First Update from the James Webb Space Telescope

[Music] thank you [Music] good evening everyone my name is Andrew fracnoy I'm the Emeritus instructor of astronomy here at Foothill College and it's a real pleasure for me to welcome everyone here in the pretty crowded Smithwick theater at Foothill College and everyone listening to us on YouTube to this talk in the 23rd year of the Silicon Valley astronomy lectures and tonight we're delighted to have back one of our favorite speakers perhaps the person who spoken most often in this series Dr Alex Alex filippenko before I tell you more about him I should say that this series is co-sponsored by four wonderful astronomy organizations the Foothill College science technology engineering and math division the seti or search for extraterrestrial intelligence Institute the Astronomical Society of the Pacific and the University of California observatories which includes the Lick Observatory the oldest continuously inhabited Mountaintop observatory in the world so we're very pleased to have their support and their advertising for these lectures and I if you've come from one of these organizations we especially welcome you um we try in this series to have talks on the most exciting topics in modern astronomy by speakers who can convey them the ideas in everyday language and no one is better than that than our current Speaker our speaker tonight Dr Alex philippenko he was voted the University of California Berkeley's best Professor nine times I mean once you can get away with just bad jokes but nine times that's pretty good um he's the only astronomer to contribute to both research teams whose work earned the 2011 physics Nobel Prize for discovering the acceleration of the expanding Universe he has produced five astronomy video courses with the Great Courses he co-authored an award-winning astronomy textbook which is still in print and has appeared in about 100 TV documentaries among his many awards are the education prize of the American Astronomical Society the highest prize for astronomy education in our country and the Carl Sagan prize for science popularization he is indeed someone who walks in the footsteps of Carl Sagan so talking tonight about perhaps the most exciting development in astronomy of the past years which is the James Webb Space Telescope it's a pleasure for me to present Dr Alex philippenko thank you thank you very much Andy for that very warm introduction and gosh it's it's so good to be back in person again isn't it look at this place wonderful wonderful um anyway 23 years Andy I think we owe a round of applause to my introducer Dr Andrew fracnoy I mean that is an astonishing achievement and if you consider not just the people who come in person but also those many many thousands who view the lectures online your reach Andy has been uh has been phenomenal okay well the web has been in the news really a lot folks it's been fantastic so it's a pleasure to be able to speak about the results the from just really the first year although science data started only being taken in July so it's really only half a year two-thirds of the year and uh the telescope was launched on Christmas Day 2021 only 14 almost 15 years late but better late than never it's a very complex instrument and telescope took about 10 billion dollars to to build you know so better get it right for that kind of money and it's okay that it got delayed uh comparisons are often made with the Hubble Space Telescope which is still going strong folks uh proposals for the next round of of Hubble observations are due in May and my team is busy writing proposals now just as we were writing proposals two months ago for the second year of the web telescope and we're already publishing results from the first year so the Hubble is still up there it has not died it has not been replaced nevertheless comparisons are often made and the new kid on the Block who thinks he's the center of the universe Webb City there smiling I hate him Hubble says because the attention has definitely shifted now to the Hubble to the to the James Webb Space Telescope but look uh Hubble is still up there and has been going for more than 30 years as the premier Space Telescope so that's a pretty good run uh the comparisons are are appropriate you know it's 30 years later it's a bigger telescope it had better do more things so here are a few of the main differences uh first of all being a bigger telescope in radius it's sort of radius squared bigger in area so you can think of the mirror of a telescope as a gigantic pupil of an eye and starlight is raining down upon us forgetting about the roof above us but and we look up and you know some number of bits of light photons enter our pupil and are detected by the retina well what happens at night your pupil dilates in order to collect more light there's also a chemical change in your eye as well but the more light you can collect the faint or the objects you can see or the shorter is the exposure time in order to detect a certain object so the collecting area of the web is six times bigger than that of the Hubble Space Telescope so in a sense it's six times faster all right by the way the Hubble was a fairly ordinary piece of glass with an aluminum coating which is highly reflective the web is this hexagonal structure about which I'll tell you more in a few minutes made out of chunks of beryllium you might think why the heck beryllium turns out beryllium is is very uh light per per unit volume and very stiff and performs exceptionally well at the exceptionally low temperatures 40 degrees Kelvin which the web operates and it's got a gold coating instead of a silver coating because as I'll discuss extensively in this talk the web is tuned to operate primarily at infrared wavelengths not Optical wavelengths and gold is a much better reflector of the infrared than silver or aluminum R okay so big difference in size they're tuned to different parts of the rainbow the Spectrum so the Hubble Space Telescope is tuned to observe mostly visible light but also ultraviolet at least the longer of the ultraviolet wavelengths this is the stuff that gives you a sunburn now the ozone in our atmosphere blocks most of the ultraviolet but not all of it ultraviolet can give you a sunburn I own no stock in sunscreen companies but you know where where your sunscreen so that's the ultraviolet shorter wavelengths of light than violet Hubble sees those it sees the visible light and then it sees the short version of the infrared so those are long red waves or short infrared waves Hubble goes um out a little bit out to here okay whereas Your Eyes Only See out to about here all right well the web is tuned to work almost entirely at the infrared wavelengths and and much longer infrared wavelengths than the Hubble and a little bit of the red into visible light but the web is really not a visible light telescope it's an infrared telescope and so what is the infrared well you feel the infrared whenever you're near some hot coals um after a you know campfire or something you see some visible light that's the tail end of the distribution the Spectrum so to speak you're seeing this orange and red light but the coals being hot by terrestrial standards are actually emitting most of their energy in the infrared so it's often called heat radiation but electromagnetic waves that are of a certain wavelength infrared are the same natural phenomenon as visible light just a different wavelength for the oscillating electric and magnetic fields without getting too much into the weeds and UltraViolet is the same phenomenon as well but short wavelengths then you get X-rays and gamma rays and things like that and on the long side you can get radio waves they're all the same phenomenon electromagnetic waves okay and we've learned so far the most that we've learned about the universe through electromagnetic waves now astronomers are beginning to detect gravitational waves which are a different phenomenon entirely ripples in the fabric of space and time I think Andrew we've already had a talk someone gave a talk about gravitational waves okay so so that's a big difference between the web and the Hubble all right so in that sense the web is not you know a successor to the Hubble it really it's one of my pet peeves when in the media and even some astronomers refer to the web as Hubble's successor it's just wrong first of all Hubble is still up there not not the person the telescope okay still operating and the Hubble is great at ultraviolet wavelengths and the visible and that's something that the lab fails miserably at and I'm not denigrating the web in any way they're complementary folks all right as I say my team uses both of them all right another difference Hubble is in a low earth orbit 340 miles above Earth's surface that made it serviceable by the space shuttle astronauts okay five servicing missions so even though the thing was launched in 1990 and there was a delay because of the Challenger disaster in 86 right it's you know the original Hubble was based on 1970s and early 80s technology but the astronauts were able to replace aging instruments with newer ones and with ones that had you know new detectors and new capabilities and the Hubble then maintained its utility indeed got better with time up until about 14 years ago in the last servicing mission was held so that's a great aspect of Hubble but it wouldn't work for a telescope tuned primarily for infrared wavelengths because Earth emits a lot of infrared light and reflects infrared light from the sun the sun does put out some infrared light and then there's you know the just