Quick Take
UC Santa Cruz Astronomer Emeritus Garth D. Illingworth is one of the original thinkers behind the recently launched James Webb Space Telescope. For UCSC Professor of Astronomy and Astrophysics Brant Robertson, the promise of the Webb telescope encouraged him to pursue astronomy. Both talked to Lookout about what this moment means for them.
UC Santa Cruz Distinguished Professor and Astronomer Emeritus Garth D. Illingworth has been waiting for this moment for more than 30 years. On Tuesday, he attended the NASA reveal of the James Webb Space Telescope images at the Space Telescope Science Institute in Baltimore, where he and about 150 people saw the images on a “huge screen” and several people spoke about them.
“It was an absolutely remarkable moment,” he told Lookout Tuesday, of the first images released from the James Webb Space Telescope (JWST) that this week have given scientists a glimpse into what happened in space more than 13 billion years ago, just a few hundred million years after the Big Bang. “Absolutely amazing. They’re wonderful images. The scientific value of this is just out of this world.”
Illingworth, who taught at UCSC in its highly ranked astronomy department between 1988 to 2018 served on the team that came up with the main ideas behind the James Webb Space Telescope in the 1980s – years before the launch of its predecessor, the Hubble Space Telescope. Today, he continues to be part of the JWST, alongside another UCSC Professor of Astronomy and Astrophysics, Brant Robertson.
“We’re trying to discover the earliest galaxies we can possibly find in the JWST data,” Robertson, explains from his UCSC office. For almost seven years, Robertson has taught at UCSC and leads the Computational Astrophysics Research Group.
Both continue to be highly involved with Webb.
Robertson helps lead the COSMOS-Webb galaxy survey and JWST Advanced Deep Extragalactic Survey (JADES) while Illingworth will be the U.S. lead for PRIMER and another international Treasury Program (FRESCO). Those projects are among the 286 projects (General Observer Programs), selected out of 1,000 proposals for use of the $10 billion telescope in its first year.
Both scientists focus on finding the universe’s first galaxies. Three additional broad areas of interest include how galaxies change over time, the lifecycle of stars, and planetary systems.
Lookout talked to both about their exhilarating work:
These interviews have been edited for clarity.
Can you describe how the James Webb Space Telescope compares to the Hubble Space Telescope?
Brant Robertson: Most of us grew up with the Hubble Space Telescope as the premier observatory. That’s certainly what I did. Thirty years ago or so, I was in school when I watched it launch on TV. And so we’ve learned about our universe through many facilities, but also through Hubble, which has provided these amazing images for so long.
Hubble is only so big; it’s about 2.4 meters in diameter. The power of the telescope to look back in time and to collect data is limited by the size of the telescope. They put Hubble into space and above the atmosphere because the atmosphere distorts the light so you get a very crisp picture, if you’re in space, but the size of the mirror is not very big compared to most telescopes on Earth. With the James Webb Space Telescope, now we have a 6.5 meter – 21 foot – mirror, and so it can collect much more light than Hubble could. And this allows it to be very sensitive so we can see extremely faint things that are very far away.
But also it’s sensitive to infrared. So light as it travels through the universe, the universe is expanding, and that stretches out the light. So light that is emitted in the optical (meaning using the visible part of the electromagnetic spectrum) that we see with our eyes, gets stretched into the infrared as it travels to us from great distances. So when you look really far back inside really far away. galaxies that are bright in the blue, they’re either optical light or even ultraviolet light, that light as it travels to us gets stretched so much that it arrives to us here on Earth in the infrared. Hubble had limited infrared capability.
What is your favorite image and why?
Robertson: I do have a favorite. I think they’re all absolutely stunning. But I think my favorite is actually Stephan’s Quintet, the collection of merging galaxies. It’s because there’s just such a richness in the infrared that you don’t see in the optical.
We’ve seen this before with all of these before with Hubble. And in every case, the JWST image absolutely outshines what we saw with Hubble. It’s just opening a new view on the universe. I’ve seen the Stephan’s Quintet picture thousands of times. Being able to see something that’s so familiar – that you love in an entirely new light, an entirely new view of something that is really something that you’ve always thought was amazing just knowing that it’s so so much more than you thought it was – that was the experience I had when I saw Stephan’s Quintet.I’m just speechless about it. I said stupid things like ‘Wow.’
I mean, it’s fine to be amazed, but I’m supposed to be like a professional here. The images are really so stunning that it’s beyond me, to summarize in a few words. For an astronomer, it’s emotional because you really are seeing something that you thought you knew, but then realizing yet again, the universe has so much more to teach you than you already know.
Why are scientists so focused on understanding the earliest galaxies?
Garth Illingworth: When we were designing and thinking about what the Next Generation Space Telescope (the Webb telescope’s previous name) could do in the 90s, we realized that searching for the earliest galaxies was something that it would be absolutely uniquely suited to do. As long as it was a big, cold infrared telescope in space where we now had a really dark sky, we weren’t looking for a daylit sky to try and find objects.
Hubble has been amazing with what it has done. But it just can’t penetrate, and go out as far in the universe. So that is certainly one of the major drivers, and it was what the telescope was sold on in the late ‘90s, to NASA, and to Congress...The very earliest galaxies, baby galaxies forming 13.3 billion years ago, 13.4 billion years ago, just a few 100 million years after the Big Bang, the universe is 13.8 billion years old. And we think the first galaxies probably formed around two to 300 million years later.
We can actually look back in time, the light has taken so long to reach us that we can see back in time as it were 13.5-6 billion years with Webb. We don’t quite know how far we can see back here, because we don’t really know what’s happened back there. It’s going to show us tiny little red dots and these images that are the very earliest galaxies. And these are the sort of seeds from which our Milky Way is formed. From little tiny ones, and then they combine together, and they grow, and they have four more stars, and then they combine together with others and eventually make up the massive big galaxies like our Milky Way.
So Webb will not only, I think, find the very earliest galaxies it will help us map over the whole of all time, how galaxies have come together and grown and formed stars and grown again, and combined again and interact and bang together and become one. And so you have this sequence of activities that brings about the galaxies like our Milky Way. So that’s another one of the areas that we would come to understand. It’ll be great to do. But we can come from the whole distance through the universe right next to our near sky, and look at planets around them, and Webb will be great for that.
How do you think JWST could impact our understanding of humanity and our place in the universe?
Illingworth: So I think one of the things that make you know, Hubble has had a huge impact on the culture in a way. People know about it, they love the images, and they like the stories that come from it. I think it all revolves around origin.
Regardless of our backgrounds, our political affiliations, humans are just interested in where we came from, and what that history was. And what our place in the universe is and telescopes like Hubble have helped us along that path. I think Webb is going to add dramatically to the understanding of our origins and how we came about. Not only just as people, which it won’t do directly of course, but life on other planets, how planets themselves formed and the stars formed, that Carina Nebula is all about places where stars are forming, and planets are going to be forming in there.
It’s this sort of connection to, ‘How does the sun come about’? ‘How did our earth form?’ We’re part of the Milky Way, ‘How did that actually come about?’ And so it’s this deep sequence of questions about our origins, which will take us right back to the Big Bang. I think that plays a very important cultural role. We just have this deep-seated longing to try to understand where we came from. It’s pretty universal, and people just get fascinated by this everywhere. I think that’s sort of a cultural aspect that brings people together. When you think about it, it does cost a huge amount of money, but in fact, I think it’s a bargain. An absolute bargain.
