What’s the James Webb telescope searching for?

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Speaker 4 Last week, NASA released the first first color images from the James Webb Space Telescope, and they're just jaw-dropping.

Speaker 4 The first image is a picture of thousands of these intricate, beautiful galaxies. And what's truly stunning about it is that this image is of the tiniest patch of sky.

Speaker 4 It's the equivalent of holding up a grain of sand against the sky at arm's length.

Speaker 4 There's a whole bunch of other images, including this enormous orange nebula that sort of looks like a mountain range, except the peaks of these mountains are seven light years tall.

Speaker 4 It's just been a few images so far, but the web is already showing us things we just couldn't see before.

Speaker 4 Last year, before the web launched, we made two episodes all about the telescope, how NASA designed it to take these mind-blowing images, and what kind of enormous questions they're trying to answer with it.

Speaker 4 So we thought we'd share them with you again this week, this time as one mega episode.

Speaker 4 We start our story back in 1990, when scientists first put a telescope in space to peer out at the distant universe.

Speaker 6 T-minus 10, go for main engine start.

Speaker 6 We are go for main engine start. T-minus six, five, four,

Speaker 7 three,

Speaker 7 two,

Speaker 8 one,

Speaker 9 and lift off of the space shuttle discovery with the Hubble Space Telescope, our window on the universe.

Speaker 6 This was the picture that NASA managers all over the world were waiting for. The Hubble Space Space Telescope is released.
The clearest pictures ever seen in the history of astronomy.

Speaker 6 Scientists expect it will revolutionize our understanding of how far we have come and still have to go.

Speaker 10 How far we have come.

Speaker 6 381 miles above the Earth.

Speaker 10 We see stars, blobs, pillars. Floating in orbit.

Speaker 6 The Hubble Space Telescope is telling us.

Speaker 10 Each one tells us how far we have come.

Speaker 4 When the Hubble Space Telescope launched in 1990, it was a gigantic leap forward.

Speaker 13 Hubble was something that scientists dreamed about having for decades.

Speaker 4 Science editor Brian Resnick.

Speaker 7 On Earth, we can put telescopes on mountaintops, but space, oh, putting a telescope in space, that's kind of like the ultimate mountaintop.

Speaker 4 And from its orbit around the Earth, Hubble revolutionized our understanding of the universe.

Speaker 20 Hubble taught us that the universe is expanding faster and faster all the time.

Speaker 14 It helped us determine about how old the universe is.

Speaker 22 And this is not a small thing.

Speaker 24 It's giving us these ridiculously beautiful images, the Orion Nebula, the deep field, the pillars of creation.

Speaker 4 But now we're on the verge of a new era.

Speaker 8 This is the future. NASA's James Webb Space Telescope.

Speaker 4 The Webb, which is launching in partnership with the Canadian and European space agencies, is the most powerful space telescope ever built.

Speaker 26 It's a grand scientific undertaking. A space telescope so sensitive, it can peer deeper into the cosmos than any previous orbiting observatory.

Speaker 4 Brian's been talking about the web since we launched this show and he's been speaking to tons of astronomers who all have research projects lined up.

Speaker 28 This is really the reason why I wanted to bring it to the show because this is a machine for answering unanswered questions.

Speaker 29 I definitely think that web will be a paradigm shifting telescope.

Speaker 30 We're going right up to the edge of the observable universe.

Speaker 31 The web represents the culmination of decades, if not centuries, of astronomy.

Speaker 29 We will find things that completely surprise us.

Speaker 11 It'll give us a view of parts of the universe we've never seen before.

Speaker 29 Things that fundamentally change the way that we understand the universe.

Speaker 4 I'm Noam Hasenfeld, and this week on Unexplainable, we'll be diving into the enormous question-answering machine that is the James Webb Space Telescope.

Speaker 10 How far we have come

Speaker 32 and still have the go.

Speaker 10 How far we have come.

Speaker 10 Each one tells us how far we have come.

Speaker 10 And still have the go, how far we have come.

Speaker 10 Each one tells us how far we have come.

Speaker 4 Okay, Brian, before we get to some of the unanswered questions that the Webb Telescope is going to let scientists try and answer, let's just start with the telescope itself.

Speaker 4 What makes the web so powerful?

Speaker 33 So I talked to Amber Strawn.

Speaker 34 She's a NASA astrophysicist.

Speaker 38 She's worked on web for years, and she really pointed out there are two key ways that the web improves on Hubble.

Speaker 29 The first way is really just the size.

Speaker 36 It's enormous. It's much bigger than the Hubble.

Speaker 29 Hubble's about the size of a school bus. Webb stands about four stories tall.
It's about the size of a tennis court. So it is absolutely huge.

Speaker 4 And bigger with a telescope is inherently better.

Speaker 5 Yeah.

Speaker 23 So especially when it comes to this kind of telescope, the key component is the mirror.

Speaker 29 So a telescope mirror, you can sort of think of it like a light bucket. So the bigger it is, the more light it can just collect.

Speaker 44 And Webb has this light collecting area that's more than six times bigger than Hubble.

Speaker 29 And then also the bigger it is, the finer resolution it can see.

Speaker 22 And not only is it large, it's like a gorgeous golden honeycomb with all these different segments of hexagons.

Speaker 15 Here, let me send you.

Speaker 47 Oh, cool.

Speaker 4 I mean, this looks like something that I would see in a sci-fi movie and be like, oh, wouldn't it be cool if they made things that looked like that?