the regular light that Earth emits through reflection that would land on the telescope and heat it up and stuff and so this is not a cold environment and warm things emit infrared radiation of their own and so that would swamp the light the infrared light from any celestial object that you were trying to observe it's sort of like during the day the stars are out there but their light is swamped by all the scattered sunlight scattered by molecules in our atmosphere so you don't want your telescope to be emitting profusely at the wavelength at which you're trying to observe so low earth orbit wouldn't work for the web they had to place it in a region that wasn't exposed to so much light and heat from Earth and so where they placed it was at a very special point in the sky that I'll talk about in a few minutes more it's called the LaGrange number two point it's about a Million Miles Away 1.5 million kilometers that's only one percent farther from the Sun than Earth is so the web isn't cold because it's far from the Sun like Uranus or Neptune it's called for a different reason it's only a little bit farther from the Sun than Earth is so you know if Earth gets warmed to reasonable temperatures why doesn't that telescope get warmed I'll get to that in a minute but that's where it is at this special L2 point and the reason it's special is that it orbits the Sun in exactly one year the same as Earth's orbital period And so this collinearity of the sun earth and the web is maintained all the time and you might say well why is that good well if you place the telescope at some other random Place it'll go wandering away quite quickly but the L2 point is a semi-stable point the telescope sits around there without being you know shepherded into place very much now left on its own it does drift out gradually but that's why the telescope has some fuel with which to gently put it back into place but they don't have to use much fuel much of the time because this is a semi-stable uh region Euclid I think not Euclid no um their name LaGrange points but three of them were figured out by uh Euler 30 years earlier I believe L1 L2 and L3 so why aren't they called the eulerian points well LaGrange figured out the the two hardest ones L4 and L5 and so I don't know he got all the credit see I could hardly remember yeah I think it's Euler anyone anyone there uh remember that Euler figured out L1 L2 and L3 I see a few nodding heads so okay but you know they should be called eulerian points or whatever okay anyway so why is the telescope cold well it's got these tennis court sized Sun Shields whose Hot Side reaches 125 Celsius more more typical temperature I think is 85 but nevertheless gets up to 125 because this is one of their diagrams 260 Fahrenheit holy moly but on the cool side it's down at minus 235 Celsius minus 390 Fahrenheit a 650 Fahrenheit degree differential how do they do that well there are these gossamer thin sheets 0.025 millimeters four of them I think and I think the first one is 0.05 millimeters thick of a certain type of plastic okay with an aluminum coating and the outermost two layers also have some doped silicon Coatings and so this is this amazing thing where most of the sunlight bounces off the first one and some gets through and then that bounces around and goes out the sides but some gets through and that bounces around goes out the sides and by the time you get to the back end of these thin sheets there's essentially no heat left it's incredible I mean I tip my non-existent hat to the engineers and physicists who figured this out it's incredible okay so you know these sheets are the size of a tennis court and the mirror is 21 feet these this thing wouldn't fit in a rocket right I mean it had to fit in a tin can well it's about the size of a bus or something but still it's like a tin can so they had to Halt fold the whole thing up and then unfold it and here you see the unfolding sequence and I think including the launch and all the other things that could go wrong there was something like 344 potential single point failures now you'd say all right suppose each of them has a 99 chance of working correctly that sounds pretty good to me 99 odds but these are independent events 0.99 to the 344th power is three percent I was a pessimist I will admit it I gave this contraption a three percent chance of working and then after launch well one of the single point failures had been overcome so then it was only 0.99 to the 343rd power okay look at all look at all this stuff that's going on the mirror was like a triptych and unfolded you'll see that right there boom clamped into place I was wrong that was great the telescope works like a charm it's working 25 percent better than specifications it's more sensitive by 25 percent set the bar a bit low and then you can declare Victory you know and no it's fantastic um so I didn't even want to spend a lot of my own time working on proposals for the first year of the project because I didn't think it would work no I spent more of my time uh okay so you've got the observing side which is cold and the sun-facing side which is hot how is the thing powered well it's powered with these solar power array thingies that have to get sunlight but you might think well if it's collinear with the Earth and the Sun and here's a not to scale diagram of this remember L2 is not twice as far from the Sun as Earth is it's only another one percent farther but this gives you the general idea by the way here the LaGrange the true LaGrange points L4 and L5 so if the whole configuration is collinear what should this telescope see when it's looking at the sun if it were right at that point right there an eclipse yes sort of you know Andy gave a hint they should see Earth eclipsing the Sun at all times and so in that case because the corona of the sun is so faint there wouldn't be much power going to the solar array so how do they avoid the total eclipse well they're a little bit off of it in what's called a Halo orbit these are very hard to understand I'm not sure I completely understand them but there's one of them at L1 as well and there's a telescope called Soho the solar and heliospheric Observatory which has been up for decades you can see the date here and this is what it's been doing not that it's got anything in the way eclipsing the Sun but it does this quite naturally you know at the L1 point so that's what that's what they do with the web they put it at the L2 point and you have this roughly circular orbit and so the telescope is not collinear with the Earth and the Sun so it does see the Sun but the sun shades keep the thing cold and the solar panels get the energy from the Sun so there you go the other reason it's over there is that uh if they were to look directly at the Sun the sun's radio emissions would swamp the weak signals that are being sent by radio telescope from Earth command to the to the web right because we have to tell it what to do and stuff okay all right so the 18 segments all we're looking in slightly different directions you know we now have lots of science results so I'm a skip over this in my early talks I would talk more about this they had to align them and all and so here's the telescope alignment evaluation image and you might say whoa that's really fantastically beautiful um it's not it's ugly it's got these huge spikes here six of them and then two others that are a bit fainter it's beautiful in that already you see lots and lots of background galaxies giant collections of stars but what is this awful thing ah there's nothing we can do about it folks it's What's called the diffraction pattern that occurs when light interacts with the edges of these hexagonal segments it gets bent nature does that and light also gets bent by these struts that hold up the secondary mirror right because the light comes in bounces off the primary goes to the secondary then goes through a hole in the primary and the scientific instruments are behind the telescope mirror so you've got these struts that diffract the light as well and cleverly the NASA Engineers aligned two of the struts to be parallel to the edges of the hexagon but you could not make the third one parallel as well and that's what leads to this fainter diffraction Spike so we have to remove all those things through software and stuff like that there's no way we can remove them otherwise and so I'm going to show you a bunch of pretty pictures shortly you can ooh and awe at them but if you're ooh and eyeing at that spiky thing don't please stars are not shaped that way okay you should say curse you'd Red Baron like you know Charlie Brown or something but uh yeah anyway that's what nature gives us all right so what do we have here well first of all why in the world do we want to look at the infrared I mean we've got the optical already we can see with that it's easier to build telescopes well first of all different wavelengths reveal different physical processes okay and so to give you an example of that let me just show you the same area of the sky image that different wavelengths of the electromagnetic spectrum it's a cluster of galaxies and you're looking at a square one million light years on a side a light year is the distance light travels in a year it's 10 trillion kilometers 6 million million miles try doing that at 65 miles an hour okay it's a big distance but that's the unit astronomers use okay so this is a cluster of galaxies galaxies are giant collections of hundreds of billions of stars all gravitationally bound together and this is a cluster of them of those galaxies bound together so here at visible wavelengths