Andrew Fraknoi: THE JAMES WEBB SPACE TELESCOPE

What Makes The

Webb a pioneering instrument, what the first images actually show, and what scientists expect it to accomplish in the years to come. Excerpted from the November 30, 2022, Technology & Society and Humanities Member-led Forums program “The James Webb Space Telescope: Andrew Fraknoi Explores Our Giant Eye on the Invisible Sky.”

ANDREW FRAKNOI, Chair Emeritus, Astronomy Department, Foothill College; Former Executive Director, Astronomical Society of the Pacific; Lead Author, Astronomy

GERALD HARRIS, President, Quantum Planning Group; Chair, Technology & Society Memberled Forum, The Commonwealth Club of California—Moderator.

ANDREW FRAKNOI: It’s my pleasure tonight to talk to you about one of the most exciting things going on above our heads, which is the James

Webb Space Telescope, which really is a giant eye on the invisible sky. I want to show you some of the work it’s already done.

The James Webb Space Telescope was launched on December 25th of last year after years of delay and problems. The most complex telescope we’ve ever launched into space, and it’s operating, I’m happy to say, flawlessly, a million miles from Earth [operated via] remote control across all that distance.

But the story of the telescope really begins in the year 1800, when an amateur astronomer and musician by the name of William Herschel discovers that there are invisible rays coming from the sun. Herschel was a great experimenter, and he was playing around with a prism. You’ve played with a prism, where light goes through the prism, it goes out in all the colors of the rainbow. He wanted to measure the temperature of each color of the rainbow; so he took a thermometer and carefully measured, and then he got to the red color and he went beyond the red color and the thermometer still kept going up in temperature. He said, “Whoa.” He started again, and he went beyond the red color, and the thermometer kept going up.

Something invisible was heating up the thermometer beyond the red, below the red. So this eventually got known as infrared, just like infrastructure is stuffed below the street. Infrared is a color below the red, and he discovered the first invisible rays coming from the sun of the infrared world.

The infrared universe turns out to be quite different from the universe you know with your eyes. And that’s what I’m here to talk about tonight. Now, in fact, his discovery was only the beginning. It turns out that the universe shines with a great array of different invisible rays, and the light we see with our eyes is an incredibly small minority of the ways that the universe can shine. So we’ve had to develop telescopes and instruments for each of these other kinds of waves.

Gamma rays, x rays—which you know from your dentist—ultraviolet, infrared, microwave, radio, television, the cell phone frequencies that you use, wireless— all of these are invisible rays that inform us about what’s going on in the universe. And because many of these rays are actually absorbed in the atmosphere, we put telescopes above the atmosphere to tell us what’s going on. The infrared is certainly one of those where we need to go into space to get a good view.

Now, we already had a good telescope in space, the Hubble, but it’s now more than 30 years old and its mirror size was limited by the size of the payload bay in the space shuttle, which launched it.

The James Webb Space Telescope was launched folded, and it had to unfold like petals. Once it got to its destination, that was our biggest scare: What if it didn’t unfold? But it did. It unfolded beautifully.

The bigger the mirror, the more energy, the more kind of light or infrared you can collect. The primary mirror consists of 18 hexagonal segments made of beryllium coated with gold. Now, they’re not just coated with gold, because it was a government project. Gold is actually a very good reflector of infrared, and so we use gold in a very tiny layer to reflect the kind of light we want to see.

The 18 segments have to be aligned perfectly to within 1,000th the width of a human hair. We know how to do this for mirrors we’ve already played with on Earth.

The Webb telescope is four times further from the Earth than the moon is, so it’s roughly a million miles away from Earth. It’s at a stable point where the pulls of the Earth, the moon and the sun are balanced in the right kind of way so that we can orbit the sun and keep the Webb in our view. When it all unfolded and got organized, it’s the height of a three-storey building. Just the heat shield below the mirrors is the size of a tennis court. The whole thing weighs seven tons. The sun shield keeps the sun’s energy away from the heat-seeking telescope so well that it can stay at an operating temperature of -370 degrees Fahrenheit. Don’t try to do that in your own refrigerator.

