Episode description:
When it launched in 1990, NASA expected the Hubble Space Telescope to last for about 15 years. Thirty-five years later, Hubble is still showing us the universe as no other telescope can. Go behind the scenes with Morgan Van Arsdall, deputy operations manager for Hubble, on an audio tour of Hubble’s control center. Morgan’s team keeps Hubble operating smoothly, and when something goes wrong, they snap into action to fix it. Plus, hear how Hubble tag-teams with newer observatories—including the James Webb Space Telescope—and continues to push the frontiers of astronomy.
[Music: Curiosity by SYSTEM Sounds]
PADI BOYD: Hey space nerds. Welcome to NASA’s Curious Universe. I’m your host Padi Boyd.
JACOB PINTER: And I’m your cohost Jacob Pinter. This is an official NASA podcast, and we’re bringing you on adventures through the wild and wonderful universe we all share. So buckle up, and let’s go.
PADI: We’re so glad you’re here, especially if you’re new to Curious Universe. Welcome!
JACOB: OK Padi. I have been working on something that I think you in particular are going to like because today’s story is all about the Hubble Space Telescope.
PADI: Oh I love it. I mean, talk about a telescope that can literally take you from our solar system, all the way out to the edges of the Milky Way Galaxy, and then to the edge of the universe.
[Music: Delicate Balance by Matt Norman]
JACOB: Well it’s really a treat that you’re here to help us to help us out with your background today too, because even though most of us see these beautiful images from Hubble, what we don’t see is how much work it takes to make all of that possible.
PADI: RIght. When it launched in 1990, Hubble was the culmination of one of the biggest “what-if” questions in astronomy. What if we put a powerful telescope in orbit above Earth’s turbulent atmosphere, which can blur out our view of the cosmos and block some wavelengths of light? Scientists were sure that because of those improvements, this telescope would help us see the universe in a whole new way.
JACOB: And that is exactly what happened. For the past 35 years, it has taken an incredible team of humans to get the most out of Hubble. There are the people who built the telescope and launched it. People who watch it constantly and send instructions from Earth when something goes wrong. People like you, Padi, who make sense of the science data. And even a few, select people who flew to space and fixed Hubble with their own two hands. So that’s what this story’s about: we’re going to go behind the scenes, and we’re going to hear how people keep this mission going.
PADI: It’s the perfect combination of technology that only NASA can do and people power, teamwork. So all right, let’s do it.
JACOB (on location) OK. It is Tuesday. Walking up to building three.
(in studio) On a frosty day this winter, I bundled up, grabbed my microphone …
(on location) I should get my levels, levels, levels.
(in studio) … and walked into an area at NASA’s Goddard Space Flight Center called the STOCC. That’s an acronym, which stands for Space Telescope Operations Control Center. This is the one and only place where humans can control the Hubble Space Telescope.
(to Morgan Van Arsdall) Can we go inside?
MORGAN VAN ARSDALL: Absolutely.
JACOB: Sweet. Thank you.
MORGAN: There you go.
JACOB: Cool.
MORGAN: We’re inside, in the operations control center.
JACOB: My tour guide was Morgan Van Arsdall. Morgan is a deputy operations manager for Hubble, so she oversees the team that keeps the telescope healthy and safe.
[Music: The Science of Design by Carl David Harms]
We looked through a big observation window into a room with two men.
MORGAN: And the two people you see here are two of our commanders. There are about six people on the planet who are actually certified to send commands to the spacecraft.
JACOB: We were standing behind the commanders, looking over their shoulders. They sat at stations with several computer monitors, each filled with color-coded letters and numbers. They were laser-focused on the displays. To me it was an overwhelming amount of information.
MORGAN: In the back is a big map of the whole world, and you can see the dots on it where Hubble is, but also where the communication satellites that we use are. So we can see where we are in relationship to that. And then on the actual computers there, we have all of our telemetry.
JACOB: Are you one of the six people who is qualified?
MORGAN: I am not. Definitely not.
JACOB: Really?
MORGAN: No, yeah. I always joke that before I retire, I want to just send one command.
