The Technology and Discoveries of The James Webb Space Telescope | Wondrium Now

hey everybody welcome back to wanderium now this is a show that highlights the best series that wondering has to offer I'm rich Burnett and today we're talking about a scientific instrument that's so powerful it can look back at the beginning of time it's no longer science fiction today we're discussing the James Webb Space Telescope [Music] our first guest is Jay lockman he's the principal scientist at the green Bank telescope in West Virginia Jay presented our series called radio astronomy let's take a quick look we're here at the surface of the green Bank telescope and behind me you see 2.3 Acres of white reflecting surface it's a special kind of white paint and it has two jobs to do one it has to keep the telescope kind of cool what we don't want to have is sunlight hitting part of the dish and deforming it buckling it and so although this telescope looks blindingly white in light in the infrared it's actually black as can be and so it radiates heat very efficiently Jay hello good to hear from you yeah thanks for joining us today um so tell me a little bit about your work at the green Bank telescope what's what's an ideal day for you there like uh you could say that I'm lucky enough where every day is an ideal day uh I've yet to do my own research and also assist the research of scientists from around the world that one of the great observatories of the world so going to work every day I drive within view of the green Bank telescope a hundred meter diameter radio telescope one of the largest moving man-made objects on land so on any given day it may be in use by three or four or five different scientists or teams of science scientists on very diverse projects so keeping track of that helping out planning for the future instrumentation helping evaluate proposals uh makes my every day quite interesting and every day quite unique can you talk about some of the technical differences between the different types of telescopes that exist sure the important thing to remember is that light comes in all sorts of different forms if it comes in very long wavelength forms we call it radio if it comes in very short wavelength forms we call it x-ray or gamma ray the light that we're used to seeing around us Optical is what most telescopes are and we're very familiar with that for many hundreds of years people have studied the universe through Optical light using optical telescopes there are some phenomena out there which are only visible in x-rays so we have to have an x-ray telescope that can detect them and measure them and follow their progress through time there's other phenomena out there that are best studied by their radio emission natural phenomena that give off radio waves but there are things in the universe that are best studied in the infrared wavelengths and that's what Webb is giving us infrared radiation is produced by anything that's warm so you've got to get this telescope up into space so that first of all the incoming radiation is not blocked by the atmosphere because infrared radiation is very effectively blocked by the atmosphere our atmosphere acts as a big blanket trapping infrared radiation so light comes in heats the ground but the ground doesn't get hot enough to give off light instead the ground gives off infrared but infrared's trapped that's our greenhouse effect so you got to get up past the atmosphere in order to see any incoming infrared emission the other thing is that the telescope itself can give off infrared and Mission that confuses the signals that are coming from very far which are typically very faint and so that means the telescope itself has to be cooled very cold you got to get it not just out of the atmosphere you got to get it away from the earth so the Earth is not shining on it so the sun is not shining on it so the most amazing thing about the web is this big sale like thing which is actually a shield it's actually a sun shade and it keeps the telescope and its equipment cold so it gets about 50 degrees Kelvin above absolute zero and that's the surface itself and that's so your surface is not emitting infrared radiation and then the instruments that actually detect the signals have to be cooled even further so it's a complicated system lots of Parts parked somewhere where you can't get at it to fix quite a challenge getting it there and the entire scientific World breathes the huge sigh of relief at the successful launch and the miraculous deployment now you say it needs to be cooled but is it that it needs to be cooled or does it just need to be shielded from the heat of the Sun and then the vacuum of space does the cooling for it both the shielding from the Sun and letting it radiate into the vacuum of the space gets you most of the way it's all the way there's no active cooling of the dish itself that's just what the dish is and but for the instruments themselves they need to be cooled even colder we have the same problem with the green Bank telescope because the ground around us gives off radio waves just like it gives off infrared and so we have to package our receivers up there at the focal point into doers they're filled with liquid helium and pumped down to just a few degrees above absolute zero so that kind of technology is very similar you have to get your the noise from your receivers can be a very confusing thing and really limit your sensitivity in both the radio and the infrared so similar technology is used to cool those receivers down you can't just use it passively passive shielding is good enough for the reflecting dish but not good enough for the receivers um for folks who aren't familiar with the technology of say terrestrial telescopes myself included I would imagine a large series of lenses is all it takes for one of those telescopes to operate that's not the case is it there's actually a lot of electronics that goes into it just to clarify a detail there may not even be a single lens for big things it's much more efficient to use a reflecting surface something like that like a dish I mean I've got this piece of aluminum foil here okay and so as you can see the aluminum foil reflects light really well but you'd never use it for a mirror because that's the wrong shape so you've got two things going you've got to reflect the radiation whether it's in the infrared Optical or radio and you've got to shape it you've got to focus