you see the contribution of stars Starlight basically okay that tells you about the galaxies now here's the view in X-rays and here I make an important Point you're not seeing the x-rays here because we can't see x-rays you're seeing the visible light representation of a picture taken at x-ray wavelengths where this is the brightest part in X-rays and it's assigned sort of a yellowish white tinge and then here are cooler parts and they're given this kind of purple color so there's some sort of a cat color palette there's a a code you take some x-ray wavelength or brightness and in this case brightness and assign it to a certain color in all the infrared pictures I'll be telling showing you the long infrared wavelengths are assigned a red color the medium infrared wavelengths are going to be assigned a green color and the short and thread wavelengths are going to be assigned a blue color so you get an RGB image of an intrinsically infrared picture of an object okay so but in all the web pictures I'll be showing you you'll be seeing the visible light representation of an intrinsically infrared image okay but here's an a visible light representation of the x-rays and what they're showing here hot gas between the galaxies that simply wasn't visible at Optical wavelengths and here at Radio wavelengths well there's that Central Galaxy right there it turns out it has a giant black hole there but it energizes particles near it that then go shooting out along two Jets sort of a violent Universe Andrew used to have a course called the violent universe and stuff and so all these Jets of particles get shot out and then the electrons which are moving at nearly the speed of light slow down and get captured by magnetic fields and they spiral around and that emits a type of radiation called synchrotron radiation doesn't matter what it is my point is it comes out at Radio wavelengths and it forms these big old huge lobes and you wouldn't have guessed it looking at the visible light right so again the radio waves are teaching you something completely different about this object so it stands to reason that if we look at the infrared we'll learn new things as well okay all right so now some science issues okay first we can study the evolution of galaxies I've mentioned that galaxies are these giant gravitationally bound collections of stars we live in one the Milky Way galaxy this isn't a picture of it if any of you have a picture of the Milky Way galaxy from this Vantage Point come see me afterwards I would like to purchase usage rights from you okay but we're like a mouse in a maze it's hard to tell what the maze looks like but through studies of our Milky Way we think it looks roughly like this maybe it has a bar in the middle but whatever so how do these things form and how do they evolve with time first of all they're gigantic they're a hundred thousand light years across and stuff how do they form well they formed long ago and then they grew with time but we don't see things right now as they were long ago to do that we have to look to very great distances because it takes time for light to travel from there to here so the greater the distance to which you look the farther back in time you are looking and if you assume that you know little baby galaxies back then evolved into more mature galaxies and older galaxies like the ones we see now you can study the evolution of galaxies but to do that we have to look far away and thus far back in time the problem with looking farther away is that the universe is expanding not here in this room not in our solar system not in our Milky Way galaxy but in the space between galaxies and even more correctly the space between clusters of galaxies space is expanding our teams found 25 years ago that is spending faster and faster with time that's really really weird that's the whole Dark Energy stuff I've spoken about that here before but this expansion of the universe stretches intrinsically ultraviolet and Optical light into infrared wavelengths and you see that going on right here you've got light from the stars in the galaxy being emitted on UltraViolet and Optical wavelengths but the stretching of space turns those wavelengths into the infrared by the time they reach us and so you can't see the earliest galaxies by looking at visible light alone oh okay so all right we reach Monday July 11th NASA's big press conference was going to be the next day but they gave us a teaser on July 11th a cluster of galaxies whose name is smax0723 whatever and you're all not because of that thing there or that thing there or that thing there someone might be interested in those particular Stars maybe they have some weird exoplanet orbiting them but for the purposes of this picture those are annoying nuisances the U and the ah are all these fuzzy blobs so first of all this is a small patch of the sky imagine a grain of sand held at arm's length imagine how small that looks there's something like 10 000 galaxies in that grain of sand and we now have many such pictures plaster them on the sky they all look broadly the same you can estimate that there's something like what one trillion galaxies one million million galaxies within the realm of the web in our so-called observable part of the universe we don't see the whole universe we only see part the part from which light could have reached us so the the number from the Hubble wasn't much different it was a couple of hundred billion uh so this isn't you know super new but it's still awe-inspiring that there are so many galaxies and by the way a more recent picture Pandora's cluster that's like five of those tiles right next to each other contiguous and there's obviously sort of two major clusters of galaxies here this one and this one and that really annoying thing right there there's 50 000 galaxies in this picture so that's just like mind bending right all right back to this one here the other thing is you'll notice that some of these galaxies look like little arcs like this so this is the phenomenon of gravitational lensing again we knew about this from Hubble or even earlier than Hubble there's visible matter and dark matter in this cluster of galaxies that's bending the shape of space and by the way the passage of time space time we call it and that then makes a distorted view and a magnified a brighter view of a background Galaxy and you can get some of this effect if you take the bottom of a wine glass and look through it at your name or something that you have on a sheet of paper or a marble or something it'll look distorted and stuff and move the wine glass around and you'll get some of these arcs you'll even get pairs of arcs that come from the same object but on opposite sides of the thing so uh you're seeing gravitational lensing and again that's not new but it helps confirm what we had seen with Hubble and things like that there's a lot of dark matter in this cluster so this was mostly a PR shot but there's a lot of new things here too they're among the faintest ones they're those little things right there I don't know if you can even see them but those some of them are extraordinarily distant primitive galaxies that's what the web was built for to see the first galaxies that are forming you know and they're pathetic looking and that's you don't necessarily ooh not them but that's the what's interesting in this picture and shortly after the publication of this this picture okay first of all astronomers sent in dozens of research papers within a week you know analyzing the galaxies because these data were made immediately public and unfortunately among the good papers there were also some bad papers and uh the media like Sensational headlines and so they then focused on one of the bad papers that said that the Big Bang didn't happen now this is an astronomer who used to do good work um I won't mention the astronomers name at all but uh but said astronomer had a book 30 years ago called The Big Bang didn't happen and he's sticking to his story despite 30 years of the Hubble and the Keck telescopes and the many many the microwave background telescopes and other such things that put the Big Bang Theory on very Solid Ground the idea being the universe Started Hot dense compressed and expanding that is on very Solid Ground we don't know why it started this way necessarily blah blah blah you know but but it did start this way and you know but what he said was that while these galaxies look so well formed after such a short time after the big bang that clearly the Big Bang didn't happen right the only way to have well-formed galaxies is that uh the Big Bang didn't happen this went viral it's complete baloney it's it's fake news so to speak okay don't believe it all right and you know there were many articles written about why you shouldn't believe this but it was based in part on a research article submitted by some colleagues of mine including Brenda fry who had been a graduate student at Berkeley is now a professor at Arizona State and the the title at least the provisional title I don't know if the editor allowed this in the end but panic at the discs first rest frame Optical observations of Galaxy structure redshift greater than three that means that they're like 10 billion years old blah blah blah panic at the discs This was meant to be a joke it was a play on words unbeknownst to me there's a pop rock band called Panic at the Disco how many of you had heard of Panic at the Disco the younger generation had I I mostly I'm not you know I hadn't heard of them but Panic exclamation wait at the Disco so the interesting thing well by the way no James Webb Space