Cosmic Instability: How a Smooth Early Universe Grew into Everyone You Know

[Music] good evening everyone and welcome to the silicon valley astronomy lectures a program of introductory talks on exciting developments in astronomy now in its 21st year my name is andrew fracknoy i'm the emeritus chair of astronomy at foothill college in silicon valley and this is the 21st year that we've been bringing these lectures first just to the auditorium at foothill college but now over the web to listeners and viewers all over the world and i want to welcome everyone who's watching us all around the united states and in far-flung corners of the world these talks are co-sponsored by the foothill college science tech engineering and math division by the seti or search for extraterrestrial intelligence institute by the venerable astronomical society of the pacific and the university of california observatories which includes the lick observatory right here in silicon valley and we appreciate the help of all those organizations in making these talks possible uh we are we are in for a special treat tonight as our talk entitled cosmic instability how a smooth early universe grew into everyone you know is going to be given by john mather and i'm going to introduce him in just a moment i want to remind everyone that in this rather complex audio-visual setup that we have we ask you to ask your questions by emailing our special email address astronomy at foothill foothill.edu that's astronomy.foothill.edu and dr jeff matthews the astronomy instructor at foothill college is standing by to collect your questions and to ask them at the end of the talk um so without further ado let me now introduce our speaker dr john mather is senior astrophysicist and the senior project scientist for the james webb space telescope at nasa's goddard space flight center his research centers on infrared astronomy cosmology and the development of new instruments for exploring the universe the james webb space telescope is going to tell us about is our next great project of telescopes in space and the entire astronomical community is really looking forward to that dr mather was a project scientist and a principal investigator for the cosmic background explorer satellite with which the leftover radiation from the big bang was measured precisely for the first time for his work he's received numerous awards including the nobel prize in physics in 2006 and three honorary doctorates tonight as i said he's going to talk about how the early universe grew into everything and everyone you know ladies and gentlemen it is a privilege for me to introduce to you dr john matt thank you andrew i'm delighted to be here with you and i do have a story to tell you which might or might not be true but i'll give you my best so i have uh some uh beautiful view graphs to show you because i'm an astronomer that's what we do uh so let's see if that will work here so uh this is a picture of the great james webb telescope that was just mentioned to you uh it includes a golden hexagon it's not really solid gold this is the telescope that will unfold in outer space beginning in october this year when we plan to launch it it is a joint project of nasa with european and canadian space agencies and of course with a large contingent of engineering and technical talent in southern california at north of grumman where that's our big industrial partner right now i'm pointing out that this is a project of available to all human beings you can write a proposal if you're an astronomer and we'll read it and uh and can think about whether that's really a great idea if so we just might point the telescope at your favorite target so i will tell you more about that process later but i want to start closer to the beginning so oh well i was what did i do now um so um when i was a child uh people didn't really have much of a clue about how the universe grew into what we have uh it was thought to be so complicated that divine intervention was required and that was actually uh not so far from the thinking of physicists even into the mid 20th century so um and on the other hand in 2000 years ago uh the some of the essence of thought had already been done the atomic theory was recognized as an explanation for how for instance a glass of water can evaporate turning into invisibly small particles so lucretius wrote in this poem of uh more than 2000 years ago about this he saw that pieces could grow together uh go into things that you could know and give names to and then they would disappear so we have a little bit more quantitative story than that but it's still the same story that he was telling us so long ago so uh here's how we tell it now more or less uh we've know of four forces of physics and we know about thermodynamics so quantum mechanics tells us that everything you were taught about particles actually means that they're a little bit wavy and everything about a wavy thing that you've learned in school is actually got some particle nature to it but at any rate we calculate these properties and basically telling us how do all the pieces fit together so we've got 92 different kinds of atoms and we know the chemistry of how they stick together to make molecules so this is basically the story of all the lego blocks of the universe and they're all determined by these mysterious but probably correct stories of quantum mechanics um physics students have to learn how to make the calculations but in for today we just need to know that there are lego blocks of many kinds and then they can fit together uh something we uh have known for many centuries of course is about gravity isaac newton described it very well and then einstein improved on it but basically it has a feature that hardly anyone appreciates outside astronomy which is that gravity enables material to spontaneously heat up in school you don't learn about how a little block of of ice is going to spontaneously boil but in in astronomy we do that uh because gravity can pull material back together uh releasing gravitational energy and turning it into kinetic energy so this is the great instability of the early universe continuing to now so then another thing we've learned of course in the last couple of centuries is about thermodynamics we see that there is a local order for instance when you see a crystal of ice you say isn't that beautiful isn't it beautifully orderly so how did that happen well of course when the ice was made the heat that it