it so that it all comes to your receiver all at once and so the web telescope has these big segmented mirrors and each of them is very precise but they had to get those 18 mirrors focused directly we have an image here of the green Bank telescope surface and you can see a person walking on it I mean this is bigger than a couple football fields but you can see that it's made of panels what findings would you like to see it what is your dream findings that you'd like to see come from the James Webb Telescope you know that's a little subtle and let me just say that when I saw one of the very first images and here I'll display it for you it's this amazing image of galaxies a field full of galaxies and so what I find very interesting here first of all you're struck by all these things you know these fuzzy blobs scattered all about you see the starburst pattern of stars that are in the Milky Way so those things with Starbursts are in the Milky Way they're in the foreground but most everything else in there is really really far away but you see these streaks of light these arcs of light that seem some of them kind of centered on that fuzzy blob in the middle that fuzzy blob in the middle is distorting space because of its gravity and objects that are behind it get distorted as if you're looking at some kind of fun house mirror we all know about lenses problems with lenses that can distort things in this case it's not a problem it gives us a tool for studying the actual Gravity from these objects now in the upper right hand corner of this figure is pretty much a normal little Galaxy and it's easy to find lots of these in the image and this is a Galaxy kind of like the Milky Way it's got a center it's got some swirling spiral arms and you know it's just hanging out there up in the corner of the image but you go down to another segment of the image and what you see is a Galaxy like the Milky Way an image of the Galaxy like the Milky Way that looks like it's been put on a hot surface that has kind of melted and distorted and that image is distorted by the gravitational field of that fuzzy Galaxy that you see down below until it's left you can see the individual pieces of the Galaxy and what's so beautiful about this is we're measuring the bending of space by matter most of the matter we know is dark matter and we don't know much about dark matter but in this case we can see the way it's been and we can say you know there's no big blobs it's a very smooth bending and that's just the first image from Webb and I think we're going to get so much out of web from um it almost accidentally you know any place that points in the sky we're gonna get we're going to see wonderful things were there on any other images Jay that really strike you as as showing something mind-blowing for lack of a more um educated word no it's a great word there was a lot of the images were showing details in objects like planetary nebulae stars that have blown off their outer shell or regions where there's star formation molecular clouds and that is really going to have to be studied in detail to get any kind of understanding of what we're seeing it gives us another level of detail what I'm waiting for are the surprises I'm waiting for the little fuzzy thing off in the corner that someone says hey what in the world is that you know um something like wind when it's launched and opens up a new Vista for us surprise is always to be expected and almost always delivered and it just you know it opens up our philosophical Horizons as well as our physical promotions so Jay are there any current projects at the green Bank Observatory that you're you're excited about well there are several but one in particular is very exciting because the green Bank Observatory has been around for 65 years and we've always just received radio waves we've received radio waves that are naturally given by objects in space or on occasion we have worked with NASA transmitters where they transmit signals to an asteroid and we receive the signals there but recently we've put a transmitter on the Green Bank telescope and are using it to start doing radar studies of the solar system and this is one of the first images from those tests wow it shows a crater on the moon in incredible detail this is the highest resolution image of the moon ever been taken from Earth you could find a school bus if it was parked inside that crater and let me tell you what was more amazing is that the transmitter was 700 Watts That's The Power of a small microwave oven wow so with the transmitter of the power of the small microwave oven you can get details like this and so we're hoping to be able to put a more powerful transmitter on and be able to get unprecedented detail not on just the moon but on the planets but near Earth asteroids these things that you know were liable to collide or possibly collide with the Earth in some Future Part of planetary defense it's a brand new technology for green bank and one that I think you're going to see pay off in the years to come well Jay where can people find out more about you and and the work that you're currently doing well you can come to greenbankobservatory.org the website and green Bank West Virginia is with an easy day's Drive of an awful lot of people it's really worth the trip to come here and see the National Science foundation's instrumentation at work right on thank you so much again um I look forward to talking to you soon thanks and bye I'd like to take a quick moment to remind you that Jay is one of the hundreds of great presenters we work with at one dream in addition to series about astronomy you'll also find topics like history mental health foreign language instruction and personal development and if you want more cool stuff on the James Webb Telescope we actually have a few interviews with astronomers who are physically using it in their studies there really is something for everyone on wandrium so come check us out if you want to binge watch something watch something that's smart buy experts on biodiversity am I in history physics art streaming is a lot smarter with one dream one dream because I wonder knowledge is now streaming at wandrium our next guest is astronomer physicist and philosopher Sean Carroll Sean is the presenter of a few of our fan favorite series including physics of time Dark Matter dark energy and the Higgs boson Sean's work tends to lean into mind-bending areas of physics and