Telescope images do not debunk the Big Bang okay jwst provides an intriguing look at the early universe but it's not yet rewriting fundamental theories of the cosmos it by now it is actually this was August 22nd um but the point is that this author was making was that uh it's not yet rewriting the textbooks in that the Big Bang didn't happen in in that sense uh the author is right uh here's another one ask Ethan this guy knows what he's talking about read ask Ethan it's good good article has the jwst disproven the big bang no oops no no no no just no can't be much more emphatic than that the jwst has truly blown our scientific minds but it's a pure crackpot idea that the Big Bang is now disproven okay so um the interesting thing going back was that these are negative images so what's dark should appear bright but there are these very uh early galaxies that seem to have formed discs already well ordered rotating structures and they're only half a billion years old or something so that's very interesting Galaxy Evolution Theory would not have predicted that such well-formed disks could be so young okay doesn't disprove the Big Bang it shows us that our galaxy evolution theories were incomplete but that's good you want new telescopes and Large Hadron Collider and things like that to not just confirm what you already thought but to throw you something new kind of like our accelerating universe it would have been a bit more boring if we had just found that the universe is decelerating you know so this is good we have something to learn about Galaxy Evolution Theory okay moving on going back to this um not only do we have the pictures all right but this is a sophisticated audience you often go to the Silicon Valley astronomy lecture series I am going to talk about Spectra all right and you rarely see them discussed in the media because they would lose most of their readership but you pass Galaxy light through a prism or some similar device and you get a rainbow and you can measure the brightness of the light as a function of the color or the wavelength and if you're a trained spectroscopist you can tell that that galaxy has some stars that have neutral sodium in them and singly ionized calcium and hydrogen this is what we do these are the Fingerprints of atoms all right this is where you get a lot of the physics from spectroscopy especially when coupled with imaging so here are some Spectrum okay brightness versus wavelength going from short blue to red but now we're looking mostly at infrared wavelengths okay and you kind of have to follow these integrated circuits to figure out which Galaxy is being shown the Spectrum but here's one and this is a well recognizable pattern of things I've been studying this pattern of lines for for 40 some odd years since my graduate school days they're caused by oxygen and hydrogen but shifted to a wavelength which is way longer than is normal and so by looking at the expansion of the universe you can tell we're seeing this galaxy as it was 11.3 billion years ago out of a universe that's uh about 13.8 billion years old so this is at T equals 2.5 billion years and then this one here which is easier to follow 12.6 billion years ago Universe was only 1.2 billion years and this one here um 13.0 okay you can hardly see that's why I said you don't ooh and ah at the things that are most interesting when you just look at the picture that one's even farther away and this one 13.1 billion years that's when the universe was only 700 million years old so indeed we are seeing some of the earliest formed galaxies with Webb which was one of the things it was supposed to do and in a more detailed Spectrum you start seeing you know not only oxygen lines you see neon and stuff in a very young Galaxy and so it's interesting because all the elements heavier than hydrogen and helium and a smidgen of lithium all those other elements were produced by nuclear reactions deep in the cores of stars and then exploding Stars ejected those elements into Interstellar space and some of them gravitationally collapse to form new stars which then evolved and exploded and yada yada and ultimately we came along but it'll be interesting to study the chemical evolution of the universe by looking at the detailed Spectra of galaxies in our universe when the universe was very young so that's very interesting okay all right the next thing not sure when my clicker isn't working is that here's another instrument this one these Spectra were taken with an instrument that gets the spectrum of sort of one Galaxy at a time in great detail but you can also get more crude Spectra of a bunch of galaxies at the same time by using a thing um that basically disperses the light over the whole field of view and here are two little arcs so I claim those were gravitationally lensed images and I even said that there are pairs of arcs that are the same galaxy so here's my evidence there's the dispersed Spectrum left to right now here's a plot of brightness versus wavelength in the infrared and you see this pattern of oxygen and hydrogen lines again at the same wavelength which means that those galaxies are at the same distance and with the same relative intensities right the hydrogen could have been stronger than the oxygen or the oxygen could have been equally strong but they're not they're they're the same relative intensities and so that basically means that we're looking at two distinct images of the same galaxy really cool and try this with your the bottom of your wine glass at home all right I'm gonna accelerate my talk a little bit here so I'm involved in in this kind of research actually with a former postdoc of mine Pat Kelly who's now a professor at University of Minnesota and we studied this cluster of galaxies that has this nice Arc there and the modeling people in our team theorists and stuff figured out that these three unimpressive looking dots G1 G2 and G3 are are the same object okay and we took Spectra of them and we just uh we just got this paper accepted in in science Magazine and there it is there's those oxygen lines in the hydrogen line that are shifted way out to five and a half micrometers or microns okay way out in the infrared and um so this this is one of the highest redshift galaxies this is a Galaxy scene when the universe was only about 500 million years old this is not the far this one away the highest that I've seen published is um corresponds to a universe that's only 400 million years old instead of 500 but hey we're close and this redshift is just a technical thing for basically how much to longer wavelengths these familiar lines have been shifted so that's kind of cool all right so the web is doing really well already at studying early galaxies another way of studying the evolution of galaxies is to look at more nearby ones here's Stefan's quintet five galaxies but only four of them are in a group this one is only 40 million light years away the others are 290 so it has nothing to do with it so it should be called a quartet but the point is is that they're interacting with each other gravitationally and they're merging together now we can't watch that process in real time but we can see different galaxies in different stages of merging and learn how galaxies evolve when they merge with others and so this is a Prelude to what's going to happen to the Milky Way galaxy and our nearest big neighbor the Andromeda galaxy in about three or four billion years when they start merging together and they will look like a train wreck for a while and then they'll settle down to form we think an elliptical galaxy not a disky spiral one like this and we already have a name for it milk amida or milk dromeda whichever you prefer Milky Way and Andromeda okay so don't worry be happy this isn't going to happen anytime soon and even when galaxies merge together Stars only very rarely if ever directly Collide because the space between the stars is so big nevertheless we can get a Prelude to what's going to happen to our galaxy all right with objects like Stefan's quartet all right I mean I like galaxies so I spent the bulk of my time just now talking about them but here's another reason to look at the infrared you can see through clouds of gas and dust by dust I mean fine little particles more easily in the infrared than Optical wavelengths and even more easily than even more easily at Radio wavelengths but radio telescopes don't give you the same Clarity the same resolution you have to make gigantically big ones like like the Event Horizon telescope how many of you saw the orange donut the shadow of the black hole in m87 it was above the fold in most newspapers and then a few years later the shadow of the black hole in our Milky Way that was all done with radio telescopes but a whole bunch of them at different different continents okay um so infrared gets uh pretty good Clarity and you can see more easily through gas and dust so it's sort of like on a foggy day you might not be able to see an office building a couple of blocks away but you can still hear your favorite radio station because the long waves just have an easier time getting through junk all right so what kind of junk am I talking about well here's the Pillars of Creation one of the most iconic Hubble pictures I'm a Hubble hugger this is a fabulous picture it's clearly clouds of gas and dust that have so much material content that it becomes gravitationally unstable and it collapses to form new stars and you can study those stars at Radio wavelengths to some degree and so we knew this is going on but here is the infrared View and by the way this is well within our own