Ending the Mission and Legacy

I'll start with Steve's Wikipedia description . Noik Wipedia it says what Steve. Stephen Eils is a professor of astrophysics at Cardiff University where he is currently head of the astronomy group. In twenty fifteen he was awarded the Herschel Medal from the Royal Astronomical Society for outstanding contrib utions to observational astrophysics. He also writes articles and books about astronomy. But more than that, Steve was my PhD supervisor. He's a good friend. We've known each other for a very long time. He's a fantastic researcher and he has brought along with him some copies of the story of the book that contains a story that he is going to tell us today . So without further ado, I'd love to welcome Professor Stephen Eles who's going to tell us the secret history of a space mission. So welcome Steve . Okay, good everyone, hear me at the back. Oh cool. Okay . So what I'm going to do today is try and give you an idea of what it's like to be part of a space astronomy mission . So there's going to be some astronomy but it's also going to be a lot about actually what it's like to be part of these huge collaborations that do space astronomy . And perhaps I should give you a bit of background about myself . I didn't do amateur astronomy when I was younger . I can't recognize things in the sky and I feel quite intimidated by some people here who show me these star maps and say, well , we just go from star star to and you can find things. I don't know how to do that. My wife doesn't think I'm an astronomer because every time she sees something in the sky and says what is it ? I say, well, I don't know. In fact, the only reason I know now what's in the sky is because Jenny told me about this app that allowed you to actually look and see . I told my wife this which was a mistake so she now knows I just look at the app when anyway so, I didn't do astronomy when I was a kid . The reason I got involved in astronomy was really the Apollo mission and also science fiction . So some of you may be old enough to remember the sort of first Doctor Who episodes. I watched Doctor Who. I got really excited about going to other planets, all that kind of thing. So I gradually became an astronomer . But then for the first twenty years as an astronomer , what I did is I used big telescopes around the world and it's I found it quite romantic. You go to Hawaii and you got a mountain and use a telescope. But the truth is it was actually quite easy because you go to a telescope and you have a telescope operator and you tell the telescope operator where I like to point at that position and it scored quite straightforward. And the only things you should need to worry about really are the weather also whether the instrument works. So it's quite an easy thing. But then sometime at some point just by look , I got involved in the space a space mission, the Herschel Space Observatory, which is shown here on the launch pad. And so I'm going to tell you about that. I'm going to tell you about some of the things that you discovered . But I think what I do first is I'm going to show you the launch of Herschel and I want you to imagine what it's like. So just a bit of audience participation here. Could you put your hands up if you've ever built anything? Any kind of device, okay? Oh my God, Jesus Christ . So a lot of you have done that. Actually, I did do something and when I was thirteen years old, I tried to teach myself electronics and I managed to build a little transistor radio set , one transistor radio set and I tried to do more complicated things that it didn't work and at that point I gave up electronics and I've never built anything ever since . But But if you are if you put your hands up, what I want you to do is you are going to be the instrument team. I'm going to want you to imagine building an instrument for the Herschel space of duration who is now on the top of that rocket, okay? The rest of you are like me , you're going to be an observer. You're going to be someone that's in the Herschel teams and you have been involved in planning the mission . Now Now so to get you in the complete mindset, if you built an instrument, what that means is you've just spent ten years part of a huge international team building an instrument. You've actually sat there 's your working life nine to five, you've been in the lab building an instrument . It's been quite high pressure . Every now and then your instruments have slipped behind schedule . And if it's really serious you hit a thing called the critical path, which means your bit of the instrument is holding up the instrument which is holding up the launch of the telescope. So you can imagine that it's pretty stressful. When that happens, when you hit the critical path, you have to come in weekends, you have to apologize to your family, you have to work. So it's been very stressful but now finally your instrument is on top of this rocket. But you just spent ten years of your life building an instrument which is strapped to the top of this Arianne five rocket, which is a big chemical rocket like the things on bonfire night . So it's quite scary because these things blow up occasionally . If you're an observer like me, you've still invested quite a bit of time, but it's probably been a couple of years. You spent a couple of years going to committee meetings trying to plan the program for the rocket. But it's still a couple of years of your life. So you've now a lots' invested in this rocket and it's successfully working. And I guess the other thing you have to remember is rockets do blow up. This is an Arianne five . The first Arianne five that was launched was going to launch a commercial satellite, but the commercial satellite fell through and it was decided or European space agency offered the launch slot to the Cluster Space Mission, which is a space astronomy mission, and of course the cluster team say, Oh yeah, sure . I think ninety seven seconds after the launch of the first Arian five, it blew up . And that went cluster went down the tube. A lot of people lost their jobs . The reason it went it blew up was because there was some code left from the previous Arian four rockets and the Arianne four rockets were not as powerful and the Belgian team that had designed the software had designed it so that if the acceleration hit a certain threshold the software would realize that the rocket was off course and would self destruct and that's what happened . And the only people that were pleased about this were the Belgian team because it meant their software worked . So anyway, what we're going to do is I'm going to show you the launch. So you have to imagine the situation I was really scared when I watched the launch because I never had to worry about my rocket, my mission blowing up , so it was really quite sort of a scary so you just have to imagine . So what we're going to do is we're going to see the launch, hopefully . And so you might I mean, you're probably not going to be too stressed by this because I wouldn't be talking about it if it actually blew up . And I can't follow that. Is it off enzyme context . This Nef Wit , cis , sank , cat tran du h top Alim ka Alimeth is a pie decoration If you heard, I don't know if you heard Alex into the mic saying, My God, fabulous . Wonderful shots into the blue, blue sky. On a daylight. Something we don't see every day. We hope you enjoyed that. We'll have some replays at the end of the broadcast and you can see it again. seven hundred and seventy seven seven oh tons lifting off at eight zero . Yes we, know hear the noise coming from the launch ped arriving here at the vicinity of the launch control center. Takes over a minute. Takes over a minute. Takes a minute to make it fourteen kilometers. Yeah, two hundred and fourteen kilometers. So what's happening now? We have the first two flight phases the boosters . The two solid boosters give a very strong initial boost that will increase velocity from zero seven thousand two hundred kilometers per hour let',s say four thousand five hundred miles per hour, approximately twenty