had in it went elsewhere and that increased the order the disorder of the rest of the universe so overall the entropy of the world increased when that happened but nevertheless it looks beautiful and orderly to us in very recent times we've started to learn about non-equilibrium thermodynamics and so you and i are all examples of what i call spontaneous heat engines nature has found a way to use us to increase the entropy of the world we eat our food and turn it into whatever we like to do and that is a way of increasing the rate of combustion of the food to make carbon dioxide so we are here in order to increase entropy uh while we do our thing so part of the story is there but now let me step back a little bit uh because we are aware now that there is an expanding universe i'll show you more about how we come to think this but the universe is expanding now started out smooth and very hot and it was very unstable first uh from various nuclear reactions particle reactions and then as gravity acted on the early universe material to turn it into the big structures that we see today we know the universe is probably infinite that is to say it has no boundary it can keep on going indefinitely far in every direction at least in your imagination there's one exception to that you cannot go infinitely far back in time the universe does seem to have an age although you cannot get to the first moment there is no such thing as a first moment in our story now the last two lines on my chart here tell you about the complexity when i was a little kid we did not yet know that the dna in our genes was in encrypted in a double helix and now we know that it's a digital code that all of our living cells come with decoders for that digital information so you don't think about it but your body is actually made up of about 30 trillion digital computers all reading their their codes and doing whatever they need to do so that you and i can continue to uh live more or less as we are uh until those cells decide that they're going to stop cooperating so there's a pretty amazing thing to think about that each one of those 30 trillion living cells has its own instruction set and its own determination to do what it's supposed to do in its environment so we've learned about evolution from this story and now we say i say this is not just a the survival of the fittest as people used to say this is about the survival of the lucky because there's nothing particularly fit in a changing world nevertheless we are lucky uh we are the ones who came down out of the trees and learned how to cook and how to hunt and how to farm and how to build gigantic civilizations of billions of citizens that would have been impossible for the other uh creatures with whom we share this world anyway another thing that we've come to recognize is something engineers love to do we build feedback loops and control systems so each one of those 30 trillion cells in your body has been set up to more or less maintain itself biologists call it homeostasis so it's got feedback loops that replace the dead pieces with new pieces and keeps on going for a good long time so engineers do this on purpose and we're still astonished at how many many control loops and feedback loops there are inside a single cell not to say 30 trillion of them operating at once to make you so pretty amazing story of cosmology and biology all in one little chart it's not enough detail here for you to test it but this is a general idea so we've known for a couple of hundred years how to calculate some instabilities uh euler told us back in 1757 how to do this calculation uh when is something going to collapse if you put a big weight on top of a column uh when is it gonna collapse as compared to when is it gonna buckle so he figured that out and uh and it's pretty simple college students learn this one it takes a little more calculation for college students to do this problem if you look at a cloud of gaseous material out there in space uh hydrogen atoms and helium and so forth you can calculate whether gravity is going to be able to pull it together to make a star and so his search james jeans gave us this back more than a century ago in 1902 so we know how to calculate some of these things but it darned if it doesn't get complicated really fast so here's an example of uh spontaneous heat engine uh you and i are spontaneous heat engines this is a uh one of personal importance to us uh this is the hurricane harvey that sat over texas for some weeks for uh just at the very same time that we were testing the instrument package for the james webb telescope in the vacuum tank right under that bullseye there so at any rate this is an example of how spontaneous complexity can occur uh given a energy flow so it's not surprising that we can exist when you take this perspective but now this is all pretty hard and i don't know how to do biology so now i want to work now on the easier parts of astronomy so i'll stepping back uh almost a century uh edwin hubble drew us this graph in 1929. each of the little dots on this graph is a galaxy a galaxy represents about a hundred billion stars held together by gravity orbiting around a common center and what he's showing here is how far away he thought they are and how fast they're going away from us and so there's a pretty important factor on this chart number one is most of them are going away from us with a speed about proportional to distance and if you divide the distance by the speed you get the apparent age of the universe so back in 1929 this is the first evidence we ever had that there was actually an age of the universe and it was about two billion years according to him because his distance scale was incorrect but we took a long time to find his mistake other thing that's really interesting here is several galaxies in the lower left corner there are actually have negative velocities they are headed in our direction so in some billions of years we're going to have a wonderfully exciting collision except you and i won't be here to witness it personally but somebody will so if you believe this story of the expanding universe then you should be able to figure out what it was like when it was young so it was calculated in 1948 that it should have been very hot when it was young and the heat should still exist it should still fill the today's universe and we should even be able to calculate the temperature so the calculation then said it should be about five degrees