Avi Nelson - Space, above and beyond
Jan 12, 2013|
Avi welcomes Harvard Professor Peter Galison, author of Objectivity and discusses special relativity and white holes
Transcript - will not be 100% accurate
Nelson welcome to the program. We're gonna begin this afternoon. Well you step back for a moment when we celebrate the passage of time. One year changes to another we usually I'm very celebratory mood in the sense of having a big bash with. There actually some sober reflections that should come along with one year changing to another as we become aware that the we are all finite time. And the passage of time is something which is a burden on all of us I thought was appropriate therefore that begin a new year to. Take a look at the physics of time what time means with the -- terms of the. Physical universe. So we're gonna begin the program today with a special guest professor Peter -- Lawson is Pellegrino university professor. He specializes in the history of sciences was the philosophy of science he's also the director. Of the collection of historical scientific -- instruments. Available later we'll get to another one of his talents which is in the filmmaking don't implement. So professor -- should welcome and thanks for joining us this afternoon. Now let's begin with the talk about time which I guess became revolutionized with -- Einstein and I think everybody has a fascination with. Albert Einstein he was. In the unusual category of becoming a a world superstars of theoretical physicist. And one of the reasons was because he had. You've given us a dramatically new. Perspective on the issue of time from a physical point of view. What's interesting is that. Certain changes in physics that physicists think of it absolutely. Crucial for instance. That process. Was often thought that anything that you could see happen if you look that in a mirror that -- process to also. We now know that's not true in the people that discovered it not to be true. Won the Nobel Prize for it. But nobody got very excited about that outside of physics but when -- changed the -- -- time. It. Absolutely precipitated a radical shift in the way people understood the world and artists. Philosophers. Architects. Every night nature of modern poet. People across the cultural spectrum. Found this to be an astonishing change. And so partly what's interesting. To me is to think about what was happening back in 19100. That made the question of time. More than. Even that kind of change if you had given Nobel Prize for it -- change that transformed our culture. And that's what Einstein did in 1905 he said. There is no such thing as what he once called it universal to talk. There's no one -- -- -- takes place in the universe but rather simply moving observer carries with him or her. A particular time to back to that motion to their bank of harassment -- that change was immediately shocked. Well and it goes against our intuition because we tend to think of time being absolute. Everywhere. And at the same time applies regardless of who you are and where you are. And the reason that we don't. Find that to be and that that Einstein's concept is not into it. It because we're never moving fast enough to see these effects really come into lark are personally existence right. That's true and there are many aspects of relativity that are like that for instance Newton to Einstein in some ways was speaking to. Thought that the idea that there was C universal time and universal. Notion of space. Property called from -- mathematical and absolute time from mathematical -- -- face. He thought those things were really ultimately. What this -- doubt that all the knowledge you wrote his great work is Magnum opus. The work that really transformed. Modern physics. In the that -- later part of this seventeenth century and became a model even for our own founding political documents in the United States. Our founding fathers in the United States talked about. Scientific law and universal law they have in mind with Newton has done and Newton thought that time was like. A river and probably -- that something that was probably even a point. That it was like. The consortium of god it was something that existed outside of any emotion any person any observer and he frame of reference. It was just. What Einstein would later called universal to talk. If you're just joining us good afternoon on the line with the is professor Peter -- -- of Harvard. And we started with a discussion about time from the physical point of view motivated by the fact that we just changed the calendars to another year. And we're going to talk a little bit about that matters pertaining to the universe time and the speed of light in -- in energy and things like that. Those of you have questions the phone numbers 8774694322. And I'll stayed at the outset there's no such thing is a dumb question of course these these concept -- a difficult. To understand hard to grapple with. That's why people spend lifetimes and even then I'm only a partial understanding of the so don't be too intimidated least in terms of asking question. Not at all effect I think you know Einstein once. Was asked why did you ask these questions about the nature of space and time. And he said well it's because he like to ask questions that normally only to a sort of impose. So. -- all on adult children here. Now the idea though is that time slows down when you are moving so if somebody goes by very quickly. His clock would actually show less elapsed time. And as I understand that they've actually measured this a very slight effect with flying in is it wasn't a jet that flew around the world. And