percent of the targeted funnel velocity. The GDO just said that all parameters of the flight are nominal. So we're doing fine. We have we're into the first powered flight phase. Arianne has three powered flight phases and one is unpowered. We'll describe each of them in turns. You can follow her along on her trajectory. Right now, as you mentioned, the two solid boosters and the core main engine are burning . Yes, they're for two point three minutes so burn of these solid boosters. Boosters should burn out in about ten seconds. You'll probably be able to see that because the skies are clear unless she disappears into the clouds . And after separation, we shall have lost seventy five percent of the mass at liftoff. Right on time. The boosters, the Dios call out the separation. This is what it looks like up there. There's two of them that fall away. The other one is out of the cabin. Gorgeous images from the separation . , so it was successful. Launch was successful . But as I show later, there's a whole series of things that are going to happen later that are also nerve wracking because things can still go wrong. So the rocket is not blown up , but if you' there instrument if you're an instrument builder, your instruments are not blown up, but on the other hand it hasn't worked yet . All the instruments were powered down during launch, but the launch is a lot of vibrations and, although the engineers tried to make sure that you could launch a camera and vibrate it and it would still work, you're not going to be certain yet until you get some observations. So we'll get onto that later . As I said, it was rather nerve wracking . And one of the reasons why it was nerve wracking, in fact, I still find myself my blood pressure goes up when I watch this . One of the reasons it was nerve wracking is we knew that Herschel was going to do some revolutionary astronomy . And so let me kind of explain why that is. So here we've got the electromagnetic spectrum and the visible range of w avelengths is right in the middle and all these you'll be familiar with many of these words x rays, UV, gamma rays, etc . These are all wave bands in the electromagnetic spectrum consisting of waves with wavelengths between certain values . And all these wave bands bar one had been used before for astronomy . And every time somebody had opened up a new wave band for astronomy , big discoveries had been made. So back in the day after the Second World War, when radio telescopes started to be used , astronomers discovered the existence of quasars , of rotating neutron stars pulsars , of radio galaxies, and also the cosmic microwave background was discovered as a result of that technology. So we knew that in the past, every time a waveband had been opened up for astronomy, exciting discoveries would be made . And the final wave band that hadn't been used for astronomy very much at all before was the sub millimeter wave band and that is the waveband that Herschel was designed to observe in. So we actually we were pretty sure or we thought there was a chance that you know the, first people that did big submarim eter surveys of the sky would discover really exciting new things that had never been discovered before. So that was one of the reasons we were very excited . And the other reason we were kind of excited was we knew or we thought we , we knew that the sub millimeter wave band held the answers to some fundamental questions about the universe . And the first of those questions is how does a star form ? I think this is a play ise. Somebody mentioned the playodise a few moments ago . Very easy to I should say I'm saying it's very easy to observe stars. So I don't know how cloudy it's going to be tonight but in principle it's easy to observe stars . And so you might think that, well, it'd be fairly easy to investigate how stars are formed . Well, the big problem with understanding how stars are formed is this stuff here . So here's a horse head nebula , it's a kind of black area in space and the reason there's a dark area here is because of cosmic dust . And the horse head nebula is actually a big cloud of gas and dust . And these clou ds are where stars form . And the problem is that the dust gets in the way of optical radiation . So you can have the best possible optical telescope. You can have the Hubble, Hubace tbleeles Scp ope, all the observing time on the Hubble Space Telescope, you still will not be able to observe star being formed simply because of the cosmic dust . The cosmic dust consists of tiny solid particles in interstellar space. So you think of dust as big a bit like smoke, little tiny fragments . The dust particles are made of what we call heavy elements, things like silicon and iron and oxygen . They tiny, typically about two microns in size. And these fill galaxies and it means that when you try and observe stars or as they form, you just can't see them because the stars form deep inside these clouds of gas and dust . So the reason why submillimeter wave band we thought would be important for understanding how they're formed is it kind of gave us a way of looking through the dust, although it's a little bit complicated to explain. Here is a big cloud and I've drawn a little cartoon in the middle of a newly formed star. We often call these proto stars uniform stars deep inside the cloud of gas and dust and the visible and ultraviolet radiation from this star , you can't see it because it's absorbed, the radiation is absorbed by the dust g rains around it. Now the dust grains they absorb the energy in the optical and ultraviolet light and that means they're heated a little bit and they're heated just about enough to emit sub millimeter radiation. The dust grains around the start then emit sub millimeter radiation, then the sub millimeter radiation travels through the rest of the dust and eventually is detected by a millimeter telescope. So you're not exactly observing the protostar, but you're observing you can see exactly where the protost are. So you're kind of observing through all the surrounding levels of dust right close to the prototy, so we were kind of pretty sure that Herschel would tell us a lot about how stars are formed. And then the other big question that we wanted to address is another origin question and that is how the galaxy is formed. Now you're all kind of interested in astronomy, so you probably know what the immediate thing I'm going to tell you , this is a picture of the Hubble deep field. So this is a traditional optical picture of the sky, but taken with the Hubble Space Telescope is it was in the nineteen nineties, it was one of the deepest, most sensitive optical pictures that had ever been taken of the universe. And if you look at this beautiful image , there's a star there , but everything else in this picture is a galaxy . And because the image is so sensitive , we're seeing the light from galaxies that are a long way away , which means that we're actually looking back in time . So the most distant galaxies in this image the light has been traveling for them from them for about ten to twelve billion years. So that means we're actually looking back in time ten to twelve billion years. So in this picture, there are galaxies at every kind of time in the past from about twelve billion years ago the present day. And so you might think trying to understand how galaxies formed, it's just a matter of taking an image like this looking far enough out into space that you're looking far enough back in time that you can see the galaxies being formed . That is kind of true. You can look back in time to see the times of the first galaxies, but the thing that complicates matters interstellar dust again because the galaxies all contain dust. And here's the optical picture of the Hubble Deep Field . This is a submill er picture that was taken in the late nineteen nineties with a very primitive submillimeter camera . And in the optical picture there's about a thousand galaxies present . In this sub millimeter picture there's probably about five and it's hardly any detail at all . The white areas are basically the