In fact, the whole setup with the cooling and everything that had to happen, NASA reported that [there were] 344 single points of [potential] failure in the process of setting it up, and every one of those worked. So let’s hear it for NASA; they don’t always do things well, but this they did great.

So the setup [of the telescope]: Basically, infrared energy comes in, hits [a] gold mirror, bounces to the secondary mirror.

You [can] see through the hole in the middle of the gold mirror to the scientific instruments which are behind it. It’s those scientific instruments that then analyze the light, make pictures for our eyes to see, and tell us what’s going on in the infrared universe. The sunshade is always pointed at the sun and keeps the sun’s heat from interfering with the delicate measurements we want to make.

Light Show

Infrared can show us things that we don’t even suspect are there.

Firefighters use infrared scopes so they can peer through the smoke and see what’s going on. In the same way, we peer through the smoke of the universe, through the dust of the universe, to see what’s going on in ways that visible light can’t show us.

. . . We get waves of energy coming from the universe to tell us what’s going on. And those waves travel at the speed of light. Infrared is also something that travels at the speed of light. That speed is 186,000 miles per second, which in your more familiar units is 670 million miles per hour. Everything we know about the universe tells us that that’s the upper speed limit of how fast things can go. And although it’s extremely fast, we live in a big universe, and therefore it takes a while for information to get here. That delay is a lot of what I want to talk about tonight. We use a measure of distance called the light year, which is the distance that light travels in the course of a year. So we can all do the math together: 186,000 miles every second times 60 seconds in a minute, 60 minutes in every hour, 24 hours in a day, 365 and a quarter days per year—you’ve all done this in your head—and the answer is 6 trillion miles. The distance that light travels in one year is 6 trillion or 6,000 billion miles.

Now, you might say that’s a lot, but the nearest star, which we call Alpha Centauri, is four light years away. So 25,000 billion miles. Okay. So four light years away from the nearest star; all the other stars are even further away. So it’s going to be some delay before the information gets here. Betelgeuse C is part of the constellation of Orion the Hunter. Betelgeuse is one of the brightest and easiest-to-see stars in the sky, but it’s about 600 light years away, which means the light we see tonight left Betelgeuse 600 years ago and the news we get is 600 years old.

All right. That’s the star picture. It gets even worse with the galaxies. If you now look at how the stars are organized into these giant galaxies and you look for a major galaxy, a galaxy you can bring home to mom with pride, our closest major galaxy neighbor is two and a half million light years away. So that means the light we see tonight from that galaxy left there two and a half million years ago. And it’s two-and-ahalf-million-year-old news now. CNN fans say “This is unacceptable; I want to know what’s happening right now.” But you can’t see what’s happening right now. There’s a delay built into the universe because of the speed of light. And for astronomers, this is wonderful, because what do you guys expect us astronomers to be able to do? You expect us to tell you the story of the development of the universe over billions of years? How could we possibly do that? The only way we can do it is by looking at things really far away, where the light has been on its way to us from billions of years ago, and can therefore tell us what was happening billions of years ago.

The further away from us we look, the longer the light took to get here and the further into the past we’re able to look. And we built the James Webb Space Telescope to look really, really, really far into the past.

Jupiter dominates the black background of space in this image from JWST. The image is a composite, and shows Jupiter in enhanced color, featuring the planet’s turbulent Great Red Spot, which appears white here.

Seeing the Universe

The first Webb telescope image was released at the White House. It was a really awkward ceremony where no one quite knew what to say. [See photo on page 31.] You’re looking at really distant galaxies, tiny little dots, each of them consisting of billions of stars, but so far away they look like little dots. But that’s the game here with the James Webb telescope. We can see really far back into the past. There are, we think, objects on this picture looking almost back to the beginning.

