A year of discovery from the James Webb Space Telescope

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An image from NASA’s James Webb Space Telescope shows the Rho Ophiuchi cloud complex, the closest star-forming region to Earth. (NASA)
An image from NASA’s James Webb Space Telescope shows the Rho Ophiuchi cloud complex, the closest star-forming region to Earth. (NASA)

A million miles away from Earth, the James Webb Space Telescope is peering deeper into the universe than humankind ever has before. It's been a year since the JWST's launch. How do scientists rate its performance so far?

"I can’t think of a space mission that worked better than promised and that’s what Webb is. Just amazing," Marcia Rieke, principal investigator for the near-infrared camera on the JWST, says.

The JWST has returned astonishing data and images of exoplanets, dying stars, the formation of galaxies and the birthplace of stars.

"Hubble was amazing. But it was nothing compared to this," says science writer Joelle Renstrom. "It’s just the better we get at seeing, the more there is to see. And it’s just kind of leads to all these questions of, 'Wow, what else are we going to see? What do we not know we don't know?'"

Today, On Point: Delighting in the first year of discovery from the James Webb Space Telescope.


Marcia Rieke, Professor of Astronomy at the University of Arizona, principal investigator for the near-infrared camera on the James Webb Space Telescope.

Nikole Lewis, Associate Professor of Astronomy at Cornell University. She's involved with dozens of observational campaigns with the former Spitzer and current Hubble and JWST Space Telescopes. Previously she served as the JWST project scientist at the Space Telescope Science Institute.

Also featured

Lisa Dang, Postdoctoral fellow at Université de Montréal.

Joelle Renstrom, Science writer, also teaches rhetoric at Boston University.

This image combines images of the iconic star-forming region Pillars of Creation from two cameras aboard NASA’s James Webb Space Telescope. Near-infrared light also reveals thousands of newly formed stars – look for bright orange spheres that lie just outside the dusty pillars. (NASA)
This image combines images of the iconic star-forming region Pillars of Creation from two cameras aboard NASA’s James Webb Space Telescope. Near-infrared light also reveals thousands of newly formed stars – look for bright orange spheres that lie just outside the dusty pillars. (NASA)


Part I

MEGHNA CHAKRABARTI: Today, let's give ourselves the gift of stepping back from the tensions and tragedies in the regular news cycle, and instead talk about something that's working, and working beautifully, beyond expectation and expanding human knowledge past the boundaries of our imagination.

This month, NASA released yet another spectacular image caught by the James Webb Space Telescope. This one is of the Rho Ophiuchi Cloud Complex, and it's a vast field of towering, swirling columns of gases enshrouding the light of baby stars. And it's a wonder to behold.

The James Webb Space Telescope, or JWST, is celebrating its first year of operational science. It's situated 1 million miles away from Earth and peering as far back into the universe as we ever have.

BILL NELSON: By nature, we are explorers. We are frontierspeople. And so the question that we often ask is, "Who are we? Where are we? Why are we here? How is it that it developed that life as we know it has been created here on this stony, mid-size planet, revolving about a mid-size star that we call our sun? Is there life out there in the cosmos?"

CHAKRABARTI: NASA administrator Bill Nelson. That was his answer when asked by CBS News why humanity needs missions like JWST. Jane Rigby is NASA project scientist for the James Webb Space Telescope Mission and she says the telescope is breaking boundaries.

JANE RIGBY: What Webb is giving us that's new is a perspective that is sharper, that is clearer, that sees further back in time. That sees the parts of the universe that have just been invisible to us. Because if you look with your eyes — or even with Hubble — at this part of the sky, all you see is black. You can't see any of this.

CHAKRABARTI: This is On Point. I'm Meghna Chakrabarti. In April 2022, we spoke with astronomers Marcia Rieke and Nikole Lewis about what went into getting the JWST a million miles from Earth, an incredible feat in its own right.

Rieke is a professor of astronomy at the University of Arizona. She was principal investigator for the near infrared camera, or NIRCam, on the JWST. Lewis is a professor of astronomy at Cornell University and served as project scientist at the Space Telescope Science Institute for the Webb program.

In that April 2022 conversation, the telescope had made it to its desired orbital point and NASA was vetting JWST's instrumentation. It hadn't begun any of its scientific missions at the time, so we talked with Rieke and Lewis about what they hoped to learn from this expensive, ambitious project.

Well, today we've invited them back on the one year anniversary of JWST'S science mission to see if those hopes have been fulfilled. Professor Marcia Rieke, welcome back to On Point.