JACOB: For the most part, the STOCC feels like a normal government office. Think fluorescent lights and quiet hallways. But one thing that sets it apart is the decoration. Some of Hubble’s most iconic images hang on the wall in big, poster-sized frames. Morgan shows me her favorite. It’s one of a series called Ultra Deep Fields. In the image, we see more tiny dots of light than I can count, all suspended in the blackness of space.
MORGAN: I think they’re really cool for two reasons. The first is, when you look at these Ultra Deep Field images, you get a sense of just how enormous the universe is. All of these dots in here—almost all of them—are galaxies, not stars. So when you look at this, you can get just overwhelmed by how much stuff there is in the universe, right? It also is a really good example of the pointing of Hubble and how important and how really good that is, because these deep field images aren’t taken in one snapshot. As Hubble is going around the Earth, it will often have to lose the—lose where it’s pointing, go around the other side of the Earth, and then be able to pick up that same exact spot to take another set of images, so being able to hold steady, and then also re-point to that exact same position and hold steady again, is a really unique capability that Hubble has, and it’s critical to being able to do the kind of science we do.
JACOB: Ever since 1990, Hubble has been orbiting Earth, giving us these new windows into the universe. I mean, entire generations of kids have grown up with Hubble images in their textbooks. And even today, Morgan says it’s an amazing feeling to tell strangers that she gets to work with Hubble every single day.
[Music: Above the Line by Phil Smith and Ken Bowley]
MORGAN: A lot of times people are very excited and, Oh, that’s really cool. Tell me about it. I also not infrequently get the, “Oh, is Hubble still out there?”
JACOB: Well, Padi, today on Curious Universe, we’re shouting it from the rooftops.
PADI: Hubble is still out there! And it’s still giving us mind-blowing discoveries.
JACOB: We’re going to hear more about how people on the ground control Hubble and how they snap into action when something goes wrong. And we’ll also hear how Hubble tag-teams with a new generation of space telescopes. But before we do all that, Padi, I want to hear a little more about your experience working with Hubble. Like, what specifically did you do with Hubble? What did you research?
PADI: When I got to Goddard I was just out of graduate school, and I came to work on one of the first-generation instruments called the High-Speed Photometer and polarimeter. So we looked at all kinds of objects that we could learn about in the ultraviolet and the optical, like quasars. We looked at pulsars. We were very interested in looking at some typical pulsars—like the Crab pulsar that we know so much about—but also some pulsars that are like a twin of the Crab to see if we could use all that information to put together a really consistent model of what pulsars are—rotating, rapidly rotating neutron stars. So it was very exciting to be part of that first generation of science with Hubble.
JACOB: So like, when Hubble launched in 1990, were you watching it? Do you remember where you were, watching it on TV, something like that?
PADI: Oh wow. So I—like my first memory about its launch was that it wasn’t going to launch on time because it was scheduled to launch soon after the shuttle accident. So that was a huge, devastating blow for so many reasons: the loss of people, the delay to the telescope also. So I do remember when it launched, that feeling of, OK, we’ve overcome a huge obstacle. We’re going to put this telescope into space anyway. It was very exciting in those early moments, but of course once we started to get those test images down right after launch, everything was not exactly as we expected it to be.
JACOB: We’ll get into that. I have to tell you something, though, which is that I am a couple of years younger than the Hubble Space Telescope.
PADI: Wow.
JACOB: I mean, when I was in school, these were the photos we had in our textbooks, right?
PADI: Can’t imagine.
JACOB: The one that’s always stuck with me is the Pillars of Creation. It’s that iconic photo of the Eagle Nebula. You see these towers of gas and dust rising up through the cosmos against a blue-green background. It was on posters and classroom walls when I was a kid—like, it’s just burned into my brain. And I can’t imagine a world without Hubble, you know, because it’s always been there. And I know so many other people grew up the same way. It’s just been such a gift for those of us who did grow up like that.
PADI: I think it was also a gift to not grow up like that. So, when I was getting really interested in astronomy I was looking at the best images that ground-based telescopes could give us, and those were of course beautiful, awe-inspiring, evocative. But it wasn’t until Hubble launched that you could really start to get away from some of the blurriness intrinsic in those images and really start to see a very clear, vivid picture.
