...how scientists will use the James Webb Space Telescope? (with Vivian U)

Ever Wonder? / December 8, 2021

We’re continuing our coverage of the James Webb Space Telescope, which is scheduled to launch in the coming weeks, and is expected to be the world’s premier space telescope. In our last episode, we talked to engineer Stephanie Hernandez about what it was like to help build this telescope. If you haven’t already, please give it a listen! 

Okay, so last episode was all about how we built the telescope, but what about the people who will look into space with it? 

Ever wonder how scientists will use the James Webb Space Telescope? 

Today, we’re going to meet someone who has been dreaming for years about what we could see with this technological marvel.  

Vivian U, PhD (@JustTheLetterU) is an assistant research astronomer at the University of California, Irvine. She will also be one of the first people to conduct research with the James Webb Space Telescope! Vivian explained to us what she hopes to discover by pointing Webb at colliding galaxies and supermassive black holes, and why this telescope is expected to be so good at peering through dust. 


Perry Roth-Johnson (00:06):

Hello! This is Ever Wonder? from the California Science Center. I'm Perry Roth-Johnson. We're continuing our coverage of the James Webb Space Telescope, which is scheduled to launch on December 18, 2021, and is expected to be the world's premier space telescope. In our last episode, we talked to engineer Stephanie Hernandez about what it was like to help build this telescope. If you haven't already, please give it a listen! Okay, so last episode was all about how we built the telescope, but what about the people who will look into space with it? Ever wonder how scientists will use the James Webb Space Telescope? Well, today we're going to meet someone who has been dreaming for years about what we could see with this technological marvel. Dr. Vivian U is an assistant research astronomer at the University of California, Irvine. She will also be one of the first people to conduct research with the James Webb Space Telescope! Vivian explained to us what she hopes to discover by pointing Webb at colliding galaxies and supermassive black holes, and why this telescope is expected to be so good at peering through dust. It's a fascinating conversation full of wild and trippy stuff—Let's get into it.

Perry Roth-Johnson (01:17):

Dr. Vivian U, you're an assistant research astronomer at the University of California, Irvine and you will also be one of the first to conduct research with the James Webb Space Telescope—Vivian, welcome to the show!

Vivian U (01:27):

Thanks for having me.

Perry Roth-Johnson (01:29):

Yeah! And Devin Waller, co-host of the show is also here with us. Hi Devin!

Devin Waller (01:33):

Hey Perry, it's nice to be here. Hi Vivian, thanks so much for joining us!

Perry Roth-Johnson (01:37):

So Vivian, we're super pumped to talk to an astronomer like you, who will be one of the first to use the James Webb Space Telescope. Uh, as you're well aware, it's expected to be the world's premier space telescope and is scheduled to launch this December. You'll be getting some of the first pictures back from Webb for the—for the observation programs you're leading, where you'll be looking at supermassive black holes, really exciting stuff. But before we get into your research, I want to start with some basics about the telescope itself and what you hope to achieve with it. First of all, just what is the Webb Telescope? How do you talk to your friends and family about it?

Vivian U (02:11):

Well, the James Webb Space Telescope is going to be one of the world's premier telescopes in a sense that it is going to be a very big space telescope. Um, that's going to be working in the optical infrared. A lot of folks call it the, uh, uh, successor to Hubble Space Telescope, whose legacy we all are very familiar with. Um, and it's going to be, you know, both better and different in, in, in some sense where its primary, um, observations are going to be in the infrared wavelengths. And it's going to have a lot of advanced instruments, uh, that we've never had before put in space. So in that sense, it's going to be a really kind of revolutionary type of instruments that we're all looking forward to using.

Perry Roth-Johnson (02:53):

What are you most excited to hopefully discover with Webb?

Vivian U (02:57):

Well, uh, because I'm looking at the centers of these interacting galaxies with web. What I'm really hoping to look at is actually how the, the gas and other materials within the galaxies going to be falling into the central massive black hole and how that kind of spews out back into the environment of the, of the galaxy, uh, through this process that was not previously accessible to us.