sub millimeter sources, the sources of submillimet er emission. And the crucial thing is that if you go to the brightest sub millimeter source and you go to the same position on the optical picture , you don't find anything there at all. What this image is telling you is it's telling you there's galaxies that are so shrouded in dust that you cannot see them even on what was then the deepest optical picture that had ever been taken of the universe. So as a result of the work in the nineteen nineties, we knew that many of the first galaxies are basically hidden by interstellar dust. And so that was the second reason why we thought Herschel would be important because it would allow us to see lots of these objects and really study the first moments in the birth of a galaxy . So before I get on to some of the astronomy that Herschel did , let me tell you a little bit more about what it's like being part of a big space mission My kind of mentor in this, so as I said, I didn't get involved in space astronomy till I was middle aged and a lot of the stuff I knew I found out was completely new to me and my mentor , who I'll introduce in a moment, told me he said to me, Steve, a space mission is a little like a Hollywood movie . And it is. One of the reasons it's like that is because often people don't even remember who had the original idea . And it takes a long time for the thing to be developed. People get involved, people leave the team . There's a huge cast of people So it's very, very complicated and very big budget. And if you've ever seen one of these Hollywood movies and stayed at the end for the credits and you look at especially one of these superhero movies you, find all these , you find about a thousand lines of people involved. So a space mission is a little like a Hollywood movie. Now, however, in this case, we actually do know who had the original idea. And we know why the original idea came about . Could anyone know recognise this planet? Okay, obviously we recognise this planet because you're amateur astronomers, although actually as you'd have to look down to see it, you wouldn't necessarily see this anyway. This is I'm being stupid. This is the Earth . And the reason it's interesting is it's a very interesting planet. One of the reasons it's an interesting planet is the blue planet. It's a blue planet because this planet contains a lot of water . Now , we know there's a lot of water on our planet and a very fundamental question to ask is how much water do you find elsewhere in the universe , how much water is there in the other planets and in the universe at large . And in principle is an easy way to answer this because one of the things that we do routinely in astronomy is you can actually figure out what things are made of in space because you observe what are called spectral lines which every element, every molecule emits radiation at certain very distinct wavelengths. So figuring out how much water there is say in a distance around a distant star in a way is quite simple. You just look for the spectral lines from water . The big problem is that because we live on a very watery planet, the water in our atmosphere absorbs those particular spectral lines, which means that from the surface of this planet, you can't observe water elsewhere in the universe. So back in the nineteen nineties , a guy called Tys Tys Grau proposed to the European Space Agency that a semimeter telescope be launched into space to observe the water because a sem eter wave band is where the water spectral lines appear . And from the date nineteen eighty four, Herschel was launched in two thousand nine. It was twenty five years from the time that Tys had this idea to the time that the mission was launched. And as I said, it's like a Hollywood movie, big teams, long delays, and I don't think Tys was even involved in Herschel by the time it was launched . However, one thing that so space astronomy in general has the big teams long delays , but one thing that I think was unique about Herschel was it was so much fun . So when I was writing my book about it, I interviewed lots of people involved in the mission and one of the people who I interviewed was a guy called Michael Round Robinson, who's not the most fun loving character , but he said I'd been involved in seven space missions and Herschel was the most fun . And one of the reasons it was the most fun were the people involved . My mentor in law of this, somebody that January will remember is this guy here , a guy called Matt Griffin and Matt was the leader of the team that built the probably the most important instrument for Herschel. So it's called the Spire Camera and it was led by Matt and he had a team of one hundred and fifty scientists in eight different countries. And Matt was another guy at Cariffl University . And Matt and a number of other people made the project fun, but one of the things Matt did was that he had this big team from different countries and to make sure that people got on and interacted well had. a We team meeting every six months in one of these countries and Matt always tried to arrange some big social events . And he was very inventive in this. So one of the social events was a trip to the Oxford Greyhound races and Herschel actually sponsored a race of this and this little chap here is the winner of the Herschel race at the Oxford Greyhound Stadium . So Matt made things fun . And this was one of the things he also did, which is I didn't find so much fun at the time. So remember, launch was stressful . Five weeks before the launch , the teams that built the instruments and the teams that designed the observing program hadn't got anything to do because Herschel was out in French Guiana Everyone was getting ready to launch it, but I had nothing to do. The instrument teams had nothing to do . So you have to remember it was a very tense time . And the other thing you have to know to understand what happened next is that in the nineteen nineties the European Space Agency was very short of money and at the time there were two spacecraft or two space astronomy missions that were in preparation. One was Herschel and one was Planck . And there was a big financial crisis and various people wanted to cancel the missions or merge the missions. And in the event what happened was that the ESO decided to launch Herschel and Planck on the same rocket . And so here's the Arianne V Career in French Guiana, here is Planck, here is Herschel, above it . Nobody was very happy about launching the two spacecraft together . One of my friends said it was a high risk fudge designed to make the things happen. And everyone said, Well, it's putting all your eggs in one basket. So it was a bit scary . But we thought it'd be okay . And then five weeks before launch, Matt sends the team a memo describing a meeting that has taken place that day at European Space Agency headquarters in Paris . And it was terrible. So it's march thirty first, a day I remember vividly . I'm sitting there in my house reading my emails late at night on the thirty first of March, get this message from Matt. He describes this meeting that's taken place and apparently there's a crisis in French Guillana because they've suddenly discovered the ESA technicians have discovered that the pointing system on Herschel is broken. Now the pointing system on a telescope is a thing they use to point in different directions. We were going to use Herschel to observe all these different galaxies and gas clouds. So you obviously have to point the thing in the right direction. So it was a total crisis . And the meeting that had taken place in Paris, Paris had been designed to come up with a solution. And they looked at various options and the first option to me was the obvious one, which was that, okay, things still on the ground, let ship Herschel back to the Netherlands, to the space technology center in the Netherlands and fixed the problem . And the meeting had looked at this option and they had decided that this would cost about one hundred million euros . Which sounds an awful lot, but it was only ten percent of the