[Music: Discover the Unknown by Marc Aaron Jacobs and David Wittman]
JACOB: Well, for folks like me who weren’t there at the beginning, let’s rewind the clock back to 1990. This is a time when the first commercial digital cameras are becoming available. There’s this new thing called the World Wide Web starting to get traction. And on April 24th…
LAUNCH ANNOUNCER: T-minus ten. Go for main engine start.
JACOB: … Five astronauts headed to the launchpad and climbed inside space shuttle Discovery.
LAUNCH ANNOUNCER: … And liftoff of the space shuttle Discovery with the Hubble Space Telescope, our window on the universe.
JACOB: The space shuttle flew to an altitude of more than 300 miles above the surface of the Earth. And then, astronauts used a robotic arm to carefully lift Hubble out of a gigantic cargo bay.
CHARLES BOLDEN: That shows about two inches starboard. Good clearance. Still looks good.
PADI: The telescope itself looks something like a lipstick tube with antennas and solar panels sticking out the sides. It’s about the size of a school bus, and on Earth, it weighs roughly the same as two elephants. But in space, suspended by that robot arm, Hubble was weightless.
STEVEN HAWLEY: Sure looks like I want to go to starboard.
CHARLES BOLDEN: Starboard? Yeah. I’d go ahead and do it. Because you’ve got … (fades out)
PADI: So one thing that makes Hubble complicated is that you have to think of it as two separate types of things at once. It is an amazing telescope, and it is a satellite. So o nce Hubble was in space and the team ran through some tests, everything checked out on the spacecraft side.
JACOB: But as a telescope, things didn’t work the way they should. Hubble could only take blurry pictures. Or, in the words of Ed Weiler, who was Hubble’s top scientist at the time, the mirror had a spherical aberration.
EDWARD WEILER: You can almost think of it—if you’ve got bad myopia, which you could say our telescope has now, and you put your glasses on, you can correct totally and get 20/20 vision.
JACOB: Essentially, Hubble needed glasses, and NASA saw a way to fix it.
EDWARD WEILER: We can take advantage of an insurance policy that we haven’t talked much about. And that is, we started a long time ago to plan a maintenance program.
LAUNCH ANNOUNCER: Three, two, one …
PADI: Three years later, astronauts headed back to the telescope.
LAUNCH ANNOUNCER: … And we have liftoff! Liftoff of the space shuttle Endeavour, on an ambitious mission to service the Hubble Space Telescope.
[Music: Uncovering Secrets by Mike Joseph Fraumeni and Lester Frances]
PADI: Now, NASA had always planned to send astronauts back to Hubble. They could replace worn out parts and install new scientific instruments, kind of like taking your car in for maintenance. By 1993, a new camera was ready with adjustments that canceled out the flaw in Hubble’s mirror. In space, once again orbiting 300 miles above Earth, astronauts grabbed the telescope with the space shuttle’s robot arm.
RICHARD COVEY: Houston, Endeavour has a firm handshake with Mr. Hubble’s telescope.
MISSION CONTROL: Copy that. There are smiles galore down here.
PADI: Then they performed a marathon series of spacewalks that lasted more than 35 hours.
JEFFREY HOFFMAN: OK.
THOMAS AKERS: Start with the handle bolt, right Jeff?
JEFFREY HOFFMAN: Yes.
THOMAS AKERS: Good job guys. Dorothy, do you want to grab the CRD …
PADI: It was extremely complex. These astronauts were real people that had been trained by the team on how do the instruments work, how do you remove the instruments, what tools will work? There was so much collaboration there.
(chatter of astronauts’ radio)
And there was so much excitement. They were projecting it onto the big screens in teh auditoriums here, and people would come in. It was like you were watching the Super Bowl or something, so much anticipation. And just to see it all come together over such a long period of time and have it be so successful, it was peak NASA.
When it was all over, Hubble’s new camera did the job. It could see clearly, just as NASA had originally promised. Since then the telescope has delivered iconic image after iconic image.