kelvin five degrees above absolute zero uh which was impossible to measure in 1948 uh unl unless perhaps you'd known there was a nobel prize waiting for you if you could so it wasn't actually discovered until 1965 and then suddenly uh a huge mad scramble was on for students and professors to go measure this cosmic background radiation it is very bright at wavelengths of a few millimeters and so when i was a graduate student in berkeley in 1970 or so it was just after this had been discovered i was looking for a thesis project so i found paul richards and charles townes and mike werner and they were all thinking about measuring the cosmic microwave radiation so i said i'd like to do that so i worked with them and uh we made a thesis project for me and to tell the truth uh that was a a it was a bust the uh experiment failed to function on the first flight and i got to write a thesis about an a failed experiment fortunately the design was good it was uh finished out by my fellow students and fac and advisors and so it did work the next time but anyway i left berkeley with a failed experiment and under my belt and i thought well i'm never going to do that again that's too hard and then i got to nasa job in new york city to do become a radio astronomer and shortly after i got there nasa said we'd like proposals for new satellite missions so this was 1974. it was just five years after we had landed on the moon and nasa's thinking well what are we going to do now so anyway i said boss my thesis project failed we should do it in outer space he said we'll call up our friends and we'll write a proposal and so we did and i thought that'll never work but it's worth trying but it did work so two years later i moved here into goderich space flight center in greenbelt maryland and uh we decided to build it so um there it is uh an artist concept in outer space uh kentari carrying three instruments to look back towards the beginning of time two to measure the cosmic heat and one to look for the light of the first galaxies so because real engineers made it work it worked fine and it was a little scary but it did work so within a few weeks we had our first data i showed this graph to the american astronomical society and we got a standing ovation for a graph so why did we get a standing ovation for a graph it's because it said the big bang story the one we've been telling all these years is actually about right all the theoretical predictions and measurements match up as well as you can see on the graph later on we got the error bars down to 50 parts per billion so okay this was a pretty tremendous success there was another thing we were really trying to do though which was to look to see is this cosmic heat equally bright in all directions and so we measured that too this was the first time it had ever been measured and so this is a second instrument on board the observatory the picture to look at is the one in the lower right hand corner which is representing the entire sky with hot and cold spots on it that are very very faint the average temperature is about 2.7 degrees and the variations are about one part and a hundred thousand out of that so stephen hawking looked at this chart and he said that was the most important scientific discovery of the century if not of all time it took a little while to for me to understand why that was so important to him and to us but now i think i can tell you uh number one those spots represent density variations in the early universe and we could not exist if they didn't exist so we are here because of them the uh we believe that gravity acting on those denser regions was able to stop the expansion of the material and turn it around to form galaxies and stars and planets and then people of course second we figure out from this map that most of those spots come from something called cosmic dark matter which only astronomers can measure and nobody can see so it's still a great mystery and the third point is if we could ever understood stand what makes those spots we would perhaps have the clue for quantum gravity which is still one of the great mysteries of astronomy and physics anyway so from that we said uh many things follow we should be able to uh make up a picture of the whole universe we know the statistical properties of the early universe and now we can summarize it here it was very hot and very compressed when it was young there is no center and no edge although people often say wasn't the universe compressed into a point no it wasn't that was an incorrect story people told you it has always been as far as we know an infinite universe expanding into itself there's also not a first moment there is no such thing as the time of zero in our story and so you can't get there from here just as there is no smallest positive number the time of z actually equal to zero is not included in the story so it's not a big firecracker there is not a moment of creation uh there is nothing before the beginning of the universe that we know about but of course we're thinking so that's the story uh of the early universe then how it leads to us and now let's tell you a few more details we need to have a telescope to take pictures to see because everything is much too complicated to figure out from prediction alone so the hubble telescope was launched just a few months after the the kobe satellite that did the work i just showed you and it has taken pictures to tell us the details um we for instance learned that not only is the universe expanding but it's going faster and faster so a few years back astronomers believed that gravity would pull all the galaxies together and they would certainly slow down the expansion then we went and looked and it wasn't true so these three men got their nobel prize in 2011 for discovering that the universe is accelerating going faster and faster all the time so um huge surprise don't believe us when we tell you we know everything we know everything that we know and we're happy to be surprised so now we can make a movie for you of how we think this might have worked this is a uh an observatory in a computer box we have uh colleagues who can run the supercomputers to simulate how gravity could pull material together in the very first moments after the big bang so this movie is called illustrious and it represents millions of cpu hours and many many many people hours uh understanding how to make this go but what they've given us is a simulated box of early material you know and