The Webb Deep Space Telescope

LINKS:
How the James Webb telescope works: https://graphics.reuters.com/SPACE-EXPLORATION/TELESCOPE/klvyknwbrvg/
Image One – SMACS 0723: https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-delivers-deepest-infrared-image-of-universe-yet
Hubble’s view of SMACS 0723: https://hubblesite.org/contents/news-releases/1996/news-1996-01.html
Image Two – WASP 96B: https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-reveals-steamy-atmosphere-of-distant-planet-in-detail
Image Three – Carina Nebula: https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-reveals-cosmic-cliffs-glittering-landscape-of-star-birth
Image Four – A dying star: https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-captures-dying-star-s-final-performance-in-fine-detail
Image Five – Stephan’s Quintet: https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-sheds-light-on-galaxy-evolution-black-holes

EPISODE TRANSCRIPT
It cost 10 billion dollars … took 25 years to build… and it’s 1.5 million kilometres from home. This is your Squiz Kids Shortcut to the Webb space telescope—the podcast where we dive into the who, what, when, where, why and how of the big news stories. I’m Amanda Bower.

And I’m Bryce Corbett.

Not long ago, NASA – the American space agency – released the first five pictures taken by its new James Webb Space Telescope. And Bryce, I’m not sure that five photos have ever had such a massive impact! Scientists say that it will take YEARS for them to study everything they’ve discovered in just those five pictures. And of course, there are many more to come.

Today, we’ll take you through HOW the Webb telescope is able to take such incredible pictures… WHAT we’ve learned so far from them… and WHY scientists say it’s important to look into deep space.

Listen carefully – there’s a Squiz at the end!

HOW
Okay, Bryce, let me take you through what the James Webb telescope is, and how it works. It weighs seven tons – about as much as an African elephant – and it looks like a silvery diamond, with a golden piece of honeycomb on top. Now, that’s not how it looked when it was tightly folded inside a rocket on Christmas Day, 2021, and shot out 10,000 km into space. Once it left the rocket, it began to unfold, in an incredibly complicated process that took thirteen days.

I know we don’t have time to cover all those steps, but you’ve put a graphic guide from Reuters in the episode notes.

It is extremely good and helpful. So, once those 13 days had passed successfully, Webb then spent 29 days travelling away from Earth, until it was 1.5 million kilometres from where it started! On its way, it slowly unfurled five thin, silvery sheets of foil, each about as big as a tennis court. Those sheets are like a giant sun umbrella, protecting the telescope from the light and the heat of the sun, moon, and Earth. That’s really important, because it means that distant light signals won’t be lost when the telescope is taking pictures.

And how does it take those pictures?

That’s where the honeycomb-like structure comes in. It’s made up of 18 gold-coated hexagonal mirrors. A hexagon, of course, has six sides. Those mirrors are as tall and wide as a house, and what they do is capture light to make the pictures, and they’re able to capture really faint light constantly, thanks to the brilliantly calculated orbit of the telescope, which prevents it from being in the shadow of the Earth and Moon.

Shadows are bad?

Yep. Simply put, the shadow blocks the view. The Hubble telescope, for example, which until now had taken the best images of our galaxy we’d ever seen, goes in and out of shadow every 90 minutes. But Webb can operate around the clock. And what it’s doing, basically, is going back in time.

What? It’s a time machine?

Nothing that tricky! So to understand this, we need to remember that light does take time to get places. It travels very, VERY quickly – almost 300,000 kilometres per second – but that means that when we look up at the moon, we’re seeing it actually as it was 1.3 seconds ago. When we see Jupiter, we’re really seeing what happened on that big planet 40 minutes ago. So things get really long ago, really quickly. When we look at the Andromeda galaxy, which is the closest one to our galaxy, and the only one we can see with the naked eye, we’re seeing what happened there 2.5 million years ago.

Okay, so if we can see 2.5 million years into the past with our own eyes, how far back can the Webb telescope see?

Great question. Those mirrors can pick up light sent from 13 BILLION light years away… meaning that its pictures are showing us what those galaxies were like 13 billion years ago, really close to the Big Bang.

Wow. And WHAT have they shown us, so far?