Perry Roth-Johnson (03:21):

And how come is it? Because when the galaxies collide, something happens?

Vivian U (03:25):

When galaxies interact a lot of materials. Um, and by materials, I mean, you know, stars, dust gas, uh, all of that kind of gets stirred up and they get disturbed and then they, uh, eventually use the angular momentum and they fall towards the center and all that dust is, you know, pretty in some way, but it's also blocking our view into the center and with basically the infrared capability of James Webb, we would be able to actually peer through the desk and see what's going on behind the desk screen.

Devin Waller (03:55):

Vivian that's really interesting. So infrared, so let's start with infrared light. You can actually peer through the dust and any other things, I guess, that are in the way for you to actually see what's at the center of galaxies. So can you kind of break down what exactly is infrared light and where does it fit on the spectrum?

Vivian U (04:15):

Yes, very good question. So the way I think about infrared to the first order, it's to maybe perceive it as like temperature, right? It's um, when you think about, uh, maybe you've seen some demonstrations of infrared cameras at museums or other places, a lot of times you can, you know, if you just take it, use a visible camera that we're all used to, you can see what your eyes can see, but if you kind of, uh, hide behind a, uh, plastic bag, a black plastic bag, then you can't see anything, but the black plastic bag. But if you then look at yourself through the infrared camera, through that plastic, that you can actually see an image of presumably a person, because you are warmer than the plastic bag. So places where you are warmer, it's going to appear brighter in this infrared image. And so, you know, same thing, you know, with it, uh JWST we would be able to kind of see through the dust because there's going to be heat. There's going to be energy is generated. That is not actually, uh, visible in the visible light, but they will be, uh, visible to us through, uh, an infrared machine.

Perry Roth-Johnson (05:23):

Okay. So we're going to use infrared on Webb to see through the dust and look at the galaxies with the really bright centers. They're super massive black holes. I heard you mentioned that earlier, uh, just for our listeners, what is a black hole?

Vivian U (05:38):

Well, that's also a very good question. Um, so black hole is probably not a hole because we astronomers a lot of times. misname things when we first discovered them. Uh, but in fact, they are a very compact and dense objects. So black holes are just a, a, uh, condensation of like all of the material, very packed, very compact in a very small volume of space. And in fact, it's so compact that the gravity is going to be so strong that not nothing can escape, not even light can really escape from it. And therefore when no light is emits from these objects and they appear black, um, because you can't see light and then they sort of look like a hole in space. I suppose, if you look at a patch of sky, then that's why we call them black holes, but also black holes. Um, they are, uh, categorized by different, uh, masses. And usually we like to think about masses because they are a kind of an easy property of them that we can measure as opposed to, to spin or anything else. And also, uh, knowing their masses tells us something about the ways that different wastes that they might've been formed. So there are different categories of these black holes. Uh, there are things that were called the stellar mass black holes, which are the smallest of the group, and there are the intermediate mass black holes, and there's also the supermassive black holes. And then their breakdown, um, is somewhere between, you know, uh, 10 to a hundred solar masses or this massive, uh, our sun, uh, for the smallest, um, black holes or stellar mass black holes, and then somewhere, uh, at a million or more solar masses, supermassive black holes and somewhere in between is like, uh, are the intermediate mass black holes?

Perry Roth-Johnson (07:25):

Did you say a hundred million times to massive or sun?

Vivian U (07:30):

Yeah, the ones that I, the ones I routinely steady are about a hundred tens of a hundred, hundred million solar masses. That's right.

Devin Waller (07:38):

Supermassive black holes. And in the center of massive galaxies, they seem to play an important role in the formation, or at least the evolution of those galaxies. I read somewhere that you wrote that black holes are driving galaxy evolution. Can you tell us more about what that means?