Speaker 38 Yeah, and they did.

Speaker 29 And because it's so big, there aren't any rockets that are big enough to launch it fully deployed. So the whole thing has to be folded up to fit inside a rocket.

Speaker 34 The engineers had to find a way to kind of origami it into a smaller package so it can actually fit on a rocket ship. And then once it launches, it will have to assemble itself in space.

Speaker 4 So I'm sorry, assemble itself?

Speaker 43 Yeah, it's well, it's supposed to.

Speaker 29 So that whole process of building a deployable telescope in space is sort of the source of a lot of the engineering challenges.

Speaker 4 Okay, so the web is super big.

Speaker 4 What's the second important difference between the web and the Hubble?

Speaker 49 The type of light it collects.

Speaker 29 Webb is an infrared telescope, so that means it sees the universe in infrared light, light that's a little bit more red than what our eyes can see.

Speaker 16 Hubble can detect visible light, which is what our eyes can see, but webb can see what's invisible to our eyes.

Speaker 4 And as far as all the frequencies of light go, red's at the lower end of the spectrum, right? Like longer wavelengths, lower energy.

Speaker 15 Yeah, so light comes in a lot of different flavors.

Speaker 48 So blue would be very high frequency.

Speaker 7 And then if it gets lower and lower frequency, it gets redder and redder and redder, and then it drops into infrared.

Speaker 4 And what's the advantage of having a telescope that can see infrared?

Speaker 52 This relates to something we were talking about a couple of months ago on our episode on Henrietta Levitt and the end of the universe.

Speaker 47 Okay.

Speaker 48 We talked about how the universe is constantly expanding, right?

Speaker 4 Right, more space all the time.

Speaker 54 So scientists discovered that by looking at the quality of light coming from different parts of space.

Speaker 46 And it turned out things that were farther farther away from us looked redder than the things that are closer to us.

Speaker 7 This is called redshifting.

Speaker 29 Space is expanding, and as light travels through space from those distant galaxies, the light is literally stretched by the expansion of space.

Speaker 13 Imagine a star that's really far away, and the light from that star to get to us has to travel through space.

Speaker 7 But that space itself is expanding, and that space is stretching the light until eventually it gets so red, it drops into infrared.

Speaker 36 And what that means here is that web, because it collects infrared light, it can see these very far away things that Hubble just couldn't see.

Speaker 15 Things that are so far away, the light might have started off in the visible spectrum, but is now infrared.

Speaker 4 So the web will literally be seeing things that are so far away that no one's ever seen them before.

Speaker 48 Yeah, infrared telescopes are really sensitive.

Speaker 29 And because of that, the telescope has to be very, very, very cold.

Speaker 7 Because anything that is warm will glow in infrared.

Speaker 29 You and I, all your listeners, we're all glowing in infrared light. If the telescope was warm, it would just glow and see itself.

Speaker 16 So to keep it cold, the web actually needs to be sent really far away from the Earth.

Speaker 29 Webb is going to be a million miles away. That's about four times further than the moon.

Speaker 10 What?

Speaker 15 It's going to be in a place where it's shielded from the heat and light of the sun and the the earth.

Speaker 4 Sorry, four times the distance of the moon?

Speaker 48 Yeah, yeah, really very far.

Speaker 14 So this is not going to be orbiting the earth.

Speaker 24 This is going to be orbiting the sun,

Speaker 14 but also keeping itself in line with the earth. It's called a Lagrange point.

Speaker 4 So it's orbiting the sun with us,

Speaker 4 but like at the same pace that we're orbiting the sun?

Speaker 54 Yeah, it's pretty wild.

Speaker 28 That is insanely cool.

Speaker 29 And when you add all those together, you know, the size of the mirror, the wavelength of light it will see, what we're going to get is a telescope that's about a hundred times more powerful than Hubble, if you can even imagine that.

Speaker 36 This is a super high-stakes mission.

Speaker 57 The web, it's going to be nearly a million miles away.

Speaker 58 And once it's there, we can't fix it.

Speaker 49 And what's haunting this whole project is that the Hubble needed to be fixed.

Speaker 55 After it was launched in 1990, the images from it just came back fuzzy.

Speaker 60 But I am extremely concerned by the fact that after spending almost $2 billion over a 12-year period, we only now find out that this kind of mistake could occur.

Speaker 33 And it was kind of this national joke.

Speaker 62 Have you heard about the problems with the Hubble Space Telescope? Yes. A billion and a half dollars.
We put up a telescope and it's out of focus.

Speaker 23 And so astronauts had to launch on a space shuttle and fix it.

Speaker 43 Give the Hubble reading glasses, so to speak.

Speaker 58 And they could do that because Hubble was close enough to the Earth where you could launch a shuttle and get there and fix it.

Speaker 62 And they called the NASA official repairman, and he said he'll be up there sometime in the 21st century between noon and five.

Speaker 4 I just, you build the greatest, biggest telescope that humanity's ever assembled, and it's like, oh, it's blurry.

Speaker 5 Yeah, yeah.

Speaker 43 But you can't just go and fix the web if it breaks.

Speaker 18 It's way too far.

Speaker 58 It just has to work.

Speaker 4 So have they been sort of like double checking everything, like waiting a while to make sure they're not making any reading glasses mistakes.

Speaker 44 Yeah, it's just taken such a long time to get here.

Speaker 49 People were talking about the successor to the Hubble before the Hubble even launched.