[Music: Upward Together by Frederick Percy Davenport Lomas]
Hubble showed us nebulae, ethereal clouds of gas and dust, where stars form and die; galaxies with long spiraling arms that hold an unfathomable number of alien worlds; and even the heart of our own Milky Way Galaxy and detailed shots of familiar planets like Mars and Saturn.
JACOB: When it launched, NASA expected Hubble to last about 15 years. Thirty-five years later, Hubble is still showing us the universe.
MORGAN: I think the Hubble operations team, as well as all the Hubble scientists and everybody that has anything to do with it, understands really deep in our core that we are entrusted with a national asset, with an international asset. This is not our telescope. This is everybody’s telescope, and we don’t take that lightly.
JACOB: Astronauts returned to Hubble a total of five times, most recently in 2009. But there are no more servicing missions planned. So it’s up to Morgan and the entire operations team to keep Hubble going.
MORGAN: Our operations team is responsible for making sure that the telescope is healthy and safe, so that it has everything working, has all the power it needs, pointing where it needs to be, the science instruments all working correctly, so that we can get the amazing science that you see.
JACOB: So let’s pause for a moment and consider just how intricate all of that is.
[Music: Micro Life by Peter Larsen]
In a nutshell, Hubble has to receive instructions from Earth, maneuver itself so that it points the right way, and stay locked on to one small part of the sky, all while it orbits Earth at 17,000 miles an hour, which is more than 27,000 kilometers an hour, for those of you who use metric.
PADI: Here’s another way to think of it. Hubble’s pointing and control system is so precise that it’s equivalent to shining a laser on an American dime and holding it there from more than 200 miles away, or well over 300 kilometers. One of the tools that makes that possible is called a gyroscope. It determines which way Hubble is turning and how fast.
MORGAN: You can imagine the experiment that you probably did in middle school with a bicycle wheel, where the ice skater holds the bicycle wheel and you spin the wheel real fast, and then when she turns it, her body turns. The gyroscopes use that same basic physics of a spinning wheel, and as the telescope turns, it can sense how it’s turning.
PADI: Besides that, Hubble has a few other tools to get its bearings. It has a sensor that tracks its position relative to the Sun; a magnetometer, which uses Earth’s magnetic field, kind of like a compass; and, to zero in on exactly the right target, Hubble relies on something called a Fine Guidance Sensor. Scientists have compiled a kind of atlas of more than 19 million objects in the sky, called guide stars. Hubble uses those as reference points.
MORGAN: So they have this huge guide star catalog, and they send that information down to us that say, OK, you’re looking for a star of this brightness in this location. And then our Fine Guidance Sensors know, OK, this star is too bright. It’s not the one I want. I need to keep looking.
JACOB: Of course that’s how things are supposed to go, and over its 35 years, Hubble has a pretty incredible track record. But just like your car or your phone or anything you use every single day, things can go wrong. And that’s where the operations team really earns its stripes.
MORGAN: We like things to be quiet. Our—one of our catch phrases around here is boring is good.
[Music: Obsessions by Carl David Harms]
PADI: When Hubble launched, there was a team of people watching it 24/7. Overnight, on weekends, on holidays, there was always somebody in the control center. These days, the team works a normal nine-to-five shift. The rest of the time, an automated computer system looks out for anything unexpected.
JACOB: The humans plan Hubble’s maneuvers about a week in advance. If something goes wrong, the computer sends a text message alert and the team takes it from there, sending instructions for the telescope to use certain equipment or to maneuver in a certain way.
MORGAN: When we’re going to be doing things on the fly is when things are going wrong. Actually, just this morning, there were some commands because one of our fine Guide. Sensors had an issue. So the team was here about eight o’clock this morning. They wrote up the commands and sent the commands to the telescope.
JACOB: So the thing that happened this morning, like, how often does something like that happen that you have to address?
MORGAN: It’s a good question, and I joke that I want my daughter to do a science fair project on the timing of anomalies, because I swear they happen over holidays or at night, not at two in the afternoon on a Tuesday. We’ll go months without any problems at all.
