What We’re Learning From The James Webb Space Telescope

JWST has detected the earliest galaxies in the universe, but some look “more mature” than expected. Is it time to rethink how galaxies form?

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Speaker 00

  WNYC is supported by Bayer. Science is about asking questions, testing, trying again. It's not easy, but it's relentless. It evolves, and that's why science delivers. Learn more at sciencedelivers.com.

• 0:14Ira Flatow?

  Science Friday is supported by MathWorks, creator of MATLAB and Simulink software for technical computing and model-based design. MathWorks, accelerating the pace of discovery in engineering and science. Learn more at mathworks.com.

• 0:31Flora Lichtman?

  I'm Flora Lixman, and you're listening to Science Friday.

• 0:37Flora Lichtman?

  Today in the show, checking in on the Webb Space Telescope, which has been out there low-key answering little questions like, what's the universe made of? And posing new ones, like, was Einstein wrong?

• 0:50Speaker 03

  Before launching Webb, every other scientist you would ask, they would be excited about the surprises, and it's given us many.

• 1:00Ira Flatow?

  And here to field your questions is Macarena Garcia Marine. She is an astrophysicist and instrument scientist at the European Space Agency. She's also deputy project scientist at the Webb Space Telescope, based at the Space Telescope Science Institute, famously in Maryland. Welcome to Science Friday.

• 1:20Speaker 03

  Thank you. Thank you for having me.

• 1:22Ira Flatow?

  Let's talk about this, because there's so many really interesting things going on, so much exciting news. Let's start with the news this week of this super-old galaxy, right? I mean, this is, to me, it was mind-blowing. Was it mind-blowing to you?

• 1:34Speaker 03

  It was mind-blowing to me, yes.

• 1:35Ira Flatow?

  Tell me why that is.

• 1:37Speaker 03

  Because we're talking about galaxies that existed about 280 million years after the Big Bang. That's nothing.

• 1:45Flora Lichtman?

  It's like a baby galaxy.

• 1:46Speaker 03

  It's like a baby galaxy.

• 1:47Ira Flatow?

  So they discovered this galaxy going way back in time.

• 1:50Speaker 03

  Way back in time. And let's remember, the universe is about 13.8 billion years, with a B. So this is a baby galaxy, and for a baby galaxy, it has had the time to actually have stars and reaching the galaxy and producing some additional chemical elements on top of hydrogen and helium. So it's really, really a fast way of growing galaxies.

• 2:11Ira Flatow?

  How old should it be to be, to make those things, instead of what it is now? What would you expect the age to be?

• 2:19Speaker 03

  I mean, it depends on when they start being. So stars, they can last, depending on their mass, they can last between millions and billions of years. But we don't really know how these very first stars were. They may have been thousands of times bigger than the sun. So that's...

• 2:38Ira Flatow?

  So why is your head exploding?

• 2:41Speaker 03

  Because this is really why we launched the James Webb Space Telescope. The primary science case was to observe these very first galaxies and very first stars. And actually, this is the oldest we have confirmed with spectra, which is like the fingerprint or the DNA of the galaxy. So you decompose the light and can really make sure how old that galaxy is. But there are candidates that are based on imaging that are even older.

• 3:10Ira Flatow?

  There are older ones?

• 3:11Speaker 03

  Yeah, they are only candidates. They are not confirmed, but because they are only based on imaging. But those galaxies, it's very interesting because they have been observed with Webb, but using gravitational lensing. So that is nature helping us by enlarging galaxies that are really far away. So these galaxies are fainter. And the researchers, they think that probably they are the progenitors of these other galaxies we are seeing that are brighter and slightly closer. So it is mind blowing.

• 3:45Ira Flatow?

  So what is it here? Do we have to rewrite the laws of physics? Or do we have to rewrite how we think galaxies form?

• 3:54Speaker 03

  I think we have to rewrite how we think galaxies form at that time of the universe. So that things like the Big Bang, the cosmological theories we have, they still hold. But we need to make adjustments to really understand how the galaxies form. It's like the chicken and egg thing. Is it first the stars, is it the black hole? How does this all come together?

• 4:15Flora Lichtman?

  Do these findings make us rethink anything about our own galaxy?

• 4:20Speaker 03

  I think what is making us rethink is if you go closer to us, still in a very young universe, we already see galaxies with spiral arms and even with bars. So to me, that's also a surprise that in such an old universe, we already have those structures that take millions of years and billions of years to take place. So in that sense, yes, it is really making us rethink, how long do you need to make those structures?