came back and and they. That showed that there was just a fraction of a second less time the past reportedly playing them for the rest of us on earth. That's so if you have two identical atomic clocks. And you fly one around the world and that one out and back. You'll find is the last time collapsed on its. On its lead out that on the one that stayed home. But the fact that many other ways in which we see this for example -- particles that the particle like electron only at the Saturday. And -- normally -- decay is quite quickly. But even that the Earth's surface and it doesn't make any sense in certain way really puzzled people in the. Earlier part of the twentieth century that the article on TV is because they get created in the upper atmosphere. When these cosmic rays -- into the top of our oxygen nitrogen out there. And then they shouldn't make it all the way down even happened very fast the syndicate before they get to this service why are we seeing. And then finally people realized this was just I'm done talking. That these particles which normally -- tiny fraction of the second. Had bit -- at -- time slowed down and so could live long enough to arrive at the surface of the -- There was something like a Geiger counter you can actually see these things. Sitting here all the time and -- Another kind of proof. Einstein's idea that moving objects have their clocks runs closer to speak is true. Now this would be away then theoretically of going into the future right we could. It was somebody went on a rocket ship and flew very fast and times slowed down when he got back to earth. Time a greater period of time would have passed for the people on earth than for him and soul and you could do this indefinitely in the he could come back in the -- -- today's fifty years and and he could have aged five years or even come back after his twin had died. That's true and we can. That's remarkable circumstance could make it possible to explore it very distant practice -- we could figure out how to get up two years. Separations speeds in the US that. But it is speed of light you could send somebody out they could exploit distanced. The distance. Star and then cut and come back now when they came back say they wouldn't know anybody here this. Things would have changed on the Europe beyond recognition that they could do that. We what we can do in other words -- just slow down a clock but we cannot go backward. I don't know I ordinary. Yeah I mean. And and that in a way makes basic sense because. Well there are any number of paradoxes but the one that people bring up -- supposed -- back in time and and shot your grandfather and in which case you wouldn't exist and how could you go back in -- -- There's a fundamental logic I guess to the idea that you can't go back in time and and displaced history. That's true Einstein challenged many things better understanding of the world but he believed in the kind of strict causality is. In this respect we do today get. Modified by some aspects of quantum physics -- that topic for today but in relativity. Causality is expected. If you take a hammer and they could collapse could that there's no frame of reference in this bad timing doesn't break the glass. Now what is true is that something that looks simultaneous in one frame of reference if you hold your arms out and snap your fingers. At the same time. I'm moving observer coming towards you. Was he -- fingers snap before the other. This Bible literally. Is reality of but causality. Is not. We're talking with Peter Yeltsin university professor at Harvard. Now here and he specializes in the history of science philosophy of physics and and be the intersection sometimes as you brought up earlier -- between politics and and physics. -- the it's not just time however that changes when you go birds that strike. Length also change -- space changes and -- changes. That's right in fact if I holed up let -- just stick. You know I should stop I think this. That when we measure the length of something where. I was involved they might -- -- why is that true and as a realistic I'd just look at -- side the other side he helped flies between them. So when you have a moving objects they Abbas goes spot. And I wanna know how long that buses. A better measure of the front of the bus in the back of the bus the same time that I could get myself. Very confused if I measure defined -- about say -- it's going from left to right and then wait. A little while and look at where the fact is I could -- the bus was in the wrong. Because the back of the dress would have moved up. So every measurement of the moving object. Involves measuring the front in the back of the object at the same time. So I hope -- it is crucial. That leads you immediately see if you disagree in one fame. And another thing is that what simultaneous you're gonna end up disagreeing about winning. And that's what happened. So in some way is the way to think of relativity at this part of relativity is that Einstein says that. I'm -- time depended on an observer. Published at how fast you're moving and that means. That link is gonna end up. Relative. -- those differences once and another. I know these concepts to people look -- ever had a course in relativity or or read about it. Sound so alien and and so. Distorted. As to be and -- at some level -- first reaction is I can't possibly be true. I guess we should emphasize that as we've had a hundred years of experimentation. On this. And these concepts introduced by Einstein are absolutely true -- mean they've been. They've been proven in numerous experiments over the course of the past century. That's true