Speaker 34 And the James Webb Space Telescope was originally supposed to launch in 2010 and cost around a billion dollars.

Speaker 15 Now, the costs have ballooned to $10 billion,

Speaker 39 and it's just way overdue.

Speaker 4 And they're still planning to launch it, right? That's the plan?

Speaker 27 The plan is to launch by the end of 2021.

Speaker 24 And

Speaker 7 this, this can change.

Speaker 43 So, so don't at me if it does change.

Speaker 15 But, and then after it launches, you know, there will be some time like it has to deploy, has to do all these things that we talked about.

Speaker 4 Unfold in space.

Speaker 22 Yeah. Yeah.
Fingers crossed.

Speaker 63 But then, you know, the science will start.

Speaker 49 And this is one of the things that really drew me to the story is that anyone can use the Web Space Telescope.

Speaker 4 What do you mean? Like there's like a terminal somewhere that you can walk up to and like check out space?

Speaker 43 Yeah, put your eye next to it.

Speaker 55 Put in a corridor.

Speaker 7 No, anyone in the world can write a proposal, say, I want to use web to look at this.

Speaker 4 Can we use it?

Speaker 28 Yeah, yeah. I wanted to know, too.

Speaker 15 I asked Amber at NASA.

Speaker 29 Absolutely.

Speaker 29 I mean, you might need an astronomer friend to help you out.

Speaker 4 Should we apply?

Speaker 55 You know, I looked into it and

Speaker 49 I think it's a little bit over our heads to do this.

Speaker 29 Yeah, it's pretty competitive to say the least.

Speaker 21 So in March 2021, the Space Telescope Science Institute, which runs the web and other space telescopes, they sent out emails to scientists who had applied to use the web.

Speaker 15 And these scientists on this day were furiously checking their emails to see if, oh, were their proposals accepted?

Speaker 14 And it was kind of like all huddling around and finding out who got parts in the school play. It was an exciting day.

Speaker 30 We totally felt like underdogs.

Speaker 64 It feels like a dream.

Speaker 65 It was honestly a truly amazing feeling.

Speaker 64 I think I was just stunned for a good minute there. I probably cried a little bit.

Speaker 65 I'm pretty sure I jumped up out of my chair in my office and shouted out, yes, yes, yes, yes.

Speaker 4 And Brian, you've been talking to these scientists for the last few months, right?

Speaker 14 Yeah, I've been talking to scientists who have been awarded time to use the telescope.

Speaker 15 And these conversations, they just leave me with a big smile.

Speaker 54 These are people who get to explore the frontiers of the cosmos and they just have so many unanswered questions.

Speaker 4 What kind of questions are they trying to answer?

Speaker 49 Is there life on other worlds?

Speaker 4 Big one to start with.

Speaker 47 Yeah.

Speaker 58 And, you know, they're looking for life and not, you know, necessarily in our neighborhood, in our, like on Mars or Venus, although there searches for life on those planets.

Speaker 58 But they're looking for life on worlds called exoplanets, which are planets that revolve around stars that are not our sun.

Speaker 4 So, planets in like entirely different systems?

Speaker 58 Yeah, yeah. And scientists in the last decade or so have detected so many of them.

Speaker 58 There's just been this exoplanet revolution, but we've detected them with smaller telescopes, and it's just hard to know a lot about them.

Speaker 58 We just can't study them super well, but that's going to change.

Speaker 34 The web is going to give us a whole new view onto exoplanets. And I talked to an astronomer, Lisa Deng.

Speaker 34 She's a PhD student at McGill University, and she's been awarded time on the the web to study an exoplanet.

Speaker 64 This is the first telescope proposal that I ever submitted that was successful. It made me feel like an astronomer for the first time.

Speaker 4 What kind of exoplanet is she looking at?

Speaker 49 Oh, this is so rad.

Speaker 37 So I was looking down the list of like of projects approved for the web, and I just stopped at Lisa's because she's going to study one of the most extreme planets we've ever discovered.

Speaker 64 I want to use the James Webb Space Telescope to look at K2141b, the lava planet.

Speaker 47 A lava planet?

Speaker 34 Yeah, like when we get outside of our solar system, planets can get really weird.

Speaker 64 It probably looks like hell.

Speaker 44 So we know this planet is there, but we really don't know much more about it.

Speaker 34 We just haven't studied it in detail because we just haven't had a big enough telescope.

Speaker 42 So I asked Lisa to help me imagine what could be there.

Speaker 64 Oh, I have so many mental images of what this planet could look like.

Speaker 25 This planet, the first thing to know about it is it's really close to its star.

Speaker 64 It's so hot on this planet that you could sustain a temperature that would melt the continent on the planet.

Speaker 23 Anything on that surface is just the hottest thing you can imagine.

Speaker 64 So instead of having oceans of water like we have here, we have oceans of lava on this planet.

Speaker 47 The floor is lava.

Speaker 16 But then there also could be weirder things.

Speaker 13 So like this world isn't like an uninteresting place.

Speaker 64 So things that I'm hoping to look for is maybe clouds on this planet.

Speaker 14 But they wouldn't be like any clouds you've ever imagined before.

Speaker 64 Instead of having, you know, clouds of water molecule like we have here, these planets would have clouds made of rock.

Speaker 59 And these clouds, even if they're made of rock, they can still float because the particles in them would be small enough.

Speaker 64 It's probably looking pitch black, like dark black cloud, but depending on the shape of these particles, maybe they could be shiny or a cloud of crystals.