MARCIA RIEKE: Thank you very much for having me again.

CHAKRABARTI: And Professor Nicole Lewis, it's a pleasure to have you back as well.

NIKOLE LEWIS: Hello and thanks for having me back.

CHAKRABARTI: Okay, so the easy first question here and Professor Rieke, I'll start with you: Has JWST met or exceeded your expectations so far?

RIEKE: Oh, it has totally exceeded my expectations. I mean, we had all these plans of how we'd work around this, that, or the other problem, and we've not had to use a one of those. The performance has been just spectacular.

CHAKRABARTI: And Professor Lewis, same question to you.

LEWIS: Yeah, it has definitely exceeded my expectations. When the data comes down, it is almost pristine. It makes my job easy. (LAUGHS)

CHAKRABARTI: Now, I would love to hear both of you throughout this hour, just sort of even talk with each other at times if you want. So don't wait for me to direct all questions individually to either of you. But so I'm just wondering how often in science does something like this happen?

Not to say that, you know — there may be anomalies or quirks in the future. We don't know that yet. But to have such a tremendous start to a long-term, highly complex mission, is this a common or rare thing in your experience?

RIEKE: In my experience, to have something work this so far beyond its original projected performance is — I can't think of another case.

There have been other missions which worked very well out of the box, like the Spitzer Space Telescope. But something that has just kind of blown through all of the requirements and just delivered the way Webb has, that is really unusual.

LEWIS: Mm-hmm. Yeah. And I have to agree with Professor Rieke that, you know, even during my career — I was involved with Spitzer, of course when Hubble launched and gave us our first images, there was a little bit of some issues. We have really just never seen something work beyond our expectations, right out of the box.

CHAKRABARTI: So the issues from Hubble, just to remind folks, were problems with its ability to focus. Right?

LEWIS: Right.

CHAKRABARTI: But Hubble was close enough to Earth that we could send astronauts up to fix it, which is not an option with JWST being a million miles away.

LEWIS: Exactly.

CHAKRABARTI: Yeah. And so, honestly, the fact that it's worked so brilliantly is just a marvel of science and engineering, I have to say. I wanna know from both of you and actually, Professor Rieke, let's just start with you for a second, because JWST is doing a lot, right?

It's peering very, very deep deeply back into the origins of the universe, which distant galaxies would be roughly your realm of expertise and Professor Lewis, you're looking at exoplanet science. So, Professor Rieke, is there a particular image from any one of the sort of distant galaxies experiments that you find particularly arresting or indicative of the telescope success so far?

RIEKE: Oh, the deep survey that my team and our collaborators from NIRSpec have done with some images that visually, eh, they don't look like much, but as soon as you analyze the light from these objects, you realize that you're seeing almost all the way back to the Big Bang. You're seeing only stuff as they were 320 years, 320 million years after the Big Bang.

And so essentially right out of the box, we've come close to achieving one of the key goals of the mission, one of the ways we persuaded people to spend $10 billion. And so the image itself, when you look at it from, oh, a distance of a couple feet on a computer screen doesn't look that much different from a Spitzer image. But when you bore in and you actually look at the details, you go, "Oh my gosh, we've done it."

This image shows a portion of an area of the sky known as GOODS-South. More than 45,000 galaxies are visible here. Using these and other data, the JADES team has discovered hundreds of galaxies that existed when the universe was less than 600 million years old. (NASA)
This image shows a portion of an area of the sky known as GOODS-South. More than 45,000 galaxies are visible here. Using these and other data, the JADES team has discovered hundreds of galaxies that existed when the universe was less than 600 million years old. (NASA)

CHAKRABARTI: Okay, so this is the Advanced Deep Extragalactic Survey you're talking about?

RIEKE: Yes. Which we've dubbed JADES as a way to refer to it.

CHAKRABARTI: Okay. So I'm looking at an image of it available online. And by the way, folks, a lot of the JWST images that we're gonna be talking about today are available, there's links to them on our website.

So Professor Rieke though, I'm looking at this JADES image and you can zoom in on it, which is kind of amazing. I think I've heard you say previously that there were, are there 45,000 galaxies in this one set of images?

RIEKE: That's right. And you know, sometimes people ask me, "Well, why haven't you released a summary of all the properties of all the galaxies in your field?"


RIEKE: And I have to say, "When you got 45,000 of 'em, it takes you a little while." (LAUGHS)

CHAKRABARTI: (LAUGHS) It's remarkable. So when you say this is 325 million years after the Big Bang, that is early, early, early given that --  how far back are we saying the Big Bang is going now? Because I think this is a number that I haven't been able to keep track of. 13 billion or something like that?