they've rotated it in front of our eyes so we can see it and you can see that it doesn't take very long for it to form into objects and for them even to be arranged in strings and flat sheets and this is all the result of gravity operating on random inputs but who would have known um we only know this because we look both with our eyes and with computer stimulations by the way here we're showing uh explosions happening so what happens to make an explosion while stars can occasionally use up all the fuel that they have and become unstable so that's one way that an explosion occurs another one is that a a black hole can form and as material falls into the black hole huge amounts of energy can be released so both of them have huge effects on the on the neighborhood and in fact such processes would have been happening in our own milky way galaxy as well so up until just about this time in the history of the universe when the solar system forms about 9 billion years after the beginning and about 4.6 billion years ago so to my way of thinking this is one of the most beautiful movies there is um and uh the computer folks keep on improving it so that it actually resembles quite well the pictures that we can make with the hubble telescope we've even gotten so good at this that we can say i'm going to study the galaxy over there that was simulated and see if it looks like a real galaxy and tell you all the details so is this a hugely important telescope that you don't think of as a telescope because it lets you see time as well as space so now i want to show you what we're doing currently to test out this story here is the great james webb space telescope james webb was our second administrator at nasa and he was the person who said john kennedy this is how we can get to the moon and he made it happen he also said mr kennedy we need science we need scientific laboratories around the country we need scientific discoveries we need to send probes through the solar system to mars and out of the solar system we need to put up telescopes and mr kennedy said well we're kind of bankrupting the country but we'll do it anyway so anyway it's a certainly an amazing man to uh to recognize uh by naming an observatory for him anyway here is the uh summary of the project there's the great observatory with its uh six and a half meter that is to say uh 21 foot hexagonal mirror protected by a enormous sun shield about as big as a tennis court our international partners are listed here at nasa with europe and canada our industrial partner northrop grumman in california um the observatory will be operated by the way the same way that we do this hubble telescope as an institute in baltimore maryland that does it so we're sending it up in uh october is the plan and we'll show you a little bit more about it so just to tell you a little bit about how do we decide to do something like this uh in 1995 there was a committee formed and here's the alan dressler the chair of the committee and they wrote a very poetic little book and they said okay we've got what we got from the hubble we can see how powerful it is and you know the next step is this please build us a telescope that's more powerful and can see infrared light and while you're thinking about that please also find out how to observe earth-like planets around other stars so that's even harder and we haven't done much of it yet but we will so anyway then he went and met the head of nasa um that's dan golden there and uh golden announced to the astronomical society that uh the committee that wrote the report was not nearly ambitious enough we're going to build a bigger one and he got a standing ovation so that's uh sort of gave us a clue that we had a good shot at building this despite how hard it turns out to be so then we wrote some more books uh committees are formed to decide what to do and these are pictures of the books and then here on the far right is our expected culmination with a watch of the ariane rocket in october just to give you some sense of the pace of history it's you may say geez it's taking a long time from my perspective it it's running as fast as we possibly can to make this happen anyway so what are we going to look at there are four major themes that we use to decide what to build uh the one in the upper left says well let's look at the first things that happened after the big bang the first galaxies that grew uh the process where the first stars lit up and started to rip the hydrogen gas back apart into ions that is to say protons and electrons how did the galaxies grow how do their scars grow and how do they grow to have planets and finally let's see what we can do about those individual planets themselves with a great telescope in space so i'll show you a little bit about how we're going at this number one here's the telescope it's an optical system comprising a a combination of three mirrors a big elliptical primary mirror almost a parabolic mirror small convex secondary mirror the light bounces it back into the insides of the works there and then the sort of most important features of this are that it is cold it will be cooled down to about 40 kelvin 40 degrees above absolute zero so that it does not emit infrared light to speak of uh and it will have to be adjusted to be the right shape when it's cold um we make it out of these 18 pieces of beryllium uh and the beryllium is extremely thick thin it's about two millimeters thick uh but nevertheless it is stiff and it is polished to have the right shape when it is cold so an astonishing engineering feat that was actually completed just up the road from you in richmond california by tinsley laboratories that's where they did the polishing so um we are so proud of that mirror and it's uh going it's going to be fine so then we have a package of instruments that basically this is a summary for uh for astronomers of what do we do we have cameras and spectrometers cameras that take pictures and spectrometers that spread out the light of the stars or galaxies into rainbows so that you can tell what's in them and how fast their things are moving so very powerful general purpose instrument package covering the entire wavelength range from 0.6 micrometers which you could see with your eye out to about 28 micrometers which you certainly could not so anyway hugely different science you can do with the different wavelengths so how sensitive is it well if you were a bumblebee one square centimeter hovering out there at the