• 4:46Ira Flatow?

  Do you have any, any idea on that?

• 4:49Speaker 03

  Well,

• 4:49Ira Flatow?

  Can you give us a little bit of?

• 4:51Speaker 03

  We know, for instance, that bars, at least there is one galaxy that we have seen with Webb that has a bar when the universe was about 2 billion years old, very early still.

• 5:01Ira Flatow?

  Yeah, but these are much earlier, right? These galaxies.

• 5:04Speaker 03

  Oh, yeah, yeah. The first one we were talking about, they are really babies. They are bold and bright, yeah.

• 5:10Flora Lichtman?

  Let's go to the phones. Let's go to V in Ventura, California. Hi, V.

• 5:13Speaker 04

  Hi, I'm on Science Friday.

• 5:17Flora Lichtman?

  You're on Science Friday. Go ahead.

• 5:19Speaker 04

  Awesome. Yes, I have a question. As of recently, the James Webb Telescope found that there was kind of a void around our Milky Way galaxy. I was wondering if you had any sort of insight into this, if maybe it's a possible black hole that we're going towards, or if it's maybe some sort of dark matter we don't know about.

• 5:37Flora Lichtman?

  A void around our Milky Way galaxy. Have you heard anything about this?

• 5:41Speaker 03

  Honestly, not, but you've mentioned the black, you've mentioned black holes and you've mentioned dark matter. So in both areas, Webb is also contributing. At the center of our own galaxy, there is a supermassive black hole, millions and millions of mass in there and with stars circling around and materials circling around. So we're looking into that with Webb, not only the surrounding of the black hole, but all the structures around it and how that impacts the environment. And when it comes to dark matter, we are also Seeing via things like gravitational lensing, how does the ma... So gravitational lensing is a situation where you have, for instance, a cluster of galaxies that are really, really massive.

• 6:24Speaker 03

  They are so big and so massive that they bend the light around.

• 6:27Ira Flatow?

  Yeah.

• 6:28Speaker 03

  So when you do the calculations, you find out that there is actually mass missing. So that means there is something like dark matter that you wouldn't see, but you know it's there because it affects the light. So in that sense, yes.

• 6:40Ira Flatow?

  Do you think that dark matter has anything to do with the formation of these mystery galaxies that you've just discovered?

• 6:47Speaker 03

  I don't know. That's a good question.

• 6:50Flora Lichtman?

  This is one of Ira's favorite topics.

• 6:51Speaker 03

  I love that, yeah. Well, the truth is that there are many things we still don't understand, which is exciting.

• 6:57Ira Flatow?

  I'm glad to hear you say that.

• 6:58Speaker 03

  Yeah.

• 6:58Ira Flatow?

  Yeah, because a lot of people think science knows everything.

• 7:01Speaker 03

  No, we don't. No. But that's a good thing.

• 7:04Ira Flatow?

  Yes.

• 7:04Speaker 03

  Because that means that we still have many, many questions that need to be answered. So we need more data and more generations of scientists really looking into this.

• 7:12Ira Flatow?

  I've had, and I've had, when we've talked about this before, I've had scientists say, you know, I like the chase more than the discovery.

• 7:18Speaker 03

  Exactly. The chase is great. And actually, before launching Webb, if you, every other scientist you would ask, they would be excited about the surprises, and it's given us many.

• 7:28Flora Lichtman?

  What are you chasing?

• 7:29Speaker 03

  Me personally? I've been chasing, following up with the, what she was asking, the center of our own galaxy, actually. We got data very recently on some structures around the black hole, so I'm very excited looking into that.

• 7:44Flora Lichtman?

  Are they interesting? What's, what are you finding about them?

• 7:46Speaker 03

  Well, we're still looking at the data. So we'll see about that.

• 7:50Ira Flatow?

  All right, let's go to the phone. San Antonio Tully in San Antone. Hi, welcome to Science Friday.

• 7:56Speaker 05

  Hi, thanks so much for taking my call.

• 7:58Ira Flatow?

  Go ahead.

• 8:00Speaker 05

  My question is, I'm not sure if this was an active decision that was made, but how was it decided what direction the telescope was sent in, in space? How was, how was that trajectory decided?

• 8:11Ira Flatow?

  Wow, yeah, and what direction to find these galaxies?