RIEKE: Yeah. 13.7 billion years ago is when the Big Bang happened. And so we've — we're seeing light that's been traveling toward us for longer than the earth has existed.

CHAKRABARTI: Much longer. Much longer than the earth has existed.

RIEKE: Much longer.

CHAKRABARTI: Okay, so I'm seeing this like, amazing field of, you know, crowded with galaxies of all shapes and sizes — spirals, I guess those are the ones I recognize the most. They're different colors. Is that — are these false color images or are they, why are they different colors?

RIEKE: It is a false color image. The default way that the image comes up that you're looking at assigns, red, green, blue to three different NIRCam filters. And so that's how you get the colors.

So the things that appear red are in fact brighter at the longest of the NIRCam wavelengths and the things that look blue are bluer. Of course, your eye can't see infrared, so you wouldn't see any of these colors. But what we've done is tried to categorize the objects according to the properties of the light that they're emitting.

CHAKRABARTI: Okay. So I mean, I know you could just spend years and years of your career analyzing everything that this one data set is providing. But is there something in particular here that you could point out that you find especially lovely or surprising when you started examining it?

RIEKE: I think there were two things that have been surprises. Well, at least two. Just one is the sheer number of relatively very small, dim objects that when you analyze it, they're in this realm of 300 to 500 million years after the Big Bang. And there are more, many more of those than our models predicted.

And the other thing is that as you've noticed when you scroll around, you can see shapes and some of the galaxies are quite red in color, which suggests that they've got a lot of dust in them, just like our own Milky Way has. In fact, that's partly what makes that recently released Rho Ophiuchi picture so pretty is that there's dusts and gas swirling around. There are more galaxies with a lot of dust than we might have predicted, and so we're still, still trying to digest what this all means.

The nebula of WR-124, a Wolf-Rayet star, is 10 light years wide. It’s made of material cast off from the aging star and dust produced before the star’s eventual supernova. (NASA)
The nebula of WR-124, a Wolf-Rayet star, is 10 light years wide. It’s made of material cast off from the aging star and dust produced before the star’s eventual supernova. (NASA)

CHAKRABARTI: Okay. Well and the dust is important because it helps build other things in the universe as well. So, okay, Professor Marcia Rieke. We're gonna come back to what happened at the dawn of the universe. And Professor Lewis, I definitely want to hear from you about what you're seeing regarding exoplanets out there thanks to our 1 million mile away eye on the universal sky, the James W — sorry, the James Webb Space Telescope, which is celebrating its first year of science. We'll be back. This is On Point.

Part II

CHAKRABARTI: Marcia Rieke is with us today. She's a professor of astronomy at the University of Arizona and Nikole Lewis joins us as well. She's associate professor of astronomy at Cornell University and they have come back together on On Point a year after we first invited them on. And we're talking about the James Webb Space Telescope and celebrating its first year of astronomical and cosmological observation.

Professor Lewis, so we heard Professor Rieke talk a little bit about some of the more remarkable images that she's analyzing now regarding the beginnings of the universe. You're an expert in exoplanets. Can you talk about one or two that Webb has looked at and what you found?

LEWIS: Yeah. And to echo sort of what Professor Rieke was saying was that when we get these images down, sometimes they aren't as beautiful as the images you'll find online, but they hold so much rich information. And that's particularly true for a lot of our exoplanet images. Often we just see blobs, for lack of a better term. (LAUGHS)


LEWIS: But when we sort of smear the light out from those blobs into what we call spectra, we're able to tell a huge amount about those objects that are, you know, light years away from us.

And one of the objects that we looked at early on in JWST's science operations was the sort of, I would call a warm Jupiter called WASP-39 b. And when looking at that planet, we were able to actually detect carbon dioxide for the first time in that planet's atmosphere using JWST and to also see hints of really interesting chemistry happening with sulfur.

CHAKRABARTI: And why were those two things very interesting?

LEWIS: Yeah. So if you look at around our own solar system --  you know, I'm trained as a planetary scientist, so I always start in the solar system. And, of course, JWST has given us beautiful images of solar system planets which we can talk about more.


LEWIS: But when we look around in the solar system, many of the atmospheres of the planets, you know, us and Venus, Mars in particular, have carbon dioxide as a key species in the atmosphere. And it's a key component of understanding how those planets formed and evolved. And looking farther into the future at smaller rocky worlds, their potential to host life.