he's here with us today to talk about how this telescope will change our understanding of the universe Sean hi welcome thank you for joining us today thanks very much for having me so let's get right into it what are some of the discoveries that we're expecting to see from the the James Webb Telescope you know the jwst the web Space Telescope is the successor to the Hubble Space Telescope but it's different in two important ways one way is it's just bigger okay it's actually further away so if it breaks we can't fix it like we did the Hubble Space Telescope but being bigger is very important it means it can collect more photons collect more light it can see further out into space see dimmer objects but the other thing is it's looking at a slightly different set of wavelengths the Hubble Space Telescope looked at visible light just like our eyeballs do our eyeballs are tuned to visible light because that's what gets through the atmosphere so we can see things here on Earth and Hubble basically showed us the image of the deep sky in those wavelengths but the jwst is looking at infrared light and that's important because when you look at things very very far away in the cosmos the light is stretched by the expansion of the universe it is redshifted as we say it goes from visible light to infrared light and that infrared light is exactly where the web Space Telescope is looking so it's basically tailor-made to look for very dim far away objects in the universe so in the images that we've seen already what are some of the cool discoveries that we've made you know the most obvious thing is something that many of us anticipated which is that we're seeing galaxies further away than ever and when you look into space a distant object you're Looking Backward in time as well so to us these galaxies that we're seeing are very very young they're recently formed so you know once we get better ways of looking at the universe of course we're going to see things that are even further away and that's what we're learning it might just be like a pixel or two on an image but you're getting data about the different wavelengths of light coming from those pixels and that lets astronomers say yes this looks like a Galaxy at an unprecedentedly large distance away from us so with the amount of galaxies that are out there in the universe will there ever be a telescope powerful enough to take a picture and just see a a a a straight field of white and red and blue without any black in the image well no not quite not not this kind of uh image that we get from jwst because galaxies coalesce out of the primordial plasma you know we live in a universe that is about 14 billion years old since the Big Bang at the Big Bang or just afterward the universe was very hot very dense very smooth and rapidly expanding so it was just a plasma a Charged particle gas everywhere Okay the reason why the particles were charged is because it was so hot and so dense that atoms couldn't stay together if you have you know two atoms they would just bump into each other and all their electrons would go flying what that means is that the Universe was opaque at those Early times because light would just bump into some of these charged particles you can't see past that primordial plasma but about 380 000 years after the big bang it had cooled off enough that the atoms could recombine that the hydrogen and helium could grab all the electrons around and now the universe looks transparent so we see the light from those Early times but it's been stretched out to radio wave frequencies microwaves in particular we call it the cosmic microwave background radiation and that is indeed everywhere because that is a smooth plasma that was all throughout the Universe but the galaxies that we see in an infrared or a visible light telescope those are localized collections of stars and gas and dust and in between them there is nothingness there really is empty space so we're being wowed by a lot of these images that are are starting to come out some of the images of cosmic Cliffs um that the now famous the Deep Field image that just shows all the stars that we couldn't see before Southern Ring Nebula is is another beautiful image but one that you can speak to directly uh since your field of studies is uh based widely on Galaxies is the Stefan's quintet image can you talk a little bit about that one and the importance of it well you know when we turned on the telescope I say we in the Royal sense I had nothing to do with it whatsoever except here at Johns Hopkins I am across the street from the people who actually did turn on the telescope at the Space Telescope Science Institute but when it got turned on of course we're going to look at some of the greatest hits first right some of the crowd-pleasing images just like Led Zeppelin is going to play Stairway to Heaven if they ever get back together so we didn't go for Pure Blue Sky scientific research right off the bat we wanted some pretty pictures okay and to me what's important about those pictures is not that there's a major groundbreaking scientific discovery but that it reminds us of the kind of universe we live in and Stefan's quintet I really love because it's a picture of five galaxies that are interacting with each other that are not just rotating around each other and revolving around each other they're bumping in to each other and they're gonna eventually coalesce to make one big Galaxy it's a good reminder that the universe is a dynamic place you know when we take these pictures one day and we take a picture the next day the pictures look more or less the same but over the course of millions and billions of years the universe is changing it's not settled down so we can see these days in a life of galaxies interacting with each other which I think is fascinating so what sort of surprises are you hoping that we'll see um from the images we get back from James Webb well I think there are two kinds of things that the jwst is really optimized for doing you know it gets very dim images using infrared light so one of the questions is what was the universe like at Early times when galaxies and stars were first forming we went from a perfectly or almost perfectly smooth plasma to galaxies and stars you know the universe got lumpier and we kind of know how that happened you know there's a slightly more dense region of space here a slightly less dense region of space there and things coalesce