there
that had this big picture of the primary
mirror of the Hubble Space Telescope and
I didn’t know much about Hubble but I
talked with the folks from the company
and I was really amazed at how powerful
this telescope could be a few years
later in 1990 NASA launched the Hubble
Space Telescope and it was brought up
into low-earth orbit by the space
shuttle and it was deployed and the
first images were sent down to the
ground but there was a really big
problem there was trouble with Hubble
the primary mirror of Hubble was
actually ground to the wrong
prescription and all of the images
coming from Hubble were blurry so this
was a real crisis for NASA was only a
few years after the space shuttle
Challenger had blown up and so NASA put
together a team and decided it was going
to fix Hubble it but it was already
planning on upgrading Hubble but it had
to come up with a way to fix this
optical problem and in about three and a
half years two instruments were built
that fixed Hubble one of the instruments
was an instrument called co-star which
had little arms that deployed with
little mirrors that kind of acted like
contact lenses to fix three of the
instruments that were already in there
the second instrument was called the
wide field planetary camera 2 and it was
– because their wide field planetary
camera one was already in Hubble and the
second one had little corrective optics
inside of it that took this amazing
image of the spiral galaxies that you
can see which demonstrated that Hubble
was repaired their astronauts who
actually did spacewalks to put these
instruments in Hubble but once it was
repaired it was fully operational and it
was able to do the science that it was
intended to do about two years later one
of the things it did was a was taken
image of a real dark patch of the sky
this patch of the sky we called the
Hubble Deep Field basically Hubble
stared at the same dark patch of the sky
for ten days which was a really long
period of time for Hubble this was about
as long as it stared at any one region
of the sky it took over 340 exposures
with different filters and all of this
was put together
into what we call the Hubble Deep Field
now some people especially astronomers
who look at the Hubble Deep Field have
what Einstein called a cosmic religious
experience because in looking at it
you’re actually seeing the evolution of
the universe from when the universe was
now the Hubble Deep Field is an amazing
image of the universe but it doesn’t go
all the way back to the very beginning
of the universe and in fact the
astronomers looking at the data from
Hubble decided that we needed to build
yet another telescope that could fill in
the void the void I’m talking about is
really a void in our understanding of
the cosmic history of our universe it
turns out that some of the very first
light that was generated in the universe
came as remnants from the Big Bang there
was this huge explosion and inflation
and there was a slight thermal emission
in the form of microwave light that was
generated and actually two satellites
that were developed at the institution I
work at at the Goddard Space Flight
Center have mapped that microwave
background one of them called Kobe the
cosmic background Explorer one dr. John
Mather a Nobel Prize dr. John Mather is
now the project scientist for the Webb
telescope so that was the first very
remnants of light that we’ve seen with
satellites but then there was a sort of
dark period where the universe became a
opaque because what happened was protons
neutrons and electrons kind of got
together they formed atoms and the atoms
tended to prevent light from getting
through but at some point the the atom
started to clump
there was little gravity wells the
gravity makes stars the stars eventually
explode into supernovae and those
supernovae create ultraviolet light that
ionized
the atoms and that create light that we
can see and so we start getting stars
and start getting supernovae we start
getting to a period we call Rihanna’s
ation somewhere between a few hundred
million years after the Big Bang and a
billion years which Hubble can see that
Rihanna’s ation period is actually the
period when the first chemical elements
were formed some of you may know that
supernovae generate chemical
because of the amount of energy you have
what was just hydrogen and helium can
now become things like carbon nitrogen
and oxygen so if we can see into that
epoch of time we can actually see the
formation of the chemical history of the
universe but Hubble can’t do this and
the reason is kind of complicated so
bear with me it turns out that the light
from the very early universe has been
coming to us over a very long period of
time and that light the universe itself
while the light has been coming to us
has been expanding
there was the initial inflation but the
universe has continued to expand and
even accelerate and because of that we
call it the mesh of space-time the mesh
itself is in is expanding so the light
coming to us which starts as visible
light and ultraviolet light is being
redshift it is being stretched because
of this the expansion of this mesh into
the infrared and that infrared light is
what we need to look at in order to see
this early epoch of time Hubble was not
designed to see that light and in fact
Hubble has a major challenge in being
able to do that which is Hubble’s
primary mirror that mirror that I saw at
that career fair is actually operated at
room temperature which is roughly 70
degrees Fahrenheit or 293 degrees Kelvin
and at that temperature because of
something called blackbody emission
every every body produces infrared light
but at room temperature you produce a
lot of infrared light that would
contaminate the image that you’re trying
to see the the mirror itself would