And sulfur is also a key species that we see. I think one of the places we see it most in the solar system is Jupiter's Moon Io, which is basically spewing sulfur. And that creates all sorts of complex chemical interactions, which again, can be interesting in terms of thinking about the habitability and the formation of life on planets beyond our solar system.

CHAKRABARTI: So help me remember my exoplanet history here since it's also such a new field. Have there been other planets previously — or exoplanets previously studied where carbon dioxide and sulfur were found in their atmospheres outside of the solar system?

LEWIS: No, we have not had firm detections without the infrared capabilities of JWST. I'll come back to the Spitzer Space Telescope, which I started my career on and love dearly. We had hints that we might see something like that, but we didn't have what we call the resolution to be able to determine exactly which species were contributing to the light that we saw.

CHAKRABARTI: Oh, so this is truly a first then?

LEWIS: It is truly a first.

CHAKRABARTI: Okay, and so what new questions then pop into your mind with the ability to confirm that, okay, there's planetary activity out there where you have recognizable signatures of CO2 and sulfur in the atmosphere?

LEWIS: Yeah. It's particularly interesting for this because this is a gas giant. And actually we didn't really think that there should be a lot of carbon dioxide in these gas giant atmospheres. And so it probably means that they formed in a very sort of different location from our own gas giant planets in our solar system.

And so that's really telling us a lot about, you know, where do planets form around other stars? Do they form in systems that look a lot like our own solar system or are they really forming in a very different fashion? Which could open up the idea of could there other be other systems that look like ours or are we really quite unique?

CHAKRABARTI: Yeah. Okay. So I've gotta ask you. I mean, I know that JWST is not the project in which — I mean, at least for now — that scientists are gonna try and point towards planets that we think could harbor, or could be home to, if not life, then circumstances that would maybe help life that we recognize arrive. Okay?

But putting JWST aside for just one second, I mean, the universe is so vast. I think we've confirmed that there are many, many, many, many planets out there — so many that there's gotta be some that have the same Goldilocks zone properties that Earth does. So do you think that eventually one day in a future mission, we will be looking at planets that could be habitable?

LEWIS: Yes, most certainly. I mean, we've confirmed thousands of exoplanets and thousands and millions more currently exist in our solar system. Most definitely. And JWST is playing an important role in the whole idea of the search for life.

We are looking at Earth-sized planets that are around small stars, what we call M dwarfs, cool stars that are not like our sun. And many of them are in fact in what would be considered the Goldilocks zones of those systems. And so we're trying to understand if those planets could have properties that could support life or if, you know, really we can only get ideal conditions for life around more Sun-like stars, which will be definitely looked at with future missions like the Habitable Worlds Observatory.

CHAKRABARTI: Okay. So we'll come back and talk about that in a minute here. But Professor Rieke, I appreciate your patience in listening to what Professor Lewis had to say about initial exoplanet observations. But tell me more about what Webb is revealing about that earliest, earliest chapters in the universe's history.

RIEKE: I will do that in one second. I wanted to add one thing to what Nikole has been saying, that Webb was designed and sold initially on the basis of searching for the most distant galaxies. And I remember people making the argument that once you build an observatory to do something that difficult, it'll be useful for many other things. Because when the mission was being designed, there were far fewer exoplanets known, and in fact, there were no requirements placed on the mission to be able to do the kind of work that Nikole was doing.

But it shows that a well-designed, well-engineered project can do many things and that we don't — we're not just making it up when we say, "Okay, we're going after the most distant galaxies, but trust us, it'll be good for other things." And I think we're seeing that notion bear fruit.

So back to your main question. As we go through this enormous set of imaging — and now we're getting spectra as well — of these very distant galaxies. Some of the things that we want to probe actually connect back to what we see nearby and planets and so on. And we're trying to trace out how we went from the Big Bang, which basically left us with hydrogen and helium and a tiny little bit of lithium and a couple other light elements — but no carbon or oxygen or nitrogen.

And we're already seeing some traces that in the early universe, these critical elements for life are getting manufactured in stars more quickly than we might have predicted. And so again, another very important mystery to unravel is how what we might call the chemical evolution of the universe preceded, which is obviously very important for our understanding life and where else it might be.

