Instant Genius - How the James Webb Space Telescope is helping us discover the secrets of the cosmos

Episode Date: May 19, 2024

In the short time since its launch in 2021, the James Webb Space Telescope has produced some absolutely breathtaking images of the cosmos. And there’s much more to come. In this episode I speak to the head of Space Science at the UK Space Agency Dr Caroline Harper about her new book Unseen Universe: New secrets of the cosmos revealed by the James Webb Space Telescope. We talk about some of the highlights of the telescope has delivered so far, including incredibly detailed images of Jupiter, its Moon and some of the most distant stars and galaxies ever observed, how it can look for extra-terrestrial life on exoplanets, and also about some of the future space missions that Dr Harper is most excited about. Learn more about your ad choices. Visit podcastchoices.com/adchoices

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So you can experience exceptional sound at home. Music just as the artist intended. Visit name audio.com to learn more. And welcome to Instant Genius, a bite-sized masterclass in podcast form. Each week you'll hear world-leading scientists and experts talking about the most fascinating ideas in science and technology today. I'm Jason Goodyear, commissioning editor of BBC Science Focus. In the short time since its launch in 2021,

the James Webb Space Telescope has produced some absolutely breathtaking images of the cosmos, and there's much more to come. In this episode, I speak to the head of space science at the UK Space Agency, Dr. Caroline Harper. We talk about her new book, Unseen Universe, New Secrets of the Cosmos, revealed by the James Webb Space Telescope. We discuss some of the highlights the telescope has delivered so far, including incredibly detailed images of Jupiter and its moons, and some of the most distant stars and galaxies ever observed. We also talk about how it can look for extraterrestrial life on exoplanets,

and about some of the future space missions that Dr Harper is most excited about. So Dr Caroline Harper, welcome to the podcast. Thank you. It's good to be here. So first off then, can you tell us a little bit about yourself? You have a very interesting job. Yes, it is very interesting. I'm head of space science at the UK Space Agency. So I look after a team that manages the UK contributions to space science missions around the world.

And as a result of that, I ended up writing a book about one of the missions, James Webb Space Telescope. So yeah, that's what we're going to be talking about today then, your book Unseen Universe, which, as you say, is all about the James Webb Space Telescope. It's a lovely book with lots of great images in it. So first off, what was your aim in putting the book together? Well, I think that JWST, James Webb Space Telescope, is completely groundbreaking in what it's able to do.

We're already seeing that in the stunning images and credible data that we're getting back from the mission. And I just wanted to capture that. It's so exciting. It's thrilling. The scientists around the world who are working on this can't believe their luck. They say things like, we never expected it to be this good. So I just thought it was a really good subject for a book.

I wanted to share that in a way that, I hope, is accessible, easy for people to understand who perhaps aren't space scientists, have nothing to do with space science, but want to know a little bit more about it. Yeah, absolutely. So let's learn a little bit more about it then. So what exactly is the James Webb Space Telescope? Okay.

The James Webb Space Telescope is the biggest, the most powerful telescope that we've ever launched into space. We launched it on Christmas Day in 2021 from the European Space Port in French Guyana. And it's an observatory mission, so it's doing a lot of things, a wide range of things. But its primary objective is to let us look out into the most distant reaches of the universe so that we can see the light coming from the most distant objects in the universe. Effectively, that's looking back in time around 13.5 billion years at the earliest stars and galaxies as they formed not long after the Big Bang. So you say it's called the James Webb Space Telescope. So where exactly in space is it? It's in a special orbit. It's not orbiting Earth like the Hubble Space Telescope. It's traveling around the sun.

It's a million miles from Earth and it stays in line with Earth as the Earth also orbits the sun. It's at a place called the second Lagrange point, or L2. And this is a place where all the different forces that are operating on the spacecraft, including the gravitational pull from Earth, for example, are pretty balanced. So it's quite stable there. And JWST doesn't need to use much fuel to adjust and keep itself on station. It also means that JWST can turn its back on the sun and the Earth, so they're both behind it, and it can have an unobscured view of deep space.

And that's really important because JWST is designed to detect the really faint infrared light that's coming from very distant objects. So it can't really have its view contaminated with things like thermal energy from the earth and the sun. It has to stay really cold. That's why it has a huge sun shield, actually. It's equivalent to, I think, an SPF factor of around a million. So talking about the infrared observations that it's making, let's have a look at the instruments that are on it. You know, there's quite a few instruments on it, actually, aren't there? Yeah, yeah.

So there are three instruments working in the near infrared range. There's a camera, near cam. That's for taking images. And then two spectrographs, near spec and nearis. And they both split light coming from objects into different wavelengths. So you get a spectrum. And examining the spectrum from an object will tell you about its physical properties, things like its temperature and its mass and its chemical composition.