total cost of Herschel, which was about a billion euros . But anyway, one hundred million euros in the context of the ESA budget was too much. So I could feel myself tense now as I'm describing what happened. They had decided there was a better option . And they looked back to the work that had been done in the nineties looking at merging the two missions and they had realized that they could bolt Herschel and Planck together and they could use the Planck Pointing system to point Herschel in different directions in the sky . Okay ? And so what they had decided is they would do that and then for the three years of the Herschel mission, Planck would point Herschel around the sky and then at the end of that time they'd separate the two missions and then Planck would do its own mission. I just thought this was terrible. I'd be anticipating it all the time because I just assumed that something would go wrong. And I read this email and I just sent a message back to Matt copied to all two hundred people in the team and I just let go. I don't think I'd use any four letter words, but I was pretty close to it. I was just saying I just had a total rant about the ESA bureaucrats But I thought, you know, fine . Went to work the following morning . I still haven't entirely forgiven that for that one. Anyway , five weeks later it was launched . And this is the last picture that human beings had of Herschel. This was a picture taken by a guy called Gustavo Muller, who was an Argentinian amateur astronom er and he's got a picture here which has got Herschel there . Plank is now safely separated thank God and this thing is the cage that was used to keep the two missions on the Arianne five. So they've suc cessfully launched, they're on their way . But we still don't know whether the things are going to work or not. Obviously I'm here so you know they're going to work, but think back to the time people who have built an instrument , you don't know whether your instrument is going to work yet . And Matt said to me once, he said, I wasn't worried at all about launch. He wasn't worried at all about launch because what worried him was whether his instrument would work. If Yarrien five had blown up, he said nobody will ever know whether we built the instrument successfully. It'd be fine . So Matt's moment is about to come because eight days into the launch he's going to turn on his instrument and see if it's actually responding . But the first thing I should tell you is where Herschel's going. And this is going to this is important because Herschel is going to go a long way from the earth. So Herschel is going to a place called the Second Lagrangient point, L two , which is about a million miles from the Earth and it's on the opposite side of the Earth from the Sun . And the reason for that if at L two , Herschel will orbit the Sun in the same time that the earth takes to orbit the sun, which means the sun, the Earth and Herschel always be in a straight line. So it's important with a space telescope not to point it close to the Earth or the Sun and if the Sun and the Earth are always in the same direction, it makes it much easier . The other reason why L two is important is because it's so far from the earth , it means that any submillimeter radiation from the Ear th will be less important . And one of the problems with the submillimeter wave band is everything emits submillimeter radiation. You're emitting a huge amount of sub millimeter radiation as you sit here. Submillimeter instruments, cameras emit lots of submillimeter radiation unless they're cooled to incredibly low temperatures and the Earth is a huge beacon of submill er radiation. So the further from the Earth you go the better . Now the problem with L two is it's so far . So if anything is going to go wrong with the instruments now, you can't send anyone up to fix it. So some of you will remember what happened to Hubble when it was launched in the early nineteen nineties , Hubble , they launched Hubble , took a picture of the star . The star was out of focus and they realized the mirror on Hubble had not got the right shape. There had been an error in the grinding program that ground s the mirror for Hubble. Now, fortunately, because Hubble is only flying about three hundred miles above the Earth, it was possible to send astronauts up in the shuttle to put a basically set of spectacles on Herschel on Hubble to fix it. But we know this is not going to happen with Herschel, it's going too far away. Anyway, eight days into the mission, Matt has to turn the thing on and Herschel is now so far away that it takes light or radio waves four seconds to get to the instrument . So Matt is going to press the switch, he's going to send a signal to Herschel , it's going to hopefully wake his instrument up . If the instrument wakes up a mirror's going to move and that's going to create a wiggle and four seconds later his bat's team is going to see something on the screen. They're going to see a wiggle on the screen. But you have to remember it's going to be a very long eight seconds. Okay ? So I'm going to before I show you what they saw, I'm going to put my hand up and then eight seconds later I'm going to switch the slide. So you just have to think about this. So this is your whole life here, well not your whole life. Your working life is hanging in the balance here if you built the instrument, if you're an observer doesn't matter. Not so much anyway. So put the hand up . You saw the wiggle. So that's the wiggle that appeared on the screen. So that's the next step. So the instrument is now woken up. So it's kind of survival launch, you don't survive launch to some extent . But you're not going to know whether it's actually really working until you take the first picture . First picture is what we call first light and that occurs on all telescopes. You have a telescope on the ground. You always have first light when you first use it to look at a star or something and see if you're actually detecting anything . So first light for matched instruments I'm going to show you the first light team . Here's the first light team. It's not a very exciting venue. It's just an office in the Rutherford Appleton Laboratories. This is Matt at the back . These are the this is the first light team and the reason they look happy is they've just had a really bad fifteen minutes because when they first looked at the first light images they couldn't see anything and they didn't think their instrument had worked . But by fiddling around with the data reduction pipeline, they finally saw something and this is actually what they finally saw . These are the first light images from Matt's camera . These are pictures of two nearby galaxies . In fact, you could probably look at these tonight I suspect because it's april overhead. These are Messi objects. You got all these telescopes out here. If the clouds clear, I've challenged you to see Messi seventy four Messi A sixty six Is that right? Okay, so sixty six so the challenge is C Messi A sixty six. Anyway, these are the first light submillimeter images of these two galaxies. These are the first two ever submillimeter images of these galaxies. Now, as it happens, these sub millimeter images do not look that different than the optical images. So we've not really seen anything new here . But what was really important when they looked at these first images is if you look at the M seventy four images, you can see all these red dots . Each of these red dots is a distant galaxy. And this is submetre radiation from very distant galaxies. So these are the galaxies that I'm talking about, the galaxies early in the history of the universe , galaxies that are basically in a formation phase that are emitting submill er radiation. So when Matt saw these pictures, he knew that the telescope, his camera was going to be successful . So let me now go through some of the discoveries that Herschel made . So some of the most spectacular pict ures were the very early pictures when Herschel took images of the clouds of gas and dust in our own galaxy. And these are some Herschel images