The central region of the Chamaeleon I dark molecular cloud, which is 630 light years away. The cold, wispy cloud material (blue, center) is illuminated in the infrared by the glow of the young, outflowing protostar Ced 110 IRS 4 (orange, upper left). (NASA)
The central region of the Chamaeleon I dark molecular cloud, which is 630 light years away. The cold, wispy cloud material (blue, center) is illuminated in the infrared by the glow of the young, outflowing protostar Ced 110 IRS 4 (orange, upper left). (NASA)

CHAKRABARTI: Mm. Okay. You know, I'm recalling that another really interesting thing that both of you shared with us when we had you back on in April 2022, was this novel way in which telescope time was being allotted on JWST, right?

That NASA and the ESA [European Space Agency] and the Canadian Space Agency had come up with a system where there would essentially be sort of almost a blind selection of the most compelling proposed experiments. And that meant that it opened up the possibility for a lot of younger researchers to perhaps gain access to the telescope. Am I remembering that correctly, Professor Lewis?

LEWIS: Yeah, I think we discussed that towards the end of our conversation back in April.


LEWIS: Um, but this is the, what we call the dual anonymous proposal review process, which was actually first initiated on the Hubble Space Telescope. And it was so successful that it seemed obvious to carry it over for JWST.

And it has certainly borne fruit in looking at the diversity of what we call principal investigators selected on observations for cycle one and now cycle two.

CHAKRABARTI: Okay, so we actually reached out to one of those young researchers who had an experiment selected for cycle one.

Her name is Lisa Dang. She's a postdoctoral fellow at the University of Montreal, and she studies exoplanets and their atmospheres. And with a team of other researchers she submitted a project proposal in November 2020. She hoped to study the lava planet K2-141 in hopes of learning more about its makeup that might tell us more about the interior of our own planet. And Lisa was very excited to learn that her project had been chosen for the first year, or cycle one, and here's what she told us:

LISA DANG: For me, it was kind of the first time that I felt like a real astronomer, like a real adult astronomer. Uh, just because I was able to get time on this like, big telescope.

One of the things that strikes me the most is a lot of the projects that I was expecting to see approved were probably approved. And I think there's a lot of usually competing teams that are applying for the same target, for example. But it's nice to see that because there's less emphasis that was put on the institutions of the people on the team and the name of the people on the team, the proposals were evaluated for their merit and how well they were presented rather than how good and competent of a team they had.

Two outcomes from this is that a lot more young researchers were able to get time on this first cycle, but also a lot of institutions that are not necessarily like the top tiers institutions were able to get time as well.

CHAKRABARTI: Lisa has received her data from JWST and her team is currently processing the numbers. And she doesn't yet have, of course, the final analysis. They're still working on it. But she told us she thinks they'll be able to reveal whether that planet that they're looking at has an atmosphere or whether it's been blown away by the heat of the star it orbits. So looking forward to Lisa Dang's discoveries.

Professor Lewis, let me ask you, especially in the field of exoplanet astronomy, it seems like it's one that's new enough that there haven't been, let's say the established personalities or egos or lab politics that might emerge in other more, like, older fields of science. Is that, is that true?

LEWIS: (LAUGHS) I think that's a fair statement and I'd like to hear Marcia's opinion --

CHAKRABARTI: You're laughing! (LAUGHS)

LEWIS: I am. I am because I think within science, you know, scientists have opinions. We are opinionated people by nature. And so I think saying that we're a field without any opinions or egos is probably not fair. But I will say we are still a relatively young field and one that's still trying to find itself. And a field that has grown very, very rapidly, which means the majority of people that I work with these days are early career.

And so we're trying to find ways to build collaborations such that we can focus on community rather than competition. And I think one of the best examples of that was the Early Release Science program for both the transiting exoplanet community and the direct imaging community, which brought together hundreds of scientists and managed to get them to work together on a single project.

CHAKRABARTI: Okay. Well, if I may, when you spoke with Hilary, our producer for this show, I think you said that fields that are a little less interdisciplinary or --

LEWIS: Right.

CHAKRABARTI: Or more that produce more Nobel-worthy material, you got a lot more personalities there, right? (LAUGHS)

LEWIS: Yeah, that is a true statement. I think, if you think about a Nobel Prize and people who are aiming for a Nobel Prize, they certainly have a certain, um, shall we say, level of ego. I, again, came into this as a planetary scientist, and exoplanets is a place where you have this sort of crossover between planetary science, astronomy, chemistry, geology, a whole bunch of different fields, and most of us come into it with no eye on a Nobel Prize in the future. (LAUGHS)

CHAKRABARTI: For now. (LAUGHS) But I mean, I'm just kidding you. I mean, I hope that the pursuit of pure science is always the first goal. But, you know, I think you said that when you started your career there were, I don't know, less than a hundred established exoplanetary scientists. But now, with the ability to gain so much more data, so many more novel observations, there are many more people in the field — thousands even?