And then we have an instrument that operates not in the nearer, infrared like the other three, but in the mid-infrared range, that's called miry. And that one has both a camera and a spectrograph. And then finally, there's a fine guidance centre that enables really precise pointing of the spacecraft while it's taking its images and making its measurements. And the important thing about JWST is really this increased sensitivity that it's got compared with other telescopes in space due to the really large mirror, the biggest mirror ever flown in space, so big it had to be made in segments and folded up inside the rocket for launch. and then unfurled and aligned perfectly in space, a tremendous technical achievement.

I hope you're getting the excitement coming across. This is why I'm so keen on this mission. So it's that real power from that big mirror, coupled with the ability to operate in the infrared wavelengths that means we can see these very faint, very distant objects out in the universe much more clearly than we've ever been able to do before. So the whole thing works together to deliver that objective for us. So that's one of the sort of key facts. that makes it different from the other famous telescope, the Hubble Space Telescope. That's right, yeah. So you mentioned there it's incredibly sensitive.

Can you give the listeners an idea of exactly how sensitive it is? Yeah, incredibly sensitive, definitely. It's designed to complement and build on the work of the Hubble telescope, but it's much more sensitive than Hubble. Hubble's been sending us amazing images of the cosmos for 30 years, and JWST, with its much bigger mirror, is going to build on that and take us a step further. it's actually 100 times more sensitive than Hubble. It can see objects 100 times fainter.

And I'm told it's actually good enough that it could detect the heat from something as tiny as a bumblebee as far away as the moon. So that's pretty sensitive. And because it's optimized to see in infrared light, it's really good at observing the light from these really faint, really distant objects. So we're talking about your book

and it's full of lovely images over the cosmos, all sorts of different things. But how are those images put together because it doesn't work, you know, like your phone camera or something, does it? No, indeed. No. So the first thing to say is that we can't see the images coming back from JWST because they're in infrared light and we can't see that. So what the telescope sends back is exposures that show us the number of photons, the number of light particles that reached its detectors. And the more photons there are, the brighter the image. And the images are then

artificially assigned colours that we can see to highlight features in a way that our eyes can process. Different colours are chosen to represent different wavelengths within the infrared range. And what we end up with is called a representative colour image. And the reason there's this focus on infrared is that these distant objects, the light from them, is always going to be in the infrared wavelengths. So as light is emitted from a celestial body and it travels through space, it gets stretched into longer wavelengths because the universe is expanding and it stretches the light. And longer wavelengths equals redder light. And ultimately, the light from the most distant

objects gets stretched into really long wavelengths and it becomes infrared light. So this is where we have to be able to take these data from JWST and convert it into something that we can see that isn't infrared light so that we can interpret the information that comes back. So that effect is the famous red shift that people talk about. That's right. Ambition comes in all shapes and sizes. At First Citizens Bank, we roll with your goals because we're built for what you're building. Fit for your ambition for Citizens Bank.

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Well, I think we all want to know where we came from. Deep into space is far back in time, because when you look at something that's a really, really long way off, the light has taken a long time to reach us. And when we view a very distant object, what we're actually seeing is how the object looked back when the light was first emitted from it. So JWST can look back in time around 13.5 billion years. It's been called, you know, a time machine. And, you know, we need to be able to look that far back to see what was happening when the very first stars and galaxies were forming soon after the Big Bang out of a sort of a dark soup where there was no light gradually forming and developing and the first stars emerging, the first galaxies developing. And then what happened to those galaxies? They interact, they merge, they form galaxy clusters. How does all of this impact on the evolution of the universe going forward?

So there are a lot of questions that scientists want to answer, and to do that, we really do need a time machine like JWST. So what are some of the key observations in that area that the telescopes made up to this point? Well, one of the things that interests me most is that JWST's turned up a bit of a surprise for us. If you look back that far, what you're not expecting to see is really large, really mature, well-formed galaxies with plenty of structure. you'd expect to see that nearer. That means later on in the development of the universe. They've had time to develop. But when you use JWST to look back,

we've been really surprised to see that there are actually far more large, really quite mature galaxies in the early universe. And what that means is we have to kind of rewrite the textbooks a little bit, and we have to figure out what's going on. Our best theories of how the universe evolved are being challenged by the sorts of information that JWST is providing. So that's not a problem. That's really exciting.

It tells us what we don't know, and it gives us even more questions to ask with this mission and future missions. So widening things out then, so the universe is expanding. What can the telescope tell us about that? Are there any observations that have added to our knowledge there? Yes. So the universe is expanding.