and what we're seeing here is radiation from dust . And the colors in the images tell you the temperature of the dust. Now none of the dust is very warm . Probably the warmest dust here is about minus two hundred degrees centigrade . But the very cold dust is shown in red , the white and the blue is warmer dust. So you can see where there are things that are warm dust. And the first big discovery that was made and it kind of jumped out of the screen so it wasn't some kind of subtle discovery was that the intercellular gas and dust seems to be distributed in long filaments . So that I talked ear lier about stars forming in clouds of gas and dust and we tend to talk about or for years we've talked about intercellar gas as being in these big clouds. And the term cloud is just something we've taken from our kind of natural world because in the first observations, gas observations of the interstellar gas they saw things that looked like clouds, but we now think that cloud is kind of not really quite right. Actually the structure of interstellar gas is filamentary. You see a web of filaments everywhere . And the second big discovery was that where you see the hot dust, places where the dust is warmer, places where there's prototy, newly formed stars . And what we found or what the teams found is that stars always appear to be born in these filaments. So the places that stars are born is in these filaments of gas and dust . So the origin of stars and I'm describing the discoveries very quickly , so there's obviously a lot more than that, but I'm just going to go through one after another. So the next one I want to go through is how the question of how another origin question, how was the actual dust formed ? And this may not be super exciting to you, but for people like me that spent our careers looking into cellular dust the question of how the dust grains were formed in the first place is quite an interesting one. And one of the possibilities had always been that dust might be formed in supernovae because dust is made of things like silicon and oxygen and silicon and oxygen are made in supernovae . And back in the eighties , astronomers had a huge opportunity because of the discovery of a supernova called Supernova nineteen eighty seven A. Now , one of the irritating historical facts about supernov an astronomy is the telescope was first used in I think sixteen oh nine when Galileo used it to observe phaser Venus and Moons of Jupiter . The last visible supernova in our own galaxy was five years before that . And in the four centuries since no supernova had been discovered in the galaxy, which meant that we found supernovae and other galaxies, but they were very faint. It was very hard to investigate what was going on. But supernova nine hundred and eighty seven A wasn't in our own galaxy, but it was in the large magiantic cloud which is the closest Dwarf galaxy to our own. So it gave astronomers a huge opportunity to really study how supernovae what happens to a supernova. And in particular people like me in the twenty five years since supernova nineteen eighty seven A, we looked for the dust we looked for any sign that dust was being formed in the supernova, and we hadn't really seen anything . So when Herschel was launched , people generally assumed that dust could not be made in Supernovae. But then sometime after launch , Herschel observed the large magnetic cloud and you can't see very well here because it's a bit too light. But right at the position of supernova nineteen eighty seven A there was, a faint blob . And when people figured out how much dust that meant, it meant that about a solar mass, a son's worth of dust had been formed in Supernova nineteen eighty seven A. And the reason it had not been seen before that the dust is very, very cold and it didn't radiate it only radiates in the sub millimeter wavelength. So the reason it was discovered was simply because of the launch of Herschel . Now I said that M seventy four and M sixty six don't look that different in the sub millimeter wave band than they do in the optical wave band. Here is a galaxy where there is a difference. Okay, here's the audience participation. Who can recognize this galaxy? Well, this is a lot higher fracture than a normal gap okay . Okay, so this is M thirty one . This is a picture taken by an amateur astronomer. It was taken with a I happen to know this because I looked it up. It's taken with a sixteen inch telescope in Massachusetts by a guy called Robert Gendler, I think . It's the kind of standard picture that's always used of Andromeda although with the new technology technology that's available now, I know that amateurs can get much better pictures of M thirty one than this picture because I've seen them . And anyway, M thirty one , biggest nearby, sorry, biggest closest big galaxy to our own. So very, very important . And we ended up , I mean I was not involved in the previous work, but I was involved in this because it was my team that did this . So we decided we'd observe Andromeda with Herschel . It wasn't actually straightforward to do this because in the first round of Herschel observations, Andromeda had been missed. And it was only when I was a slightly complicated story, which I wasn't intended to give, but I went to the first Herschel meeting which was in Madrid and I was in a bar in Madrid talking to another astronomer, a Belgian astronomer called Martin Gas Martin Bas, and we realized that Herschel had not been observed. And we kind of made a sort of pledge to each other. We go back to Cardiff and he would go back to Belgium and we get eight hours of observing time from each team to observe M thirty one Andromeda. And Martin successfully did this and I went back to Cardiff and sent a message r to theound nearby galaxy team which is all over Europe and said look, no one's observed Andromeda. Can we just spend eight hours of our remaining time to do this? And the leader of the team was a very nice person, a friend of mine called S ue Madden in Paris and she said, Oh no, we can't do this because I want to use all the remaining observing time to observe Darf galaxies, which are actually interesting galaxies. But I thought this was absolutely crazy. Anyway, Sue did agree that we'd have a vote on it. So you don't really think of astronomers having vote somewhat to observe, but we had a real vote on doing this and at I came in the morning of the vote was about to be counted, or the votes had come in, and a friend of mine, a guy called Walter Gear, he came to me, he said, Steve , you've got to do something . You're two votes behind . The French have voted as a block against observing Andromeda and in favor of voting in favor of observing Dwarf Galaxies. So I kind of felt like some kind of old fashioned sort of politician I was sort of sending emails around everyone I could think of who hadn't voted say, please think about this. Observe Andromeda. So we did observe Andromeda , but it was partly as a result of kind of slightly shenanigans in the vote. So we observed Andromeda and this is what we saw which is very different than what you see the visible wavelength . This picture appeared on Stargazing Live on the BBC in early twenty ten and we observed it early because the BBC team wanted us to. So the BNBC team actually very helpful. They contacted the European Space Agency and said, Could you bring Herschel ahead in the schedule? So we did this. And you can see is something very different. So in the optical picture, there's a big red bulge in the centre of old stars , faint blueness in the disk and the blueness is because there's a lot of stars being born in the disc and new stars tend to be blue stars . What you see in the sub millimeter picture it's you're observing dust radiation from dust and there's not that much radiation in the center because in the center of Andromeda, there's lots of old stars, but very little gas and dust. But what you do see in Andromeda that you don't really see in the optical picture is this huge ring . And the ring is there because there's large numbers of stars being formed in a ring around