Brian Greene: The Cosmos in Twenty Minutes

now we are going to move to the whole world to be explained to you by Brian Greene and Brian will be interviewed by Walter Isaacson as you know the CEO of the Aspen Institute my former editor at time who will be tempted to edit my interview my introduction and the universe parts the fabric of the universe unfolds Brian Greene has written the fabric of the universe the avid fabric of the cosmos the elegant universe Icarus on the edge of time which I love and the hidden reality the trio of books that deal with multi versus the fabric of the cosmos relativity we are supposed to within 20 minutes actually 18 minutes and 17 seconds give you the whole story of the cosmos and the universe so Brian let's begin at the beginning how did it begin how did it begin oh good question oh we don't know but we have some ideas and the idea is that it expanded yeah so the the most refined idea which is by in my opinion no means confirmed is an idea called inflationary cosmology which tries to answer a somewhat more refined version of the question how did it begin what was it that caused space to start swelling in the first place we all believe that the universe is expanding the observation support that what got the expansion started and the inflationary theory says that gravity itself is the culprit because even though the gravity that we're familiar with in everyday life is attractive pulls things together Einstein's theory which you wrote extensively about shows that in certain exotic circumstances gravity can be repulsive so you have a repulsive force that at the very beginning pushes things out does it create space and time as well as particles and matter it's again a hard question but our best answer at the moment is that space and time needed to exist already for this phenomenon to take place but what inflation does is it leverages the pre-existing space and time which could be a tiny little nugget and turns into a large cosmos so it basically takes space and time as an input very small yields big space and time and matter and energy as the output so if time already existed when this happened what happened the day before this happened yes I knew you were going there which is why I've played defense here and said I don't know five times already in the first two minutes so we don't know but we have ideas right so one possibility is that the notion of before is a concept that doesn't actually make sense when it comes to the beginning of the universe a good analogy is think about the concept of heading northward on earth right so if you're heading northward you pass by someone you say point me in the direction of further north they point you continue to walk you pass somebody else same question they point you in the northward direction but when you get to the North Pole itself if you ask somebody there how do you go further north they look at you sort of oddly quizzically the notion of going further north in the North Pole doesn't make any sense so going back in time doesn't make any sense that's right so at the beginning of time just like the North Pole that may be where the concept of time only comes into play and there's no notion of before when it comes to the beginning how do we get from general relativity to figuring out both mathematically and theoretically the notion of a big bang well that's an exciting and curious story Einstein himself after he fashioned the equations of general relativity which people can read the wonderful history of in your book he started to apply the theory to a variety of circumstances the orbit of mercury being one famous one the bending of starlight by the Sun but he also noted that if you applied the equations to the whole universe it gave rise to an unfamiliar unexpected result which is that the fabric of space itself should be stretching or contracting the universe couldn't be static and that cut against the philosophical perspective of the time including Einstein so Einstein changed the equations to ensure that that result wouldn't come out that the universe could be unchanging on the largest of scales then fast-forward to 1929 when Edwin Hubble turns powerful telescope to the sky and sees that the distant galaxies are all rushing away the universe is expanding Einstein kind of euphemistically smacks himself in the forehead and says why did I change the equations when I could have predicted this amazing fact about the universe just for my own mathematics yet calls it as big as blunder so then they walk the cat backwards that if it's expanding they say well it had to have all been in this single point that's right you basically in the hands of brilliant Belgian priest was the first person to really articulate this most precisely a guy named George lameta he used in Stein's math the face value math not the method Einstein mangled to meet his own philosophical prejudice he uses a map to turn the cosmic film in Reverse and the universe gets smaller and smaller and smaller and therefore he comes to a primordial nugget from which everything would then emergency call it the primordial atom and the name Big Bang that came later on I think it was a radio interview I think was with Fred Hoyle who was a critic of this theory was talking about on the radio and he said ah the Big Bang you know this is like derogatory description but of course it's the name that stuck and it's our best understanding of how things started and you mentioned that Lemaitre and others get to it by walking the mathematical equations it's sort of what you do I don't think people actually know that you're also a professor of mathematics and in