I mean as -- as I mentioned every time you you look at. Particles coming in from outer space we proved relativity everytime you turn on an accelerated that you prove relativity when you mr. You're seeking that and you turn on you in your cellphone user GPS to find out where you are. If you take away the relativity has been built into the way that machine works. You won't you'll get wrong answers in a matter of seconds. You'll be able to navigate -- the going doing your car with this GPS all of those. We built this into our. Technology you know relativity is not just for physicists that Femi glad he's big article laboratories. It's in this stuff up. It's everywhere. Now as intimidating as the subject of votes is for those brave souls who want to ask a question we're reviewing Huckabee graded on the question. This is not supposed to be a graduate seminars on the phone lines are -- U 877. 4694322. Is the phone number 68680. Is the a text message code. And like I got one message here Peter from a six point seven says these -- Boson coming on is against. -- I doubt that's the so called god particle that was just recently. In effect found along the diocese of little violence and yeah. Both on that really great discovery we have that here that's very well accepted that was made by. Wind again class silence salaam back in the 1960 years. And added it figures in years it's really every time we put a pass to it it seems the tacit. But why in great mystery remained and that was. The part of what -- what they're hearing did was sustain its electricity and magnetism ordinary electricity and magnetism like you have. When you plug something into a wall or have a permanent magnet your refrigerator. And it was connected to the one of the forces that hole and Adam did that holds matter together called the -- force. Now the strange thing was that. Right and travel infinite distances and its associated with the fact that like made up of these. Particles but -- no -- called proton that's what ideas the bunch of protons. And they -- probable. The -- across the universe that you want. We see things from stars that are thousands of like here's the right. -- -- The problem is that the weak force. The force that hold it together or not these massive particles like the photon that heavy particles that headache. And so they only get a short distance before they fall apart. You may have heard that -- sometimes successful call they called w.s in -- That is indeed the holes that kind of matter together only left the White House I helped them that the particle and a -- was particle -- connected. That's what this theory that it's said that the one of the forces that holds matter together and the lights are really the same force. Well that should Boson explains why some of these particles that have been some of the same now was. That's why it's so important to central to ideas are ideas you know buying physics. Peter -- Allison is my guess for this force portion of the program. We were not gonna take the whole program. And in this direction so they'll be stopped for more mundane politics a little bit later. But he -- university professor. That don't harbored. And he is -- area of specialty is actually quite wide ranging from history of science the science that philosophy of science. Here's an inch in question that which texted in Peter there's a difference 617. So it could you please ask your guest this question if I observe an object fly past me it's a 60% the speed of light. And observers second object fly past in the opposite direction of the first. What I not observe their velocity is relative to each other to be a -- and 20% the speed of light. Yes that's true. You concede to particles approaching each other vested in the speed of light. But you would never received but what if you're flying with the rest going particle he would do the right going particle approaching you have less than the speed of light. That sounds paradoxical. But it's not it really has to do with the fact that. That time is relative to other friends settle in -- third kind. You could see two other things approaching faster than the speed of light but from any one thing you would never see another thing approaching -- Yeah and -- and this comes from the fact that we usually just had velocity together which is what it is I think is very good question wolf raised by the call because that's the fun. When the fundamental. Almost paradoxes here. The EU. We tend to add velocity of these together simple addition you're going thirty miles an hour and a caller and you. Throw something out or shoot something out another thirty miles an you expect it's. That the particles traveling sixty miles an out but it turns out and burn at very high speeds that addition is not quite right and that's why you went up with this. With this paradox. I want to get to as -- Stephen Hawking put it the one equation known on the street. And that's. MC squared. And that of course led to well the old one aspect of modern physics but take us through that equation here. Quote I did this. That's Einstein and wanted to know whether an object that had. And exceed more energy in and others say a billiard ball it was hot as opposed to a billiard ball that was cold. Would have more inertia would be harder to get going. And the answer is yes. So and then she seems to add to the inertia of objects. They which is really what we mean ultimately by Matt how hard is something to accelerate through deep in space and you wanna. -- a volleyball even though there's no gravity it's still hard to get the bowling ball going it's harder to get -- Map that the Boeing -- was made out