Milky Way galaxy it's only 6 500 light years away same image in the infrared look at look at this quartet of stars here there's not a hint of them there well maybe that one is one of them but look at this group right there maybe one of them is that one I don't know look at this group here I don't see anything at the same location there's a bunch of stars all over the place we are seeing inside this cloud of gas and dust right right you're seeing newly formed or still-forming stars as promised with the infrared wavelengths and the clarity that the web gives so the pair here is a very stunning view I still love this picture again it has not been replaced by the web picture and I'm a web hugger now too they're completely complementary so lots of dust where there's Stellar birth the stars and the planets are born from the dust and gas there is also dust created by Stellar death and this is an object known as a planetary nebula has nothing to do with planets but early astronomers found these things they looked like a disc that sort of looked like a planet but Spectra showed that the gas was thin and not you know not some solid object you know or even you know a dense object like a star so it was a nebula and turns out these are dying Stars our sun will do something like this in about six or seven billion years so this is the future of our sun but based on Hubble studies it was thought that that was the star that's explode that's expanding dying quickly slowly and the infrared picture you see a companion star here and this is actually the one that ejected this nebula and the reason it's not visible at um Optical wavelengths is that a cocoon of dust has formed in the ejected gases and so that helps hide it it's also quite a cool object and that makes it more infrared bright so here you're seeing Stellar death all right I just this segues into it you can see colder objects more easily they emit mostly infrared light now you might think coals are hot yeah they're hot compared to skin but coals in a campfire are cold compared to typical stars on a Celestial scale coals are cold okay and so you can see cold or cooler things in the infrared than in the optical so again the infrared is this part here sunlight is white light it peaks in the visible in the yellow red people often call the Sun a yellow star it is not a yellow star it's a white star sunlight is the definition of white light the physiological effect of the entire rainbow falling on our retinas is that we call it white light I even know professional astronomers who call the Sun a yellow star they're just wrong and I argue with them and even scientists can be bullheaded and I can give them 17 different Arguments for proving that the sun is white but they still claim it's a yellow star anyway no big deal I have many pet peeves as my wife Noel will tell you anyway so uh so here's this is a bit technical but again it's just Spectra showing brightness doesn't matter exactly what the units are and what the numbers are versus wavelength from short to red I mean to long you've seen these before and so these are called black body Spectra Planck Spectra but so here's the sun 5800 degrees Kelvin at its surface and sure enough it peaks in the you know kind of yellow green part of the spectrum it actually does emit quite a bit in the infrared a hotter star Peaks at the near ultraviolet wavelengths you see that so it's easier to see the hotter stars in the UV this is a 10 000 degree star now let's go to a cool star 2000 Kelvin it Peaks at like one and a half micrometers infrared 1000 degree star there are such Stars okay peeks way over here at almost three micrometers all right and not much light filtering into the optical so your coals coals in a campfire are about a thousand Kelvin round number so the part you're seeing is this part when you look at Kohl's where it's emitting mostly is that part then there's really cold things and amen that mid infrared and really really cold things 100 Kelvin what's still a factor of 30 35 warmer than the universe as a whole which is only three Kelvin but they're way out at far infrared wavelengths okay so you might say well there isn't anything that's that cold you know I mean there are though so here's the sun it emits that visible light here's a low mass star it's pretty cool emits largely in the near infrared then there's you know Jupiter which is mostly reflected light from the Sun but it also emits some thermal radiation in the far infrared but there are these things called Brown dwarfs which is sort of the way you look at it either very massive planets or very low mass stars they have some characteristics of both they do undergo nuclear fusion for a while but of a special form of hydrogen called deuterium so there is some nuclear fusion but not the regular kind where it's just protons and then planets don't have any nuclear fusion okay um so I don't know these are kind of at the boundary but they're really cold Kelvin or 500 you know so in fact here's a headline that just came out recently new called distant brown dwarf so this thing f90w this means it's observing at 0.9 micrometers in the what we would call the near infrared just beyond what your eyes can see and there's nothing there at wavelengths a bit longer than what your eye can see and then here's 1.15 micrometers and oh there's something there and then 1.5 micrometers 2 micrometers 3.56 ooh now that's starting to look bright and then 4.44 micrometers look at that so that's one of these dudes that uh you know it's peaking well who knows where it Peaks but it's a lot of light is showing up here so it's probably just a couple of hundred Kelvin or so maybe like this or something you know maybe 500 Kelvin so that's kind of neat all right so that's uh that's nice and then then you have dust that that can form and um I actually meant to put this where I showed a dying star I slightly reversed the order but that's okay it's okay a supernova like this one here 1987a that has ejected gases it can produce dust too kind of like the planetary nebula thing sorry about messing up the order there a little bit but I'm on I'm on a couple of teams that are studying the production of dust in the ejected gases of supernovae tremendous explosions not these gentle burps little eruptions that produce planetary nebulae so we just submitted a an article that's now being peer reviewed and the web data are these blue dots here and the point is is that they peak in the far infrared actually this is a very cold dust just a couple hundred kelvins and moreover we can sort of tell that the dust resembles graphite more than silicates because silicates have a spectrum that has a dip here and the data seemed to be above that dip more in line with graphite so this Supernova that went off nearly you know 20 years ago and I studied it at Optical wavelengths now it's producing dust and we've studied that dust with the web okay and then finally getting closer to home and very near the end I myself don't do planets but planets are our own solar system are are quite cool both in temperature and scientifically and my colleague IMCA de Potter had this image the early release data from Hubble of from Webb sorry I'm a Hubble hugger but I've been living with it for half my life okay and so uh you know and more than half of my professional life right so two-thirds of it three quarters of it anyway um so this is a picture of Jupiter with its Great Red Spot in the infrared and again this is some color palette that's showing you the infrared and don't be disturbed that they didn't make the Great Red Spot look red maybe they should have maybe I'll tell emka hey you should at least make the Great Red Spot look red okay these things here are auroras they're Northern and Southern Lights Jupiter has a strong magnetic field that traps particles and stuff and then here you see all these colorful bands which are storms and things like that and imka had this interesting quote this is August right again this is the early months we hadn't really expected it to be this good to be honest said planetary astronomer Inca de Potter yeah being honest too she didn't think that the telescope would work either well at least I think she thought that it would work but not work this well but it's working really well and then here's Neptune a ground-based picture with some stars and its biggest moon Triton uh and then here's the Voyager 2 spacecraft image which showed rings that had been surmised from ground-based data though not directly detected they're these little arcs and stuff but they're thought to be complete rings and it turns out that was the last time we saw those things because in conventional photographs you can't see them um but look at that here's the jwst image and let me zoom in on it to get rid of this awful looking thing there there they are there are the rings and they are complete rings they're brighter in some parts than others and then here's a bunch of little moons and stuff which we knew about and then here's some developing storms on Neptune so that's kind of cool again I I'm not you know a planetary astronomer but I I gotta admit this is really pretty cool but there's only so many planets in our solar system eight sorry about that folks eight is the correct number I will convince you of that later on sometime but my former student Mike Brown I think has given talks on that he's the one who officially actually led to Pluto's demotion sorry about that it's still an interesting object it's one of the biggest Kuiper Belt objects that doesn't mean that it's uninteresting okay it's the first dwarf planet Noel makes these t-shirts it says