distance of the moon from us we would be able to see you with the time exposure so it's originally aimed at extremely faint objects but then we said well gosh the solar system is important too and there's some very bright things here can you do that too so the answer is yes uh take very short exposures uh of the uh the moon sorry of mars and everything on out from there so we can see it and we'll certainly be looking another picture for astronomers this is a curve a set of curves showing that the telescope is very much more sensitive than anything else so um i should skip over this but at any rate being at the bottom of the chart is good so very very sensitive equipment so what are we going to look at we will certainly be looking at the first galaxies this is a piece of the uh hubble deep field a place where astronomers decided to point their telescope for two weeks uh where there was almost nothing there that they knew about there's a star in the lower right hand corner this little thing with colored spikes sticking out and there's i think one other star in this picture that is off the edge of the picture but at any rate all the rest of these things are little galaxies as observed by the hubble and hubble's observatory said ah well we can't see the first galaxies they're too faint they're too far away too far back in time need a better telescope so we'll certainly be doing that project again much better as far as we can with infrared we will be looking inside these beautiful clouds this is an example of a cloud nearby where stars are being born today what you see on the left is the traditional view of what we call the pillars of creation it is a very dusty area dust prevents us from seeing inside with ordinary visible light but we know that inside that dusty cloud are new stars being born and so what we what would you like to do to see inside you would like to have infrared capabilities as we have some infrared with the hubble telescope we see that on the right hand side but this is analogous to when you go to the airport and they look through your clothes to see if you're doing something you shouldn't do and they use longer wavelengths of light they use millimeter wavelengths to see around the fibers in your clothes so they don't get much detail don't be too worried but they can see around the the fibers just as astronomers can see around the dust grains by using infrared light here's an example of how the view of this other nebula changes as you go from visible wavelengths to infrared it's a dramatic change and we will certainly be looking for that uh change with the uh with the webb telescope series you see cycling in colors we will be looking in the solar system uh two amazingly exciting uh targets for next visits by nasa europa is a satellite of jupiter we know from the galileo mission which went there to take pictures many years ago that europa is a wet place it has an ocean covered with ice there are warm water geysers spitting up something and we would like to go see what's in those we would like to see if those geysers have organic material any sign of life in that ocean a more ambitious project would be to land on the surface and either melt your way in or drill your way in or just go to the right place where water is already coming out so we certainly want to go there the one on the right is a map of the surface of titan titan is the large satellite of saturn and it is unique in the solar system that it has rivers craters dunes weather of course the liquid on that surface is hydrocarbons methane and ethane and other other hydrocarbons so but they have geology what they use for rocks on titan is water ice and this is a fascinating place uh for many many things we are even sending a helicopter to fly around those short distances on the surface of titan so if there is by the way any possibility that life does not have to be based on liquid water this is the place you would find it because we have something so similar to terrestrial conditions except a colder version that this is certainly a place to look you know to see if if the kind of life that you are familiar with is the only kind we will certainly be looking at planets around other stars here is our method or one of our methods uh as a planet uh goes around a star once in a while sometimes it lines up and passes in front of the star and blocks some of the starlight so when it does that the this apparent size of the planet depends on the wavelength of light because of the various chemicals in the atmosphere of that planet so some of the starlight goes through the planetary atmosphere on its way to the temple scope and we can tell what's what so we are already planning to observe uh about nine earth-sized exoplanets uh five neptune-sized ones and 16 jupiter-sized planets by this method so we will not plan or we're not expecting to see signs of oxygen in an earth-like planet we don't think we can but we'll certainly be looking so very exciting planetary exploration is coming with us now just to wrap up i want to show you a little bit about um how do we get there how do we get the observatory up into space so we started by putting the telescope itself together in the clean room here at goddard space flight center in maryland and there it is the golden hexagon which was absolutely beautiful to look at and then we decided we better find out if it can survive launch we put it in a clean tent we put it on top of a shaking device which can apply about 50 000 pounds of vibration force to this very delicate telescope and we decided okay it survives uh we will go on and put it into uh the next step so to get there we put it in its giant mailbox and drove it around the highway to andrews air force base here in maryland and the entire truck and shipping container went into the airplane and then they flew it down to uh to our houston base johnson space center took it out again put it in the vacuum tank there was called chamber a which was uh used by the apollo astronauts to rehearse getting out of their lunar capsule and walking down the ladder onto the surface of the moon so a very historic spot next wrong direction here then we put it back in the airplane send it to california where it is now that has been attached to this piece which is the warm piece of the observatory and we have just sent it through its last vibration test and it is unfolded now we are in the process of folding it back up so that it will go into the next shipping container and here is