of rat than it was made out of wood in the same side so. NASA the resistance to acceleration of resistance to getting it going. It is really what we mean by men. And what Einstein said that it was bad equation. Is that these in Russia as an object. Depends on -- anarchy contents how energetic it is so the hotter it is the harder it is to accelerate. And that turned out to be very important. Because that -- for instance to the possibility. That you could take some matter. You know at some uranium for example and turn it into energy. That tiny amount. Matter it can be converted into a lot of energy. Expression goes yeah equals MC squared means the speed of light some big numbers. And when you square that even a bigger number seven the small amount of mass. I'm this huge numbers can -- a lot of energy and that's what happens for example in an atomic bomb. We're going to Peter official -- we got the pause should do something Monday in light paying the bills here we talked about it and concepts and visit. And to those -- you were calling and we'll take your calls on the other side of the break the phone number 87746. Night. 4322 Peter Galveston is professor. History and philosophy of the physics of Harvard. We're talking with him more to come on the other side of a break I'm on the Nelson. Peter Palestinians my cash for this first portion of the program and university professor of physics history of physics philosophy of physics or science at Harvard. We're talking about matters pertaining to the universe -- thoughts and calls are welcome Peter thanks for bring list through the break. Oh we have to be able calling in so let's go to the phone like 877469432. To the toll free number he heard another one displayed. The -- just before we went back on it. And that number works as well. From 617 Mary Erica. -- -- -- and next up on the program good afternoon. You don't what are -- can explain a little bit more about people. Okay. I've heard about black holes were white -- -- Well there is that this. Black holes. Places where that matter has gotten so compressed. That says nothing not even light can escape from them so. If you imagine trying to launch. Haven't descendant cannonball into orbit from the surface of the guys. Yes travels certain you know five miles a second to whatever it has to get out. And debt but as if you imagine sleeping here so that it was happening. Diameter than it is now he has pursued it even harder to get to get into orbit. And if you kept slipping it more and more. The speed -- escape would get eventually so great that it would be a hundred -- 6000 miles the second and then. He's not even light would be able to escape. When matter is that compressed and we know from the economy that there are places where this is so -- the center of our galaxy. And many other places in the in the in the universe where -- black holes except the black holes are famous -- science fiction and in popular. Discussions because where you can make that roach motel you can check in with you can check out and not thinking get out not even not a radio signal not why not. No matter and nothing can come out once it's. Past the point of no return. We're cosmology it is speculated. That it might be possible for our it'd be something like all right now you know why all the winners somehow. Massa that was both of those things that were falling into a black hole might somehow crossed over and be admitted somewhere else. That is it's very interesting that is speculations and the people that work on on on some ideas related to that. But they don't know we have the proven status. That black holes do black holes you can really demonstrates that they existed concede. Junk floating around the black hole and by the speed of that junk because it's the surrounded and that radio signals we can judge yeah well. How -- Did that a little bit as. And by looking at the effect on your -- stars we can -- how massive it is. This is a combination of that fact that it's very small and very massive we can determine that there black holes. The black holes exist. Why holes are -- insisting cosmological. -- of physical idea that says don't have the sense that. Okay. That any job. I actually interject your way or another question that was to a text and -- is there enough evidence yet to discern whether there's one universal perhaps an infinite number. That's a really interesting question that the very hot topic. Debate. And that the the idea of which seems so wild. I go back some way to end up people we're trying to understand the strange aspects of quantum. And one idea was that when quantum mechanics says that. Some random. Something's say that it could dictate to the left into the right. A -- -- in fact. This strange. They cause all unpredictable and that was actually as a reflection of the fact that both things happened. But they occurred in -- in two different universe is that this is constantly breaking off. Into other universe and more recently. This idea's been revised and expanded. As a way of understanding. Cosmology. And people would be done to ask the question about whether. -- laws of physics are the way they are. Because. They're million other universe is that infinite number of the universe is where the laws are different in every possible imaginable way. And that the fact that we are here is really not an amazing act of great rock. We know we're here because these are the conditions where it could be like saying isn't it amazing that my grandfather survived the war. For the patent that wouldn't be here to ask the question so everybody who's here as a grandfather of course father's about the -- that's