Pluto first of its kind dwarf planet right so so why it's better to be the first of its kind rather than just planet nine and a rather diminutive one right anyway okay so the my last reason for looking at the infrared the infrared Spectra can reveal the presence of water and possible bio signatures or maybe even if we're lucky techno signatures so how do we do that most of the Stars you see in the sky have planets going around them the Kepler Telescope showed that pretty emphatically and there are other telescopes now tests NASA's terrestrial thingy looking for terrestrial-like planets but the the orbits are pretty randomly oriented relative to us but some small percentage half a percent to a percent are going to be Edge on to our line of sight and that means the planet will pass between the star and us once per orbital period and the planet blocks some of the light not much of the light here the scale here is weird 98 99 100. so zero is way down there in the sub-basement of this building so in this case only one and a half percent of the light was blocked but still this allows you to find these planets what's even more interesting though is this gray area there that's a hypothetical atmosphere okay that transmits some of the Stars light but absorbs some of it as well which part well it depends on what atoms and molecules are in that atmosphere okay so by taking Spectra of the star before and during the transit which is what this process is called and comparing them you can potentially find out what elements exist and what molecules exist in the planetary atmosphere and again you take a spectrum okay and you look at the strengths of these lines and you see if they're any different relatively speaking during Transit than not during Transit and this has been shown before indeed the Hubble did it over a decade ago look at that some star to own hdt09458 The Starlight filters through a sodium Rich planetary atmosphere you send the light through a spectrograph you get the sodium doublet as it's called and you get it in the spectrum of the star when the planet isn't in the way but you get it with relatively stronger depths when the planet is in the way the total amount of light goes down but the relative strength of the lines goes up because now you have this extra sodium in the atmosphere of the star so that's the idea so still going back to July 12th that to me in a sense the most exciting result of the NASA press release was this one so I say in a sense The Best For Last even though I personally like galaxies and black holes and supernovae so here's a spectrum quiz at the end what is a spectrum okay brightness versus wavelength right and here are the data they're noisy but that's okay this is a very difficult measurement to make especially as you go out to the longer wavelengths but the best model fit is this curved line here this blue thing here and it shows the presence of water in the atmosphere of this exoplanet wasp 96b orbiting star wasp 96. not a you leave out the a a is discriminated against the star is wasp 96 the first exoplanet found is 96 B so this is a very weird planet it goes around the star in like a day and a half or two days for comparison Mercury the closest planet to our sun goes around in 88 days so this is what's called a hot Jupiter yet its atmosphere has um has water you might think that's kind of surprising Why didn't it evaporate away it's because this planet orbits a very cool low mass dim star called an M dwarf and it didn't have enough radiation to evaporate the water away but this is very interesting because if you can find water in these extreme circumstances you know people are beginning to find planets that are more the mass and size of Earth and about the right distance from the star that they orbit to have liquid water or water in the gaseous phase or ice or maybe all three and at least on Earth all life that we know of right now is based on water and chains of carbon of course and someday it'll be silicon integrated circuits right chat GPT is going to replace our human conversations and all that kind of stuff right and I'm pretty convinced that if we live long enough our evolutionary descendants are likely to be computers and robots you might find that to be just a horrifying thought or you might think it's absolutely thrilling okay but whatever silicon life might dominate later but at least initially carbon-based life probably dominates everywhere where there might be life and that carbon based life has to be in an aqueous solution in in water or some other really good solvent where then a whole bunch of chemical reactions can occur so our astrobiologists have a mantra follow the water okay first find a planet that has some water in it and then direct all of your telescopes out that planet and look for signs more definitive signs of of life and here's a simulated spectrum of what we might expect in the future this is not a real Spectrum but in addition to the water here you see a very interesting thing ozone oxygen molecules O3 and methane CH4 bovine flatulence as Carl Sagan called it okay comes from Life decaying organisms they're abiotic mechanisms to make methane as well indeed we see variable amounts of methane in the atmosphere of Mars but few astrophysicists think that there's active Life on Mars or or even necessarily whether there ever was Life on Mars but but at least the presence simultaneously of methane and oxygen suggests some more or less continuous production methane mechanism for methane because methane oxidizes very quickly in the presence of oxygen and so unless there were some Source making new methane the methane would quickly oxidize and you wouldn't see it in the Spectrum anymore so this would be a signpost of potential life and then you'd really direct all of your resources to look for things and what might we find you know pollutants maybe we'd find chlorofluorocarbons right which we're destroying the ozone Zone the whole and science taught us that we shouldn't do that and guess what the ozone is coming back that's great that is a success story of homo sapiens one of few success stories it seems but anyway well we'll see many success stories but will we survive uh in the end but anyway you know we might find other other things as well so so that would be really interesting but anyway I hope that gives you a flavor for what's been done only some of what's been done with the web so far I only had one hour and then we need questions and stuff stay tuned for maybe 20 years of of jwst results I forgot to mention that they aimed so well at the L2 point that they only had to use a little bit of fuel to nudge it in there that's like you know from San Francisco to New York almost a hole in one and you had to cheat only a little bit at the end because someone helped you out that means that there's a lot of fuel left over to nudge it back to the L2 Place uh and it should last 20 years not just five years which was The Benchmark that NASA had aimed for so here we are at exactly one hour and uh I'll take questions okay there's some orderly procedure I think for this right now okay first of all I have to say now I know why it's nine times thank you thank you for a great talk and you can just see that the future can they hear me no I don't know maybe you'll hear borrow mine no no no you you hold on to that because that's okay here they can turn this on well no oh no well okay anyway I can see why it was nine times that he got voted best professor and now now we're gonna have time for questions people are lining up already but if you have a question please line up in an orderly way and to curate these questions and make sure that everybody stays orderly I'm going to recall to the stage Jeff Matthews okay very good all right lots of lots of people up there very good I'll try to answer them quickly uh so we get as met through as many as possible thank you very much for this comparison of Hubble and James Webb Telescope I have another question so so in case of the Hubble telescope it was launched and it was expected to perform I forgot maybe five or ten years and it was extended for another 10 another 10 and it could be serviced so it may stay for a while but in case of James Webb Telescope there is a service limit and it may not be expected extended for as long and it's sooner or later it will run out of you so what's the limit how long it will stay yeah and will it stay as long maybe he can see Planet X yeah yeah so you know um the nominal Target was five years and unless something goes very badly wrong getting it up to 20 will be fantastic right that's four times longer there's no fuel tank right you can't just remove the lid and stick a fuel tank there right there it would have increased the cost I'm not privy to all the things that were going on so it would be very difficult to service it but in 20 years time physicists and Engineers might come up with a way of taking a spacecraft up there and you know I don't know drilling a hole or I have no idea but never say never maybe there will be a way to refuel it but it's not meant to be refueled so when it dies it dies the other way it could die sooner actually is that there are micro meteoroids out there little tiny bits little Pebbles left over from asteroid collisions and things like that within the first month of the webs launch or opening up of this whole Contraption a rather big one hit one of the segments number 18 or whatever it was and that was cause for concern because that was sooner than had been anticipated so it meant either that we were really unlucky and there are not many of these things out there but one of them