the centre of Andromeda, you don't see these in the visible picture because of all the dust . But the dust absorbs the optical light from the stars, the dust is heated a bit and then emits some millimeter radiation and so, you see this beautiful ring. So in this case, the submillimeter is giving you a different perspective on the universe to the optical picture. Now I said that one of the big questions we addressed is the origin question of how galaxies are formed . We found lots of very distant galaxies and this shows one of these galaxies . Now this is actually not a Herschel picture. This is a more detail ed sub millimeter picture we took a few years later with a telescope called the Atakama Large Millimeter Array, but it's of a sub millimeter galaxy, a sub millimeter emitting galaxy that we discovered with Herschel. And what you see is something very strange. This is a some millimeter picture and you see this kind of ring or partial ring . And what you're seeing here is there's a thing called a gravitational lens in this picture. There's a galaxy right in the middle of the ring that you can't see . And the reason you can't see it is that it contains very little dust, so it's emitting very little submill er radiation , so it's invisible in our submill er picture . But the gravitational field of that galaxy is bending light or submillimeter radiation from a more distant galaxy around it. So if you think about it, if you imagine I'm a gravitational lens, there's a galaxy behind me, the radiation from that galaxy is being bent around me by the gravitational my gravitational force. And so you get this very strange thing and the gravitational lens , the invisible galaxy, is kind of like a big cosmic magnifying glass. It's a slightly strange cosmic magnifying glass because it's not only magnifying the radiation, it's also distorting it. And obviously that's not a good thing in a magnifying glass. But it's possible to correct for the distortion and take this, correct for the distortion and then what you get is something like this , this is the sub millimeter image of that distant galaxy, but it's now being corrected for the distortion. So even though this is obviously visible colours it's a representation of the submillimeter radiation. So it's a sub millimeter picture. And you see it doesn't the galaxy doesn't look much like galaxies nowadays got these big blobs everywhere . And in this case , this particular galaxy we are actually looking twelve billion years ago . So we're looking back in time and it's important to realize we are really looking back in time here because often when astronomers say you look back in time, it's tempting to think, well, what they're doing is they're inferring what was their back in time. But we're really looking back in time . In the same way that when you're looking at me , you're actually looking back in time a small amount because the light from me is taking a nanosecond to get to you. So you're actually looking at me a nanosecond back in time. In this case, we're looking twelve billion years back in time because the radiation has been traveling twelve billion years. So we really are looking at a galaxy twelve billion years ago . And the first thing that's kind of interesting, this is a galaxy that's being born. First thing that's interesting is it's a very small galaxy . In terms of physical dimensions, it's not particularly large. So in our own galaxy the kind of sun is in the galactic suburbs and is about thirty thousand light years from the center of the galaxy. So here's the sun, here's the center of the galaxy, about thirty thousand light years between them . This whole distance here is about six thousand light years. So when we look at these very young galaxies, they're physically very small . But the other thing that's interesting is that although they're physically small, most of the mass is still there. So the mass of this galaxy is around about the same mass as our galaxy, but it's packed into a region much, much smaller . Now one thing we could do , I said it's a kind of a galaxy. It's in the process of formation. Haven't really explained why we know this. The reason we kind of know this is we can estimate how rapidly stars are forming in this galaxy. And the stars are forming in this galaxy about one hundred sixty times greater than the rate at which they're forming in our own galaxy. And this means that's fast enough to build a whole massive galaxy in about one percent of the age of the universe. It's still a long time, but it's only a tiny fraction of the total life of the universe. So we're pretty sure these galaxies are galaxies in the process of formation. And then finally a couple of things we found we found that this galaxy is spinning like our galaxy is, but it's spinning five times faster and we also discovered that its disk is collapsing. So we found've some quite fundamental things that this galaxy , although we still don't know, this is one galaxy, we still don't know whether this is typical of other galaxies. disc collapsing . Well, I kind of I didn't explain very clearly that at all . We've got a rotating disk and what we were able to do was to measure kind of look through the dis k to look at the spread of velocities and it's possible to show that the spread of velocities suggests that the disk is actually collapsing that way . Twelve billion light year, twelve billion years back in time , kind of mind blowing . Let me finish off with a question that is much sort of more kind of basic , bring it back to a human level . Hopefully it won't rain tonight . But that water , where the big question is, where does the water come from So the water comes from the clouds obviously but the water in your bathtub obvious answer would be the water comes from nearby reservoir, but then where does the water come from before that ? Now one thing I never realized myself fully is the water molecule is incredibly stable. So actually the water on the Earth now, same water molecules on the Earth now were there four and a half billion years ago. So the water on the Earth has been over here a long time . But then you say, well okay where, did the water come from before that ? And we had a partial answer to that before Herschel went up, and the, um we knew we knew we knew some things . So we were pretty sure that a lot of the water in the universe forms on the surface of dust grains, another reason why dust is important , deep in these big clouds of gas and dust in which stars form. So I've shown that here. So here's a big cloud of gas and dust . These are some little dense regions and these little dense regions are going to collapse to form stars . And we know a lot of water in the universe is in these big clouds as is layers around dust grains . And we knew that these dense regions would eventually collapse to form stars. Here's an artist visualization. Here's a star forming. And actually what happens with one of these little dense bits is it collapses to form a disc. So you get you collapse to form a star in the middle, but then there's a disc around it and the disc around it will eventually form planets . And then the planets form out of the disc . Now the big question though was when the disc forms here, the disc gets very hot. So we weren't really sure whether the disc would be so hot that the water molecules that were formed here would then be split into hydrogen oxygen in the disc and then what that would mean is then the water that's in the planets would have reformed in the disk. So the water molecules on the Earth today would not be the same water molecules that were deep in this molecular cloud . Summarizing a huge amount of observations, what we found or the Herchel teams found was that in the disc , the disc does not actually get hot enough to destroy the water . So what that means is that the water that does come out of the taps today and the water that may fall from the sky tonight was once in the ice surrounding dust rains deep inside molecular clouds. So the water trail that leads to the Earth started life deep inside a giant molecular cloud with the water