NASA's Curious Universe - Webb Space Telescope: Into the Unknown

Episode Date: November 23, 2021

The James Webb Space Telescope is going to open a new window into the universe. It will show us stars, galaxies, planets, and other objects as we’ve never seen them before. In the first of four episodes of our mini-series, we focus on the great science that Webb will do.

I think the Webb Telescope will attract the attention of everyone. Number one, because it's a huge technical thing to do, and number two, because we're going to discover things nobody ever knew about. And I suppose number three is we'll make pretty pictures, but I think the great discoveries that really fit into our history of ourselves. How did we get here from the Big Bang story, the expanding universe? Galaxies growing, black holes growing, stars blowing up, new star system, being produced, planets growing around those little stars.

We might also get some big surprises, too. I like to think that our imagination has been limited all along, and we probably still find something we never thought of. I think we will. This is NASA's curious universe. Our universe is a wild and wonderful place. I'm Patty Boyd, and in this podcast, NASA is your tour guide. In just a few weeks,

the world's most powerful and complex space telescope will begin a journey like no other. From a million miles away, the James Webb Space Telescope will gaze out into our solar system and beyond. It will peer back in time 13.5 billion years to when our universe was merely a toddler. We want to understand how, out of a hot soup of chaos, the first stars and galaxies took shape. The James Webb Space Telescope will look at stars and planets near and far to search for clues to our origins and to the question everyone wants to know. Are we alone? The James Webb Space Telescope is such a fascinating mission

that we are dedicating four episodes of this podcast to learning about its science, engineering, people, and launch. This is part one, focusing on science. I'm John Mather. I'm the James Webb Space Telescope Senior Project Scientist, which means that I work with scientists and engineers from day one. John is a scientist at Goddard Space Flight Center. We introduced him briefly in season two.

He holds a Nobel Prize for his work on the Cosmic Background Explorer, a satellite that showed us the first baby pictures of the universe. I thought, well, we're never going to do anything exciting again like that. And then I got a phone call. NASA headquarters at Ed Weiler called up and left a message saying, 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. Immediately, I abandoned all other ideas and said yes. That was October 1995. I remember that it was really fun getting started. The first day that we had a sketch by a person who knew how to draw on the big whiteboard, that says it could look like this. And, you know, it pretty much looks like what that man drew. Except we had a lot of different ideas about how it would get there.

But we knew we needed to build something bigger and more powerful than Hubble. The Hubble Space Telescope launched in 1990 and has changed our understanding of the universe in many ways in the last three decades. But even in the early days of Hubble, a committee of scientists was thinking about what would come next. They called it the next-generation space telescope. So they wanted two things, actually. One is another more powerful telescope that could do intrad astronomy,

which the Hubble could not do. And they also said, by the way, we also want to know about planets around other stars. We were just getting hints that there were some of them out there because a few had been found in that very year. And so they said, please figure out how to do that, NASA. So NASA has done both. We'll talk more about the great things that Webb will discover and investigate in a moment. But first, we need to talk about light.

One thing that's not intuitive to humans is that light actually travels. Just like if you were to get in the car, you wouldn't be at your friend's house instantaneously. It takes you time to get there. That's Alex Lockwood at the Space Telescope Science Institute in Baltimore, where she is the Project Scientist for Web Science Communication. Light has a speed limit of 186,000 miles per second. Keep that in mind as Alex explains how looking out into the universe is like looking back in time. When light is created from the sun, it takes eight minutes of that light wave to move, just like a regular wave does, through space and hit the Earth.

You'd call that eight light minutes. So basically the closer something is, the newer it is. The further away it is, because the light that's hitting our eyes now is the light that has traveled for that amount of time. That light is actually a preserved fossil of what that thing looked like billions of years ago. To become the groundbreaking science powerhouse that scientists envisioned, Webb would need to sense a special kind of light called infrared. infrared light is really good for looking at distant objects in the universe because it lets us see through cosmic dust.

There's a lot of dust out in the universe, just like probably under your bed and mine. Okay, it's not literally the same kind of dust, but you get the picture. And it blocks our view of things like stars that are being born. Dusty environments are wonderful for creating things. new stars are formed, but if you can't see through the dust, you don't know what's going on as that star is being born. And that's a very, very interesting environment and tells us about our own origins because after the star is born, planets are formed and all of the evolution that leads to where we are today. So with James Webb, we'll be able to see through the dust out in the

universe into these environments where stars and planets are forming and really get insights into the origin of planetary systems that we've never had before. Here's something even weirder. The light from the distant parts of the universe gets stretched out as it travels for billions and billions of years. So short wavelengths become longer as they travel. If a galaxy billions of light years away is emitting visible light, it may reach us in the infrared, which is a longer wavelength. That's because empty space itself is stretching out faster and faster as we speak.