not. That's not as strange as. As a sense of Soviet hit it's somehow amongst some -- has been that the conditions of our. Of all the world that we live in a place it's not too hot to have water not too cold have liquid water and that Adams are bound together with a great density for us to listen and so on that that's actually because the world has -- addresses. So varied there's so many different copies of that that we happen to live in the wind it's suitable for us now other physicists say that's crazy. That's the wrong way of thinking of that. That's really what we should do -- to look harder the physical laws and show why the laws are the way they are and couldn't be otherwise. So it's it's the big debate about whether there are many copies of the universe. And we just happened to. The trends that we live in the universe that allows life. And ability of the universe other other physicists say not at all that actually the way matter -- the fundamental laws of nature. Really couldn't be very different from -- that from the way they are. Peter when I was looking you up that Harvard I came across the on online news Harvard is said happened at one article that talked about. Day that -- researcher at Harvard has found that one in six stars such about 17% animal stars. In our galaxy has an earth sized planet now there are something like a hundred billion stars in our one galaxy. And there are 100 billion galaxies is united is pretty big place. But is interesting that there could be that many Earth's around because if there are. If there are hundred billion stars and 17%. Of the -- sized planets. It may be that that will find something that is similar to where we are although these plans to issue that. We're moving very quickly and very we're very close to the stars so they wouldn't be habitable in the sense that we understand it what about these search. Four other planets and other life. That might be similar to our own. I think they you know these these things called -- so planet's. I think you accept -- of one of the great most interesting discoveries that you can think of in the last decade to. Stay this idea that. We thought that pilots might be extremely rare. And what's amazing is my concern formula of the -- to ethics facilities. You can people actually began to discover axle plants with very primitive apparatus like. You know that telescope a couple of feet high -- -- -- Detector that could look at it which which they were looking for was. -- changes in the light. From the stars that indicated the passage of the climate. In front of the stars now at first he could only find. Very big stars -- were pretty close to of the activists of the city's. I systems analyst of this size and that I want the necessary to -- the reason for that was in this series it's. All the pilots were very big and very close to the stars but those are the ones that we could -- it's like looking for a UT's under the lamppost I mean. That doesn't it. And the thing brought down qualities that I found near -- as well. That's because that's the place -- there -- defined but that doesn't mean that there aren't -- elsewhere and that's troop requirements as well now in the last couple of years. The technology. These searches has gotten more sophisticated. And we've begun to these small appliance. Planets that might be. At least have the condition that they were far enough away from the sons of the water could be neither I vaporized. And the right side of the -- -- gravity for her other civilizations to live on so I think this. Extraordinarily large number of times it was as big surprise to many astronomers. It's -- very exciting event whether we're actually seeing. Says signals the flight from other places and I I don't know but I sure hope that. Peter Allison professor of physics history of physics philosophy physics from Harvard with make. 877469432. To the phone number and Paul you're next on the program good afternoon. But hey good afternoon gentlemen. Fascinating topic today by. My question. For the professor is about -- his opinion on time travel. Where he's taken -- theory that. Time is like a racetrack. And sort of circular and to get -- to -- you've got to go forward at a faster rate of speed you know living. Okay that thank you Paul what we've talked about this a little bit but that. It's not unusual Peter for and not everybody tunes and -- to begin at a Kroger and chuck. -- you know in a way we know that it is time travel and that is. Mrs. what I think was offensive that a little bit and we talked about. The fact that you removing them fight if I'm. Running by. But yes station. My clock would be seen is going slow. And I'll be looked out his window and does so we. If I would go out to a distant stars and to then turn around and come back I would end up younger than that body was staying at the that the station. And that's certainly a sense that. And then it literally the picture -- -- reversed positions on the island. I. But -- -- so he's like you know when you think he wants to think of time as a racetrack you can people moving on the racetrack but going back in time. -- from the point of view of relativity in from all we know now is impossible. So I mean I know there are some. There was an interesting moment of that -- -- year and a half ago and the group -- and thought they had found neutrinos -- Now was particles that don't interact much with the rest of matter but they do interact. They can travel through Europe many times about stopping for instance. That these particles might be going faster than the speed of light. If that would themselves. Then it would have been a possible to. Influence