generate so much infrared light that you
would not be able to see these very dim
infrared objects so if you want to see
these objects you actually need a
telescope that’s about 50 degrees above
absolute zero about minus 400 degrees
Fahrenheit and by the way it needs to be
bigger than Hubble Hubble’s a two point
four meter primary mirror we need a
mirror that’s about six and a half to
seven meters in size just to collect
enough photons because these objects are
so dim so we need a humongous telescope
that’s really cold and that’s really the
key driver that led to the development
of the design of the James Webb Space
Telescope
the mirror is so big it’s actually
bigger not only than the Hubble mirror
but even a the Herschel mirror which
worked at very long wavelengths and it’s
so big it will not even fit in a rocket
without being folded up so to fold it up
we literally have to segment the mirror
we actually have 18 individual primary
mirror segments each one of them has
seven actuators these actuators move in
fractions of a wavelength of light one
20,000th the diameter of a human hair at
the temperature of minus 400 degrees
Fahrenheit to align the 18 segments as
though they’re one it’s one monolithic
mirror it’ll do that in space there are
wings that have to unfold the secondary
mirror has to unfold and then to cool it
which was one of the biggest challenges
we’re talking about cooling thousands of
kilograms of mass to this incredibly
cold temperature we actually do it
passively and we do it by deploying a
very large sun shield that’s about the
size of a tennis court and that’s
literally five layers and we do this at
a very unique orbit
unlike most observatories which were in
low-earth orbit really close to the
earth where they’re constantly seeing
the Sun and then not seeing the Sun
which is the way Hubble works by the way
Webb is actually gonna go really far
from the earth one and a half million
kilometres too far to be serviced the
way Hubble was the reason we go that far
is there’s this unique point there
called the Lagrangian there’s actually
five of these Lagrange points but the l2
Lagrange point which is at a point a one
and a half million kilometres from from
us here and on earth at that point we
can actually keep the Sun the earth and
the moon on one side put up this large
Sun shield and basically block anything
that’s warm and let the telescope cool
and the and the instruments and the only
thing the telescope is seeing is the
inner layer of that sun shield which is
cold and deep space which is even colder
and over many weeks in space the
telescope will cool down will align it
and then it becomes the observatory
that’s the James Webb Space Telescope in
addition to just a telescope we also
need instruments and so Webb has four
scientific instruments and Webb can do a
lot of different science not just study
the early universe but three of the
instruments were specially designed to
really focus on this early universe
science and they do it in a very
complimentary way which is gonna make it
even more powerful one of the
instruments is a near-infrared camera
that kind of picks up where that Hubble
wide field planetary camera leaves off
and goes all the way up to a wavelength
of 5 microns it’s a near-infrared camera
with lots of filters that can take
basically the equivalent of the Hubble
Deep Field but in the near-infrared a
second instrument also operates at the
same wavelengths but it’s actually
what’s called a multi-object
spectrometer which is a very unique
thing we didn’t have one of these on
Hubble on Hubble we actually have a
spectrometer that just can look at one
individual object at a time what this
will do what this instrument will do is
it actually has a special technological
device that was developed actually by
folks at the Goddard Space Flight Center
it’s a little MEMS device MEMS stands
for micro electromechanical systems it’s
a little series of little tiny shutters
that are each about the diameter of a
human hair and you can program them so
that you only open shutters which have
say a galaxy on them so that the only
thing getting through your instrument
are the things that you want to look at
the galaxies and nothing else and on
each of those galaxies you can take a
spectra you can take you can spread the
light out with say a grating or a prism
and actually see the wavelength
composition of each individual galaxy
and from that you can determine the age
of each galaxy you can determine some of
the chemical contents of those galaxies
and we can do that and look back during
this first epoch of time and see how
things evolved in a sort of scientific
manner the third and final instrument
actually works at even longer
wavelengths than the first two it’s a
mid infrared imager which picks up where
the other two leave off at five microns
and goes all the way up to the longest
wavelengths that web can do which is 28
microns and that really fills in that
the extra parts of the spectrum which
you would want to look at to understand
the really really early universe and
that particular instrument is very
challenging because it has a detector
that operates below 10 degrees above
absolute zero so we are very far along
in developing this observatory I’ve
personally been working on it for 16
years since I
worked on the Hubble this past summer we
actually had the telescope and the
instruments together we brought them to
the Johnson Space Center in Houston it
turns out that they have one of the
largest vacuum chambers on the planet
which is why we went there we actually
had to build a whole clean room to get
the telescope into it we built a helium
shroud that allowed us to cool the
telescope we’ve had special optical
optical equipment that works at
cryogenic temperatures we put it in the