Scientists are so perplexed about why this happens, they call the mysterious engine of this expansion dark energy. But that's a topic for another episode. John's Nobel Prize-winning research helped confirm that our universe began in a rapid expansion known as the Big Bang. The Webb telescope won't look quite that far back. But it will look at a period of the early universe no one has ever seen before. If you ask a bunch of astrophysicists what they're most excited to learn from Web,

chances are they'll all have different answers, since Web is going to look at so many different kinds of objects. But when scientists began planning this complicated mission more than 25 years ago, they had one goal in mind. To see, where did the first galaxies come from? Some of the very first galaxies that were born after the Big Bang. The first galaxies to form. The first galaxies in the universe.

The very beginning, the first galaxies, the assembly of the first galaxies. It's a little hard to keep track of all the different structures in the universe, so let's review what a galaxy actually is. Our solar system consists of our sun and all of the planets, asteroids, and comets that orbit it thanks to the powerful gravity of our host star. But the sun doesn't sit still. It's actually on a really long orbit around the center of what we call a galaxy,

the Milky Way, which contains about 100 billion stars. Here's Alex again. If you look at our own Milky Way, we have a large, reasonably large, spiral galaxy that has a distinct shape similar to what we can see in the World Pool Galaxy, for example, you have these beautiful spiral arms and what we say is a lot of structure.

And so at some point, the first galaxies that were just kind of small clumps of stars over billions of years, those galaxies converged with each other. We believe this spiral shape is a natural progression out of galaxy evolution and mergers. Studying the first galaxies will teach us about how the Milky Way evolved. We're hoping that if we understand what the earliest galaxies look like, and we can look at galaxies nearby us that represent more evolved galaxies,

that we can put together the picture of what does a typical galaxy life look like? And we can guess that these earliest galaxies that we're seeing might look something like the Milky Way does today. At the center of our galaxy is the center of our galaxy is the world. of our galaxy is a super massive black hole called Sagittarius A Star, weighing the equivalent of about 4 million suns. In fact, there's a supermassive black hole at the center of nearly every galaxy. But today we have no idea how they got to be there and grow so big, so fast. It's a chicken and egg problem that Webb may help solve. I'm hoping that we find out which came first, the black

holes are the galaxies. It might be that the Big Bang made the black holes directly. It might be that the first generations of stars led directly to black holes and that they just disappeared. We have some evidence that that can happen, that a star can just collapse and turn into a black hole. We now know that black holes can meet each other and combine and make bigger black holes. This is actually pretty common, but nobody knows how that ever got started. So we'd like to know about that. Somehow, galaxy as big as ours, the Milky Way has several millions worth of stars all collapsed into one gigantic black hole in the middle. And some galaxies are even bigger. They have billions of stars all squeezed into one tiny black hole. So this is a huge mystery, and I think we'll find out.

That's just awe-inspiring when you think about it. Not everyone is most excited about Webb's revelations about the first galaxies. There's observations of Mars, Jupiter, Saturn's rings, Uranus and Neptune, Pluto, comets. What have I left out? That's Heidi Hamill, Vice President of the Association of Universities for Research in Astronomy, or ORA. She's been involved in some truly epic moments in solar system exploration. When Heidi started out in graduate school, she focused on astrophysics. You know all that stuff about how stars and galaxies work.

But when it came time to focus on a dissertation, she turned her gaze to giant planets that no one knew a lot about. I'm like, you know what? We know so little about Uranus and Neptune that anything that I learn will be expanding the envelope of knowledge. Heidi had already established herself as a world expert in this mysterious blue planet by the time Voyager 2 took the first-ever close-up images of Neptune in 1989. Some telescopes have a wide field of view and show us a broad perspective of what's out there, finding new planets, galaxies, and more. Webb, on the other hand, will look in closer detail at cosmic objects that scientists have already located,

located to get to know them better than ever before. It's sort of like we have a puzzle with one-tenth of the pieces we need to put the puzzle together. James Webb Space Telescope is going to add more pieces to this puzzle. It's going to help us, particularly studying the dynamics of the atmosphere and the chemistry of the atmosphere. Some of the objects that Webb will study have already received visits from other spacecraft. other spacecraft or will in the near future. But they're still worth looking at with our shiny new observatory.