Vivian U (07:57):

Of course, um, so yeah, one of the, you know, some of the relationships we've observed in the past, you know, when we look at black holes and we look at the, these massive galaxies that they seem to recite it and seem to be ubiquitous really, uh, reciting in, is that actually the more massive the galaxy, the more massive the central supermassive black hole seems to be. And so at first glance, maybe that seem intuitive, uh, to some folks, but, uh, when you really think about the difference in size between the two entities it's, as if we're saying that something, the size of our planet, uh, cares about, you know, and scales with that of a baseball bat. And so, you know, this is kind of a surprising finding that hasn't really puzzled, so that in one, understand what physical processes are involved so that the two entities seems to relate to one another. And so this is what we call the co-evolution of black holes and galaxies, uh, describe the fates of how, uh, the galaxies and black holes seemed so intertwined. And so they're really interacting with each other via what we call a feeding and feedback processes, where the galaxy feeds gas to the black hole to grow it. And that in turn releases energy to feed back into the galactic host to really influence its stars and, and, and other material in it. And consequently, it's a it's fate. So, uh, this is how we describe that, you know, the black holes and galaxies, uh co-evolved together.

Perry Roth-Johnson (09:27):

Did you say something, the size of a baseball bat is affecting something the size of our planet. So the black hole is the baseball bat in this analogy. And the galaxy is the plant. That's crazy as a baseball fan. I appreciate that analogy very much. So, like, would the galaxies the really big galaxies, if they didn't have a super massive black hole in the middle, would they fly apart or like, do they need it to hold themselves together?

Vivian U (09:56):

Well, I mean, so far what we've seen is that, uh, there is, seems to be one in every, in every galaxy. So whether it's, you know, the galaxy probably grew it to begin with, and then they just kind of have been growing together. It's more of the conventional system. So we, it's almost hard to imagine that if you won't have a black hole in and massive galaxy, um, is I wouldn't say it's holding it together, but I think it's just the fact that as its forming somehow the black hole hasn't been growing with it. Uh, if that makes sense.

Devin Waller (10:28):

We did an earlier podcast episode where we talked about the shape of the Milky Way and how we have evidence strong evidence that it's a spiral galaxy. Um, and we know that there, you know, different shaped galaxies. So do you find the same kind of phenomenon where you have a super massive black hole at the center of all of the different shaped galaxies? So you regular elliptical, all of those.

Vivian U (10:50):

Yeah. I mean more or less, um, we, I wouldn't say we've looked everywhere, but at least all the we've seen there seems to be evidence, uh, that, that they do exist in all these massive galaxy.

Devin Waller (11:01):

What is it? Can a galaxy evolve without forming a supermassive black hole, the center? Well, so maybe

Vivian U (11:08):

I would go back and talk a little bit about, you know, you mentioned the different types of galaxies, so you had a spot spiral, galaxies, elliptical galaxies. And so, um, if we, if we think about it as having seen different types of galaxies in the sky, and most of what you would see are either what falls into one of those two character categories. And then we also see the irregular, but there's probably much fewer in number. And so one of the things we want to figure out is how, you know, these galaxies might relate to each other or not, you know, and one of them kind of working theory is that they probably do evolve from one to the other. Um, and one of the, uh, uh, theories that, you know, my Ph.D. advisor has come up with many years ago was actually how the spiral galaxies they interact and they collided with each other. And in the process, which is a relatively quick thing that happens maybe in a billion year or couple billion years or so. Uh, and that's the irregular stage that we might be seeing. And then before they, uh, they become those elliptical galaxies that are again, kind of, uh, evolving passively and the, the way, uh, that we think that this happens. Now, I wouldn't say that every galaxy goes through that stage, but when galaxies do go through that phase, they experienced a lot of changes, such that they changed the shape. They changed the gas content, they changed the color, they change the size, they changed a mass, um, and the black hole along with it. And so the process that I focus on is trying to understand if and when these galaxies do go through this merging process, what happens to the black holes? And so, um, when we have these spiral galaxies, we have measured, you know, what they're, what the massive black holes are, but then during this merging process, it's actually where the mess happens. And because we can't really see what happens behind it, we don't really know how quickly do gas gets a formed. All the gas actually get sucked in, or is that some of it get dissipated or does it get formed by stars? Does it get blown away? Um, we don't really know the details. And so, but somehow after this process, and then they come out and, you know, become these, you know, uh, elliptical galaxies again, then they somehow fall back into that same relationship that you might've expected. You know what I said about larger galaxies being more, uh, massive. And so, uh, in that sense, then we believe that a lot of these black hosts do grow with this interacting process. So while the is interacting, I mentioned how gas and material falls into the center. And also some of that gets accreted onto the black hole. And that actually helps to add to the mass of the black hole and helping it to grow. Um, if some of the galaxies don't experience this process, perhaps they're, um, gases in, uh, either gas comes from somewhere else comes from the cosmic web, or it doesn't, uh, get used up as quickly, then maybe they just grow slower, slower, kind of in a linear relationship. But in the processes, I study then lot of dramatic changes happen during this, uh, few billion years of galaxies lifetime. Um, and that's, what's fascinating to me and what we're really trying to understand with JWST.