a picture of this one it's a special ocean going barge which will take it through the panama canal on its way to the launch site in french guiana and we're going there because the european space agency is buying the rocket and there's a good place to launch from and it's a good rocket then in october we push the button and this happens it goes up into space and then we very carefully unfolded my remote control in outer space so that'll be a scary time we have however done everything we should to make sure that it'll work here is just one last beautiful picture of the observatory in the clean rooms while it's partially unfolded uh we are sending it out to a place called lagrange point two it's a one and a half million miles uh sorry one and a half million kilometers one million miles from earth in the opposite direction from the sun so it'll be overhead at midnight here and it's a great place to put a telescope because it doesn't get any further away it stays with us all year long and we can communicate with it very well it's also the only place in the solar system where the sun the earth and the moon are all appear to be in a straight line so you can put up a one-sided umbrella and protect yourself from the heat so here is our scary movie you know it took uh seven minutes of terror to land on mars this is different this takes a couple of weeks and unlike the mars landing this does not have to be done all at once we have the opportunity and the plan to take each step make sure that it works try again if it doesn't work exactly right because we have two ways to accomplish everything every motor has two sets of electrical windings and two controllers for instance it's an extraordinarily complicated creature and you'd say are you sure you have to have it that complicated and the answer seems to be yes we tried very hard to find an alternative that was simpler and the answer was well if you make it smaller and simpler it won't do the job so let's go on and do this is we just know that it's really hard so it takes about two weeks to go through this process that i'm showing you here of unfolding everything and getting it into about the right place then it takes another total of six months to get everything completely focused up tested and ready for doing science so if we launch on october 31st then we should be ready to show you beautiful pictures at the end of april in 2022 so of course this is a picture no human can ever see because in space the telescope will be in the dark so and now i want to move on to what's next because of course building the web telescope is not the only thing astronomers want to do we have other great ambitions now it's pretty hard to put a telescope into space so let's see what we can do on the ground so here are three gigantic telescopes under construction on the ground the biggest one is the european one it's the 39 meter telescope it's being built in south america it's about six times as large as the webb telescope but it's stuck here on earth so that's good because you can get to it to make it work better it's bad because air is turbulent and it blocks the infrared light especially that you would like to see nevertheless it's worth trying so um we will be using this uh amazing technology called adaptive optics back in 1953 it was conceived but nobody could actually do it then now we do it on purpose and it's developed by military technology and then redeveloped by astronomers now it's not secret anymore so the concept is point the telescope at a star make sure that you can adjust the mirrors of the telescope so you get a sharp image of that star and the whole area around the star will also be a sharp image so it can compensate for the turbulent atmosphere of the earth and get short pictures this way even with that gigantic telescope so a tremendously startling uh spin-off of the webb telescope technology is the picture on the right uh the person who figured out how to polish those wonderful mirrors for the webb telescope said well i could figure out how to do this picture on the right as well uh i will work out the math i will show you how to make the parts and now when you go to your eye doctor you can get the same kind of adaptive optics concept to look into the back of your eye and if you're a san francisco or oakland football player you will say i need to see better can you make me see better and the answer is yes they can use this system to correct your natural lens and your eye and get 2010 vision so if you want to know how they're so good at seeing so things so far away um they can't help so uh so this is possible uh and so let's say well how are you going to do it well we have many ways but this is an idea that i'm working on currently that i thought you might be interested in we can put a natural we can put a laser guide star in space to focus the telescope on and we can put it wherever we need it at least for a while so working on this idea and uh you never know whether we'll get chosen to do it but i think it could happen um and if we could do that then we could get really sharp pictures and then the next step after that is let's put up a star shade uh it's about 100 meters across in the same kind of orbit i cast a shadow of a distant star right onto the biggest telescope we can get and if you could do that you could get picture on the right hand side you could get earth venus and mars in a one-minute exposure so it's not impossible um it's pretty hard just but not impossible so if you want to know are there little planets out there with life like we have on earth this is one of the ways to try it's not the only way it's one of many but the others will basically all require putting another even bigger and better telescope in space so if you could do this then we'd be able to get a spectrum a spectrum like this shows the molecules of the atmosphere of another planet and the one i am so thrilled about here is that the blue curve is what we think we would see if we could look at another earth way out there we would see these little ripples that are labeled with oxygen and water and oxygen and water and water and we would be able to say yes there's a planet out there that is a lot like earth it has oxygen so um it might be possible it'll take us uh quite a while to do this this is a hard project but anyway i think i should come back to the original questions and say well how far could we go uh can you go to the stars and the answer seems to be no um the answer to fermi's