chamber in July and started our test and
lo and behold about the third to fourth
week of August of this past year we got
the telescope cold enough to start
taking the optical data to do the
end-to-end tests that we that weren’t
done on Hubble and some of you may
recall what happened during that period
of time hurricane Harvey hit just as we
had hit operating temperature and so 120
people down in Houston made it through
hurricane Harvey we made it through all
of our tests the telescope looks
incredible I think it was sort of a
message from nature reminding us how
difficult it is to see the early
universe so now the telescope is
actually sent to Northrop Grumman in
Redondo Beach California and just this
week the spacecraft and Sun shield which
the Sun shield is now folded up and it
sits on top of the the spacecraft will
start undergoing their acoustics and
sine vibration testing these are
environmental tests to say that it’s
okay to launch in a rocket the telescope
and instruments have completed all of
their environmental tests so that when
the spacecraft and Sun shield are
complete these two different pieces will
be put together and the full observatory
can be go through its final testing we
expect that the launch of this will be
in about two years from now and when we
launch it just like Hubble’s data led to
the data that we learned from that led
to the Webb telescope it’s our
expectation that we are going to learn
things about the early universe that
will make us want to understand it even
better and we also think we’re going to
learn things about other aspects of the
universe for example exoplanets I
mentioned that
web will also look at exoplanets it
turns out when we started web there
wasn’t even a detection of a single
exoplanet and as we were developing web
we realized that it could be this really
powerful device for understanding these
planets around other stars you can
actually look at them as they orbit
those stars and you can measure their
spectral content and understand their
atmospheres now web can do that using a
technique called the transit method and
that allows web to understand the
atmospheres of those exoplanets perhaps
looking for harbingers of life however
web wasn’t designed to really look for
what we call sun-like planets and we
think sun-like planets are the most
likely ones that we can find those
aliens that we were hearing about
earlier so web isn’t real likely to find
life but it’s possible that it will find
all sorts of chemical signatures that
will lead us to want to understand it
even better and so I leave you with the
thought that I think it’s very likely
that someone here today just like when I
was visiting that career fair a few
years from now will be the one to help
ask the questions and answer the
questions that we raised with the Webb
telescope thank you very much [Applause]
Rochester and there was a company there
that had this big picture of the primary
mirror of the Hubble Space Telescope and
I didn’t know much about Hubble but I
talked with the folks from the company
and I was really amazed at how powerful
this telescope could be a few years
later in 1990 NASA launched the Hubble
Space Telescope and it was brought up
into low-earth orbit by the space
shuttle and it was deployed and the
first images were sent down to the
ground but there was a really big
problem there was trouble with Hubble
the primary mirror of Hubble was
actually ground to the wrong
prescription and all of the images
coming from Hubble were blurry so this
was a real crisis for NASA was only a
few years after the space shuttle
Challenger had blown up and so NASA put
together a team and decided it was going
to fix Hubble it but it was already
planning on upgrading Hubble but it had
to come up with a way to fix this
optical problem and in about three and a
half years two instruments were built
that fixed Hubble one of the instruments
was an instrument called co-star which
had little arms that deployed with
little mirrors that kind of acted like
contact lenses to fix three of the
instruments that were already in there
the second instrument was called the
wide field planetary camera 2 and it was
– because their wide field planetary
camera one was already in Hubble and the
second one had little corrective optics
inside of it that took this amazing
image of the spiral galaxies that you
can see which demonstrated that Hubble
was repaired their astronauts who
actually did spacewalks to put these
instruments in Hubble but once it was
repaired it was fully operational and it
was able to do the science that it was
intended to do about two years later one
of the things it did was a was taken
image of a real dark patch of the sky
this patch of the sky we called the
Hubble Deep Field basically Hubble
stared at the same dark patch of the sky
for ten days which was a really long
period of time for Hubble this was about
as long as it stared at any one region
of the sky it took over 340 exposures
with different filters and all of this
was put together
into what we call the Hubble Deep Field
now some people especially astronomers
who look at the Hubble Deep Field have
what Einstein called a cosmic religious
experience because in looking at it
you’re actually seeing the evolution of
the universe from when the universe was
now the Hubble Deep Field is an amazing
image of the universe but it doesn’t go
all the way back to the very beginning
of the universe and in fact the
astronomers looking at the data from
Hubble decided that we needed to build
yet another telescope that could fill in
the void the void I’m talking about is
really a void in our understanding of
the cosmic history of our universe it
turns out that some of the very first
light that was generated in the universe
came as remnants from the Big Bang there