LEWIS: Yeah, when I started in my graduate school career, I actually started in solar system research, looking at Mars, in fact. I mean it's just that there weren't exoplanet research projects to be had. And so I was really part of the first wave of, um, early career scientists coming through.

And now, you know, it's a very popular idea as people apply for graduate school to think about studying exoplanets, just given the sheer amount of information that exists now.

CHAKRABARTI: Okay. So Professor Rieke, I'd love to hear your thoughts on then what JWST as a tool, as an instrument, and how it might have an impact on, you know, who does astronomical science or opening the doors to more people in the field. Do you think that there's a connection there?

RIEKE: I think there is a connection there because if you look at the history of the Webb project, when I first joined the teams trying to kind of sketch out what the mission would look like back, this was in the sort of 1998 era, roughly. I was one of the few women participating in the project, and all of the technical people to speak of were men.

By the time we got to commissioning, there were many women playing leadership roles on the engineering side. If you looked at the science working group and the leaders of instrument teams, several of the teams were led by women. And there's also been quite a contingent of people — and this has partly helped by teaming with both Canada and the European space agencies — people who speak a range of languages. I think Webb has done a quite good job at reaching out to the Spanish speaking community.

And so the whole mixture of people has changed over the 25 years I've been associated with the mission. And I think it's partly because Webb just kind of broke all kinds of barriers, so to speak. It's a different way to build a telescope. We've tried to do many things in a more diverse, equitable way, so to speak, tried to encourage a broad range of different kinds of science. And so I think the mission will have several legacies for the astronomical community. Obviously, this scientific one being the easiest to see, but many in the societal side as well.

CHAKRABARTI: Mm. Well, today you're hearing from Professor Marcia Rieke and Professor Nikole Lewis. They're two astronomers who joined us first, back in April of 2022 to talk about the James Webb telescope, and they've come back today after the Webb's first year of scientific discoveries to tell us what they've found so far and what could come next. So we'll have a lot more when we come back.

Part III

CHAKRABARTI: The James Webb Space Telescope isn't just a telescope. It is a time machine. When the JWST sees light from a galaxy that's 13 billion light years away, it means that light has traveled for 13 billion years before it touched the telescope sensors, which means that light is 13 billion years old. It is literally the light of the incomprehensibly distant past.

JOELLE RENSTROM: I don't think that we're supposed to be able to comprehend what that timescale means, and I don't really think we're supposed to be able to comprehend how big our infinite universe is either.

CHAKRABARTI: Science writer Joelle Renstrom.

RENSTROM: I don't know who really can wrap their head around the fact that we can see into the past. There's something amazing in the fact that we can know something in an intellectual way, but not really be able to know what it means because it's so big. And that just reminds us that we're human. If we walk away from it thinking, "Wow, we are so small," then, I don't know, how much more can we comprehend than that?

CHAKRABARTI: We are a species whose entire history of existence amounts to a minuscule fraction of the blink of an eye in cosmic time. Knowing this is what gives cosmology the power to make the human soul yearn toward poetry. Something no one knew better than legendary astronomer Carl Sagan.

CARL SAGAN: The surface of the earth is the shore of the cosmic ocean. On this shore, we've learned most of what we know. Recently, we've waited a little way out, maybe ankle deep, and the water seems inviting. Some part of our being knows this is where we came from. We long to return and we can because the cosmos is also within us. We're made of star stuff. We are a way of the cosmos to know itself.

RENSTROM: When he talks about the universe knowing itself, I think he's talking about us as representatives of the universe. and as we learn about the universe, it is like the universe learning about itself. So exploring the universe is also self-exploration.

SAGAN: So over the dying embers of the campfire, people watch the stars.

RENSTROM: Another one of his quotes that I love is that he talks about science, especially space science, being a profound source of spirituality — as distinct from religion, that was important to him. Spirituality being a sense of awe, something that brings you back to the essence of breath and life.

SAGAN: And they did it, I imagine for many reasons. One, it is just dazzling. And we today, living in polluted — under polluted skies and in cities with light pollution have mainly forgotten how gorgeous the night sky can be. It is not only an aesthetic experience, but it elicits unbidden feelings of reverence and awe.