JACOB: In the summer of 2021, Hubble was, in Morgan’s words, boring. And that was good. Scientists were using the telescope to study a comet racing toward the Sun and to survey distant galaxies. Morgan was even looking ahead to some family time for the Fourth of July.
MORGAN: And then we all got a text message that said that our science computer had gone into fixed mode, basically gotten shut down by the other computer.
PADI: Until this problem was solved, Hubble couldn’t do any science. So the team jumped into action. At first, Morgan didn’t think it was a huge problem. The science computer had gone into fixed mode before and it always came back online.
MORGAN: We all have computers that inexplicably shut down sometimes.
JACOB: Just unplug it and plug it back in.
MORGAN: And that’s literally like, well, let’s try to turn it back on, right? I mean, we thought about it for a few days. We did some analysis. We made sure as much as we could that it was safe to turn it back on, but then we just turned it back on, like, let’s see if that works. It did not.
[Music: Dream World by Colin Nicholas Baldry and Tom Kane]
PADI: Now Morgan had a real puzzle. It turned into a marathon of 12-hour days as engineers studied the problem from every angle. Maybe Hubble had an issue deep inside its complex network of computer hardware. Maybe the power system was feeding the computer the wrong amount of electricity. For days and then weeks the puzzle continued.
MORGAN: Eventually, we got to the point where all of the easy things didn’t work, and that’s, I think, when everybody sort of started to have the real pit in their stomach that this was, this wasn’t our normal anomaly that we can recover from in just a few days. This was a massive issue.
PADI: NASA doesn’t plan to send astronauts back to Hubble. If Hubble was going to get back online, it was up to the people on the ground.
JACOB: Fortunately, Hubble has some fail-safes built in. Some of its key systems have redundant, backup versions. If the first one fails, you can shut down almost everything, switch to the backup, and turn it back on. This is a leap of faith, because if you shut down Hubble’s science computer, what happens if you can’t turn it back on? After weeks of studying the problem and running simulations to see how Hubble would respond, the team decided to make that leap.
MORGAN: And even when we did that, this was, in a certain sense, just another test, like, let’s hope that this switch is the one that works. And it did, fortunately.
PADI: On July 17, 2021, after more than a month offline, Hubble picked up right where it left off.
[Music: A Gentler Journey by Nick Herbertsen, Tord Jungsten, and Danny Cullen]
Over its lifetime, Hubble has taken 1.7 million observations and scientists have used Hubble data for more than 22,000 research papers. And thanks to the operations team, those numbers are still climbing.
MORGAN: We work really hard to keep it going just as long as we can, just as efficiently as we can. We know how special it is to everybody
PADI: After 35 years in space, Hubble has a lot left to give. As long as the telescope keeps flying, the operations team will be there, making sure the rest of us can see the universe through Hubble’s eyes.
JACOB: Today, NASA has a whole fleet of observatories in space. They collect data about the universe in as many different ways as we can manage, including visible light, infrared, ultraviolet, X-rays, and gamma rays. There’s the James Webb Space Telescope, showing us unprecedented detail from the early days of the universe. And when it launches in a couple of years, the Nancy Grace Roman Space Telescope will shed new light on dark matter, dark energy, and other mysteries. I wanted to know how scientists use Hubble today with these other, newer telescopes. So I got ahold of Brian Welch. He’s a NASA astronomer.
BRIAN WELCH: Because this is the Hubble 35th anniversary, I found a Hubble 20th anniversary pin in my office when I moved into that office, like, three years ago, so I figured I would wear that.
JACOB: That’s perfect. Is it just a picture of Hubble?
BRIAN: Yeah, it’s just a little engraving of the telescope and the year 1990 to 2010. So yeah, it’s been in there for a while.
[Music: Always Onwards by Peter Lavoz and Harry Collins]
JACOB: Brian used Hubble to discover one particular star called Earendel. It’s the most distant individual star ever observed. In fact, the light we see from Earendel traveled for almost 13 billion years before it eventually bounced off of Hubble’s instruments. Brian will explain in a minute how he found Earendel—and why he’s going to keep studying it.