Perry Roth-Johnson (14:19):

I am so fascinated, um, at how clever astronomers are, because you, you said when galaxies collide, it's a relatively quick process. And I know in cosmic time, a billion years is a relatively quick process, but just like walk me through the practicalities of how astronomers figured out that one type of galaxy collision might've led to a different shape galaxy like irregular when it takes a billion years for it to happen. And humans live, you know, maybe a hundred years on a good day.

Vivian U (14:50):

Yes. Well, so I'm going to be a little bit biased in my answer here because I'm observational astronomer so in my opinion, I think that, you know, we have served these galaxies. I know we wanted to come up with a story too, to kind of connect them together. And actually, you know, when we studied these nearby galaxies, as I mentioned, we see a lot of detail there. So like really beautiful Hubble Space Telescope images out there that can really show you the title tails and the bridges. What happens when you kind of smashed together two spiral galaxies. And, and then you can see that the centers of the gases kind of get closer and closer to each other. And, and then at the end, you know, you're, you're merging, you have come up with single, uh, elliptical, but of course, you know, I would give a lot of credit to my, my, uh, theorist, uh, colleagues for really tied all of this with an with beautiful simulations. And so with their simulations, then they actually are able to, you know, uh, kind of follow this process by, uh, by using different computer codes simulations to, to show how this process could possibly happen. And then when we match simulations to our salvation, it's like, wow, you know, the, it seems consistent, right? That the theory is consistent with our observations and pay. Maybe we, we just learned a thing or two about how these galaxies might've evolved and, you know, the serial simulations, then we also are able to, uh, get some tight timescales or estimates of these timescales. And so we can, uh, I don't, you know, no one can really lift a billion years to really that this has happened, but, you know, it seems, uh, consistent with the observations that we've made at least. So those are our working theories until something else tells us that we're wrong.

Perry Roth-Johnson (16:30):

Uh, the beauties of computer programming. For sure. We're all looking forward to Webb's launch this December. Uh, where are you going to be when it launches? Are you doing anything special or it's still too early to tell right now?

Vivian U (16:43):

Yeah, I don't have, I haven't started booking catering, uh, trying to get parties going or anything like that also depends on a little bit on how COVID goes, but hopefully we'll be able to maybe do a little bit of watch party, either with my colleagues through zoom, or maybe even in person in our department and just kind of all cheer on and watch the successful launch and deployment of the telescope. That'd be fantastic.

Perry Roth-Johnson (17:07):

And from what I understand, fingers crossed Webb launches safely, it goes out to where it's going to live about four times further than the moon is from earth right now. Uh, how long does that take and like, where are you going to be when that happens? And you get the first images back from Webb.

