- [Narrator] This is the Hubble Space Telescope
that has revolutionized how we look at the universe.
And here is its successor,
the James Webb Space Telescope.
It's the largest
and most powerful space telescope ever built,
and it's about to launch later this month.
- You could almost think of it
as a telescope to complete this grand question
of when did the first galaxies form?
- [Announcer] Liftoff of the Space Shuttle Discovery
with the Hubble Space Telescope,
our window on the universe.
- [Narrator] The once trailblazing Hubble Telescope,
launched in 1990,
and has been orbiting Earth ever since,
capturing visuals like this,
a composite of filtered and colorized images.
Its ability to see light
from billions of years ago
has opened a window into early parts of the universe
but it could never see the very oldest galaxies.
But now the James Webb Telescope
has the necessary technology
to capture the earliest forming stars and planets,
and possibly a glimpse into how life first began.
The James Webb Telescope,
named after the former NASA administrator,
is one of the largest international scientific efforts
in US history.
- Learning about the sky tells us more
about how our planet, how we came to be.
- [Narrator] For over three decades,
Dr. Eric Smith has been innovating telescopes for NASA.
After working on Hubble,
he then spent the last 25 years developing Webb.
- You can make the case
that the history of 20th century astronomy
was building ever-larger telescopes
to see ever-farther galaxies.
- [Narrator] The Hubble Space Telescope
takes images of planets, stars and galaxies
some billions of light-years away
while staying in Earth's orbit
where it can be repaired.
Hubble primarily scans the cosmos
in the same way our eyes process visible light,
which enables it to view hotter, younger stars.
Colder stars, which can be billions
of years older are less visible to Hubble
and this is where the James Webb Telescope will shine.
Webb will observe the universe
in a different way than Hubble
using primary infrared light,
which isn't visible to the human eye.
- When you look in the infrared,
you're studying things that are a little cooler,
so you see cooler stars
of which there are many more than the hotter stars.
It's also easier to detect faint things,
like planets and exoplanets.
- [Narrator] Infrared light allows the telescope
to unveil thick clouds of dust
that surround galaxies and nebula,
revealing more detail and information
about how stars and planets first formed.
Here are two images of the same nebula
that Hubble took,
one using visible light and the other using infrared.
But James Webb will be able
to take infrared images with even more clarity,
and sensitivity than Hubble,
and this will help it accomplish one
of its core missions,
looking back further in time to the earliest galaxies
that formed after the big bang.
- The way Webb will be used to see these first galaxies,
you take pictures of different patches of the sky,
and you count the number of faint galaxies you see
down to a certain brightness level.
And at some point,
you would expect to see a cliff,
saying there are just no more galaxies below this.
- [Narrator] The very faintest objects
that Webb will see
are some of the oldest lights in the universe,
revealing a window back in time.
And what powers this new telescope
to see galaxies that formed billions of years ago
is cutting-edge technology.
The $10 billion James Webb Telescope
is 100 times more powerful than Hubble
and much of that power comes
from its massive primary mirror,
which is over 21 feet wide,
nearly three times larger than Hubble's.
It will be the largest ever put in space.
And part of what makes it so powerful
is what the mirror segments are composed of.
- They're made of beryllium,
which is a very light weight material
that's stable at the very cold temperatures
we want the telescope to operate at.
And then because we wanna study the infrared part
of the spectrum, we wanna have the smooth surface coated
with something that reflects infrared light really well,
and that substance is gold.
It's actually a very thin layer.
It's only about 1,000 atoms thick.
If you scraped up all the gold
that was in Webb, it would only be about the size
of a golf ball.
- [Narrator] Webb also has advanced sensors
and scientific instruments onboard
to help scientists analyze the cosmos.
One instrument is the near infrared spectrograph,
which is designed to determine
what kind of elements or chemical compounds
are in distant parts of space.
- In the big bang, we had hydrogen and helium.
Pretty much nothing else.
Everything else was made in stars.
So if you see a spectrum of an object
that has pretty much just only hydrogen and helium,
then you know you're seeing one of the first objects
to be formed.
- [Narrator] And this is key.
One goal of Webb is to give insight
into when it would have been possible
for habitable planets to first form,
which could hold clues
into how the universe and life first began.
For Webb sensors and scientific instruments to work,
they need to be kept cool,
which is why a huge sun shield
with layers the thickness of a plastic bag is used.
And to see some of the universe's oldest galaxies,
Webb will also need a crystal clear view.
This is why the telescope
will travel about a million miles away
from Earth towards deep space
where it cannot be repaired like Hubble can.
- Most of our space telescopes orbit the Earth nearby.
So why do we have to go a million miles away?
Primarily, it's to be far from the Earth,
which itself is a very bright object in the infrared.
- [Narrator] As advanced as Webb is,
it won't be the last telescope
to search for life beyond Earth.
A recent report from the National Academy
of Sciences recommended that an even larger telescope
should be designed in the next decade
to look for life on exoplanets,
opening the window of possibility
for finding extraterrestrial life.
(pensive music)