- [Narrator] After decades of work,
NASA's James Webb Space Telescope or JWST
is about to start its million-mile journey.
The Hubble Space Telescope, launched in 1990,
opened up new windows on the universe.
But scientists expect that JWST
will reveal even more,
revolutionizing our understanding of the cosmos,
and perhaps bringing us closer
to answering the age-old question are we alone?
- The whole launch date is gonna to be filled with emotions.
It's an engineering marvel
that we as humans, we have never done this before.
- I feel very nervous but excited
and just ready to go.
- I mean, there's so much riding on this telescope.
It's been decades of work
that's gone into it.
- It's taken us a long time to get here
but man, we're so excited,
we're so ready for this to go.
This will be a transformative facility,
and it will show us so many things
that we just haven't seen.
- [Narrator] JWST is the most powerful
space telescope ever constructed.
With a mirror almost three times wider than Hubble's,
it'll be able to see objects 10
or even 100 times fainter.
- This is the biggest telescope
that has been built in space,
and because of the complexity of the design,
this is no doubt the most complex machine.
And it is magnificent.
- [Narrator] JWST's mirror is 21 feet wide,
and made up of 18 different sections
that fold up tightly for launch like origami,
and will need to unfold perfectly once in space.
- We're not just talking about having to develop
lightweight mirrors, but we need 18 of them.
They all have to match each other
such that they can be aligned
to a degree of accuracy
that's about a 10,000th of a human hair.
- [Narrator] While humans see the world
through visible light,
there are many wavelengths invisible to the human eye,
such as X-rays, and infrared.
Sensing infrared light,
which can be detected in the form of heat,
JWST will be able to peer through dense clouds
of space dust that block visible light
so it can reveal previously hidden secrets
of the universe, like early galaxies
over 13.5 billion years old,
and the formation of stars and planets.
And because JWST
is an incredibly sensitive infrared telescope,
its scientific instruments and detectors need
to be kept at extremely cold temperatures
to suppress infrared background noise,
and function properly.
To help JWST keep its cool,
scientists built a sun shield
about the size of a tennis court,
nearly 70 feet across when deployed.
- Radiation from the sun travels through space.
It doesn't care about the fact
that the telescope is far away.
And so we have to keep the mirrors
and the instruments in constant shade
and that's what the sun shield is for.
- [Narrator] About five days after launch,
they'll start to expand the sun shield.
Once that's complete,
about 10 days after launch,
they'll start to unfold the mirror.
It'll take 30 days
and a million miles for JWST to reach its destination.
Then, it'll start the six-month cool-down
and calibration process.
If all goes according to plan,
JWST will commence its scientific operations
in June 2022.
And scientists are excited to see what it finds out
about the early universe and the first galaxies.
- We're gonna see so many points of light
from different distances,
and that is in itself going to be a revealing moment
in how rich the universe truly is,
and how much is actually going on out there.
- With Hubble, we pushed the boundaries
to a few hundreds million years
after the Big Bang.
JWST will look past that
and will be able to cover the very, very early phases
when the first stars appear,
when the first galaxies are assembled,
and the universe that we see today is shaped.
- [Narrator] It should also reveal the evolution
of stars and planets.
JWST's infrared instruments will be able to peer
through the kinds of dense dust clouds
where star and planet formation begins.
- So if we can understand how other planetary systems
out there form and where they form,
it's gonna be totally revolutionary.
We can track its history.
So this has profound implications
to understanding how our solar system came to be.
- [Narrator] And sense the atmosphere of exoplanets.
- With JWST, the infrared light allows us
to see water vapor in the atmospheres of exoplanets
but also, we can see things like methane
and carbon dioxide.
And depending on the type of planet
that we're looking at,
we can actually measure how much of these molecules
are in the atmosphere.
And that composition can tell us
whether there's any indications
of the elements of life
that could be possible on these exoplanet atmospheres.
- I think we'll be surprised how strange
and different those planetary systems are.
Will we even recognize life?
We don't know.
I think that the whole point of going
to all the trouble of building a telescope
as big as JWST is because it provides us
with a brand new way to look at the universe
and every time humanity has looked at the universe
in a new way,
it has been transformative
as it has been surprising.
(lively music)