some ways mathematics is now your guideposts to figuring out this will is how physical reality is so is that where math sort of takes over and becomes a guide of physics yeah I mean I'd say the one lesson that we've learned since Isaac Newton is that for reasons that we can't fully yet understand math seems to be the right language for describing phenomena in the universe math is the shining light that can illuminate the dark corners of reality that we've not been able to access directly right we can't literally see the beginning but we can use the math to peer back using the equations to get some understanding of what happened at the beginning but don't we need to at some point have some evidence from physical reality no but what about the cosmic know we do know no it's absolutely crucial and and yeah and without that we're just sort of speculating and the evidence comes from so many places so first Einstein's mathematics makes predictions about things that we can directly access like the bending of starlight by the Sun which was tested in 1919 during a solar eclipse and just as Einstein predicted the stars were slightly shifted in the sky because of the sun's presence and you know you know the story well but perhaps not everybody does I'm Sundin gets a telegram alerting him that his ideas had been confirmed through the observation and somebody asks him professor Einstein what would you have said if the data showed that the theory was not confirmed and he said I'd be sorry for the dear Lord because the theory is correct you know so so this is how certain you know he was of these ideas but that's just one example when it comes to cosmology in the Big Bang we can use the equations to make predictions for how much residual heat should be left over from the Big Bang today the so-called cosmic microwave background radiation and we can make predictions on how the temperature of that heat should vary from one location in space to another and then we can do measurements and the measurements agree with the theoretical predictions to fantastic accuracy and that is a breathtaking confirmation that this mathematics is not just speculation that the math is actually aligning with how the world works give me an example of that measurement of the cosmic background radiation I mean what they go to the north pole or South Pole so there are many ways to access it you can access it through satellite born telescopes such as the you map experiment the Wilkinson microscope which has done a fantastic job at measuring the microwave background radiation the microwave anisotropy probe but the more recent one I think is the one you're referring to is the so called bicep2 experiment down at the South Pole where for three years a team of astronomers pointed this telescope at a patch of the Solar polar sky and extracted information about the microwave background radiation that again bears out a yet more subtle prediction and this is radiation that actually emanated from the bang yes so in the beginning it was hot right really hot and as universe expanded the heat was spread out it diluted and it cooled down and you can calculate how cold it should be today and it's about 2.7 degrees above absolute zero so that's the temperature of deep space not when there's sources like stars nearby but if you're in deep empty space that's the temperature but you can go one step further and not just calculate the average temperature you can calculate how the temperatures should vary from place to place and the math shows that it should vary by on the order of one one hundred thousandth of a degree tiny variation and you can do these very precise measurements and indeed see the temperature variation in just the pattern that the mathematics predicts what do you mean when you call something the fabric of the cosmos it's a hard question is space really a thing or is it just a useful concept in order to organize our perceptions of reality you're over there you're further away in space the tables yet further is space merely the vocabulary that allows me to articulate locations or is space really a thing and nobody fully knows the answer to that but in Einstein's general relativity and different people interpret it differently I see space as a thing in Einstein's theory based meaning the fabric of space and time together that's right space and time are stick together and I would exist even if nothing else existed that's right that's right and there's been a lot of debate about this you know if you were to remove everything from space the moon the Sun earth everything what would be left would you have an empty universe that still has space and time or would you have nothing I mean a good analogy is if you take an alphabet right and you start to remove the letters Z and X and a and B when you remove that last letter what's left is it like an empty alphabet not really it's like nothing because the alphabet comes into existence with the letters that make it up is that true of the universe does it come into existence only when they're stuffed populating it or can there be an empty stage called space time that would exist even in the absence of matter I think it's the latter there's a wonderful thought experiment which you deal with and I think your first book Newton's bucket yes explain how that helps you think that there is a fabric of space yes so this is a thought experiment that Isaac Newton came up with when he was trying to understand basically if space was a thing and he imagined taking a bucket and filling it with water and he noted that as you spin the bucket the water climbs up the sides of the buckets I think you know