Like me, Brian remembers looking at Hubble images when he was a kid and feeling a sense of wonder. He says today, working with Hubble, wonder is part of the job.
BRIAN: In truth, there’s a lot more math involved, but there’s still a good amount of just pulling an image up on my computer, staring at it and pointing at things and saying, “What is that?” and then trying to figure it out from there.
JACOB: Why do you think Hubble is so impactful, like, even on a level where kids can understand?
BRIAN: A lot of sciences, kind of take a lot of data, and it takes a lot of work to understand what you’re looking at and what you’re seeing in that data. But one of the wonderful things about Hubble is that anyone can look at these images and be in awe of the beauty of the things that we’re seeing, and you don’t need that math background, you don’t need the deep understanding to see that this is something incredible in the universe that we’ve been able to capture with this incredible telescope.
JACOB: Well let’s talk about one specific way that you’ve used Hubble. We’ve got a picture pulled up here in our studio. And to start, why don’t you just tell me what we’re seeing in this picture?
BRIAN: Yeah. So this is an image of a galaxy cluster. So all of those fuzzy yellow blobs that you’re seeing around the image are galaxies within this cluster. You can think of a galaxy cluster kind of like a city of galaxies. It’s this very dense region where you’ve got hundreds to thousands of galaxies all sort of living in the same small area. They’re some of the most massive objects in the universe. And all of that mass, in this case, happens to create something that we call a gravitational lens.
[Music: Set in the Sky by Nicholas Smith]
So the mass actually warps the space around it. And so when you have an object behind the galaxy cluster. The light from that background object moves through the warped space and kind of acts like it’s moving through a glass lens, so that light gets distorted and it gets magnified. And what we have in this image is a case where there’s a very small object within one of these galaxies that turns out to be an individual star that is magnified by thousands of times. So we’re seeing it thousands of times brighter than we would normally be able to so we can actually pick out the light from just this one individual star from the rest of the galaxy, in a way that is really difficult to do without the aid of that gravitational lens.
JACOB: So you have—there’s sort of like us, there’s this big cluster of very massive galaxies, and then there’s whatever’s beyond it, kind of all in a row. And the galaxies are so dense that we can almost like see around them, to see whatever is behind them, right?
BRIAN: Yeah, exactly. You can kind of think of it like looking through glass that has different shapes. Honestly, the best example is like the bottom of a wine glass. That’s kind of the closest analogy to how the gravitational lens actually warps the space. So if you look at something through the bottom of a wine glass, it starts to bend. You start to get these really long arcs. If you hold the bottom of a wine glass up to a light, it almost looks like it’s making the light into a little circle around the base of the wine glass.
JACOB: Huh. So this image we’re looking at, there’s a helpful guide on the image, because there’s an arrow pointing it, one little dot of light. What’s special about that one little dot of light?
BRIAN: That little dot of light is the most distant star that has been observed so far. So it’s an individual star that we’re seeing within the first billion years of the universe. So it’s so far away that it’s taken the light from that star about 13 billion years to travel from where it originated to our telescopes. So it’s sort of incredible that we can see something so small and so distant in the universe. And it’s very special to me, because it’s sort of the first big discovery that I had, and it’s been a really exciting thing to get to work on.
JACOB: I’m trying to imagine what it must have been like for you to, like, realize this. Was there some kind of, like, eureka moment, like, as you’re pouring through everything?
[Music: Praxis I by Alexis Francois Georges Delong]
BRIAN: Not so much a eureka moment as, is this possibly something like this? Could this really be true? sort of moment. At first, we kind of thought there’s no way that could be real. And we kept modeling. There were several weeks where I was just creating more and more models, tweaking more and more parameters, trying over and over to see if I could make something that explained all the data that we had. And it turned out that the more we tried, the more it stuck around. It was a bit of a slow burn, but eventually we convinced ourselves this looks like something that is actually real.
JACOB: What tells you that that star is so far away, so much farther away than everything else in the image? Because looking at this 2D image, you know, everything looks kind of the same distance to me.