Stars, like people, have lives with stages. I divide the stages of a star’s life into these categories because they parallel what people do. There’s the prenatal stage; the birth of a star; adulthood, which lasts a long time; then a mid-life crisis for every star; old age, where the star kind of falls apart; and then death. Eventually you put the star in the stellar graveyard. Each of these stages has been understood, not for the sun, which is doing everything very slowly, but by looking at stars in different stages of their lives.

What the James Webb telescope is especially good at is the first two stages: prenatal star formation and then the birth of stars. We have great hopes for really learning a lot about how a star is born. That’s great, because adult stars we see quite well with the Hubble. It is stars that are so faint and so shrouded with their birth material that we can’t see them with the Hubble—and that’s where the Webb specializes.

Star birth is often hidden. The constellation of Orion [can be] seen with our eyes and a good telescope. Lots of stars, bright stars, make up the constellation figure. But you see mostly stars in visible light. [In] the same scene in infrared, what you see is the hidden raw material of stars, the stuff from which stars and planets and maybe even future Commonwealth Club members are formed. You see literally the dust, the dirt and lots and lots of gas, which transforms itself through gravity into stars and planets. The infrared shows you; the visible light does not.

So let’s take a look at one such region of star birth called the Carina Nebula. Stars that were born inside this cloud of raw material began to shine, and that light illuminates the raw material. You can see glowing clouds, because stars have been born inside those clouds and their shine makes the cloud shine.

But I want to show you a specific region a little distance away from the main nebula. [It is] a young cluster of stars that formed relatively recently; they’re only about 12 million years old, which for astronomers is really young.

There’s a kind of cavity that you see here. . . . At the bottom left, you can see winds from the star are pushing at that cavity. [Even with] a Hubble picture with some exaggerated color of this little piece of this starburst region . . . we see some beautiful things. We kind of see a wall of dust from the bottom and then some gas glowing in blue at the top. With the James Webb Space Telescope, you can see that what looked like a region mostly of dust has actually got a lot of holes in it and many more stars.

These stars shine more with infrared and not so much with light. So we’re looking into the cloud, seeing baby stars in the process of being born and seeing a lot more detail in the clouds of raw material. Pictures like this are going to give us a much better understanding of the first stages in the life of a star.

So here is another nebula called the Tarantula Nebula. What [you can see] is a huge region, 340 light years across, and you can see that there’s all this dust, which is gaseous material. In the middle [is] a cluster of stars. That cluster was born very recently. It’s energy is pushing out the center of the cloud, excavating, if you will, a cavity in the middle. And those cavities tell us that some pretty energetic adolescent stars are in the middle. Just like teenagers have way too much energy, these young stars have way too much energy and push out the material from which they formed. As they do that, they compress the material, they push it out and compress it. And from compression comes more gravity, comes more stars being born. So we’re seeing some beautiful images of star birth. They nicknamed it the Pillars of Creation. And it looked pretty good with the Hubble. But the Webb . . . just makes the Hubble pictures look pathetic in comparison. [See Pillars of Creation image on the opening spread of this article.]

Those young stars are not yet hot enough to give off light, many of them, but they glow distinctly in the infrared colors that the Webb is sensitive to. Then they took another picture at a particular color and wavelength range where those stars are not visible and the dust glows. You can see that those same pillars are thick with dust full of raw material, even though they look a little bit transparent [when viewed in different wavelengths].

So depending on which kind of wave you’re looking at with the Webb, you get information about different parts of the picture, young stars [in one], raw material and particularly dust [in another wavelength]. These pillars, by the way, are 4 to 5 light years tall. So you’re looking at vast amounts of raw material and lots of star formation going on.

Planetary Discovery

Next I want to focus on what is perhaps the most exciting discovery in astronomy in my lifetime, which is that in the last 30 years or so, we’ve discovered that there are planets orbiting other stars.