WHAT
Okay, for you to really understand what the first – and probably the most famous – picture shows, I want you to imagine that you’re holding one grain of sand on your fingertip. Now, you’re going to reach your hand up as high as you can. How much of your view of the night sky is blocked by that one grain of sand?

The teensiest, tiniest bit!

That is the size of the patch of sky that this picture captures. It’s the galaxy cluster known as SMACS 0723, which really doesn’t roll off the tongue too nicely. What’s really crazy is that this image – just this image – shows us thousands and thousands of galaxies. I’ve put a picture in your episode notes, Bryce, and you can see there are bright shining stars, and then these kind of fuzzy little orange caterpillars. Each one of those little caterpillars is a new galaxy.

Oh my goodness. My brain is having trouble processing this. And that’s just in a patch of sky the size of a grain of sand when I look up?

Amazing, right? How many of those grains of sand are in the sky? And the detail is just incredible. Also in your episode notes is an image of the same patch of sky taken by the Hubble Telescope in 1996. It took Hubble, which orbits pretty close to Earth, and it took that telescope two weeks to capture its picture – the Deep Space Webb telescope captured its version in just one morning, and the difference in detail is incredible. The parts of the image that look the reddest are the ones that are furthest away… so what we are seeing happened about 13 billion years ago.

Unbelievable. Okay, what does the second photo show? And I’m not sure I have enough space in my brain to take it all in, but hit me anyway. 

This one is actually not a picture, but sort of a graph, and it’s breaking down the light coming through an exoplanet’s atmosphere. This is a bit complicated, but it’s worth straining your brain, because it’s pretty amazing. First of all, an exoplanet is just a planet that’s not in our solar system. Webb pointed its honeycomb mirrors at a giant hot gas planet that’s about 1,000 light years from Earth called WASP 96-B – again, not exactly a catchy name! Now what was really clever is that the image was intentionally taken as WASP 96-B passed in front of the sun it orbits around. So what Webb was picking up was the light that had gone through, and been filtered by, the planet’s atmosphere. Scientists back on earth could analyse what they call the “chemical fingerprints” from the planet that came through in that light, and they’re pretty sure that it is a steamy planet, with lots of water vapour, and clouds, in its atmosphere.

Hold on. Does that mean that Webb will be able to capture similar information from lots of planets, and help us figure out if there are other places that could have living creatures on them?

Exactly right. Life in space! Astronomers – the clever, clever people who study the stars, moons, planets, and more – expect to be able to see if there is oxygen, nitrogen, carbon, and other things in the information sent back by Webb. They’ll be looking for what they call the biosignatures of life – clues that a planet’s atmosphere is being affected by living things.

Unbelievable. I think I’m saying that a lot in this particular Shortcut. Well, that’s one reason to send a telescope into space! WHY else do astronomers say it’s important to look into deep space?

WHY
There’s always this argument, Bryce, about whether we should be spending $10 billion on a telescope to look at other planets when there is a climate emergency on our own planet, people who are hungry, wars, and so on. But actually, the climate situation is one reason that astronomers say it could be helpful to look back in time, into space. They’re looking for planets that also show evidence of having had climate change, and learning from what happened to those planets in the past, in order to try to help our own planet.

And I suppose they’re also studying history, in a way – learning what happened in the past in other galaxies, which could help our understanding of our own galaxy.

That’s pretty much exactly what they say! The third image from Webb show how stars are born in the Carina Nebula; the fourth shows a dying star’s final performance, as it puffs off its outer layers; and the fifth image is made up of 1,000 separate images, stitched together to show five galaxies called Stephan’s Quintet. It honestly looks like they’re dancing around each other and a supermassive black hole, about 300 million light years away.

Astronomers say that they will be spending YEARS learning from all the information captured in just these five images.

And what really blows my mind, Bryce, is that these five were considered tests —practice pictures before the real work got going. Imagine what they might find next.

THE S’QUIZ
This is the part of the podcast where you get to test how well you’ve been listening…
1. The Webb telescope captures light using gold-coated what?
2. What is the name for planets outside our solar system?
3. Which is the image that you think is the most exciting and interesting?