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?

[MUSIC] 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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