even kids do this at the beach right you spin around and climbs up the side you would call inertia that's right so so the the water has some intrinsic quality called inertia that causes it to resist that motion and when it resists it kind of gets pushed out it goes up the sides so he imagined doing that in a completely empty universe now there's some issues about that because gravity is part of what makes the shape so we actually imagine now taking two stones same idea connecting them by a rope and spinning them around would the rope pull taut and to Newton it was obvious that the rope would pull taut even in empty space and therefore he said what is that rope and Rock spinning with respect to there's nothing there there's no earth no Sun no anything therefore the rope and the rocks must be spinning with respect to us something called space space itself must be setting the benchmark reference with respect to which that motion is happening others and came along and said now we disagree you remove everything from the universe and you take your little spinny rocking neo ropey thing and it's not going to pull taut it'll just kind of stay completely limp and it's still an issue that people debate is there any evidence we could find one way or the other it's very hard to remove everything from the universe right that's a that's kind of what you'd like to do so what you do is you try to find alternate implications of one perspective or another and I would say as today most people haven't done a survey but I suspect that most people would say would pull taut that space does space-time does set the reference frame for a certain kind of motion accelerated motion but there are others who are holdouts and disagree with that what do we learn from the Large Hadron super collider we learned a lot we learn how to build the biggest experiment that our species has ever embarked upon these are really you know the the fantastic temples of the 20th 21st century they are our pyramids in a sense but in terms of the science that we have extracted the most important thing is the discovery of the Higgs boson the Higgs particle I think most people have probably heard something I mean people know about this Higgs idea right so there is this particle that was predicted mathematically in 1964 by Peter Higgs and many others who really deserve equal credit for it but it was just a mathematical idea that was a solution to a puzzle how do particles get mass how do they resist being pushed when you want to speed them up or slow them down and the idea was space is filled with a kind of molasses like substance called now the Higgs field like a steam bath that we don't see that's all around us and that gives mass to particles that's right as particles try to move through the steam bath this cosmic molasses they experience roughly speaking a kind of resistance like drag force and that was the relationship of the Higgs field to the fabric of space-time well if the Higgs idea is correct there'd be virtually no distinction between them this substance would fill every nook and cranny of space and in a sense it would be unremovable unless somehow you could recreate maybe the temperatures of the very early universe so the analogy that I think sort of captures that idea is you know I don't know do you have any tattoos okay well good I don't know where you were lucky and I am NOT going to ask but imagine that you start to have more and more tattoos and ultimately if you cover your entire body then the distinction between your skin and the tattoo becomes kind of meaningless you are the Illustrated man at that point you're completely covered with tattoos similarly space is completely filled with this Higgs stuff and if you can't remove it there's almost no distinction between space and the stuff that fills what if they hadn't found it and they had found that there is no Higgs field does the entire standard model of quantum theory go out the window well that would have been far more exciting for a theorist less exciting you know for Peter Hale we know would we have lost mass and lost weight well I don't think the universe cares much about our understanding of the universe so it would have shrugged it off a silly little humans but the the a wonderful thing as a theorist we would have been sent back to the blackboard to answer these deep puzzles where does the heft of the fundamental constituents come from that would have been enormous ly exciting for an idea that we thought was the answer to be proved wrong we are not there sometimes is a misperception that physicists are scientists more generally get stuck on an idea and they become so wedded to it that they'll hold on to it even in the face of evidence that suggests the contrary no it's completely opposite we love it when ideas that we cherish are proved wrong that's the biggest opportunity of a lifetime to try to come up with the next new idea that will take its place now in this example it was a wonderful triumph of mathematics and experiment where the idea was confirmed now mathematics has led you to super string theory of which your very associated explain why the math led you there well since the 1960s and 70s people have tried to put together Einsteins ideas of gravity the general theory of relativity that we've been talking about together with another theory the theory of the small ingredients quantum mechanics and uh yeah I'm sign try everything on his deathbed he was doing it well sort of Einstein was trying to put gravity together with electromagnetic theory to build a unified theory thinking that he could do an end run around the uncomfortable features of