Which came first, the galaxies or the stars? New space telescope may answer cosmic riddles.
Dec 24, 2021

Which came first, the galaxies or the stars? New space telescope may answer cosmic riddles.

The James Webb Space Telescope, scheduled to launch on Christmas Day, is much more powerful than the Hubble, says Nobel laureate Adam Riess.

Many in the science community, and fans of space and science in general, are awaiting the launch of the James Webb Space Telescope, scheduled for Saturday, Christmas Day.

NASA and other space agencies have been working on this mission for more than two decades. Webb is much bigger, and more sensitive, than the well-known Hubble Space Telescope, which has already given us breathtaking images of our cosmos.

So, what can we expect from Webb?

Adam Riess is here to break down the science for us. He’s a professor of astronomy and physics at Johns Hopkins University and a winner of the 2011 Nobel Prize in physics.

He told me that for people in his field, this mission is kind of like the Super Bowl. The following is an edited transcript of our conversation.

Adam Riess: It’s a challenging mission. In particular, the first 30 days. There are a lot of deployments that go on as this telescope unfolds, sort of like origami, and just all of those going smoothly.

Kimberly Adams: What’s different about the James Webb Space Telescope, compared to say, the Hubble telescope?

Riess: Our ambitions are great. We want to see deeper into the universe. And so we really needed to build something bigger and more powerful. This one needs to unfold to become its great size. So it will have a primary mirror that’s segmented, but that can collect about 10 times more light than Hubble. And then it has extremely capable and efficient instruments that can also collect about 10 times more light than Hubble. And so between the two of them, this is going to be about 100 times more powerful than Hubble.

Adam Riess smiles wearing a blue collared shirt and a black suit jacket.
Adam Riess (Courtesy Johns Hopkins University)

Adams: So assuming everything goes perfectly, how will having access to the data from this telescope change the way that you work?

Riess: Well, there are many questions that we have sort of pushed to the limit of what Hubble’s capabilities are after some 30 years. And yet, our quest to understand at a deeper level goes on. And while it’s great thinking about the answers to those questions, there’s nothing quite like taking a look. With a more powerful telescope, we will get to the bottom of certain questions that we have about the universe that just really keep us up at night.

Adams: What’s the first thing you want to look at?

Riess: One is the old, you know, what came first, the chicken or the egg? But in our understanding of the universe, it’s really what came first, galaxies or stars? And so we will take deep images back toward the beginning of time, and see literally which came first. We will begin to break down and understand what the atmospheres of planets around other stars are composed of, and ultimately, whether those could support life. And then we will follow up on some of the biggest and most baffling discoveries from Hubble, like the fact that the universe seems to be expanding faster than we can understand. And [the] James Webb [telescope] will help us sort of follow that up and get more answers to that.

Adams: You said, looking back into the “beginning of time.” Can you explain that a little bit more?

Riess: Sure. So this is not something that we’re familiar with every day. But when we look out, even here on Earth, we look at things, we are seeing them the way they were just a short time ago. It takes light a little while to reach us. Nearby objects are so close that that delay is really negligible. But once we start looking across the universe to these great distances, we can see that delay becomes millions to billions of years. And so by looking far enough out, if we have that capability, if our telescope is powerful enough, we can look further and further back in time. And so telescopes are really time machines, and more powerful telescopes bring us closer and closer back to the time shortly after the Big Bang.

Adams: And this has also to do with what colors the telescope can see. Correct?

Riess: That’s correct. So that very ancient light that travels to us, that light is what we call red-shifted. The wavelengths are expanded by the expansion of space. And so in order to see that ancient light, we need to chase it towards those redder wavelengths, we need a telescope that is optimized in order to detect infrared or far-infrared light, and so the James Webb Space Telescope has that capability. One of the main reasons is because it’s kept extremely cold. You need a very cold telescope so that the ancient light you’re looking at is not swamped by the glow of the warmth of the telescope itself. So, by being extremely cold, by having a very large surface, and by having very sensitive instruments, we think we can capture the light from those first galaxies and stars to turn on.

Adams: You know, you often hear people talking about space mentioning that there’s more technology in your iPhone than what took a person to the moon. Can you give us a scale to understand the amount of technology in this telescope?

Riess: Wow. Well, so much of the technology is really unique to this telescope. It’s hard to exactly quantify having a sunshade that’s as big as a tennis court, and then five layers of that but incredibly thin that can unfold by itself without intervention by astronauts. I mean, that is incredible, but it’s unique technology. Of course, lots of times we learn things from the technology that helps us develop new technologies for more consumer use, but most of these things that NASA has developed for this are really sort of one-offs.

Adams: You won the Nobel Prize in physics back in 2011 for your findings about the acceleration of the universe.

Riess: That’s right.

Adams: Are you at all worried that the Webb telescope might prove you wrong?

Riess: [Laughs.] Well, I’m not giving the prize back, if that’s what you’re asking.

Adams: [Laughs.]

Riess: But no, this is the quest of science. I mean, anybody who signs up to be involved in science understands that this is a living, changing field. This is not history, it’s science. And so we will learn new things. Almost in all cases, it doesn’t so much invalidate things that we knew before, it just sort of grows and expands upon them. And so, I have no doubt everything we’ve learned from Hubble is relevant. But we will go deeper, we will go farther in our understanding of those phenomenon, and so I look forward to really welcome whatever it is that we discover.

Adams: How will this new data collected by the Webb telescope influence how NASA commits time and resources, and also how the growing private space industry commits its time and resources?

Riess: Our view of space and how best to either exploit it or learn from it really does change over time. I mean, you pick up a textbook from 30 years ago when Hubble started versus now, and they look completely different. A lot of what we do is based on those discoveries and follow up. For example, when Hubble was first launched, we did not yet know as a fact about planets around other stars, we had not yet discovered those, nor had we discovered dark energy, which makes up about 70% of the universe. And now many of our upcoming missions are actually dedicated to studying those. So there’s dramatic evolution as a result of these missions, not to mention, year by year, as we allocate the time, we allocate it based on what was learned in the prior year or years. So there’s dramatic changes, and there will be changes as a result of what we learn from the James Webb Space Telescope.

The James Webb Space Telescope in a folded, horizontal position after being removed from a packing container. (Chris Gunn/NASA)

Related links: More insight from Kimberly Adams

There is so much good reporting and writing on the James Webb telescope. NASA, of course, has a whole section of its site dedicated to Webb. There you can find lots of images of the telescope, details about all the instruments it’s carrying and information on the hundreds of scientists around the world who’ve been preparing this launch.

Space.com also has a good write-up in easy-to-understand language about just how much new technology had to be created for Webb and the stakes if any of it doesn’t work.

That’s a point that also comes up on a promo video featured on the NASA YouTube channel just for the mission.

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