the past. And you could do the -- you could undertake to kind of -- paradox that I think was talking about earlier put it in kinder gentler way and say. Keep your grandparents from Medialink. Which created the paradox of not to lose their right to have done what you just did it. So that idea traveling backwards in time. Seems to issue with these paradoxes which is what made many people including me that they do yes that this experiment it's. Was correct and in fact eventually they had to withdraw they had not coordinated their clocks correctly two different sides of the experiment. And up to the present time there's no evidence of being able to move something backwards in time but you can. You can do without it that you can travel and time that you can't do that. Remember that means by the way. For all you folks plane to go into the future you can't come back then and tell all folks about your great adventure you're you're stuck in the future. No I haven't talked to your defendants. Here. Got an email from a man says that please ask the president Alison if physics provides. An explanation for the widely observed phenomenon that. The older we get the more quickly times seems to -- I wish that was -- and the -- it's so. Did who's who went to Iraq -- psychology and maybe. Some aspects of the way. Perception. Works as we get older but I noted that Einstein used to be asked many times. We knew when you're having fun. And time seems to travel quickly is that an example of relativity and I think he -- with sympathy. He was after all -- -- as a physicist. But it really wasn't. Sure but you're just -- we've talked about concepts that to the -- are so bizarre that there would be no reason to think of that. That these elasticity of time wouldn't apply. To this phenomenon as well so -- I'm an -- question. At a deep level the idea when Einstein says the space time energy content of an object. Support these things can be different as you went from one frame to another. It's -- people from many different areas to take up this idea for example the poet William Carlos Williams. Used to this the way of justifying. Criticism of classic -- also poetic composition. The political front for instance he thought ought to be something which with Eric. And whether that was truly an application of physics and not you. Rather you know that's a bit of a stretch but the idea that. It was connected by poets to things that would try to do that was absolutely on the on the ground points. So we see that across many -- there's. The only thing that's comparable to Einstein in the suspect is perhaps Darwin. And Newton but it's really it's a company of three not more. Well you're not I would I mean Peter I've always been struck by here Newton. Gave to -- in the seventeenth century -- very Mecca and stick view of the universe that everything all the or rich were precise and everything moved like. A grand clock and then you listen to music saved from beyond Sebastian Bach and back to hole. Baroque period and it's very precise -- counterpoint. There's say that the rhythm is clear and it may be intricate but it's all very even and -- connected and I -- thought that that was a manifestation. Of sort of the connection between the intersection between music and what was known about the physical universe and then you get into the nineteenth century. With the impressionists and the romantic composers and it's a much more organic. Kind of of a composition. Perhaps more reflective of the Darwinian theories that were taking hold. At that -- displacing new but but becoming more of the focus of attention. Chances you know. Science doesn't exist in. In a vacuum isolated from the rest of life. And Newton was insisted in the -- with a theology at this time he was interested in. The chemistry -- this time alchemy he was interested in all sorts of things and that's true of Einstein. And it's true. Of Darwin as well and then once they produced this series which were on the times they would then it begins to feed back and altered their world around them. We have this idea that this was really know -- the time that there were one set of laws. -- -- and the day has its forces proportional to mass times acceleration and he said every object is excited every other objects. In the universe every grain -- and every other grain of sand. And that's definitely universal -- was true on the -- it was true in my -- it was true and -- it was true beyond. And that notion that there was one set of laws. Was radically different from anything it has been said before people before that even Galileo but there were different set of laws that hasn't behaved on the moon and they did on the so this idea that there was one set of laws that applied everywhere that was very important so I mentioned earlier that the framers of the constitution of the Americans. System of of of of loss of that that they want the laws of the natural law. The government help what people were entitled to and what their rights were and so once was I was related to this idea that. Universal law that Newton and sent out to really changed the world -- Einstein did. Hundreds -- years later. Alison is a professor at Harvard University professor and be. These -- of some of interest include. History of science philosophy of science physics itself and there's another area which I do want to get in and you mentioned one point that because equals MC squared. And him enormous amount of energy that can be liberated which led to the atomic bomb. And also then it's succession of the hydrogen bomb and you made a film as -- called about the hydrogen bomb and you're not making. Another one