paradox about where are the neighbors is it's too far that's my opinion but when we finally do develop the wonderful products of silicon valley into super intelligent robots then we can say well robot do you want to go we'll help you or um maybe not maybe let's say they want to go maybe they say anyway who knows what the distant future calls calls to do but even in a billion years from now uh the nearest stars are still going to be pretty far away so let me wrap up i'll be very happy to have your questions and i don't think i answered them all yet so thanks for coming and thanks for thinking with us about how this all might work thank you so much dr mata let's stop sharing the slides okay there we go there we go great and uh let me thank you for what in another context was called the greatest story ever told the story of how we got here and what we're capable of doing once we evolved very exciting developments and we wish you the very best of luck with the launch of the web and the unfolding of the web we're all going to be keeping our fingers and toes crossed as the latter part of the year comes but thank you again for that talk and we want to uh just mention um that the next talk in the silicon valley astronomy lecture series is going to be march 10th at 7 pm when dr eleanor gates of the lick observatory is going to talk about lick observatory during pandemic times and compare what it was like in the 1918 pandemic for a major observatory and what it was like last year so please join us march 10th at 7 pm but now i want to turn things over to your questions i'll remind you that if you want to ask a question of dr mather we are taking those questions at astronomy foothill.edu email those questions to the address astronomy at foothill.edu what i'm going to do now is to turn things over to the astronomy professor at foothill college dr jeff matthews who's going to be sharing your questions so thank you andy and thank you again dr mather for coming out and speaking uh with us this evening i'm gonna dive right into the questions uh that people have sent and i'm gonna say up front we've received a ton of questions i've tried to sort of group them i've tried to identify questions that are very similar uh to to try to hit as many of these as we can uh so um there we go so we've got a question from marina asking uh since webb was planning web planning started in 1995 and is only launching now 25 years later uh what space-based missions are being planned for 25 years from now oh goodness uh well 25 years from now is uh a long time and we haven't made up our minds what astronomers do is every 10 years we have a giant committee meeting and we write a book about what we wish for and what we think the most exciting things could be and this time we have been considering four gigantic telescopes uh two of them specially aimed at uh exoplanets and the search for planets like earth way out there uh one of them is more powerful than the other and one of them aimed at far infrared light that's a quite a different technology one of them looking at x-rays to see black holes and neutron stars and other astonishing very hot things so the committee might tell us we need them all if i were the committee i would say we need them all and uh that tells us we have probably 20 30 40 50 years of great telescopes in front of us before we run out of great ideas and then there will be new ideas all right so thank you for that and uh now we have a question from chelsea asking why is the mirror made in 18 pieces and why is it beryllium ah it's made in 18 pieces because we can't lift a big piece the telescope is bigger than the rocket so we have to fold up the telescope so we have to find some way and hexagons are actually a pretty good way to to make a big piece out of little pieces they are made of beryllium because it's extremely lightweight and very stiff and and especially this is the most important part it keeps its shape you can cool it down and warm it up cool it down it'll come back to the same shape that it was so when you say i've built it right it'll stay built okay and then we have a related question from phil asking about those ground-based telescopes uh why are ground-based telescope mirrors so much thicker and heavier than the jwst mirror oh um it's easier we had to expend an immense amount of effort to make the web telescope mirrors thin and they need to be thin because the rocket has to lift them into space so the webb telescope mass is about half that of the hubble telescope even though we have about seven times the collecting area so we can't get a much bigger rocket so we just have to make something lighter weight okay and one more question um sort of lumping together uh several several people asked something along these lines um so ellen asked how long will webb be operational oh i didn't tell you uh we have fuel on board for about 10 years of operation uh if we're lucky with the original launch and uh and the hardware it could run a lot longer okay and so then uh we've got uh going into some questions about the science that you discussed in the talk um so we've got a question uh from douglas wondering can the expansion rate of the universe vary from place to place oh um we haven't seen any evidence of that yet but we do have to test it so for instance you should see is it the same rate in all directions and here locally is the local expansion rate in the nearby neighborhood just the nearest say a few hundred million light years is that the same as it is farther away so we have done some tests we haven't seen any sign that it's not the same but it's not something you can assume you have to test okay and um sort of there's several of these sort of cosmology related questions so i'll try to sort of lump these all together um from maria we have early in the talk you said there was no t equals zero and no special beginning moment of the universe and how does that relate to what we call the big bang okay uh the way i think about the big bang is uh we can run the expanded universe backwards in our minds okay it's expanding now let all the pieces run to back together they get they collide with each other they get hotter and hotter the atoms are ripped apart the temperature goes enough the density goes up and up and finally we say i have no idea how to calculate what happens after that or maybe i should say before that so at the most extreme conditions you can imagine we don't know what to say so then i say well let's call that the