Speaker 55 And then those clouds, they can do cloud things.

Speaker 64 We can also have rain from these clouds. It would be raining rock or like raining silicate.

Speaker 34 It's truly one of the most extreme places we've discovered in the galaxy.

Speaker 4 Okay, the lava planet seems really cool and all, but why is the lava planet the place to start if Lisa is trying to search for life? It doesn't exactly seem like a place where there would be life.

Speaker 44 Yeah, it is a very extreme place.

Speaker 53 If life exists there, which is unlikely, it would be unlike any life that we can think of.

Speaker 42 But there's a bigger picture reason why she's studying the lava planet.

Speaker 34 It's because it's the perfect place for her to get really good at atmosphere hunting.

Speaker 4 Atmosphere hunting?

Speaker 64 So we don't know whether these planets even have like an atmosphere like we described on Earth.

Speaker 40 But in order to find life like anywhere, we're pretty sure a planet needs to have an atmosphere.

Speaker 34 And the lava planet is just this like big hot place that glows in infrared really brightly.

Speaker 58 So it's going to be really visible for the Webb Space Telescope. So it's just a perfect place to like learn how to study atmospheres on other planets and really refine the skills of analyzing them.

Speaker 64 So looking at a lava planet is kind of like the first target that you want to try with James Webb before you go towards more temperate rocky planets like Earth, for example.

Speaker 4 And how exactly would the web figure out if a planet has an atmosphere?

Speaker 64 So what I am hoping to do with the James Webb Space Telescope is basically to observe this planet as it completes a whole orbit.

Speaker 45 When the planet crosses in front of its star, it will come in between the star and the webb telescope.

Speaker 40 If there's an atmosphere there, that atmosphere will change the quality of light.

Speaker 42 So the atmosphere would act as a sort of filter.

Speaker 49 And then from there, like Lisa can actually create these whole weather maps of the planet.

Speaker 4 So is she basically going to have to do this, like one by one, point the web at every single planet to see if it has an atmosphere?

Speaker 36 Hopefully she doesn't have to do that all by herself.

Speaker 34 She's not alone here.

Speaker 15 She's not the only scientist studying exoplanets.

Speaker 65 I spend most of my time, not quite staring up at the stars, but trying to reveal their secrets.

Speaker 23 I talked to this guy, Kevin Stevenson.

Speaker 34 He's a planetary scientist at the Johns Hopkins Applied Physics Lab.

Speaker 4 It's exciting, right?

Speaker 65 This is the first step towards answering the question of, are we alone?

Speaker 34 He's also been approved to use the web, and he wants to know if he can predict whether planets have atmospheres or not before he even looks at them directly with the web.

Speaker 4 How would you predict whether a planet would have an atmosphere?

Speaker 22 So there's actually this really neat pattern that scientists find in our own solar system where they look at our solar system and they catalog all the planetary bodies, the planets, the moons, and they see which ones have atmospheres and which ones don't.

Speaker 48 And it turns out it's just a function of how big the planets are and how warm they are.

Speaker 65 So this is a really neat trend that we see in our own solar system. And the question is, does this trend apply to systems outside of our solar system? Is it truly cosmic in nature?

Speaker 23 There are potentially billions of planets to look at.

Speaker 34 And if we can just better predict which ones have atmospheres, then we can narrow it down.

Speaker 44 We're like a step further in the direction of answering the huge question, are there other habitable worlds?

Speaker 4 And where do we go from there? I mean, where do we go from, okay, these planets have atmospheres to is there life on those planets?

Speaker 34 Once we have confirmed that a planet has an atmosphere, the web can actually detect things in that atmosphere that might be signs of life or clues that the planet is habitable.

Speaker 65 We can detect water, CO, CO2, methane.

Speaker 43 You can ask fascinating questions like, what created that methane?

Speaker 39 Could it be life?

Speaker 65 If we want to look for a planet that's

Speaker 65 similar to Earth, we would probably want to go out and look for CO2 first.

Speaker 50 It might sound like small, small, like, oh, analyzing the atmospheres of different planets, but really, this is going to be our first step to that ultimate question of like, is there life out there?

Speaker 33 Is there another Earth-like world?

Speaker 34 Is there a place that we could live on or something to live on?

Speaker 65 There's most certainly life out there.

Speaker 65 The universe is large. The galaxy is large.
There's billions and billions of planets out there.

Speaker 47 Life has to form.

Speaker 65 We've seen it form in the strangest places here on Earth, right? The question is, will we know that we're seeing life when we make that measurement?

Speaker 52 There are just so, so many exoplanets, and we just don't know what's possible on these worlds.

Speaker 14 And the web is giving this this opportunity to really deeply investigate them for the first time, to fill in the coloring book of the planets of the galaxy.

Speaker 65 It's a very complicated universe. I want to know where we fit into it all.

Speaker 47 Are we alone?

Speaker 4 And this kind of enormous ultimate problem of are we alone in the universe is just one of these huge questions that the web can let scientists try and answer, right?

Speaker 15 Yeah, yeah. Exoplanets are a huge source of unknowns, but there are other huge areas of unknowns too.

Speaker 22 Areas that have less to do with traveling through space and more to do with actually seeing back in time.

Speaker 4 What do you mean?

Speaker 7 The farther away we look with a telescope, we see older and older light.

Speaker 24 That light has just taken a really long time to get to us.

Speaker 15 And we can take these snapshots of a universe like long past, like as it existed billions and billions of years ago.