CHAKRABARTI: Carl Sagan died in 1996. Undoubtedly, he would have celebrated the triumphs of the James Webb Space Telescope were he alive today. But I believe he'd also challenge us to think about how to look at the images returned by the JWST so that we better understand ourselves as human beings. Sagan did exactly that with the Voyager 1 spacecraft.

Launched in 1977, Voyager 1 is the first manmade machine to leave the solar system. It's now on its 46th year traveling in interstellar space. In 1990, as Voyager 1 neared the solar system's outer edges, Sagan asked that it turn back and take one last picture of Earth. The image it returned at first seems like an ocean of black emptiness, streaked by dim shafts of light. Look closer though, and you see a pale pixel. That pixel is the earth. Or as Sagan put it, "Nothing more than a moat of dust suspended in a sunbeam."

SAGAN: The earth is a very small stage in a vast cosmic arena. Our posturings, our imagined self-importance, the delusion that we have some privileged position in the universe are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping, cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.

It has been said that astronomy is a humbling and character building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another and to preserve and cherish the pale blue dot, the only home we've ever known.

CHAKRABARTI: A short recording of Carl Sagan's, "Pale Blue Dot" from the Library of Congress. You also heard an excerpt from a 1994 lecture at Cornell University, and, of course, a moment from the 1980 13-part PBS series "Cosmos."

Professor Rieke, do you find astronomy both character building and humbling at the same time?

RIEKE: I suppose so. Because when I think back to when I was a graduate student starting out getting interested in infrared astronomy, it was, you know, exciting to do a new kind of astronomy, but mostly what we were detecting were relatively nearby stars that had gone through their lifetimes and were ejecting their outer layers and becoming what we call red giants and carbon stars and so on, that were bright and infrared.

And to think that now I've helped build a camera that can see the light from the first galaxies to form. It's like, "Wow. What have I done? I hope I've done a good thing, but it's certainly been a great trip."

The protostar within the dark cloud L1527 captured by the James Webb Space Telescope. (NASA)
The protostar within the dark cloud L1527 captured by the James Webb Space Telescope. (NASA)

CHAKRABARTI: Professor Lewis, you know, I couldn't help but wonder if that call that Sagan makes about understanding ourselves better by exploring the most unknown aspects of the universe to us. Do you think JWST also answers that call? Does it help us understand ourselves better?

LEWIS: Oh, absolutely. You know, part of the JWST mission is to sort of put ourselves in context. And again, answering those, those sort of big existential questions of like, "How did we get here?" and "Are we alone?"

And so when we look at all of the beautiful images from JWST and the data that we've been digesting, I'm just continually amazed. And it does allow me to think more about, "Why am I here and what am I doing?" And in some ways just to get excited about that journey.

CHAKRABARTI: Well, can you tell me more about the reactions that you feel when you're seeing — if not the sort of really charismatic pictures, because you said for exoplanets it's kind of like a fuzzy dot — but the spectra that you're looking at, right?

LEWIS: Mm-hmm.

CHAKRABARTI: Like do you just sort of look at what's coming across your screen and occasionally gasp or think like, "I didn't expect to see that?"

LEWIS: Yeah. I mean, when we get data down and then we process them enough to be able to look at the spectra, as we call them, we are just amazed. And we actually sit around as a group, you know, the people that I tend to do research with, and we sit and we ask ourselves, "What do we think all those bumps and wiggles are?" It's kind of like a game or like if you're shaking the box at Christmas, like "What's inside?" And so that's been exciting. It's been sort of the best part of this first year of science for me.

CHAKRABARTI: Mm. Well, Professor Rieke, let me turn back to you because you know, I asked you about JWST as a telescope. But I wonder what your thoughts are about how it might expand our own knowledge about our place in the cosmos?

RIEKE: Oh, I mean that, as Nicole has mentioned, that is one of the key reasons for building this kind of a telescope. And we've gotten to the point where, you know, one of the things we always say as astronomers is that we're going to study how galaxies changed over time so that we can understand how the Milky Way came to be.

And in the early days, that sounded like, "Well, that sounds like a grand plan, but how in detail are you gonna do that?" Well, now, we actually can see how galaxies are changing as we look further and further back in time. So we go from our own kind of local neighborhood and go back in steps, and we are being able to put together a picture that shows, when combined with our knowledge of the Milky Way itself, that some of our old ideas of how the Milky Way might have formed were quite wrong. It did partly collapse out of some big cloud, but it also came together by merging with other bits, other galaxies nearby. And we're seeing now evidence that even at the very earliest times, galaxies started to merge.