We always hoped that there would be planets orbiting other stars—Star Trek was built on the idea that the Enterprise would visit a different planet every week—but we’ve never been able to prove it until recently. Now our observations just in the last couple of decades have shown us that there are exo-planets—exo meaning outside our solar system—everywhere we look. The universe is crowded with planets. It’s almost hard to find a star that doesn’t have one. Suddenly exoplanets are the rage in astronomy, and many of these exoplanets are in what we call the habitable zone, where water can be liquid, where temperatures are right, where perhaps life might be able to form. So the study of exoplanets is another area where we have great hopes for the James Webb Space Telescope today.

We already know 5,000 established planets, and more are known all the time. I want to focus in on one particular planet, which is given the terrible name of WASP-39 b. WASP stands for Wide Angle Search for Planets. This is “Target 39” and the planet is called “B.” It’s 750 light years away, and it’s an interest thing.

It’s a planet bigger than Jupiter, but weighs only one quarter as much. So in order to be bigger in size than Jupiter, it must be heated, bloated, kind of all distended. And we now understand why that is, because it takes only four days to orbit its star. What? The closest planet in our own solar system is Mercury. It takes 88 days to orbit our star. The Earth takes 365 days to orbit our star. So four days to orbit is crazy, is disgusting, is impossible. But it is. We’ve now found this with many planets, that there are planets much closer to their star. And WASP-39 b is heated by being so close to its star [and] takes only four days to go around. But because of that, there’s a lot of energy coming from it and we can begin to do studies of it

Just like in the supermarket, a unique barcode identifies each item so they know what to overcharge you for that container of mac and cheese. In the same way, lines and colors in the spectrum of light uniquely identify elements. For us, this is a science called spectroscopy. Every astronomy student spends many years learning about how to spread out the light or infrared of a star, and to understand what the different lines are telling us, just like the different lines in the barcode are telling you different things.

From that we can actually identify what elements, what compounds, what materi- als are in the star or in the atmosphere of a planet. So the James Webb telescope is able to look at the light emitted by the star. Then it can tell that if the light goes through the atmosphere of the planet, as it is in this picture. [Refers to an image on the screen.] The planet is in front of the star. It has a thick atmosphere around it. The light of the star goes through the atmosphere of the planet. The atmosphere absorbs some colors, take some colors out, and that can tell us what substances are in the atmosphere of the planet. By comparing the light of the star without the planet to the light of the star with the planet, we can tell something about what the planet’s atmosphere is made of.

That’s really hard to do when planets are hundreds of light years away. But with the James Webb telescope being so large and precise and out in space, we can do this. I’m happy to report that just this past week, a detailed report was published of the atmosphere of WASP-39 b, and you can see the different substances they have discovered; some of [substances there they discovered] for the first time in the atmosphere of an alien planet.

First of all, there’s water— that’s not new. There’s carbon dioxide. That’s the first unique identification. There’s sulfur dioxide, carbon monoxide. We’re talking about substances that we identify with organic chemistry here on Earth. Knowing what the atmospheres of alien planets are made of can tell us a lot about conditions on the surface and whether or not life might be possible there.

Gravity

Let’s move now to a much bigger realm. I want to take you to the realm of the galaxies, where each object is not a star, but a huge collection of billions of stars, and show you again what the Webb can do.

One of the things that we learned recently about galaxies is that they, too, are social animals. Just like stars gather into galaxies, galaxies gather into groups. This is a small group of five galaxies called Stephan’s Quintet after the discoverer [Édouard Stephan]. You see it here with the Hubble. Actually only four of the galaxies are connected— the four that are yellow; the blue one is an interloper and at a different distance. But this is what we see with our eyes.

Now, [with] the James Webb Space Telescope, you see much more connection between the galaxies, material stretching much further out, material which is actually being exchanged between the galaxies. You see again the raw material, but you see far more interaction and connectivity between and among these galaxies than we could see with visible light. These are the kind of images we’re going to rely on to understand the social interaction of galaxies, the way galaxies not only interact with each other, but ultimately collide—which happens to a lot of galaxies—and merge together into bigger galaxies. We think the galaxies we have today were built up from the collisions [and] mergers of smaller galaxies.