happened to hit early on that would be the good option or there are way more of these rather big stones out there and the thing will be pummeled and will degrade in quality much faster than anticipated the telescope has been out there for a long time now and no other such big one has hit so it looks like we were just unlucky in the first month however as a safety precaution we now look in a direction not toward the direction we're not looking in the direction toward which the thing is going in its Halo orbit because then the incoming particles would hit with a higher kinetic energy a higher speed and kinetic energy is one half MV squared so if you look in the opposite direction then the particles that hit your mirror are ones that are catching up with you it's like a head-on collision on a two-lane highway is a lot worse usually than someone nudging up and hitting you in the back okay so now we're we're trying to decrease the number of hits and the energy of those hits but yeah some big thing could hit at any moment right I that's always the case and there's more and more space junk at low earth orbit the Hubble images are you know I mean they've been degraded a little bit over time but not that much over 30 years but yeah something big we could get unlucky and it could hit and then the mission would be over I mean tomorrow right but so far it's been a year and things are going well and so I'm I'm you know I've been reading 20 years is now the anticipated lifetime okay thank you thank you thanks for great talk thank you yeah I like you was a pessimist about these 344 points of failure and uh was having a lot of angst when they put that thing up there but uh very relieved that we can discuss these results tonight but I was wondering if you'd engage in some Idol speculation if this thing had failed and we had a 10 billion dollar Edsel up there what do you think the consequences would have been oh it's a nightmare I don't want to even think about it right you remember the headlines after the Hubble's very very smooth but flawed shape okay when they didn't do a third test two tests were in you know inconsistent with one another what you really want to do is figure out why they're inconsistent but if you don't want to do that at least do a third test to break the tie they didn't do that they were Pennywise and pound foolish and I remember the Newsweek headline NASA's 1.5 billion dollar blunder these are not the kinds of headlines we like obviously we're not going to suppress that information and stuff right but that would have been very very bad for science in general and astronomy in particular and Congress right would have been upset because their taxpayers would be upset and why are you wasting this money and people often already say that this kind of pure blue sky research doesn't do Society any good I would argue against that um but and it does provide jobs all these engineers at ball Aerospace Lockheed Martin Northrop Grumman whatever right they're not just twiddling their thumbs okay we're advancing science and they've got jobs but yeah it would have been really bad I I don't know what would have happened but I'm glad we didn't have to go yeah I'm yeah I prefer not to you know think too much about doomsday scenarios that didn't actually happen it's like I don't spend a lot of my time worrying about the next Supernova that's within 10 light years of Earth or the asteroid that we didn't notice because it was coming from the direction of the Sun or something like that but it's good to be aware of such things and you know so we're got all these near-earth asteroid missions and things like that but fortune and I'm sure there someone had some contingency plans regarding what would be said right because I think even Kennedy I think had two versions of his speech when Apollo 11 landed right he had because it could have been a crash landing so there was a version of his speech that he gave it wasn't Kennedy it was who who was President Nixon of course Kennedy that was the one who said let's do it but Nixon had two versions of his speech he didn't have just like people running for his high office usually have two versions as well unless they don't want to admit that they lost or something you know so sorry about that no thank you very much I read that the one of the spectrograph detectors has an interesting shutter array covering sort of the pixels if you will I'm uncertain as to whether this instrument looks at many objects in one exposure or one at a time and does the spec does the shutter array somehow prevent if artery feels spectral lines from other objects or other images from interfering with the primary ones yeah I've got that right I'm not very very familiar with that instrument and the the details of the array so I'd better not answer um I just don't know about that particular instrument sorry about that thank you for your time uh our halo orbits only possible at LaGrange points yeah our halo orbits only possible at LaGrange points basically yes and it's because of the shape of What's called the gravitational potential you've got a little a little um indentation like this a little hole or even a little Hill and the um the objects certainly in the case of the hole you can imagine flick a ball right in a in a thing that looks like this and it'll follow an orbit like that the hell it's um not as clear and it has to do I believe what the Coriolis forces if you include the Coriolis forces which are forces that you feel in a rotating frame of reference but that are not one of the four fundamental forces like gravity electromagnetism strong nuclear force or weak nuclear force coriolis for example is what causes hurricanes you've got a spinning Earth and the air goes from low pressure to from high pressure to low pressure and it's going along like this but it gets moved to the side and that then turns into a hurricane so somehow when you include the Coriolis forces the the shape of this potential this gravitational potential whatever the detailed shape is and this is where I'm not even certain of the answer it allows similar orbits but it's not as obvious as if you just have a little a little cone shape not cone shape but you know an indentation kind of like this like a like a U-shaped thing where but but a rotated U where you flick a marble or you go to one of these science centers Chabot Space and Science Center and you can flick a a coin or a marble and the thing goes in and it's supposed to illustrate how it's sucked into a black hole or something but you get these orbits right when the shape of the potential is correct but at other than LaGrange points you don't have this um combination of both the gravitational pull and these coriolis forces you just so things just go flying off the L1 point is the easiest to understand the one where the Soho is orbiting so that's the one where the gravitational pull this way by Earth is equal to the gravitational pull by the sun in the opposite direction so it's sort of you know you put it there and it's stable but if you push it away a little bit it'll wander off because it's a it's an unstable equilibrium it's not the bottom of a hill you know like that so you have to nudge things back excellent thank you okay and then the just very very quickly the the L2 point is interesting because those who have taken introductory course you might think well if you're farther from the Sun if you know Kepler's laws square of the orbital period is proportional to the cube of the distance if the distance is bigger why isn't the period longer than one year oh that's a really interesting question and it's because out there the telescope feels the gravitational pull not just of the Sun which is what Earth feels but it feels the gravitational pull of the sun plus the Earth and that extra mass then propels it a little bit faster and makes it complete in orbit in one year haha so that's the physics of the L2 point okay uh hello thanks a lot um I was wondering whether field of view of James Webb yeah the field of view is small small um of order six or seven arc minutes on a side if I'm not mistaken something like that the the um Vera Rubin telescope being built right now in Chile is going to have this big old huge wide field of view we'll take a picture of the whole Southern sky and a bit into the northern hemisphere quite a lot actually into the northern hemisphere as well every two days and it'll it'll we'll find all kinds of Things That Go Bump in the night and then hopefully study them in detail over the small field of view of the web so the web is not a good search engine other than when you're looking at for distant galaxies where there's 10 000 of them in this relatively small field of view uh when I I guess I meant like if you were uh the son I was James Webb and I was going around I would be able to like scan the walls but is James Webb to like able to scan the ceiling no no James Webb can't scan the ceiling because it's configuration here are the solar panels and here it is it's got a little bit of play this way I think and a little bit of roll like that but not much because the solar panel has to point at the Sun and these sheets of plastic Kevlar B whatever it was have to Shield the main telescope so so it's looking you know basically like this but as Earth as Earth and the web orbit the sun you get access to different parts of the sky that's how it gets access to different parts of the sky awesome thanks thank you for talk um you did mention about these annoying little uh yeah these these things could we have murder modeled the diffraction and then inverted that uh using some image processing