• 8:14Speaker 03

  You mean, in which direction to find the galaxy? Oh, it's a really good question. So first, you go to the galaxies, you already know they are there. And for that, we have what we call deep fields. For instance, the Hubble Space Telescope looked into these deep fields. And we knew there were galaxies that were perhaps about 400 million years old after the Big Bang. So you look into the fields, you already have data. And you just observe during maybe 10 hours. And then you compare those images and do some tests to really understand if there are galaxies. And once you have candidates, then you go back and take a spectra. That is, you make a rainbow of that candidate.

• 8:53Speaker 03

  But yeah, the fields were fields that were already observed by telescopes like the Hubble Space Telescope.

• 9:00Flora Lichtman?

  It feels like we cannot talk about Webb without talking about exoplanets.

• 9:04Speaker 03

  I agree.

• 9:06Flora Lichtman?

  What is new and exciting there to you?

• 9:08Speaker 03

  New, everything. Webb has opened up the field of exoplanets, which is great because exoplanets didn't even exist when Webb was conceived.

• 9:17Ira Flatow?

  Maybe we didn't see them.

• 9:18Speaker 03

  We didn't, yeah, we hadn't seen them.

• 9:19Ira Flatow?

  They might have been there.

• 9:20Speaker 03

  Sorry, they weren't there, you're right. But as a science topic, what on earth, we didn't know they were there. And now there are almost 6,000 of them. So yes, it's a field that is really blossoming, lots of discoveries, lots of new molecules, observations of day side and night side. So it's really, really exciting and it's opening up a new field.

• 9:41Flora Lichtman?

  Well, there was this recent news that I think was linked to Webb about a biosignature.

• 9:46Speaker 03

  Correct.

• 9:47Flora Lichtman?

  On an exoplanet.

• 9:48Speaker 03

  Yes.

• 9:49Flora Lichtman?

  Burst our bubble, or tell us what the real deal is.

• 9:52Speaker 03

  Oh, the real deal is that, that's a very bold claim, right?

• 9:58Flora Lichtman?

  Extraordinary claims.

• 10:00Speaker 03

  Extraordinary claims require extraordinary proof. So of course, when that news came out, there was a lot of excitement. But then other scientists from the community actually look at the data and they're concluding different things. So to confirm that claim, you would have to confirm the type of planet that it is. And still, it's not clear if it's something like a mini Neptune. Or a Haitian world that is a world that is water with a very, with a hydrogen atmosphere. So we don't know the type of planet. Still not clear if the detection is solid. And still not clear if those if the molecules that are claimed are actually the ones they are because they could be something else.

• 10:41Speaker 03

  And the third thing is that even if if all the other conditions are demonstrated, DMS, which is this molecule, you can also find it in comets and you can also find it in the interstellar medium. So many open questions.

• 10:58Ira Flatow?

  When you get up in the morning, what gets you excited about what you do?

• 11:02Speaker 03

  Everything, to be honest. I have to say, every day, there is some new scientific discovery. Every day, there may be a new paper. Every day, there is something that, you know, the community is excited about. And then part of the work is also to bring that message to the public. It's not just about the science community.

• 11:18Ira Flatow?

  That's what you're here for. That's why we've got you.

• 11:23Flora Lichtman?

  Coming up after the break, we'll talk about what to expect from a possible successor to the web. Stay with us.

• 11:34Ira Flatow?

  Hey, Ira here. You've probably heard me say many times that we are all in this together. We're so encouraged by those who have backed me up on this by stepping up to support Science Friday in the face of the current funding challenges. So thank you to everyone who has donated in the past month. It's clear that many of you value science and count on public media as we do. You are the driving force behind our work. Your support strengthens Science Friday, provides stability in these moments of volatility, and your support is more crucial now than ever. So if you haven't made a donation to help close the current funding gap, you can still

• 12:16Ira Flatow?

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• 12:33Speaker 00

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• 14:15Ira Flatow?

  And let's go to the phones. Aaron in New Orleans. Hi, Aaron.

• 14:18Speaker 04

  Yes, hi. Thanks so much for taking my call. I did have a question. You know, I actually changed it to a much better one, if that's okay.

• 14:26Ira Flatow?

  We'll be the judge of that. Go ahead.

• 14:29Speaker 04

  Okay, thank you. What I wanted to ask a guest was, was that what is her opinion on the Amu Amu object? Do you think that this was something from intelligent life? Or do you think this was just some blip from another solar system that just happened into ours?

• 14:49Ira Flatow?

  Glad you changed your question. That was a good one. Yes?

• 14:52Speaker 03

  Yeah, that's a really good question. Personally, I think it was a quote-unquote "object" or "visitor" from outside of our solar system. As we were saying before, the claim of life or intelligence or anything like that, it requires really lots of proof, and we don't have that.