Vivian U (17:25):

The whole process from launch to the first set of data coming in takes about six months. So during the six months of commissioning, the, uh, obviously the, the telescope needs to get to where it lifts and then it'd be so successfully deploy, or you might've seen animations of how the sun shield needs to unfold properly and everything needs still just work. Right. Uh, and then after that, there's going to be a lot of, um, testing up the instruments, you know, they need to cool down, they need to, um, you know, take test images and, and get calibrated. And then we expect that the first set of the cycle zero, uh, data will hopefully come in six months after launch. So hopefully next summer we'll be looking at some of the first images, uh, from, from, James Webb.

Perry Roth-Johnson (18:07):

And how do you think you'll feel when you get those first images back next summer?

Vivian U (18:12):

I think I'll be really busy trying to analyze what they look like.

Perry Roth-Johnson (18:23):

You won't have time to feel, you will just be too busy.

Vivian U (18:23):

That's right. Yeah. I mean, we are doing a lot of simulation work right now, a lot of preparation work to try to you know predict and, and understand what kind of data will be coming in. And so hopefully, you know, when the real data comes in, it's just a matter of you know running them through and hopefully that they match, you know, more or less what we expect. And then we can, you know, stress to understand the science and, and delve right into, uh, figuring out science question. But yeah, I think I'll be super excited, but also really busy at the same time.

Devin Waller (18:51):

So Vivian, what else, what, are there any other stories that you want to share with us and what else do you want people to know about this?

Vivian U (18:58):

One thing is probably that we are, uh, here kind of pushing, really pushing the frontier of what we've learned and what, what we hopefully will learn, uh, you know, about astronomy. It's not, uh, you know, just trying to, you know, spend money on expensive toys, but that we are really learning from also, you know, like I said, you know, not just the astronomy, but also the engineering, but even within astronomy, there's sort of massive black holes and then there's exoplanets and, and up the first galaxies. So I think that, you know, this is going to be kind of a step for, uh, human kind to kind of make this exploration together. And, um, and I'm very excited to, to be among others, to, to be some of the first people to do so. And, you know, besides the, the things that we are anticipating that we will learn, there's actually going to be a huge space of unexplored territory, that we have no idea what we're wandering into, just because of the instruments being, being so, uh, so events and being able to peer through things at, at the, uh, for the first time, looking at things a different way for the first time. And so in that sense, um, get excited, you know, get, get excited with the rest of us. And, um, will, will just have to see what we'll get.

Perry Roth-Johnson (20:15):

Awesome. And Vivian, where can people follow you online and find your work?

Vivian U (20:19):

Um, yeah, I, uh, I have a webpage. I'm probably pretty easy to find you just look up Vivian U, Irvine or astronomy of some sort, uh, U just the letter U, um, it's, uh, my last name, um, and I am on Twitter. My Twitter handle is @JustTheLetterU, I think that will be really easy to find me as well. So I'm happy to help answer questions or talk about excitement of astronomy any time.

Perry Roth-Johnson (20:42):

By the way you have one of the coolest Twitter handles. Uh, I've seen so props to you for that. It's been wonderful talking to you, Vivian, best of luck to you and the rest of the astronomy community. We hope you all have a successful launch with Webb. Vivian thanks for joining us on the show.

Vivian U (20:57):

Thank you so much. I really appreciate it.

Perry Roth-Johnson (20:59):

That's our show, and thanks for listening! Until next time, keep wondering. Ever Wonder? from the California Science Center is produced by me, Perry Roth-Johnson, along with Devin Waller and Jennifer Aguirre. Liz Roth-Johnson is our editor. Theme music provided by Michael Nickolas and Pond5. We'll drop new episodes every other Wednesday. If you're a fan of the show, be sure to subscribe and leave us a rating or review on Apple Podcasts. It really helps other people discover our show. Have a question you've been wondering about? Send an email or voice recording to everwonder@californiasciencecenter.org, to tell us what you'd like to hear in future episodes.