NASA's Curious Universe - Our Cosmic Time Machine, The James Webb Space Telescope

Episode Date: October 26, 2020

The James Webb Space Telescope will explore every phase of cosmic history: from the formation of the very first galaxies in the early universe, to our cosmic backyard of the Solar System. Webb is the largest space telescope NASA has ever built and it is almost ready to make its journey about one million miles from Earth. 

The James Webb Space Telescope is really being built to answer some of the biggest questions in astronomy today. These are questions that almost everyone asks at some point in their life. Where did we come from? How do we get here? Are we alone in the universe? This is NASA's curious universe. Our universe is a wild and wonderful place. I'm Patty Boyd, and I'm Patty Boyd. And in this podcast, NASA is your tour guide.

For 25 years, scientists and engineers from around the world have been working to design and build a revolutionary window into the early universe, NASA's James Webb Space Telescope. The James Webb Space Telescope will be the biggest and most complex telescope that NASA has ever built. It's a telescope that will test the boundaries of human ingenuity to find and probe some of the farthest objects and reveal new details about some closer to home. In late December of 1995,

as kids unwrapped their holiday presence, the Hubble Space Telescope pointed towards a small region inside the Big Dipper and stared for 10 days. To the naked eye, it was an empty patch of sky. But that's not what Hubble saw. This little blank piece of sky was found to have factored. thousands of galaxies in it. That's Eric Smith.

He's the program scientist of the James Webb Space Telescope. The image he's talking about, the Hubble Deep Field, was packed with galaxies of different shapes, colors, and sizes. For the first time, we saw what the universe looked like almost all the way back to when it formed. Almost. Astronomers learned that none of those galaxies were the first galaxies to form. to form. And they realized then that as fantastic as Hubble is, it wasn't the right instrument to detect those first galaxies. And so this early measurement of Hubble pointed to where

its successor needed to go technically. The Hubble Deepfield image made scientists wonder. What if we created a telescope that could detect those baby galaxies? So scientists and engineers at NASA began designing a new tool that would be bigger and more sensitive, the James Webb Space Telescope. It will see deeper into space than we ever have before. And the farther we can see in space, the farther we can also see in time. That's because telescopes are like time machines. And that's not a metaphor. That's actually literally true. Amber Strawn is a project scientist for the telescope. That really stems from the fact that light takes. time to move through the universe. If you look at a light bulb across the room or

look at a street lamp across the street, the light from those light bulbs takes a tiny fraction of a second to travel across the room to get your eye. And so you're sort of seeing that light bulb as it was a tiny fraction of a second ago. So you can sort of think about things that are more distant. You know the light from the sun takes about eight or nine minutes to get to the earth. So we're seeing the sun as it was eight or nine minutes ago. The Webb telescope, one of the most fundamental and most crucial things it will be able to do is look back into time and see some of the very first galaxies that were born after the Big Bang. That's looking at a part of space that we've never

seen before. Looking at baby galaxies will give us an idea of how our own galaxy formed. And there are a few things that make Webb perfect for getting a glimpse at them. The first is its sensitivity. A lot of the things that we're trying to study are either very faint inherently or they're very, very far away. And so you need a really big, powerful telescope in order to see them. So when you factor in the size of its mirror, the amount of light it will see, and also the sort of new type of detectors that we have. have, the Webb telescope will be overall about a hundred times more powerful than the Hubble Space telescope. The Webb telescope will have the sensitivity to be able to see the light of a bumblebee

at the distance of the moon. Web is so sensitive that it can see the details on a US penny from 24 miles away. Another thing that makes Webb special is the kind of light that it will collect. It's light that our eyes aren't designed to see, infrared light. Eric explains what that means. Infrared light is what we commonly think of as heat. So if you imagine you have a sunbeam coming through your window and you put a prism down there and you see it splits the light up into the rainbow from blue to red, if you were to put a thermometer to the right where that red light was,

you would be registering the infrared radiation that's coming through as heat. You would see that thermometer going up, so you are detecting infrared radiation there. What Webb is going to do is be optimized to detect that heat radiation. But why do scientists want to capture infrared instead of visible light? There are two reasons for that. Webb wants to look at the earliest galaxies to form in the universe. When they formed early on, that means they've been participating in the expansion of the universe. And so their light, as the universe expands, gets stretched out.