Speaker 63 So they're hoping to find the very first light of the universe.

Speaker 4 Coming up after the break, cosmic dawn, the Dark Ages, and what might be the very first starlight of the universe.

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Speaker 4 Okay, Brian Resnick, science editor. Hey, before the break, you were saying that scientists don't want to just use the web to look for life on other worlds.

Speaker 4 They actually want to use it to look back in time.

Speaker 45 Yeah, yeah.

Speaker 34 If you look at something that's really far away, the light from it is really old.

Speaker 49 So something that's 100 light years away, the light from it has been traveling for 100 years.

Speaker 23 And so with the web, like scientists are anxious to kind of push this as far as they can.

Speaker 44 Like they want to know how far back can they go and what mysterious things can they see when they go there.

Speaker 34 Basically, they're excited to take what the Hubble did and just go way further.

Speaker 4 Hubble was doing this too, sort of like seeing how far it can look back in time.

Speaker 49 Yeah, yeah.

Speaker 49 Hubble did this.

Speaker 61 And it did so in a kind of radical way.

Speaker 58 The idea was just to point Hubble at this blank patch of sky for 10 days,

Speaker 34 which is weirder than it sounds.

Speaker 33 Normally, astronomers pick something to study and then they point the telescope at it.

Speaker 68 In fact, always what you do with you know what you're looking at. You don't just open, you know, the shutter, so to speak, and see what's there.

Speaker 44 This is Robert Williams.

Speaker 18 He was in charge of the Hubble in the 90s.

Speaker 68 But in my case, I thought it was really important to do. I think if you're going to make important discoveries, you've got to undertake risk.

Speaker 68 And so I told people, look, if we come up with no result, I'll fall on my sword.

Speaker 33 But then the picture came back and

Speaker 45 I should just show you it.

Speaker 16 Okay. This is the Hubble deep field.

Speaker 4 Oh, I've seen this image before. It's just this square with just tons and tons of little dots of different colors scattered around.

Speaker 37 I guess those are stars? No, no, no, no, no.

Speaker 48 Those are galaxies.

Speaker 43 Oh, so okay, so this is just really huge.

Speaker 47 Yeah.

Speaker 68 The fact is, if you look out far enough,

Speaker 68 you can actually see back in time a timeline that's like a core sample of the universe.

Speaker 4 And core sample, that's like when you drill down into the earth and you can see all these kind of past layers of sediment and stuff.

Speaker 43 Yeah, yeah.

Speaker 24 So this image, when you look at it, it looks like it's two-dimensional, but it really goes deep.

Speaker 34 Like you can, you can take this image and sort the objects onto a timeline and see layers in time like you would in a core sample from the earth.

Speaker 45 So it's kind of like they're on this archaeological dig, but for space.

Speaker 15 So nearer to us, like the more recent things in this image, galaxies look gorgeous.

Speaker 25 They have these elegant spiral shapes.

Speaker 20 But then if you look deeper in this image and you go to like a different strata, you see a few billion years before that, you see like galaxies that looked irregular.

Speaker 7 They look more like footballs.

Speaker 17 And then like even deeper before that, some billions of years before that, they look even like these kind of irregular blobs.

Speaker 21 And then even deeper, billions of years before that, like, well, that's when you get to the point where Hubble can just barely make them out and you just don't know exactly what these galaxies look like at all.

Speaker 4 So this image of sort of deep space that the Hubble took is almost like showing us these fossils of galaxies?

Speaker 20 Yeah, like fossils are frozen in time.

Speaker 23 These galaxies are also kind of frozen in time because their light has taken so long to get to us.

Speaker 57 And so this image contains almost almost the entire history of the universe.

Speaker 4 So how far back can the Hubble ultimately see?

Speaker 44 The Hubble could see back more than 13 billion years, which isn't nothing.

Speaker 15 That's like most of all time.

Speaker 22 But with Webb, astronomers are hoping to see back even farther.

Speaker 30 So Webb will allow us to see the faintest galaxies at the edge of the detectable, observable universe.

Speaker 57 I talked to Caitlin Casey.

Speaker 22 She's an astronomer at the University of Texas at Austin. She's going to use the web to go back hundreds of millions of years, even farther than the Hubble took us.

Speaker 30 The tiny specks of light in the background of the Hubble deep field will

Speaker 30 brighten and become more detailed. And then we'll get more specks of light even further in the past in the background of the web deep fields.

Speaker 4 So is Caitlin just trying to go further and further back in time or is she looking for something specific?

Speaker 47 Oh,

Speaker 44 she's looking for something that just gives me chills.

Speaker 4 What's she looking for?

Speaker 23 Cosmic dawn.

Speaker 30 We are looking for the first light that turned on at the very beginning of cosmic time and its impact on its surroundings.

Speaker 4 Is that the Big Bang?

Speaker 12 No, no, it isn't at all, actually.

Speaker 51 We can't see all the way back to the Big Bang just yet, but the universe went through a few phases to get to today.

Speaker 30 You know, we all go through phases.

Speaker 43 First, there was the Big Bang, this cosmic explosion.

Speaker 7 And then for a while there, like, everything was kind of this hot soup.

Speaker 30 Basically, there was a hot plasma that pervaded all of space. You know, you can think of it like a goopy, hot mess.

Speaker 7 And then the universe cooled a little bit and entered its next phase, where it was dominated by this kind of dense, obscuring fog of primordial gas.

Speaker 48 There wasn't any light at all.

Speaker 20 Scientists call it the dark ages.