BRIAN: The way that we initially figured out the distance was just through the colors. Objects that are further away are redshifted because the universe is expanding. So basically, as the universe expands, light travels across this expanding space and kind of gets stretched out. You can think of it kind of like, you know, if you draw a line on a balloon and then inflate that balloon, that line could go from, you know, one inch to two inches to three inches, depending on how much you inflate the balloon. The same thing happens to the wavelengths of light, and as they get stretched out, they appear redder and redder. We can figure out what’s called the cosmological redshift of the galaxy. And that is a thing that is easy to measure from just these images but also very tightly correlated with the distance to the object.
JACOB: Wow. Did you get to pick the name of this star?
BRIAN: I did, yeah. We had a few different candidates, but ultimately I got to choose it, and got to pick the name Earendel, which is an old English word that means “the morning star”. And it is also a bit of a Tolkien reference. I am a bit of a nerd in many ways, so I originally came to the name from the Tolkien character Earendel, who basically takes one of the Silmarils in The Silmarillion and gets to fly around in space with it. And so I thought that was a very fitting name. And then I went and started researching the background of that name and where Tolkien got it from and found that it was based on this Old English word that meant “the morning star”, and that just fit in so well that I figured that that was the name we should go with.
JACOB: Wow!. Have you gotten feedback from other Lord of the Rings fans who are like, “Thank you”?
BRIAN: Yeah. No, people are very excited about it. When the paper was first published and the sort of first press releases came out, I did start getting a whole bunch of emails from people just saying, like, Hey, I’m a huge Lord of the Rings fan, and this is really awesome to see this name. So I think there’s definitely some, some nerd credit there for choosing this name.
JACOB: Finding the farthest star is a very cool record. I’m curious also, what’s the scientific value in in setting that benchmark?
BRIAN: Yeah. So in addition to just the fact that it’s very cool to be able to see something this far away, Earendel is a particularly massive star.
[Music: Final Layer by Alexis Francois Georges Delong]
These very massive stars are quite rare and form in very different ways and in very different conditions than some of the lower mass stars that we see much more commonly. So in nearby galaxies, these very massive stars that we see are all things that have formed very recently and therefore have been enriched with the products of previous generations of star formation. So all of the heavy elements that stars make in their core through, you know, nuclear fusion as they live their lives, eventually get recycled into future generations, and so all the stars we see forming around us recently have a whole bunch of those metals. In the early universe, that’s not necessarily the case. There have been a lot fewer generations of stars, and so there’s a lot less of those heavier elements floating around. There’s a lot fewer metals that go into the star, and that can really change the way that stars work. You know, finding an example of a star like this and being able to study it in detail is a really unique opportunity to directly measure if these massive stars are different in the early universe compared to the massive stars that we see nearby.
JACOB: You discovered it first with Hubble data. Eventually you went back and were able to collect more data with the James Webb Space Telescope. What did you learn that you might not have been able to know with just one telescope or the other?
BRIAN: Yeah, so the Hubble telescope was instrumental in discovering the object. One of the big reasons for that was the Hubble was able to get a sort of survey of a whole bunch of these gravitational lenses. So the project that the original data came from looked at over 40 gravitational lenses with Hubble basically aiming to find some of the most interesting, most unusual objects behind these gravitational lenses. But Hubble cuts off in the near infrared. It can’t go much redder than that, and for something like this at very high redshift, most of the light has been shifted into that near infrared to further into the infrared wavelength range. So that’s where the James Webb telescope has really helped. The things that we’re seeing with James Webb are the light that we would be able to see with our own eyes if we were actually in the vicinity of this star, but it’s just been shifted so much that that appears in redder wavelengths that are too red for Hubble to pick up.
JACOB: All of us at NASA—and hopefully everyone who hears this—is in awe of the James Webb Space Telescope. NASA’s getting ready to launch the Nancy Grace Roman Space Telescope, which is going to be another big one, and Hubble’s still up there doing science. And I’m just curious, from your perspective, why Hubble is still a valuable tool, even with these, like, new kids on the block?