Here on Earth, wherever we find water, we tend to find life. That's why scientists are especially interested in finding water on other planetary bodies. Jupiter's Moon Europa and Saturn's Moon Enceladus are both covered in ice, but are thought to have deep oceans underneath. We'll be looking closely at Europa and Enceladus to see if there's evidence of water spewing out. Webb has lessons to teach us even about Mars, which has orbitors, rovers, a lander, and even a helicopter sending back new data every day. That's because every time we send a probe into space, it can't do everything. It will have sensors for specific kinds of light, and an itinerary that focuses only on particular objects or locations.

or locations. To truly understand worlds beyond our own, we need to look at them from multiple perspectives and in many different ways. It's like we have an astronomy toolbox that has many different kinds of tools in it, and you need all the tools. You can't just have a screwdriver or a wrench, you know. You can do good things with screwdrivers and wrenches, but you don't do the same things with screwdrivers and wrenches. There's one more way that web is going to change the way we think think about the universe? One that hadn't yet taken shape when John and his colleagues were

envisioning the telescope in the 1990s. Back when Webb was just an idea, astronomers started discovering planets beyond our solar system, or exoplanets. First, they found planets orbiting a dead star called a pulsar in 1992. Then, in 1995, a different group of astronomers spotted the signatures of planets orbiting 51 Pegasai, a sun-like star 50 light years away. While web scientists were planning a mission focused on the first galaxies of the universe, the list of known exoplanets started growing and growing. So there are many, many more planets out there than we ever dreamed. Most of the stars had planets.

A lot of them have more than one. And there are even a lot of loose planets that got left expelled. from their homes and are wandering around in between the stars. We'll find out something about all of this, and I think we'll be amazed. And it turned out an infrared observatory would be perfect for zooming in on the atmospheres of these mysterious worlds. With more and more planets being discovered, scientists started making lists of the ones best suited to follow up on with Webb.

Now there's a fascinating and diverse collection of planets on the schedule for web to look at in finer detail than ever before, especially when it comes to the atmospheres of these planets. It's the atmospheres that are going to tell us whether those planets could be habitable. Here's Alex Lockwood again. You step outside on a hot summer day, especially in the south, and you know that there's water vapor in the air. It's very humid, but you can't see it. If you put on your infrared goggles, you'd actually be able to see the emission of water vapor in the air. We can do that for other planets. So in fact, when I was in school, I discovered water vapor on a planet using infrared wavelengths.

That's right. She discovered water vapor on a planet. It was cool. It was really cool. But we can't see that with Hubble. It's only in these longer wavelengths do some of the really, really interesting molecules and molecules that are interesting, not only even of themselves, like water's really cool, but has implications for any kind of, you know, life-bearing signatures. So water vapor, carbon dioxide, carbon monoxide, methane, these are all molecules that we

can study in the infrared. The story of how Webb added exoplanets to its science goals speaks to my own life, too. I became the NASA headquarters program scientists for the Kepler Space Telescope, which would go on to discover more than 2,600 exoplanets and show us that there are more planets than stars in our galaxy. And now I'm the project scientist for Tess, a satellite that has already discovered 25 planets that web will study in further detail in its first year of science.

What keeps me going in this field is a lifelong curiosity about the big questions, like, are we alone? Is Earth common? Do we live in a really rare place? Generations have asked those questions, but this is the only time in history where we've actually had the ability to answer those questions with examples of planets around other stars.

With Webb, we're just walking in the door to learn so much more about our place on Earth, in the Milky Way, and in the universe. Next time on NASA's curious universe. You have the opportunity to combine science with art. There's artistic feature of James Webb that can't go unnoticed. I would hope that individuals can see something that took so much time and that also is artistically creative and that so many minds have gone into

that individuals are inspired to continue to pursue whatever, you know, career path they're going after and kind of see how it blends into the world of space. This is NASA's Curious Universe. This episode was written and produced by Katie Atkinson, Liz Landau, and Christina Dana. The Curious Universe team includes Maddie Arnold and Michaela Sosby, with support from Elisa Fielding. Special thanks to Ryland Heggy, Amber Strawn, Paul Geithner, Eric Smith, Natasha Pinol, Elise Fisher, Laura Betts, 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 with a friend. 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.nastnaut.gov. Go to NASA.gov slash Curious Universe for more information.