quantum mechanics he didn't like so much so he was hoping in some sense to let go this way and then like do that to quantum mechanics but that seemed not to really work out so we are trying the more straightforward approach to putting gravity and quantum theory together and the standard model of particle physics which predicted the Higgs particle hugely successful is unable to put gravity and quantum mechanics together that leads us to this new approach which at least on paper super string theory does but gravity and quantum mechanics together is there anything coming up in the next 5 or 10 years that you would say would help give you a physical test of what you're doing there I know ok yeah you know I wish the answer you know I can I can go speculative here uh you know which may be speculation on speculation which is always an uncomfortable place to be but just to say we don't believe any of these ideas until they make predictions that we can test so let's be real clear here if you ask me do I believe in string theory the answer is absolutely no I never have and I never will until there is experimental data that supports it having said that it is the most promising and I have to tell you mathematically compelling approach to putting gravity and quantum mechanics together and that's an important puzzle to solve that drives us to continue working on it in the best of all worlds when they turn the Large Hadron Collider back on in 2015 is it possible that some of these ideas will make contact with observation yes possible we could see evidence of extra dimensions that's one of the other features of the theory particles slammed together some of the you can get knocked out of our dimensions according to the math we would recognize that by a loss of energy people are looking for this we can see a whole class of particles called supersymmetric particles which the theory predicts that we haven't yet seen we could see microscopic black holes that would decay into a spray of other particles so all these things are possible but I don't like to place hope on them in that I consider them long shots so when they don't come through I don't want it to be hey you guys predicted that that was going to happen and then it didn't know it's possible but unlikely is it inevitable and true per string or string theory that there are other universes it's not inevitable it is one of the very controversial developments over the last 10 years it's true again believe is a funny funny word so do I believe in other universes absolutely not do I find it a compelling possibility and can I see how the math naturally suggests it and does that compel me to work on it it does but until there's observation or experimental support I don't believe anything and I guess I'm Stein once said that one of the grand questions was did the good lord have a choice yeah the way he invented the universe explained that in answering for us or for Einstein yeah so so Einstein asked a very important question which is could the universe have been otherwise could the mass of the particles be different could gravity have behaved differently did God did the lord have a choice or is somehow that dictated by logic and mathematics alone and we don't know the answer but if these ideas of other universes are correct then it's completely opposite it may be that every possibility is played out on the grand landscape of reality so rather than having one unique universe it might be all possible universes the truth is probably somewhere in between we've run out of time but let me hit you with a couple of quick things here one of which is why does this all matter well if you ask my mom it doesn't right you know allowed you to be a doctor yeah exactly right so it gives her a headache and all that kind of stuff but I think it helps many people get a sense of how we fit into the larger picture how we're part of this spectacular cosmos and I don't consider it making us somehow small and insignificant although we are but take into account these little tiny creatures walking around on the surface of the earth can figure out what happened a billionth of a billionth of a billionth of a second after the beginning and what things will be like 100 billion years into the future that to me is this amazing story so that is the most exciting drama of discovery we've ever been engaged with that's why it matters and four people want to hear more there's a World Science Festival that USIC day your wife is doing and World Science University give it a quick pitch yes a world science U is a new online platform that we at the World Science Festival have developed to try to get these ideas out to the general public but not just the level we're talking about here which is interesting and exciting but the real math behind it in a highly produced highly visual way so if you like relativity or this kind of stuff check it out it's a fun way to learn just Google World Science University fun yeah and Brian Graham and the festival is when May 28th to do and you can buy a ticket you buy tickets they just went on sale although a few things are already sold out but 50 events around the city that will allow you to immerse yourself in science Brian thank you thank you you

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Keywords: The Atlantic (Magazine), new york ideas fest, new york ideas, 2014, cosmos, Space (Literature Subject), solar system, Big Bang (Idea), universe, the universe, science, Brian Greene, Aspen Institute (Organization), FORA.tv (Organization), fora, fora tv, history, planets

Id: vmP4hV8o8UU

Length: 23min 55sec (1435 seconds)

Published: Tue May 20 2014