And when we couple that with being able to take the spectra and see what the chemical composition of the stars are, we really can begin to put together a picture of how our local neighborhood has come to be. And maybe that will also give us some clues about where it might go. And if, God forbid, we have to leave this earth, how are we gonna figure out the best other place to go?

And so I think we're, we're getting quite a picture. And I find it just astounding that as a single human being, I can look at 13 billion years of history by studying these little dots of light.


CHAKRABARTI: Mm-hmm. You know, you got me thinking about, just yesterday we did a show about the massive heat wave that's blanketing the southern United States.

RIEKE: Tell me about it! Here in Arizona — (LAUGHS)

CHAKRABARTI: (LAUGHS) I know! I was gonna say, are you on day 20 now of record-breaking heat? And the fact that we're just gonna have to keep adapting in order to live with the changes we are making on our own planet. And it got me back to that — I spent all morning once again looking at that pale blue dot image because it really grabs your heart and you think, "That little pixel is all we have."

I wonder as you're doing your research — I mean, maybe when you're in the moment and  you're trying to understand data, this doesn't happen --  but when either of you have a chance to step back, does it make you reflect back on well, maybe one day we might find another habitable planet, but it won't be in our lifetimes. It won't be in our children's or grandchildren's lifetimes. That this is all we've got right now?

I mean, Professor Lewis, does that ever happen to you?

LEWIS: Yeah, certainly. I think we might actually be able to detect a planet within my lifetime is my hope that could, in fact, harbor life or maybe has signatures of life. But the reality is, is there's no way within my lifetime or even my children's lifetime that we're gonna be able to get there. And so that's really — there is no, you know, rescue ship. This is the only ship that we have. And certainly that does make me think about how best to be a steward of the planet that we have for future generations.

CHAKRABARTI: Professor Rieke, do you have a thought about that?

RIEKE: I think I'm more optimistic than Nikole. Maybe this is optimism based on lack of knowledge, but I think we might find an exoplanet with habitable characteristics maybe in the next 10 years or so, certainly within the Webb Telescope's lifetime. But I do have to agree with her that getting somewhere else is beyond our means at the moment. But it does just reinforce how precious our planet is. And it really makes me mad when people don't care about what's going on around them.

CHAKRABARTI: Mm. Yeah. Well, you have to promise me, both of you have to promise me if in our lifetimes we do find an exoplanet that is habitable or has signs of life, you will come back on this show and we'll talk about it. (LAUGHS)

In the last few minutes that we have though, I'm wondering, there's just been a massive treasure trove in Webb's first year, so I imagine that already in both of your minds, there are so many more next questions that you may wanna ask or next areas that you wanna further explore. Even questions about the questions generated from these first data sets. So Professor Lewis, I mean, where is your mind springing to next in terms of what you wanna study?

LEWIS: Yes. Well, I've always been a big fan of studying weather on exoplanets. That's one of my favorite areas. And so I'm really looking forward to getting observations that are more detailed and deeper that allow us to understand sort of what the climate's like on other planets, which is a key part of understanding whether or not they'd be able to support life.

CHAKRABARTI: Mm. And Professor Rieke, same question to you.

RIEKE: I will second Nicole's idea of studying weather on exoplanets, and I wonder if we can learn anything about our own climate and weather by studying situations on exoplanets.

But of course, what I do, we're already realizing that what we're learning from these early galaxies is that some of the details of how stars form and come to be are not quite the same in the early universe as we thought they'd be. And this may lead us to a better model of how stars form and therefore, how our own sun and local neighborhood have come to be.


CHAKRABARTI: Mm. Well I can't thank both of you enough for coming back on the show. It's been a true pleasure. Professor Marcia Rieke, professor of astronomy at the University of Arizona, and principal investigator for the near infrared camera, or NIRCam on the JWST. Thank you so much, Professor Rieke.

RIEKE: You're very, very welcome.

CHAKRABARTI: And Nikole Lewis, associate professor of astronomy at Cornell University involved with dozens of observational campaigns with the Spitzer, the Hubble, and now the JWST Space Telescope. Professor Lewis, can't thank you enough as well.

LEWIS: Great to be here. Thank you.

This program aired on July 19, 2023.


Hilary McQuilkin Producer, On Point
Hilary McQuilkin is a producer for On Point.


Meghna Chakrabarti Host, On Point
Meghna Chakrabarti is the host of On Point.


Tim Skoog Sound Designer and Producer, On Point
Tim Skoog is a sound designer and producer for On Point.



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