And the light that started as visible light has its wavelength stretched into the infrared, even though they're emitting the light as visible. By the time it gets to us, it's infrared. And then the other reason is that infrared light can penetrate the clouds of dust, where stars form in our own galaxy. Dust is great for creating things like stars, but it can block our view of objects in the sky that we want to observe. Infrared light waves go right through the dust,

allowing us to see things that have been hidden. Web sensitivity also makes it a powerful tool to look at exoplanets, planets outside of our solar system that don't orbit the Sun. The observatory will look at these planets' atmospheres in detail, even searching for signs that they could be habitable. I'm looking forward to a few years after Webb is flying, to be out in the night sky, pointing up there and saying,

you see, you know, a little bit to the left or right of that star, there's a star that we can't quite see, but around it orbits a planet that could host life similar to ours. And that will be a pretty profound moment for humanity, I think. With this new telescope in town, you might be wondering, what will happen to the Hubble Space Telescope after Webb begins doing science? Hubble has become this world icon because of its beautiful images. Crisp portraits of Jupiter and its shrinking red spot, blue and orange glows from the relics of supernovae,

or pink dust clouds where stars are being born. They connect with people on a deep level because they're so beautiful, and it just sort of, it gets to the deeper, levels of us as humans, of our need to connect to something that's outside of ourselves. Hubble will still be very important for our exploration of the universe. In many instances, the telescopes can work together to get a more complete understanding of the objects in our skies. They'll be complementary because they're optimized for different pieces of the spectrum, and the best way to do science would be to combine observations of Hubble and web.

Now, because Hubble's operated for 30 years, it's looked at a lot of things, and you can bet that what people will do early on is take Web and go look at some of those same things to use both datasets together. You may have seen photos of Hubble, a silver cylinder with solar panel wings. Web, however, looks completely different. To construct a telescope that could look beyond what Hubble can see, NASA scientists and engineers had to think outside the box, or in this case, outside the tube.

So when you think about a telescope, you're probably imagining your sort of backyard telescope, like a tube with a mirror at the end. And if you think about the Hubble Space Telescope, that's what Hubble's like. It's like a huge tube with a mirror at the end of it up in space. But the James Webb Space Telescope is completely different. It looks like a space machine from the future. It's very sort of sci-fi, future space techie-looking thing. The telescope looks so futuristic, in fact, that it was once mistaken as a work of art.

I can remember many years ago we took a full-scale model of the telescope to New York City, and it was set up in Battery Park. A young couple came up, and they obviously looked like artists, sort of very bohemian, and they came up and they wanted to know what was this beautiful sculpture that was going to be in Battery Park, and how long. would it stay there? And so they saw Webb as an art installation and were amazed to learn that this was actually a science instrument that people were building. And so I think that's what really captures a lot of people's interest in Webb is that it's just a beautiful thing to look at. The model was beautiful,

but the telescope itself, when built, was even more striking. Amber recalls taking her first peek at the telescope. It took my breath away. I mean, it was honestly a little, it was a little bit emotional. It sounds weird to say it. It's just this, you know, it's a telescope. It's a machine. But it's unlike any machine that has been built before. The first key thing about this telescope is it is huge.

It is by far the biggest telescope that NASA has ever attempted to send into space. Top to bottom, it stands about. about four stories tall, and it has a gigantic kite-shaped sun shield that's about the size of a tennis court. The sun shield is made of five layers. Each aluminum-coated layer is as thin as a strand of human hair. The sun shield will block light and heat not only from the sun, but also from Earth and the moon. But the star of the show is what sits on top of the sun shield. It has this beautiful, iconic golden mirror that's made out of 18 separate golden hexagons. The golden hexagonal mirrors that adorn Webb look like a shiny honeycomb.

But the gold isn't just about aesthetics. Gold is really good at reflecting infrared light, the stuff that Webb wants to observe. The mirrors and the sun shield will fold together for launch and then expand like a transformer in space. What struck Amber most when seeing Webb is the people that had a hand in making it a reality. Web represents an enormous collaboration involving NASA, the European Space Agency, and the Canadian Space Agency, as well as the Space Telescope Science Institute and Northrop Grumman. Thousands of engineers worked on the project. And let's not forget the scientists at universities across the world who will use Webb for their scientific inquiries.

