Joan Cartan-Hansen, Host: It's
taken decades and is the most
expensive telescope ever built.
But what exactly do scientists
hope to find with the James Webb
Space Telescope?
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Cartan-Hansen: Telescopes on
earth have helped us observe the
stars.
But the earth's atmosphere can
distort or limit what we can
see.
So, in 1990, we launched the
Hubble telescope.
It's captured images deep in
space.
But because it's in low earth
orbit, it too has some limits on
what it can view.
So in 1996, scientists from
NASA, the European Space Agency
and the Canadian Space Agency
decided to build the next
generation telescope, now called
the James Webb Space Telescope
or JWST.
They wanted that telescope to
capture infrared light.
Maurice Te Plate is a systems
engineer on the James Webb Space
Telescope project.
Maurice Te Plate: Space itself
basically expanded, and that
basically also means that the
wavelength of the light got
longer.
And as such light, that was
originally emitted as visual
light, light that you and I can
see with our human eyes, that
light became infrared light.
And in order to measure it, we
cannot really use the current
observatories.
We need an observatory that is
really optimized for this
particular part of the
wavelength range.
And that's an infrared
observatory.
Cartan-Hansen: So, engineers
began building the telescope,
designing step by step while
solving a whole bunch of
problems.
First, the light waves coming
from the farthest reaches of the
universe would be very dim.
In order to catch that very dim
light, the telescope would need
a very big mirror.
The mirror on the James Webb
Space Telescope is made up of 18
panels and is more than 21 feet
across.
Te Plate: And in order to make
this telescope work, we need to
cool it down to really cool
temperatures, because if we
wouldn't do that, the telescope
would only see it, it would
basically see its own glow.
It would see itself glowing and
we don't want that.
So therefore we cool it down,
you know, we go to like really
low temperatures and then only
then we can measure those super
weak infrared signals.
Cartan-Hansen: How cold?
How about minus 450 degrees
Fahrenheit, colder than the
surface of Pluto.
To keep the cold side of the
telescope really cold, the
telescope uses a giant heat
shield.
The shield is about the size of
a giant tennis court and keeps
the sun and heat from the earth
and other space objects away
from the telescope.
This heat shield needed to be
light, durable and, like all
other parts of the telescope had
to do one other thing.
Te Plate: So it's so big that it
doesn't fit in even the world's
largest rockets, so it needs to
be folded up.
And then in space, it will like
unfold itself, you know, like a
gigantic piece of origami.
Cartan-Hansen: The James Webb
Space Telescope was launched on
December 25th, 2021 and spent
its first 30 days unfolding and
traveling to where it will orbit
the earth.
Te Plate: We're sending it to
this place called a second
Lagrange point, which is about a
million miles away from the
earth, which is similar to four
times the distance from the
earth to the moon.
So it's really, really, really
far away.
And we do that mainly for
thermal reasons.
We need to be far away from the
earth, far away from the sun.
And that's what we do by sending
it to the second Lagrange point.
Cartan-Hansen: Once in place and
after a
several-month-testing-period.
The James Webb Space Telescope
should start sending back
images.
Te Plate: We wanna look at the
really early universe, so that's
gonna be super exciting.
You know, this is like uncharted
terrain.
We've never done that.
It's gonna be the first time
that we'll see that.
So I'm super interested in those
first results.
Cartan-Hansen: Te Plate explains
that because light travels at a
finite speed, the speed of
light, looking at images so far
away is kind of like looking
back in time.
Te Plate: So when I'm looking at
sun, it's basically I'm looking
at the sun, how it was like
eight minutes ago because the
light takes some time to get to
my eyes.
So when I'm looking outside and
I'm looking at stars, that light
has been traveling for millions
sometimes billions of years.
So you can compare the universe
to a photo book, uh, that you
and I have, you know, it has
like pictures from when, uh, we
were like really young babies,
toddlers, then young children
and then teenagers and, you
know, eventually old men or
women.
With Hubble, we've looked
really, really deep into the
universe.
So we've looked very now, far
back in time, really billions
and billions of years.
But if we go back to that
comparison of the photo book, we
haven't quite seen those baby
pictures, those toddler
pictures, we've seen all the
pictures, you know, when the
universe was a little older, but
we've never seen the universe at
a very young stage.
And that's exactly what Webb's
gonna do.
Cartan-Hansen: Unlike the Hubble
telescope, if anything goes
wrong, the James Webb Space
Telescope is so far out in space
that we can't repair it.
Engineers thought of that and
put in duplicate systems that
might be able to take over and
fix any problems.
The James Webb Space Telescope
has about 10 years' worth of
fuel to keep it going.
After that it will go
dark.unless we can invent a way
to refuel it.something engineers
are already working on.
Te Plate says this telescope is
a new milestone in the history
of space exploration.
Te Plate: And I'm also super
excited about what we're gonna
do, uh, regarding these
exo-planets, you know, maybe
we'll find planets that somehow
are like similar to earth.
You know, maybe we find
atmospheres that have like a
similar molecular composition,
who knows?
But what I think is most
exciting is that we we'll
actually, uh, get answers to
questions that we currently
don't even have.
So the surprises, that is what I
mean.
I mean like the Hubble, you
know, the big discoveries were
like really big surprises, you
know, the stuff that nobody ever
thought of.
And I hope that James Webb will
be able to do something really
similar.
Cartan-Hansen: If you want to
learn more about astronomy,
check out the science trek
website.
You'll find it at science trek
dot org.
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