Had [Albert] Einstein been at the White

House [when] the first James Webb image [was] released, he would have been smiling. Why? Because in 1916, ’17 and from then on, Einstein proposed a new theory of gravity—a theory of time, space and gravity which we call the general theory of relativity, a complicated theory which has taken many years for us to fully understand and to prove correct, but which has now been validated in many different ways. One of the things his theory said is if gravity is really strong, it can warp the fabric of space itself. Strong gravity can twist, bend, warp space itself so it no longer behaves the way it normally does in the absence of gravity, but has kind of a bend or warp to it.

If that’s so, then if you have a galaxy with a lot of gravity and light comes through that galaxy from further away to us, the gravity of that galaxy Einstein said might warp, might twist, might bend the light from behind it in weird ways—he proposed that it would be something like a funhouse mirror or lens. Have you been to a funhouse, where you see a reflection of yourself but you don’t look like you? You look like some twisted, horrible-looking thing, because the mirror has warped your your image. That’s what we’re seeing here. We’re seeing things that look like little arcs. These arcs are warped light produced by the strong gravity in this cluster of stars. [Refers to an image showing the arcs in a field of galaxies.] These arcs are the same galaxy from 9 billion years ago, 9 billion light years away, whose light is coming from behind. This strong cluster of galaxies and the gravity of the cluster in the foreground is taking the light from further away and warping it and bending it into these round arcs. Kind of surrounding the middle of the picture in the center is where the actual galaxy from behind is, but the light has been twisted by gravity into these arcs. This is called gravitational lensing. When Einstein proposed that, it was one of the hardest things for people to accept in terms of his theory. And now here you see direct proof that light is warped by the strong [gravity] of this cluster of galaxies. Not only that, but you can see different little dots which are even further away. For example, . . . you see light from a galaxy which we see as it was 13 billion years ago. Now we think the Big Bang happened 13.8 billion years ago. So 13 billion years ago is pretty good, but it’s not a record holder.

[Even with Hubble we could see light from] a galaxy which is 11.3 billion light years away. Is that a record holder? No, not yet. But they were very excited to get these even in the first picture. Of course, they made this the first picture because they got it and examined it and made some measurements. They knew what they wanted to release. But this gave us hope that we will be able to see things that send us light from really, really long ago.

And now just last week, we got the record. [A] cluster of galaxies called Pandora’s Cluster [is] the result of the collision of four smaller clusters of galaxies. It’s about 4 billion light years away. . . . Shining faintly through that cluster, astronomers have found two even more distant galaxies. One is seen as it was only 450 million years after the Big Bang. Is that the record? Nope. But below it is a little red dot, which is a forming galaxy, a galaxy in the process of forming, seen as it was only 350 million years after the Big Bang.

And that’s the record. That’s the most distant object we have so far identified. It is 350 million years after the Big Bang. Now the Big Bang was 13.8 billion years ago. This is still a baby galaxy, probably just forming, but already shining with the heat that we call infrared radiation.

It is only 350 million years after the creation event, and already it has a unique, separate shape from [everything else]. It’s isolated into a blob, which is the scientific term for some unit. And that little blob is already, we think, disk shaped. So it’s flattened because it’s rotating and it’s going to turn into probably something like our Milky Way galaxy, which is also flattened and rotating in the shape of a disk or a Frisbee. The fact that something could form this early in the history of the universe is remarkable. The fact that we can look back to this early in the universe is mind boggling.

But that’s what we’ve been able to do. Even in this very first set of pictures from the James Webb Space Telescope. Ladies and gentlemen, I can only put it this way. We are now looking back to the dawn of time, to the first organization of matter in the universe. And the amazing thing is that this instrument that we humans built and put a million miles from Earth has the power to take us there.