was this huge explosion and inflation
and there was a slight thermal emission
in the form of microwave light that was
generated and actually two satellites
that were developed at the institution I
work at at the Goddard Space Flight
Center have mapped that microwave
background one of them called Kobe the
cosmic background Explorer one dr. John
Mather a Nobel Prize dr. John Mather is
now the project scientist for the Webb
telescope so that was the first very
remnants of light that we’ve seen with
satellites but then there was a sort of
dark period where the universe became a
opaque because what happened was protons
neutrons and electrons kind of got
together they formed atoms and the atoms
tended to prevent light from getting
through but at some point the the atom
started to clump
there was little gravity wells the
gravity makes stars the stars eventually
explode into supernovae and those
supernovae create ultraviolet light that
ionized
the atoms and that create light that we
can see and so we start getting stars
and start getting supernovae we start
getting to a period we call Rihanna’s
ation somewhere between a few hundred
million years after the Big Bang and a
billion years which Hubble can see that
Rihanna’s ation period is actually the
period when the first chemical elements
were formed some of you may know that
supernovae generate chemical
because of the amount of energy you have
what was just hydrogen and helium can
now become things like carbon nitrogen
and oxygen so if we can see into that
epoch of time we can actually see the
formation of the chemical history of the
universe but Hubble can’t do this and
the reason is kind of complicated so
bear with me it turns out that the light
from the very early universe has been
coming to us over a very long period of
time and that light the universe itself
while the light has been coming to us
has been expanding
there was the initial inflation but the
universe has continued to expand and
even accelerate and because of that we
call it the mesh of space-time the mesh
itself is in is expanding so the light
coming to us which starts as visible
light and ultraviolet light is being
redshift it is being stretched because
of this the expansion of this mesh into
the infrared and that infrared light is
what we need to look at in order to see
this early epoch of time Hubble was not
designed to see that light and in fact
Hubble has a major challenge in being
able to do that which is Hubble’s
primary mirror that mirror that I saw at
that career fair is actually operated at
room temperature which is roughly 70
degrees Fahrenheit or 293 degrees Kelvin
and at that temperature because of
something called blackbody emission
every every body produces infrared light
but at room temperature you produce a
lot of infrared light that would
contaminate the image that you’re trying
to see the the mirror itself would
generate so much infrared light that you
would not be able to see these very dim
infrared objects so if you want to see
these objects you actually need a
telescope that’s about 50 degrees above
absolute zero about minus 400 degrees
Fahrenheit and by the way it needs to be
bigger than Hubble Hubble’s a two point
four meter primary mirror we need a
mirror that’s about six and a half to
seven meters in size just to collect
enough photons because these objects are
so dim so we need a humongous telescope
that’s really cold and that’s really the
key driver that led to the development
of the design of the James Webb Space
Telescope
the mirror is so big it’s actually
bigger not only than the Hubble mirror
but even a the Herschel mirror which
worked at very long wavelengths and it’s
so big it will not even fit in a rocket
without being folded up so to fold it up
we literally have to segment the mirror
we actually have 18 individual primary
mirror segments each one of them has
seven actuators these actuators move in
fractions of a wavelength of light one
20,000th the diameter of a human hair at
the temperature of minus 400 degrees
Fahrenheit to align the 18 segments as
though they’re one it’s one monolithic
mirror it’ll do that in space there are
wings that have to unfold the secondary
mirror has to unfold and then to cool it
which was one of the biggest challenges
we’re talking about cooling thousands of
kilograms of mass to this incredibly
cold temperature we actually do it
passively and we do it by deploying a
very large sun shield that’s about the
size of a tennis court and that’s
literally five layers and we do this at
a very unique orbit
unlike most observatories which were in
low-earth orbit really close to the
earth where they’re constantly seeing
the Sun and then not seeing the Sun
which is the way Hubble works by the way
Webb is actually gonna go really far
from the earth one and a half million
kilometres too far to be serviced the
way Hubble was the reason we go that far
is there’s this unique point there
called the Lagrangian there’s actually
five of these Lagrange points but the l2
Lagrange point which is at a point a one
and a half million kilometres from from
us here and on earth at that point we
can actually keep the Sun the earth and
the moon on one side put up this large
Sun shield and basically block anything
that’s warm and let the telescope cool
and the and the instruments and the only
thing the telescope is seeing is the
inner layer of that sun shield which is
cold and deep space which is even colder
and over many weeks in space the
telescope will cool down will align it
and then it becomes the observatory
that’s the James Webb Space Telescope in
addition to just a telescope we also
need instruments and so Webb has four
scientific instruments and Webb can do a
lot of different science not just study
the early universe but three of the