BRIAN: In terms of relation with the James Webb and Nancy Grace Roman telescopes, both of those are designed to operate in the infrared. So James Webb goes from the near infrared out through the mid infrared. The Roman Space Telescope is primarily in the near infrared. Hubble is different because it operates in the near ultraviolet through the near infrared, so all bluer than what these new kids on the block are doing. It is also the only flagship-level observatory that has any ultraviolet capability at the moment. That is particularly important because you can’t observe in the ultraviolet from the ground. Once you go into the ultraviolet, our atmosphere blocks all of that. That’s very good news for us, because ultraviolet radiation is very harmful to living things, so it’s very nice that we don’t have to deal with that.
JACOB: I’ve gotten enough sunburns to know, yeah.
BRIAN: Scientifically, we need those ultraviolet photons to be able to understand the sort of high energy level processes. These are sort of things that are created by massive stars. These are things that are created in young star-forming galaxies. So to be able to understand how all of those processes work, we need that ultraviolet capability, and that’s something that Hubble is very unique in being able to deliver. Beyond that, with the optical and near infrared capabilities that it has, it delivers incredibly sharp images. It gives us incredible resolution. So we can see these very small-scale features in distant objects. We can see all kinds of detail that is really difficult to get from any other instrument.
JACOB: What does it feel like now to be working with this telescope that you saw images from when you were a kid?
BRIAN: In some ways, it’s a little bit surreal.
[Music: Infinity by Clément Durand]
It’s, you know, kind of a scenario of meeting your heroes, in a way, but in the best possible way where, you know, I kind of saw these images when I was growing up when I was a kid and was kind of amazed at how much detail you could capture of something that is so far away and how much we could learn from all of these images. And now I get to be one of the people taking this data and, you know, learning from it and working with it in the closest possible way. It’s been very exciting to, you know, kind of get to grow up with these images and now be working on data from this telescope. Yeah. I feel very lucky
JACOB: If you could boil down into one or two sentences, why Hubble is so iconic. What would you say
BRIAN: Into one or two sentences is tricky …
JACOB: Ish.
BRIAN: … because there are so many ways. Just for fun, before this interview I was looking up some of the proposals for Hubble’s first cycle of observations on the first year that it was taking data. And one of them that I stumbled across was saying that they were looking at very high redshift galaxies, which, at the time in 1990, meant redshift 2.5, which would be two or 3 billion years after the Big Bang. Hubble drove that frontier back to redshift 10, which is about 500 million years after the Big Bang. So it gave us, like, 2 billion years of cosmic history that was just unknown before. And that’s just one example. I’m sure the people who built the telescope had no idea that one day it would find an individual star within the first billion years of the universe. And so many other discoveries that have been made are kind of things that we never saw coming, but this instrument has just been so incredible that it has given us so much more than we could have possibly asked for.
JACOB: Brian Welch, thank you so much. This has been super fun.
BRIAN: Yeah, thank you. This has been great.
[Music: Curiosity by SYSTEM Sounds]
PADI: This is NASA’s Curious Universe. This episode was written and produced by Jacob Pinter. Our executive producer is Katie Konans. The Curious Universe team also includes Maddie Olson, Micheala Sosby and Christian Elliott. Krystofer Kim is our show artist. Our theme song was composed by Matt Russo and Andrew Santaguida of SYSTEM Sounds.
Special thanks to the Hubble outreach team, including Elizabeth Tammi and Jim Jeletic. There is a whole universe of information about the Hubble Space Telescope—including beautiful images and deep dives into the technical parts of the telescope—at nasa.gov/hubble.
As always, if you enjoyed this episode of NASA’s Curious Universe, please let us know. Leave us a review, and send this episode to a friend who needs more wild, wonderful adventures in their life. And remember, you can follow NASA’s Curious Universe in your favorite podcast app to get a notification each time we post a new episode.
BRIAN: Tips for a Lord of the Rings movie marathon. Have lots of snacks. You’ve got to have some po-tay-toes. My wife also recently made me a cloak, and it is incredibly cozy. So if you have the chance to make a cozy wool cloak and just kind of curl up with that and some second breakfast and watch all of the movies, that sounds like a fantastic weekend to me, honestly.
AUDIO TAG: This is an official NASA podcast.