together but there's a lot of details that go into that that we don't know why are there different types of galaxies ellipticals and Spirals and so forth did the stars come first or did they come after was there an enormously giant massive generation of stars before the ones that we know about how did black holes form okay like all of these questions are really going to be addressed by jwst and then on completely the other side of the spectrum nearby and Tiny rather than far away and big we have planets right here in our galaxy and the idea that planets around other stars was always an idea but when I was a graduate student we hadn't detected any yet and now they have thousands of them so we're really trying to learn more about that by looking at how many planets there are are they big are they small what are their atmospheres like that's an absolutely huge area of modern observational astronomy so we hear a lot and you you touched on it a bit here in your answers that we're actually looking back in time this telescope is so powerful that we're seeing the past um can you explain that a little bit yeah you know it's just the fact that light moves at a fixed speed the speed of light what I like to think of as one light year per year or one light second per second if you want to put it that way doesn't matter what units you use what it means is that in the room or you're just sitting right now looking at things it is as if to you you're looking at things instantaneously right just because the light gets to you very very quickly but the truth is you're always seeing things in the past because it takes time for the light to get from the image you're looking at to your eyeball it only shows up when we go to astronomy because in astronomy things are so far away that the difference in time actually matters the nearest star other than the sun is Alpha Centauri and Proxima Centauri which are four light years away well we look at them it looks as if what we're seeing is from four years ago whereas the galaxies that we're looking at with the web Space Telescope are billions of light years away so these days today if that makes any sense we're going to have a Galaxy that looks very different than the image we get but happily we can sort of see images from many different galaxies and extrapolate to figure out how the individual ones evolve over time is there any way that you could imagine we'd actually be able to see a galaxy in the state that it currently exists no but the good news is we can sort of figure out the statistical properties you know the good news is there's a lot of galaxies out there there's roughly speaking a trillion galaxies in our observable universe and one of the nice things about something like the jwst is we can really begin to pin down what that number is and it's quite a heterogeneous collection of different kinds of galaxies some are quite tiny some are quite big some are in clusters some are lonely out there in the cosmos so that's what astronomers care about more to be honest we don't care about the life cycle of any individual Galaxy we care about the whole retinue of all of them what they were like it early on and what it's like now so of course a lot of folks are hoping to see some sort of evidence of an extraterrestrial nature um are there any chances that the telescope might reveal life on distant planets you know normally when I get asked questions like that I have to play the part of the curmudgeonly scientist explaining why certain things are just not very likely but here I can be a little more optimistic I mean it is actually conceivable that we could get a little bit of evidence for what might be life on other planets from jwst we're not going to see you know rocket ships being launched by Advanced technological civilizations on alien worlds but what we can do with jwst is look at the atmospheres of exoplanets as we call them planets around other stars because what we think is that there is a rough difference between the atmospheres of planets with life on them and the atmospheres of planets without I mean of course here on Earth we human beings are changing our atmosphere pretty rapidly leading to global climate change but what I mean is just the existence of photosynthesis the existence of life at all can have a big impact on what the atmosphere of a planet is and that might be able to be seen by jwst observations and when we're talking life we're not necessarily talking beings who are sentient but it could be as small as as cellular life correct oh I would say it's overwhelmingly likely that it will be as small as cellular life here on Earth on our planet which is the only data point we have life began relatively quickly in the history of the earth it didn't take long which is sort of mysterious all by itself we haven't been able to reproduce that in the lab yet but it did come along pretty quickly but it was all very simple single-celled life it took billions of years for different kinds of cells to team up to make what we call eukaryotic life which is a single cell but within a nucleus inside and then it took more time for cells to gang up to make multicellular life much less you know climb onto land make intelligence all of those things okay so it's extremely possible that life is ubiquitous in the universe but all the life that will ever detect just as single cellular we don't know it could be much more exciting than that but that's absolutely something we have to take into consideration very very cool Sean thank you so much for joining me today where can people find out more about what you're currently doing yeah I'm always doing lots of things I have a website preposterousuniverse.com that collects all of them I have a podcast called mindscape doing a new course for one dream on quantum mechanics and many worlds and I have a new book coming out called the biggest ideas in the universe so there's plenty of ways to absorb all that content awesome well thanks again I always enjoy talking with you and I hope to talk again soon thanks very much all right bye-bye and that'll do it for another episode of wondering now if you want to ask a question for an upcoming guest make sure to keep an eye on our social media feeds you can find links to all of them in the description below we'll be back soon with another great show be sure to subscribe so you don't miss it

2022-10-05 01:03

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