or something can we do what could we model the diffraction could we model it yeah we do model it but it can't be removed before detection is the problem it's you know you can model it here you know and if you're really interested in that Galaxy you could model the brightness of the spike there and there but you can also wait and let the telescope take the exposure at a different time then it turns out this whole pattern rotates and then this galaxy won't be along one of those spikes so that's one way to mitigate against this issue and I have a second question what's the oldest in time we can see with the wavelength so what's the oldest in time yeah that would be at microwave wavelengths those are either very long infrared or very short radio depending on how you like to think about it I think of them as radio waves um they see the cosmic microwave background radiation and that comes from an age of the universe 380 000 years and you might ask why can't we see beyond that and it's because beyond that the Universe was so hot that it was opaque like the sun you can't see through the Sun by the way don't look at the sun unless you have shade 14 glass or a proper solar filter but you can't see through the Sun and that's because it's an ionized gas it's a plasma there's a bunch of free electrons and free electrons scatter light so easily that you can't see through it so our universe was like the Sun at ages below 380 000 years or it's like you're in a fog and you can't see through the fog and then the fog clears or you know lifts or or condenses or whatever and suddenly you see great distances so with electromagnetic waves we will never see any farther than T equals 380 000 years however there are particles neutrinos that could travel and do travel through stuff they could travel through a light year of lead and not care fifty percent of them don't care so there are neutrinos from the early universe and the trouble is it's hard to distinguish those neutrinos from neutrinos produced by the Sun or whatever and then their gravitational waves distortions in the shape of space and time caused by slight density variations in the early Universe those are called primordial gravitational waves they have not yet been detected but we hope to detect them so both neutrinos and gravitational waves could come from T just a slight bit greater than zero but not electromagnetic waves can James Webb go all the way to 380k can what can the can the uh oh the James Webb no it can't see that far um because the wavelengths are too long and at that time you know you might say well what if there was a star there and it emits light there wouldn't be a star at that time because the density fluctuations would not yet have collapsed to form Stars moreover this redshift Factor Z that I was talking about the fog comes from Z of around 1100. I was talking about redshifts of seven eight nine even 13. so 1100 would take the ultraviolet and visible light from stars and shift it way off into the radio wavelengths once again or to the very very far long infrared thank you so much one one question more okay oh one oh sorry one question oh good so we have some more time I'm quite willing to stay longer if you one question per person folks that's not my rule that's Andes and he's the boss um Professor thank you so much for your time uh I was just wondering how does the extra energy that's um picked up by the Halo orbit compensate for the uh extra amount of energy required to take the Halo orbit like does it compensate yeah so the the I don't understand the Halo orbits very well but if you take my example take a bowl this is what I was looking for some everyday object a bowl okay and just take a marble and you know flick it perpendicular to the bottom you know to the radius coming out from the bottom and you know that that marble will go around it'll eventually settle down in the bottom of the bowl but that's because of loss of energy due to friction if it were completely frictionless and you gave it a flick that thing would just keep on going makes sense so there's no atmosphere out there you know they they put the thing in the Halo orbit and then the only thing to worry about is that it does drift away every once in a while and so you have to be like a little Shepherd and use a little bit of fuel just little thrusters to just knock it back into place so the telescope mainly runs on the solar energy yeah the solar energy it has to run on the solar energy um to keep the devices working and and stuff yeah you know the shutters and things like that yeah yeah thank you so much you're welcome thank you for a wonderful lecture uh thank you I had a similar question to the earlier uh gentleman's question about how far back we can see in time uh you mentioned 400 million years light years uh sorry 400 400 million and the the farthest ones we've seen now are maybe 300 million 300 million yeah you know so we can't go back to the fog that you mentioned but how far further can we go well so it's an interesting question and it's one of the questions that the web is supposed to solve and that is when did the first stars and galaxies form um and that's thought to have been at a redshift factor of maybe 20. so we're close at 13. it only puts us another 100 million years farther so maybe at 200 million years but was it 150 200 250 that's the kind of question we'd like to answer with Webb and we're not sure it's probably not much earlier than a hundred million years it just takes a while for those clumps of the high density clumps to coalesce to form stars and then to gather together and form galaxies but we'll see as the redshift record gets broken over and over again so it is possible it is possible yeah I mean if if a star or Galaxy were found at a time of a hundred million years I will be surprised but then you know already the web has taught us that at four or five hundred million years these Blobs of gas have become reasonably well assembled into rotating discs and that was a surprise I don't think we'll find one that negative 100 million years okay so uh okay thank you so much two more questions okay yeah thanks for a great talk I was really wondering have we begun seeing active galaxies in these yeah extremely young galaxies yeah we can see some active galaxies what the gentleman is referring to are galaxies that have a giant black hole in their Center that's sucking up material around it and one of the great mysteries in astronomy right now is that we see these objects called quasars which are the most active active galaxies out to redshifts of seven which means that the Universe was only you know less than a billion years old and how did these 100 million or billion times the mass of the Sun black holes form so quickly in a sense perhaps we should have anticipated that world formed galaxies would be visible at three or four hundred million years given that we already had evidence that giant black holes existed at one billion years or 800 million so maybe that's the same you know maybe it's two sides of the same coin telling us that Galaxy assembly and evolution occurred faster than we thought but yes active galaxies in have already been studied with the web thank you these are beautiful photographs and looking at these photographs you have explained that we have found galaxies are which are well formed we are about 400 million uh years of age or 500 million yeah looking at these numbers and all this processing is there a possibility that when we are saying there are 400 or 500 years old maybe there is some effect we did not consider maybe they are actually billion years old yeah so that's one of the concerns is that especially the early headlines panic at the discs was based on inspection of the images and their colors how much light there is at different wavelengths and they then um estimate what the redshift and hence the Look Back Time and therefore the age in the universe but some of those could well be wrong the spectrum that shows you those lines of hydrogen and oxygen that the spectrum is king or queen okay so the Spectra have been taken only of a relatively minor fraction of such galaxies but some astronomers have speculated that maybe a minor fraction of some of those discs are such early stages of our universe but the other ones are actually older until we take Spectra we won't know so so maybe it's not so many of them that formed so early we'll see stay tuned in a year or two there will definitely be more news on this front because this is this is exactly the type of question that Hubble sorry web was design I've given in my career so many talks about Hubble right this is exactly the question that the web was designed to uh to address thank you awesome okay thank you so much as I'm at you know great audience as I'm putting away my equipment here and stuff if Andy doesn't mind I'll be happy to personally answer a few questions if you didn't have a chance to ask them as part of the formal session but have a safe drive home and uh keep your keep looking up so to speak oh and see the April 8 2024 total solar eclipse don't be a loser if you live somewhere where it's 95 percent you know I will not forgive you all right unless you have a really good excuse all right very good thank you [Music] [Music]

Channel: SVAstronomyLectures

Views: 43,300

Keywords: astronomy, science, astrophysics, science news, James Webb Space Telescope, JWST, space, space telescopes, Hubble Space Telescope, stars, galaxies, universe, early universe, Filippenko, space photography, astronomy images, telescopes

Id: te2zSAbyAo0

Length: 89min 45sec (5385 seconds)

Published: Mon Mar 13 2023