We know that. We can't quite figure out how fast the universe is expanding. We have some models. we have theories about what's going on that allow us to predict the rate of expansion of the universe. But what we're finding is not everything agrees. And the Hubble Space Telescope has been taking measurements of stars called Keffield Variable Stars, which are a really good sort of milestone marker for how the universe is expanding. Hubbell's been taking images and making measurements for a long time and has come up with a figure for the rate of expansion. And everyone was wondering whether, you know,

could that be a systematic error in Hubble's measurements if it doesn't agree with our models? And in fact, JWST has come along and it's marked Hubble's homework and it's cross-checked it and it's confirmed that the Hubble measurements are correct. So now, if it's not an error in the measurements that we're taking, it has to be an error in our thinking about why the universe is expanding. And again, lots more questions to answer, lots more exciting other news to pursue. But now that we're confident that JWST has backed up the Hubble measurements, we can proceed with that at pace.

So that's part of the sort of ongoing scientific process between the scientists doing the observations and the scientists doing the predictions. That's right, yes, yes, all working together. I think space science is difficult. It has to be done in partnership. It's an international endeavour. And what we see is really talented scientists and engineers from all around the world working together to ask and to try and answer some of these questions.

Yeah, so having said that, I bet scientists all over the world are sort of champing at the bit to get access to the telescope. So how do they do that? How do people decide, oh, this particular research group can have this amount of time or this one can have this amount of time? Yeah, it's a good question. I mean, actually, the images are available online to the scientific community and to the general public just to download. a lot of images are available pretty well immediately. The US Space Telescope Science Institute portal or the European Space Agency Science Data Archive are good sources of the images. But in terms of who gets observing time on the spacecraft

and therefore gets to ask their scientific questions and get the data they need to do their research, NASA run competitions and people write scientific proposals and they get assessed on scientific merit and then according to that, NASA will award observing time on the telescope for different groups around the world to get time to look at whatever it is in the universe they most want to look at. So let's have a look at some more of the beautiful images in your book then. One that really sort of stood out to me was the images of Jupiter. So, you know, how did we get those and what can we learn from them?

Yeah, you're absolutely right. I agree with you. The telescope is designed primarily to look at very distant objects, but it's also pretty good at looking much closer to home. and some of my favourite JWST images so far are indeed of Jupiter. We've been able to pick out so much more detail than ever before about Jupiter, about that we can see detail of the faint rings around the planet, the auroras at the poles, much more detail about them, and a lot about the atmosphere, which we know is really turbulent on Jupiter, including a very recent discovery of a high-altitude jet stream,

that it's actually 3,000 miles wide, tearing along at about 320 miles per hour around the equator of Jupiter, and we've simply never been able to see it before. Now we can with JWST. So it's telling us much more about how the heat is distributed through the atmosphere, how the atmosphere behaves, and how the weather is generated on the biggest planet in our solar system. So sort of related to that then, I often think moons don't get enough love.

This very famous moon of Jupiter and some of the other moons, which we'll talk about in a minute, are very, very fascinating in and of themselves, aren't they? Yeah, that's right. I mean, some of Jupiter's moons like Ganymede and Europa, they're really big and they're very icy, and we're pretty sure from measurements taken with other observatories that they've got a huge ocean each under the ice, maybe of salty water. And in places there seem to be cracks in the ice where massive plumes of vapor are jetting out, kind of like geese on Earth. And where there's water, there could be life. So that's why they're so interesting. And in fact, the European Space Agency

and NASA are both sending missions to study these moons in more detail right now. They'll be collaborating with the data from both missions. But Issa's Juice mission, Jupiter-Icey Moons Explorer, launched last April just every year ago, and NASA's Europa Clipper is due to blast off later this year. So they will go, it takes a while to get to Jupiter several years, but when they arrive and they're studying the moons, they will look at this in a lot more detail, and hopefully there'll be some really exciting insights from those missions.

But meanwhile, JWST is being used to find hotspots, so places where there are these cracks in the ice and jets may occur. And we'll try to analyse the plumes using its spectrographs to see what's in them. Is it salty water? What other molecules are present, that sort of thing. So another really interesting moon is Titan. Can you tell us about that, please? Yeah, Titan's really interesting because it's a moon, technically,

because it orbits a planet, Saturn, but it's really quite like a planet. We know it has a thick atmosphere, like Earth has a thick atmosphere, although likely it's pretty well all nitrogen. And it also seems to have lakes and rivers, too, although we think they're not water, but liquid ethane and methane. As far as we can tell, there's no other world in the solar system that has that kind of liquid surface activity apart from our own Earth. So JWST is taking a closer look at what's going on, and it's confirm that some large, reflective white patches that we can see are actually huge storm clouds and that they're moving across the surface and changing. So that's going to start to tell us a lot more about the weather on Titan using JWST. And for me, that's really useful because we're looking forward

to a NASA mission called Dragonfly, where they plan to send a robotic helicopter to the surface of Titan quite soon. And, you know, if you're going to fly helicopters, you definitely need an accurate weather forecast. So understanding about the weather on Titan is really going to pave the way for that one for Dragonfly 2. So what sort of things would we need when we find it is like the smoking gun? Ah, that's a sign of life. Yeah. I mean, so JWST and indeed Europa Clipper and Juice are, they're not going to find Little Green Man or anything like that. What they're looking for is evidence of molecules, biomarkers, things that could indicate the presence. of life or the ability to support life on those moons.