Speaker 4 So the whole universe at that point was just dark or invisible?

Speaker 23 Yeah, but then something happened.

Speaker 55 That fog lifted, became transparent.

Speaker 4 How did that happen?

Speaker 4 Is that what she's trying to figure out? Do we know what allowed us to see light?

Speaker 16 Yeah, scientists have a pretty good guess at the process that did it.

Speaker 55 So, in ScienceSpeak, when that fog became transparent, it became ionized.

Speaker 20 And scientists know what can ionize gas like that, and it's starlight.

Speaker 30 If you have like a cloud of gas and it encounters energetic light,

Speaker 30 that energetic light will ionize that gas and disassociate that cloud.

Speaker 4 So, the idea here is that light itself was the thing that changed the universe from invisible to visible.

Speaker 16 Yeah.

Speaker 30 The darkness of the universe was pervaded by light for the first time.

Speaker 30 And so if that light just has turned on, then hits that gas and really transforms the entire universe from a dark place to a light place.

Speaker 18 But they still don't know what exactly that light was.

Speaker 4 And is that what Caitlin is going to try to look for?

Speaker 47 Oh yeah.

Speaker 7 She's looking for the first stars, the first galaxies that transformed our universe.

Speaker 30 We're trying to see

Speaker 30 which galaxies turned on first.

Speaker 4 And what kind of, other than just, I don't know, being totally, obviously awesome, I mean, what kind of questions is Caitlin trying to answer?

Speaker 4 Like, what would identifying the first light of the universe be able to help us solve?

Speaker 46 So when we identify the first light of the universe, we're really identifying the first galaxies.

Speaker 28 And like, once we understand where those first galaxies are, that helps us understand the distribution of matter and dark matter in the early universe.

Speaker 55 We want to know why everything is the way it is today.

Speaker 59 It's like, you know, if you have an image of evolution of an animal, you know, you can think of the evolution of the universe similarly.

Speaker 34 Like, you need to see the earlier examples to have a complete understanding of how we got from there to here.

Speaker 4 You know, it just makes me curious about all the things the web can't do and what might come next.

Speaker 4 I mean, we know that this is like the most advanced, coolest telescope humanity has ever built, but there's got to be a next telescope, right?

Speaker 49 Oh, yeah. There's, there's always something more.

Speaker 18 The web won't be the last space telescope.

Speaker 34 There's always going to be more questions to answer, questions that even the web can't really get at.

Speaker 33 So I've been talking to a lot of scientists and I've heard about three really cool telescopes that really can push past a lot of the boundaries of what the web can't do in really interesting ways.

Speaker 4 Okay, three potential cool future telescopes. Let's start with future telescope number one.

Speaker 58 Future telescope number one would be called HabEx, which is the habitable exoplanet observatory.

Speaker 47 All right.

Speaker 61 And HabEx is all about finding an Earth twin.

Speaker 31 We could find a planet like Earth around a star like our sun and recognize it as such.

Speaker 45 This is Sarah Seeger.

Speaker 15 She's an MIT planetary scientist whose work is all about finding these other Earths.

Speaker 31 I love to describe my job as I am searching for aliens.

Speaker 34 So a big limitation of the web is that although it can see all sorts of cool planets, typically they'll be around dimmer stars.

Speaker 4 Oh, so the lava planet is around a dimmer star.

Speaker 49 Yeah, yeah.

Speaker 37 And really, there's no shortage of these planets that revolve around dimmer stars for us to explore with the web.

Speaker 37 But finding another Earth around a star like our sun would be a lot harder because stars like our sun are just so bright.

Speaker 31 Earth is 10 billion times fainter than our sun.

Speaker 45 And planets that are close to stars that are so bright are just really hard to see.

Speaker 31 So if we want to go out and search for the Earth twin,

Speaker 31 we need to go to the next level, to a different kind of telescope.

Speaker 4 So is this where HabEx comes in, the new telescope?

Speaker 20 Yeah, yeah.

Speaker 34 So Sarah is one of the scientists who's really pushing for this telescope, for this concept.

Speaker 34 And the idea behind this telescope is actually kind of simple.

Speaker 34 The HabEx Observatory will come in two parts.

Speaker 7 And one is a telescope, an optical telescope, a lot like the Hubble.

Speaker 34 But the key is the second part.

Speaker 58 It's like an umbrella that floats alongside the telescope.

Speaker 31 Literally, we want to put up a giant specially shaped screen called Starshade.

Speaker 4 Starshade?

Speaker 7 Yeah,

Speaker 34 it's actually really well named. So the Starshade exists to be perfectly aligned with the telescope and a star so that it blocks out some of that light from the star.

Speaker 31 Starshade would be in space far away from Earth and it would operate together with the space telescope.

Speaker 31 And so these things would line up just so and that we'd be able to see other Earths or other Jupiters or other planets, whatever's there.

Speaker 4 I almost imagine like an outfielder in baseball trying to catch a pop fly putting up his glove to block the sun in order to see the baseball.

Speaker 23 Yeah, so the starshade is like that, but it's enormous.

Speaker 31 It's tens of meters in diameter. And so it looks like the silhouette of a giant sunflower.

Speaker 4 And would this just be about spotting these planets or would it be about like learning more about them?

Speaker 34 Yeah, so like the web, it would be able to determine the composition of the atmosphere and it would be capable of detecting oxygen on these planets, which the web just, it's not really well suited to detecting oxygen.