molecules in these ice sheets around the dust grains . How did the whole thing finish up ? I said at the beginning that the submillimeta wave band was the last waveband to be really used for astronomy . And I kind of touched on the reason for that. And the reason for that is that everything in the universe emits sub millimeter radiation , so even detecting sub millimeter radiation is difficult because any instrument you build will emit sub millimeter waves. And the only way you can avoid that is for the instruments to be very, very cold. Now in the case of Herschel , the main way we kept the instruments cold was with this big vat here of liquid helium and the liquid helium kept the instruments at about I think three hundred millicelvins so less than a one degree cent igrade above absolute zero. So for the Hirschel Instruments for some of the coldest things in the universe . But the liquid helium container gradually running out of helium . And so we knew at some point the mission would come to the end because as soon as the helium ran out , what would happen is the instruments would immediately start to warm up and they'd be useless very quickly. So that eventually did happen and the instruments warmed up. Herschel was then useless . It was at second Lagrangian point , but then the European Space Agency are faced with the issue of what to do with it. Now the second grandium point is really good for lots of reasons, but it's not actually a stable place to leave a telescope because if you order a second point it's an unstable orbit. So anything at the second grand june point will gradually move away from it. And so ESA knew this and they had to think very carefully about what would happen to the telescope. Now one possibility was it would eventually collide with the Earth and there was the kind of hope that most of it would burn up in the atmosphere . But the problem was the mirror of Herschel is made of very tough material and where people were pretty sure the mirror would not burn up in the atmosphere . Of course, the chances are it would hit the ocean or some uninhabited place . But you can imagine the public relations issue if Herschel had actually hit by Trafalgar square, for example. So anyway, they rejected this idea pretty quickly. But there was still the big question what to do. So here are the two other options . One option that was considered was firing it into the moon And the reason that was considered was firstly if it hit the moon, it would definitely not hit the Earth. So that was a good thing . But the other possibility that came into mind was that if Herschel hit the Moon, it would fur up a lot of stuff from the collision and then people could observe that. And they'd find out more about what was what was beneath the surface of the Moon. So that was an interesting idea. And the third possibility was the slightly more boring one, which is just try and send it into a safe orbit around the sun. Now, this was seriously looked at . I didn't like it myself for a variety of reasons . I didn't like the idea of this kind of historical artefact just being destroyed , but apparently the reason it was eventually rejected was the ESA decided it'd be too expensive. It would cost money to actually do it. And they went for the cheap alternative, which would send it into a safe orbit. So it went into a safe orbit around the sun , but then of course it still got power . So how do you get how do you turn the power off ? Well someone, has to press the switch and here is the moment which Herschel was turned off. So this guy so someone had a volunteered to turn this mission off and this guy is a guy called Martin Kessler . He volunteered to turn it off. Here is the real picture of him turning it off . Ason as he did this, someone realised this was not a really good PR thing to do because you shouldn't really be smiling like a bond villain as you do it So they this is the picture on the ESA website . Why do you want to turn it off ? Well, I don't know if you leave the power on , I don't know if that has any effect on the orbit. This is one of the many things I don't know, okay? So So when I wrote this book, I had to send it to the project scientist for Herschel and also Matt Griffin, who were the people that really knew the technical side. And they pointed out so many things I got wrong. It's amazing the number of things you get wrong. So I always say that Herschel was at the second egrandian point. It actually wasn't really. It was in a huge orbit around the second egrandian point. So there's so many things that are wrong. Anyway, the reason I wrote a book about it is that being involved in a space mission is so absolutely fascinating in terms of the things that happen . It's also, I think , quite nice because it's a these always international things . You know, we look at the news at the moment and the world is on fire , people are behaving like toddlers in the Middle East . And but then you look at these things you think, well, actually , this mission was a mission of there were at least eight different countries involved, and everyone got on and everyone actually there were moments when they didn't, but everyone managed to actually communicate. So I think in a way it's a nice thing to think about this and to in astronomy and science in general, there are all these amazing , it's like the opposite side of humanity from the Donald Trump side, I would say, which I think why is one of the reasons why Trump has not actually said much about Artemis because he doesn't like this kind of thing. Especially because they had radio silence when you started brilliant. I did . Yeah . Anyway, thank you for your attention . I have copies of my book if anyone wants to buy it. I have a card machine as well if anyone wants to buy it . And I will sign it Anyway, thank you, I bet forget about buying the book. Three great staff to you. Thank you . Okay . All right, thanks very much, Steve. Who's got questions for Steve? Which is like , that's better. Ingenuity and curiosity. There's always spare a second module that stays on Earth so that they can like run test and stuff . If a launch goes bang, yep , is there a process in place where they can go let's quickly get the second one into orbit and do that ? And the second question is, is there any thought at the end of a Herschel mission where they put in a safe orbit around the sun where they might have lot cheaper instrument that they could use to maybe observe the sun to bring that into play ? Well, answering the second question first , I don't think there was anything really left on the spacecraft they could use to do anything useful . The first question is an interesting one because this actually happen there was an issue with this because there were free instruments on Herschel and on day eighty two one of the instruments died . So there was an instrument called Hi Fi and a diode blew out on day ' eighty two and they had to turn it off . And as you say, they had a spare set of electronics on the ground . And so there was a spare set in orbit actually in the instrument, but it didn't want to turn the spare set on board on because they thought the same thing might happen again. And they thought maybe they just designed it badly . But by a lot of careful tests, I mean this must have been traumatic for the team. I mean, I didn't care. I wasn't involved in that part of the mission , but it must have been really bad . But for about six months they were trying to figure out what had gone wrong and eventually they figured out that the there had been a programming error in Hi Fi Using they'd done this using the stuff on the ground and they reprogrammed Hi Fi and then turned on it again and it then worked. So all the stuff on the water that I mentioned was done with hi fi . So yes, you're right, there's always spare sets of instruments on the ground. What was the second part it was about ? Oh Oh, if the launch went bank if the launch I don't know what if Herschel had blown up on launch , Herschel and Planck blowing up on launch , I think what would have happened next would have depended on politics