So another sort of exciting area of research at the moment is exoplanets. So first off, what exactly are exoplanets? And how can we use the James Webb Telescope to study them? So exoplanets are planets outside of our solar system, orbiting other stars rather than our sun. And we're obviously very interested to understand more about exoplanets. It wasn't that long ago. We weren't sure they existed at all.

Now we're very sure and we're finding hundreds and hundreds of exoplanets and we're pretty sure that there must be a great number of exoplanets out there. So the next obvious question is, could some of them support life? Is there alien life out there? So there is a lot of interest in looking at exoplanets and JWST is no exception. It's using its spectrographs again to examine the atmospheres of these exoplanets looking in particular for any molecules. that could indicate that the planet might support life as we know it. So what it does is it uses the spectrographs to split the light that's coming through the atmosphere of the exoplanet, so that the light is coming probably from the parent star,

passing through the atmosphere of the planet. And by looking at what light gets filtered out of the atmosphere, you can tell what molecules are in the atmosphere. So that's what JWST is doing for a number of exoplanets at the moment. And a lot of this work, actually, for JWST and other missions, is on very big gaseous planets that are a long way from their parent star, because frankly, they're easier to look at. But just recently, JWST might just have detected atmospheric gases around a much smaller rocky exoplanet. It's called 55 Cancray E. They have funny naming systems for these celestial bodies.

It's about 41 light years away from Earth. And if that's confirmed as an atmosphere around a rocky planet, that's our best evidence yet of atmospheric gases on a small planet outside of our solar system that's quite like Earth. So this is another example where JWST is pushing the technical boundaries of what's possible and starting to give us these scientific insights that we've just never had before. So as you say that, the research is very much still ongoing. So by way of sort of closing, one final question is what sort of future missions or findings are you most excited about? Well, that's both a nice question and a really difficult question to answer. It's really hard to choose. There are so many missions that I'm excited about.

If I had to pick, I guess I'd pick two. So first would be the European Space Agency's laser interferometer space antenna, a mouthful. Acronym is Lisa, much easier to say, due to launch in the 2030s. That will be the first gravitational wave observatory in space, and it will observe the universe using gravitational waves. which are tiny ripples in space and time, generated by actually massive cataclysmic events like black hole mergers. So it can use gravitational waves to look at the universe instead of any

kind of light, so not UV, not infrared, not visible light, not x-rays, none of it. It's gravitational waves completely different. So this is going to be an absolutely new way to observe and study the universe and we just have no idea what that's going to turn up. So that's really rather thrilling. And then my other pick would have to be NASA's Habitable World Observatory, which is just being thought about in earnest now. That one won't launch until the 2040s. And what that one will do is take what JWST can do now and stretch it even further in its exoplanet research. It will be specifically designed to seek evidence of the ability to support life on small rocky planets like Earth that are in their habitable zone of their parent stars. So where, liquid water could exist on the surface of the planet because the temperature is just right. Some people call it the Goldiloxone, so it's not too hot and it's not too cold. It's just right for liquid water to be present on the surface. So obviously we're looking for real Earth analogs and Habitable Worlds Observatory is going to do that. Not in this decade, not in the next decade,

but in the one after. By then, the technology will be so advanced that we can use the sort of techniques we're using with JWST now to look for Earth-like planets and analyze their atmospheres. And Habitable Worlds Observatory will do lots of other things as well. But this is the really exciting thing that everyone is focusing on right now, and we're looking forward to from that mission. Sounds like there's a lot to look forward to then. Yes, indeed. Thank you for listening to this episode of Instant Genius, brought to you from the team behind

BBC Science Focus. That was Dr. Caroline Harper. To discover more about the topics we've just discussed, check out the latest book, Unseen Universe, new secrets of the cosmos revealed by the James Webb Space Telescope. If you liked what you just heard, please consider subscribing to Instant Genius on your preferred podcast platform. The current issue of BBC Science Focus magazine is out now. Pick up a copy wherever you buy your favourite magazines or download a copy on your app store of choice. You can also find us online at sciencefocus.com.

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