Speaker 7 And if HabEx and Starshade find a planet with oxygen, I mean, well, that's not like a perfect sign of life, but it sure raises the possibility.

Speaker 4 Yeah, I mean, it's probably likelier that you'll have life on an oxygen planet than on a lava planet, right?

Speaker 34 I mean, as far as we know, like we make a lot of Earth-centric assumptions about which planets are habitable and which are not.

Speaker 46 And Webb could totally, you know, destroy those assumptions.

Speaker 52 But at the same time, you know, if life can exist on Earth, like we should look for Earth-like planets.

Speaker 31 When you look up at the night sky and you see all all the stars up there, you can wonder what's out there.

Speaker 31 We can nearly guarantee that the star you're looking at has planets. And to me, it's amazing to think that we can learn something about that planet.

Speaker 31 Maybe not all the details that Earth has, but we can learn something and know about a world far away.

Speaker 4 Okay, so that's one potential future telescope, HABX,

Speaker 4 with this star shade umbrella to block out the star. Yeah.
What's another future telescope that could kind of take us past the limits of the web?

Speaker 58 So, astronomers want to build telescopes to look even farther back in time than the web can.

Speaker 4 Like before the first light of the universe?

Speaker 34 Yeah, yeah.

Speaker 23 It's kind of audacious that we even think we can do that, but it's possible.

Speaker 11 This is still something that astronomers dream of being able to do someday. I talked to Paul Hertz.
I'm the director of astrophysics at NASA.

Speaker 34 And he tells a story about what scientists think happened before that first light of the universe.

Speaker 11 When the universe was first created, it was so hot after the Big Bang. It was so hot that atoms couldn't exist.
It was just a plasma of subatomic particles.

Speaker 4 So this was the post-Big Bang hot soup phase you were talking about earlier?

Speaker 56 Yeah, yeah.

Speaker 13 And then came the Dark Ages.

Speaker 11 We can't see with light that part of the universe.

Speaker 13 But there are telescopes that can detect things that are not light. And in the Dark Ages, there were all these hydrogen atoms that were emitting these really faint radio waves.

Speaker 11 So if you build the right kind of radio telescope, very large, very sensitive, then you would be able to detect the radio waves and we could study the universe before the first stars and first galaxies.

Speaker 23 And to do this, you would build a giant radio telescope on the far side of the moon.

Speaker 15 So this is the side of the moon that never faces the Earth.

Speaker 23 And this is a real idea.

Speaker 7 There's a couple of designs out there.

Speaker 45 One is called Farside.

Speaker 25 Another is called the Dark Ages Radio Explorer.

Speaker 47 Ah.

Speaker 4 So like the moon is sort of like blocking out radiation and light and things like that?

Speaker 7 Yeah, so these early, early radio waves, they're super faint.

Speaker 34 It's just way too noisy here to hear them.

Speaker 51 We generate tons of radio noise.

Speaker 55 But the entire moon could act as this giant shield.

Speaker 11 Sure, it's thousands of miles of rock. So the radio waves can't get through that.

Speaker 4 Okay, so we've got Starshade, which allows that first potential future telescope to block out the sun and see kind of Earth-like planets. Yeah.

Speaker 4 And then we've got Farside, which is a potential radio telescope that could take us back before the first light of the universe.

Speaker 4 What is the third potential future telescope that could take us past the web?

Speaker 34 Oh, this third one is so cool.

Speaker 58 We could go back even before these radio waves.

Speaker 47 How far back?

Speaker 23 Nearly all the way back to the Big Bang itself.

Speaker 47 Okay.

Speaker 34 So this telescope concept is called LISA, the laser interferometer space antenna.

Speaker 21 Nice acronym.

Speaker 45 Yeah, let's just stick with LISA.

Speaker 4 Okay, so how would this telescope take us back before radio waves?

Speaker 63 So far, we've been talking about telescopes that quote unquote see different forms of electromagnetism, optical light, infrared, radio.

Speaker 58 These are all electromagnetism. LISA is a telescope that would detect waves of gravity.

Speaker 47 Okay.

Speaker 7 Yeah, yes.

Speaker 57 It's a little weird, but just like waves can form in the ocean, they can form in the fabric of space itself.

Speaker 21 Okay.

Speaker 36 So imagine if some black holes slammed into each other.

Speaker 13 That collision is so massive that it can shake space.

Speaker 11 So it'll be like flapping space, and space will propagate that movement as waves.

Speaker 15 Anything within that space will warp.

Speaker 24 Things will shrink.

Speaker 51 They'll be stretched out.

Speaker 55 It's like looking at a funhouse mirror, but we are in the mirror, so to speak.

Speaker 4 And can we see ourselves getting all wobbly and circusy or at least like detect these waves?

Speaker 35 Yeah, yeah. We actually have this technology.

Speaker 34 So in 2015, scientists detected gravitational waves coming from two black holes colliding.

Speaker 34 And they could potentially detect gravitational waves from right after the Big Bang, from like the hot soup phase of the universe.

Speaker 11 During that period when the universe was opaque, it was very thick and hot plasma. There were pressure waves moving through it.

Speaker 11 And that pressure makes matter move back and forth, which creates gravitational waves.

Speaker 43 These gravitational waves are...

Speaker 63 you probably guess they're really faint.

Speaker 34 And so we would need a massive detector.

Speaker 11 So we need to have a gravitational wave observatory where the two ends of it are a million kilometers apart.

Speaker 4 Sorry, one

Speaker 4 telescope system observatory thing that has ends that are a million kilometers apart?