and money because in the case of the one that did go bang in the early nineteen nineties, which was the Mission Cluster, they did send the subsequent they did send cluster two up to replace it , but I can't I'm not sure what the financial situation was . I don't know in two thousand nine , one year after the world financial crisis , I have a feeling that would have been it. Two questions. A lot of projects like this generate an awful lot of data. Yeah . So has that data, has all the data been analyzed and if not how long did these take? And the second question is did the Belgian team still write the software for the rocket launch I don't know about the Belgian team, but the answer to the first question is, yeah, all the data taken by Herschel is in an archive and astronomers like magpies because what happens is you have an idea for a project and you do the observations and often by the time you've done the observations you've lost interest in or do something else. So there's a lot of observations in the archives that haven't been looked at yet. I mean, probably most of the really good stuff has been mined, but one of the things we often do nowadays with these big telescopes is it's often more cost effective rather than writing a proposal to you doing a new observation of what you them, end up doing is you end up going for the archive looking for cool data that's never been looked at before. The reason I say that is because I have seen images where they come I have seen images where they're combining data from different missions and different wavelengths, that one of the andrometers you've got the optical tells you where the stars are that we can see today with the submillimeter showing where the stars are being formed and with the x ray data showing where the stars have died. So even though that data may have been processed, it's still useful to the scientific . No, that's what we 're that's basically a common thing we do nowadays, which is you take the data from all the so there's always different wave bands. Every time you look at a different wave band, things look different. And you know, the standard thing people do nowadays is we kind of combine that we've Jenny did in a PhD thesis . You combine data from different wave bands and you . Yeah. So my entire PhD was archival data from different missions. So yeah. Yeah . Right. Any more questions all the way at the back, Paul It's always one. It must be two now. Right, hang on. You said that crashing the telescope into the moon cost money. How exactly would that cost money instead of just like pointing at the moon and going well, okay I'm never entirely sure what the grounds were for that, but I think the issue is that if you crash it into the moon with the idea that you're then going to do what you're going to observe the plumes of material that 's sent up . As soon as you start doing that, you have to actually factor in the people you're paying to there's always a cost to keeping things going having the scientists continue to work. So I think that was all it was they would have had to pay for the scientific exploitation of it. Any more for any more? Oh yeah, oh, there's more. All right, we'll go this side . Yeah, you said it's a space mission because the water in the atmosphere precludes observing in this submillimeter wavelength from Earth. Yes . But later on you also mentioned the atacama submillimeter thing. So that's a good question. So the submillimeter simply scatter over a few things. So the submillimeter wave band , there are a few atmospheric windows. So there's a few range, small ranges of wavelength in which you can observe from the Earth. So the pictures I showed at the Hubble Deep Field were taken with a camera on the ground in one of these atmospheric windows. Now the radiation from the water is at certain spectral lines and those are almost always in the way the wavelengths that the atmosphere is opaque in. So it's a little bit at a karma the at ma large millimeter array observes in these spectral wind these atmospheric transmission windows. Right. And then there was a question over on the right. So during the conversation about the dust in the galaxy, you were saying that most of the dust was illuminated in the blue because most of the stars were blue stars . Does that indicate that after initial creation, most of the stars in the galaxy are large mass stars rather than small like the KSFs and G's? No, it's a little bit complicated. It's because the again I kind of skated over stuff. So the when population of stars form the most massive stars are the most luminous stars and they tend to be blue and they tend to tend to dominate the light and then but they're also short lived. So if you have a region in which stars are forming yellow all these short lived stars dominate the light,s of the blue stars dominate the light. There are actually plenty of red low master stars there. You just can't really see them. So in the case of Andromeda, then the other thing is that when the stars form, they eventually leave their clouds. So the dis k of Andromeda appears quite blue because some of the blue stars have emerged from their clouds, but most of the young stars are still in the clouds, so you can't see them at visible wavelengths . One of the interesting things actually is I' ve been looking at pictures of andromeda taken by amateur astronomers recently and you can see much more clearly some of the same structure that we see in the summometer. So in the summometer, we see these kind of filaments and braids . In Robert General's picture , you can't really see it particularly well, but some of the latest pictures you can see in the visible you can see these dark bands that correspond to where we're seeing sub millimeter mission. The other thing I should say is that if you remember the two pictures around Robert and our beautiful sub millimeter picture and Robert's picture taken with his sixteen inch telescope, the Daily Mail picked up on this and they made the point that our Herschel pitcher would cost European space mission cost a billion euros and this Abbot had brought on which is much better. So I felt quite felt qu Iite proud of being sort of targeted by the Daily Mail at that moment . Sorry there was one last part to this was SN nineteen eighty seven A ated a lot of dust In the very first stars, in the absence of any dust, how do the stars form if they haven't got the dust to shroud the initial clock collapsence? Well that's a that's a fundamental fundamental question. So most of the stars with all the stars we see contain heavy elements such as oxygen and silicone and that changes even apart from the dust , the existence of these heavy elements changes the way stars form. But you're absolutely right , the first stars in the universe that would have formed would have been formed basically out of hydrogen and helium. And these stars are often called population free stars . And I thought I can't remember exactly details, but I think theory suggests they should be really quite big. And one of the reasons for the James Webb Space Telescope that was launched a few years ago that the idea was she'd h ope to see these stars . They haven't really seen these stars, but they've seen very young galaxies. So dust the absence of dust, the absence of heavy heavy elements changes completely how things operate . Right then, I think we'll have to call questions there, but let's give Steve a round of applause again Ultimate astronomy is produced by Ralph, Paul, Jen, John, Damian , and Dustin, and it's free to use with attribution. Thee music by Star Salzman, with Stinger Variation by Ringe Jorgensen . We promote general science, astronomy, space exploration and rational thinking with more resources on our website at awesomeastronomy dot com If you want us to read your thoughts and comments out on the show, send us your views, opinions, critiques, or questions to the show at awesomestronomy dot com Tweet us at Awesome Masterpod or give the Awesome Astronomy Facebook page a like and leave your comments there . Thanks for listening from Sidonia Base Ed of Transmission