big bang so it's the expanding infinite universe uh in its most extreme early conditions that we can imagine okay and then um one more cosmology question sort of several people asked about the uh the video that you played where you showed the the cosmic web uh showing strand-like structures rather than you know like globular spherical things and so why why is that ah okay um well that's actually the uh sort of unexpected result of gravity operating on random initial conditions on the other hand if you wait long enough these parts do tend to pull together so our own galaxy will be colliding with the andromeda nebula in a couple of billion years so what starts out as long stringy things will end up a lot rounder in the future given time okay um so then uh you've answered a lot of questions for our audience uh i think we'll we'll make this the second to last question here um try to start tying this up um so there was a question uh somebody was asking if we use the web the james webb telescope along with say gravitational lensing maybe using our sun or maybe a planet in our solar system or something would we be able to see uh greater details maybe even surface features of distant planets oh um we can't do it with the web because it's not in the right place but other people have worked this mathematics out uh if you uh go really very far away from the sun i don't remember how far but as many many thousands of times farther away from the sun than we are uh and you sit there and you get yourself perfectly lined up the gravity of the sun can magnify a distant object and um and get immense magnification so people have worked it out i don't think we can do it anytime soon but at least we know what you would have to do oh okay and so then uh going into our our final question uh for the evening um karina was asking you know when with uh what you were showing about looking at planets why will why will these studies be looking at the planet in different sizes in different wavelengths instead of just doing the spectroscopy like you showed us at the end of the talk ah well it is actually equivalent the planet looks bigger at some wavelengths than others because the molecules are more absorptive at some wavelengths than others so it's it's really equivalent it's just a different way of saying the same story right well i'm i'm going to jump in here and use the privilege to ask uh one or two more questions okay i would love to hear what you're most looking forward to what project with the web telescope are you most looking forward to okay well it's like asking what child do you like the best i know i i'm hoping that we get a big surprise something that uh nobody has thought of to look for but it turns up so i can guess where we might get a surprise or everything we know about planets has been a surprise so i think that could continue uh we did i just don't know um that would be great the other thing i'm guessing about is things in the very early universe where um i can imagine maybe i'm not a good imaginer but something happened early on uh and all of the pieces that we're interested in um were swallowed up and disappeared so there are none of them left to find now now most kinds of things you say well they didn't all get eaten up so some of them are still left from the early times but we're beginning to get some signs that something's fishy about the very earliest times there's a measurement that says the cosmic optical background the universe is about twice as bright as you can explain with all of the pieces that you can find so are there more pieces maybe so i'm kind of hoping there's something surprising in that territory that sounds wonderful and finally let me ask what my students always want to know is who decides who's who will be in charge of deciding out of all the exciting projects that the web could do in what order they'll be done which one will be done first describe for lay people who don't know how that process works how those decisions will be made okay well the way we do it was uh every now and then like we announced there's a chance to write a proposal so we say everybody out there from uh azerbaijan to zanzibar you can send us a proposal and we'll think about it and so we form up committees and to read them so we got i think 1173 proposals it's an immense number of proposals and about all that half of all astronomers worked on the proposals so that means you got to find a committee that's fair so that's actually pretty tricky to find committee members who are not competing against the proposals that they're reading but anyway we set up this process we get a couple of hundred astronomers to read the proposals and then they vote and they say well this is what we think and then they send their letter to the director of the space telescope institute and uh they try to persuade that person that this is the right choice and usually they'll say yes and sometimes they say no and then even that's not quite enough because we say well what if somebody says something's about to happen next week i need their telescope now and so we have that process available also so like director's discretionary director's discretionary fund say uh uh a comment's about to hit jupiter has happened with the hubble telescope okay let's figure out how to do that so this sounds very exciting and i i know that one of the most exciting things will be as you said that we don't know yet all the things we're going to discover so let me on behalf of all of us thank you not just for this talk but for all your wonderful work on this telescope and we wish all the best for the telescope and for all the observing that's going to go with it thank you dr mather for a wonderful presentation well thank you andrew and i need to pass on the thanks to the thousands of people who are actually working on the observatory to make it happen great so thank you all for joining us this has been a presentation of the silicon valley astronomy lectures a regular program bringing you the latest developments in astronomy we encourage you to join us again on march 10 when we're going to be back with another exciting lecture and that concludes our [Music] evening you

Channel: SVAstronomyLectures

Views: 8,823

Rating: 4.8518519 out of 5

Keywords: Astrronomy, science, Webb telescope, John Mather, cosmology, space science, space telescopes, cosmic background radiation, exoplanets, astrophysics

Id: iEnNTmu8D4o

Length: 63min 16sec (3796 seconds)

Published: Wed Feb 03 2021