It was the representation of decades, of work that thousands of people have put in to bring together this awesome machine that will change fundamentally our understanding of how the universe works. The fact that we're going to send it to space just blows my mind. To get a telescope like this prepped for spaceflight, the team has had to go through a number of tests. like when Webb was recently put on a vibration table. And this is where we shake the whole observatory with the same violence and frequencies that it will feel when it rides the Arien 5 rocket into space. This test, where Webb was vibrated at a frequency of up to 100 times per second, was performed in early October 2020. So we've now subjected it to a simulated launch. Then we will undergo all. the deployments that it will do in space. As well as electronics tests, software tests, and a test

where the telescope is cooled down to the temperature it will operate at in space. These tests are like a dress rehearsal for when Webb is actually sent to space. The next step is to get it to the launch location across the Panama Canal. The telescope is about to go on a cruise. Literally, it will take a boat ride down to French Giana. To a space launch facility in the city of Karoo. The location is close to the equator where Earth's spin is faster than anywhere else on the planet. That spin will give the Arian 5 rocket a little extra push as it takes off with Webb in the fall of 2021. On launch day, it will be sent on a 30-day journey to a special place called a Lagrange point. There's a lot of math involved, but basically it's where the gravity

of the Earth and the Sun combine to make a stable orbital point. that follows Earth around the Sun. This allows an object like Webb to stay put relative to Earth. One of these points is located about a million miles away from Earth, about four times farther away than the Moon. That is where Webb will explore the universe. The launch is both the culmination of years of effort and the beginning of what could be decades of breakthrough scientific discoveries.

There is a lot of anticipation. Thinking ahead to launch, it's hard to know what we'll all be feeling. I've been working on the web team at NASA now for, I guess, going on about 12 years, which is a long time to work on one mission. But, of course, there are people on the web team that have literally spent their whole careers on it. I mean, these huge telescopes, these big groundbreaking missions, people spend their entire careers on. People like John Mather, Nobel laureate, who has. has been with Webb since conception. In 1995, he got a call from NASA headquarters.

We're going to start a study of this new telescope. Do You Want to Work on it? And I thought, I've never heard of anything so exciting before. I'm going to do that. He's been able to see the project grow from an idea to a fully assembled machine. When we started off in the beginning, we just had words. Bigger and colder. That's what the committee said. And then we had pictures. We had a sketch on the big whiteboard that says it could look like. like this. And then we have hardware. Now we have real people putting it all together and making sure that it works. So you see all in one glance this entire history in front of you. And finally something is getting ready for lunch and there's an awful lot at stake.

This telescope is not just for scientists, it's for the world. As Webb travels to its final destination, it slowly deploys its many complicated components bit by bit. Until finally, it will get to work trying to to answer some of those key questions Amber talked about. Where did we come from? How do we get here? Are we alone in the universe? And perhaps questions we haven't yet thought to ask. For me, the most exciting thing will be when some young astronomer thinks of a different way to use this than we ever imagined and may find something that we hadn't thought of. Those are the things that I think every

scientist lives for. It's those mysteries that are out there in the universe that we haven't even dreamed of yet. I think the universe is going to surprise us. This is NASA's Curious Universe. This episode was written and produced by Liz Landau and Margot Wohl. Our executive producer is Katie Atkinson. The Curious Universe team includes Maddie Arnold, McKellis-Sosbe, and Vicki Woodburn. Special thanks to Laura Betz, Rylent Heggy, Natasha Pinol, Felicia Chow, and the James Webb Space Telescope team. If you liked this episode, please let us know by leaving us a review, tweeting about the show at NASA, and sharing this episode with a friend. You can learn more about the web telescope by visiting jwst.nassah.gov.

Still curious about NASA? You can send us questions about this episode. or a previous one, and we'll try to track down the answers. You can email a voice recording or send a written note to NASA-curious Universe at mail.nastasa.gov. Go to nassah.gov slash curiousuniverse for more information.