instruments were specially designed to
really focus on this early universe
science and they do it in a very
complimentary way which is gonna make it
even more powerful one of the
instruments is a near-infrared camera
that kind of picks up where that Hubble
wide field planetary camera leaves off
and goes all the way up to a wavelength
of 5 microns it’s a near-infrared camera
with lots of filters that can take
basically the equivalent of the Hubble
Deep Field but in the near-infrared a
second instrument also operates at the
same wavelengths but it’s actually
what’s called a multi-object
spectrometer which is a very unique
thing we didn’t have one of these on
Hubble on Hubble we actually have a
spectrometer that just can look at one
individual object at a time what this
will do what this instrument will do is
it actually has a special technological
device that was developed actually by
folks at the Goddard Space Flight Center
it’s a little MEMS device MEMS stands
for micro electromechanical systems it’s
a little series of little tiny shutters
that are each about the diameter of a
human hair and you can program them so
that you only open shutters which have
say a galaxy on them so that the only
thing getting through your instrument
are the things that you want to look at
the galaxies and nothing else and on
each of those galaxies you can take a
spectra you can take you can spread the
light out with say a grating or a prism
and actually see the wavelength
composition of each individual galaxy
and from that you can determine the age
of each galaxy you can determine some of
the chemical contents of those galaxies
and we can do that and look back during
this first epoch of time and see how
things evolved in a sort of scientific
manner the third and final instrument
actually works at even longer
wavelengths than the first two it’s a
mid infrared imager which picks up where
the other two leave off at five microns
and goes all the way up to the longest
wavelengths that web can do which is 28
microns and that really fills in that
the extra parts of the spectrum which
you would want to look at to understand
the really really early universe and
that particular instrument is very
challenging because it has a detector
that operates below 10 degrees above
absolute zero so we are very far along
in developing this observatory I’ve
personally been working on it for 16
years since I
worked on the Hubble this past summer we
actually had the telescope and the
instruments together we brought them to
the Johnson Space Center in Houston it
turns out that they have one of the
largest vacuum chambers on the planet
which is why we went there we actually
had to build a whole clean room to get
the telescope into it we built a helium
shroud that allowed us to cool the
telescope we’ve had special optical
optical equipment that works at
cryogenic temperatures we put it in the
chamber in July and started our test and
lo and behold about the third to fourth
week of August of this past year we got
the telescope cold enough to start
taking the optical data to do the
end-to-end tests that we that weren’t
done on Hubble and some of you may
recall what happened during that period
of time hurricane Harvey hit just as we
had hit operating temperature and so 120
people down in Houston made it through
hurricane Harvey we made it through all
of our tests the telescope looks
incredible I think it was sort of a
message from nature reminding us how
difficult it is to see the early
universe so now the telescope is
actually sent to Northrop Grumman in
Redondo Beach California and just this
week the spacecraft and Sun shield which
the Sun shield is now folded up and it
sits on top of the the spacecraft will
start undergoing their acoustics and
sine vibration testing these are
environmental tests to say that it’s
okay to launch in a rocket the telescope
and instruments have completed all of
their environmental tests so that when
the spacecraft and Sun shield are
complete these two different pieces will
be put together and the full observatory
can be go through its final testing we
expect that the launch of this will be
in about two years from now and when we
launch it just like Hubble’s data led to
the data that we learned from that led
to the Webb telescope it’s our
expectation that we are going to learn
things about the early universe that
will make us want to understand it even
better and we also think we’re going to
learn things about other aspects of the
universe for example exoplanets I
mentioned that
web will also look at exoplanets it
turns out when we started web there
wasn’t even a detection of a single
exoplanet and as we were developing web
we realized that it could be this really
powerful device for understanding these
planets around other stars you can
actually look at them as they orbit
those stars and you can measure their
spectral content and understand their
atmospheres now web can do that using a
technique called the transit method and
that allows web to understand the
atmospheres of those exoplanets perhaps
looking for harbingers of life however
web wasn’t designed to really look for
what we call sun-like planets and we
think sun-like planets are the most
likely ones that we can find those
aliens that we were hearing about
earlier so web isn’t real likely to find
life but it’s possible that it will find
all sorts of chemical signatures that
will lead us to want to understand it
even better and so I leave you with the
thought that I think it’s very likely
that someone here today just like when I
was visiting that career fair a few
years from now will be the one to help
ask the questions and answer the
questions that we raised with the Webb
telescope thank you very much [Applause]
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