• 15:11Ira Flatow?

  Yeah, his original question, which I had, was whether the budget cuts are affecting your research and the research of astronomy and NASA and all the stuff that you do.

• 15:23Speaker 03

  So, at this point, we don't know, and that's a question better addressed to NASA in terms of what's gonna happen.

• 15:30Ira Flatow?

  But you don't feel it yourself at this point?

• 15:32Speaker 03

  At this point, no. What I feel and what I can really say is that the observatory is performing incredibly, the community is exciting, and the science coming out of it, it's really something worth pursuing every single day.

• 15:45Flora Lichtman?

  You know, I think for the public and for someone like me, a lot of what I see from Webb are these beautiful images, and they bring me so much joy and so much pleasure. But I wondered for you, for astrophysicists, like, do you learn something by looking at the images, or is it really just the data that underpins it that you're interested in?

• 16:04Speaker 03

  We learn a lot from images, and actually, often, you first use the image to identify candidates of special galaxies or candidates of something, and then you take a spectra because with imaging, you have much bigger field of view, you cover lots of space. But also, the different colors you use to create these beautiful images, it's a thing of, in the visible would be red and blue and green and all that, so you have infrared colors. These colors give you a lot of information, and all of these beautiful images you see, they are also used to the science with them.

• 16:39Flora Lichtman?

  So, is it like a "Where's Waldo"? Where you're like, "Oh, look, there's something in the corner that looks interesting, let's follow up."

• 16:45Speaker 03

  Yeah.

• 16:46Ira Flatow?

  Are people better at looking at the images than, let's say, AI? I mean, if you got a bunch of people together to find stuff.

• 16:54Speaker 03

  I think there is a bit of both. I think the future of astronomy, I mean, the future of many missions is to have large, vast amounts of data.

• 17:04Ira Flatow?

  Right.

• 17:04Speaker 03

  So there's gonna be some sort of machine learning techniques that can be applied for that. But behind that, I think personally, you always need a person with a brain that can do the interpretation and actually the figuring out exactly what's going on.

• 17:20Ira Flatow?

  And the Webb was specifically made to make these kinds of discoveries, right? What tools does it have to do that?

• 17:28Speaker 03

  It has four science instruments. They all operate on the infrared, so that's the type of light we don't see. But it's really, really good to see cold objects and to peer through the dust and to see very distant objects. And we have about 75% of the time with the spectroscopy.

• 17:48Ira Flatow?

  Right.

• 17:48Speaker 03

  So all of the four instruments have spectroscopic modes. We have a vast array of spectroscopy. And that means essentially, we break up the light into a rainbow. And with that, you can really understand what's going on. And they also do imaging. We do chronography, which is a technique where you can block the light from a star, for instance, and see the planets around.

• 18:11Ira Flatow?

  Yeah, you need to do that.

• 18:12Speaker 03

  You do that as well, exactly. So we don't have a lot of scientific power behind all of the instruments.

• 18:18Ira Flatow?

  What's happening, I know already, we're talking about a successor to the Webb, right? The Roman Space Telescope. How would that be different from the Webb Telescope? What would it do differently?

• 18:30Speaker 03

  Roman will be different because it will look into a different wavelength. And also, it's a different concept. Roman will do lots of surveys, really large field of view, covering large portions of the sky.

• 18:41Ira Flatow?

  And what do you learn by doing that?

• 18:42Speaker 03

  Well, you can, there's gonna be a lot of learning on transience. That is, transience is that you go to a region of the sky and observe it, and then you go back again and look for things that have changed. And that could be supernova, that could be... Galactic nuclei, black holes active, etc.

• 19:02Ira Flatow?

  I see you're not excited at all about this kind of work. I want to thank you for taking time to be with us today.

• 19:09Speaker 03

  Thank you.

• 19:10Ira Flatow?

  Macarena Garcia Marine is an astrophysicist and instrumental scientist for the European Space Agency, also deputy project scientist for the Webb Space Telescope.

• 19:23Flora Lichtman?

  Thanks for listening. Don't forget to rate and review us if you like the show. And you can always leave us a comment on this segment on Spotify. We'd love to hear from you. Today's episode was produced by Aneth Heist, but a lot of folks helped make this show happen every single week, including John Dankoski. Danielle Johnson. Beth Ramey. Jackie Hirschfeld. I'm Flora Lichtman. Thanks for listening.