Speaker 67 Yes.

Speaker 4 How is that even possible to do?

Speaker 33 Oh, you know, you put it in space.

Speaker 7 Okay, makes sense.

Speaker 67 Yeah.

Speaker 24 So LISA is it's three satellites that form a triangle, and each side of this triangle is more than a million kilometers long.

Speaker 11 And it sends lasers back and forth and it measures whether the distance between the satellites has changed.

Speaker 11 And if it changes, it's because a gravitational wave went by and shrunk or expanded the space.

Speaker 4 Huh. So is this basically as close to the Big Bang as we can get? Could we ever get further than this?

Speaker 44 Yeah, this is probably the limit.

Speaker 61 For now.

Speaker 11 Certainly the history of science says that many times we have thought something was unmeasurable or unknowable until somebody came along that was smart enough to figure out how to measure it and how to know it.

Speaker 4 Zooming out here for a second, how realistic are any of these telescopes? Are these just like thought experiments or are any of these actually in the works?

Speaker 50 Plans for Lisa are underway.

Speaker 34 The other two I mentioned, they're on like the to-do list and whether what order we get them, you know, is still yet to be determined.

Speaker 4 So is this last telescope, Lisa? Is this sort of like the ultimate telescope, the most powerful telescope we can think of?

Speaker 57 You know what?

Speaker 38 It's funny.

Speaker 34 We've been talking about telescopes in terms of upgrades, like an iPhone, but really...

Speaker 11 There's no perfect or universal telescope. Each telescope, whether it's on Earth or in space, is designed to do a particular kind of science.

Speaker 43 So LISA would be really great at hearing these primordial gravitational waves, but it would just be blind to some other things like starlight.

Speaker 34 And this is just the trade-offs you have to decide in making telescopes.

Speaker 18 You can build a telescope that's great at one thing, but it'll probably be lacking in something else.

Speaker 4 When scientists are thinking about constructing these future telescopes and weighing them against the current benefit of the Hubble or the web, are any of them asking the question of like,

Speaker 4 why?

Speaker 4 I mean, is it just like a self-evident question that we would want to understand more and see further and build better telescopes? Or is it just sort of like

Speaker 4 trying to accumulate more knowledge for knowledge's sake, just trying to understand who we are and where we came from?

Speaker 44 Actually, I got this fascinating answer from Caitlin Casey.

Speaker 58 She's the UT Austin astronomer, the one who wants to look for the first light of the universe.

Speaker 23 She told me, if you look back to the Big Bang, to the dark ages, to the cosmic dawn, the creation of stars, galaxies, planets,

Speaker 58 We are a consequence of this.

Speaker 42 Like, we can't see ourselves as being apart from this.

Speaker 50 We are of this.

Speaker 30 Humans trying to understand the universe is really the universe trying to understand itself.

Speaker 7 Yeah.

Speaker 4 I just love the idea of instead of thinking about us as humans understanding the universe, I love the idea of thinking of ourselves as like stardust and just composed of the same materials as the universe.

Speaker 4 And we're all just the same thing understanding itself. That just seems really beautiful to me.

Speaker 48 Yeah, it's like the universe has built telescopes in a way.

Speaker 59 And I really sense there's this virtuous cycle here.

Speaker 21 So as we generate what will be incredible images from the web and from other telescopes, we're only going to inspire more people to be curious and to get in and on this virtuous process of like the universe becoming self-aware.

Speaker 66 If you're listening to this episode and you're like, I need

Speaker 66 more podcasts about space, then you're in luck. Check out our series from last month called Lost Worlds.
It's all about some of the wildest mysteries buried in the deep past of our solar system.

Speaker 66 We've got episodes about what killed Venus, whether there could be life on Mars, how the moon was formed, and whether there was a civilization on Earth before humans.

Speaker 66 If you want to learn more about the Webb Telescope and the images that we're starting to get back from it, Our friends over at Today Explain caught up with Amber Strawn from NASA to ask her all about it.

Speaker 66 Check out their episode, which is out this week. This episode was reported by Brian Resnick and produced by me, Meredith Hotnot.

Speaker 66 Noam Hassenfeld wrote the music and edited the episode with help from Gillian Weinberger and Bird Pinkerton.

Speaker 66 Mandy Nguyen took the facts, Christian Ayala was on mixing and sound design, and the rest of the Unexplainable team includes Catherine Wells and Richard Seema.

Speaker 66 Special thanks to Joss Fong for sharing audio from her interview with Robert Williams.

Speaker 66 Joss produced a fantastic video for Box all about the Hubble Deep Field project in the 90s, which you can catch on Vox's YouTube channel.

Speaker 66 If you have any thoughts about this episode or ideas for the show, like please email us. We want to hear from you.
You can find us at unexplainable at box.com.

Speaker 66 Unexplainable is part of the Box Media Podcast Network, and we'll be back next week.

Speaker 66 How far we have come

Speaker 32 and still have to go.

Speaker 10 How far we have come.

Speaker 10 Each one hits us how far we have come.

Speaker 41 This month on Explain It To Me, we're talking about all things wellness. We spend nearly $2 trillion on things that are supposed to make us well.

Speaker 41 Collagen smoothies and cold plunges, Pilates classes, and fitness trackers. But what does does it actually mean to be well? Why do we want that so badly?

Speaker 41 And is all this money really making us healthier and happier? That's this month on Explain It To Me, presented by Pureleaf.

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