having to do with nuclear waste. Tourists and again the intersection between science has an abstract and sciences -- reality comes to bear perhaps you could. Explain a little bit about what you've done in the film world. Well one of my goals and making films has been to try to take aspects of science that we really are both. Important in the technological and scientific sense but also have a great impact on our lives. And thoroughbred too he atomic bomb project was built. Is rapidly. As possible because the American side that the American government army everybody believes that the Truman's square. Hard at work and they had. At first at least good reason to think that because Heisenberg and there's some of the great physicists of the twentieth sentry were still in Germany is that interest is in. And indeed it was the Germans to discovered much of what was what was known at the end of this series is that nuclear sessions so people weren't ready they thought that the Nazis got the bomb burst. It would mean the end of modern civilization. So in a war there was very little time to think about the moral or political implications with a couple handful of exceptions. The race. -- -- more political discussion. After the war that was no longer true. And wouldn't -- me in the history of the hydrogen bomb is that alongside this extraordinarily difficult technical project. Wasn't really deep seated debates among physicists and chemists and -- just. About whether they should do. What are -- what is the obligation of the sciences. It -- special obligation. Because they know the technical aspects sources say simply follow what's. Directed by the military and government. These are questions that really were and deepen its split even some very old in deep friendships among scientists that I wanted to make a film. About that they -- called ultimate weapon -- -- Obama. It's been -- times on the History Channel. But it's. It was a it was really trying to explore. What it meant to have -- more political debate around and Gary technical difficult topic. That's my current film. Yeah there's that talk about moral dilemmas they continue on it with now that the nuclear genie is out of the bottle as -- war. But it's never gonna get put back in so some questions in different form remain to this day. It's true and I think that the questions of proliferation. And the relationship the nuclear we know what roll nuclear power should play in our world is that. People some people think that is something that's going to help with as an alternative to burning fossil fuels others think of this is that. Extraordinary danger to accident during the inability to. Deal with they waste is produced which is the subject of the film that I am making now it also made a film called secrecy. About national security secrecy in democracy is secrecy system that we have now that really came out of this -- the experience -- -- with nuclear weapons. So this met this some project picture undertaking now with the tune titled containment again sure co directing it. The objective is what to understand what we should do with the spent nuclear material. That's right I mean they're different kinds of nuclear waste there's. Everything from the minds ready uranium was extracted to the fabrication of nuclear parts for weapons and powers to the old fuel that comes out of nuclear reactors. And one of the questions this. How do you contain -- how do you keep this out of our. Biological world. And you bury yet if you put in tasks near the places where it's produced do you put it into big -- It's swimming pools and hope that the bottom of that. How he what is the worry is that. About accident to a loss of water -- hasn't started to happen at Fukushima. But there there are questions. I -- -- actually some good questions as the film come up with some good answers. Well the World Series. The other side of the question is that this stuff is to help -- the plutonium is 24000 years so the government does. Required. Any future repository for this waste. The warning people for hundreds of generations about creates its own very difficult. Says this. Is that a question -- Protect populations today have you -- communities. 101000 years into the future is the subject of the film and I'm hoping we can look where we can say something useful and we that we should keep them outside. The -- we will film the yeah yeah yeah. They -- -- -- -- time for one more or call 8774694322. Brad you've been holding on thank you and you know it. Couldn't get -- wonder if you gentlemen have ever heard of grafting. Or -- sister -- side it's about a -- -- -- -- of graphite in that allows electrons difficult very very quickly and its sister gratifying. Allows electrons ago. In one direction which would -- I think it would it would switch is right I think that might be good for yours which is company they. Well coached Iowa. This -- I don't think we have and then Mike -- wouldn't be -- involved with anything like that but professionally this ring a bell with you. -- this being one of the great new areas of scientific -- excited to get every bit of that question and it was a little -- in my. It's just about draft -- I -- -- I was -- the veteran. Insisting. Properties. This you -- name -- science called -- science. Just science that's on the scale of the billions of a meter which is very small compared to everyday right the big compared to. You know elementary particles but in that in that area and assigns one of the great structures that's been explored. I think it was called -- to. And arrangements of sheets of crop of graphite and carbon that allow that have very interesting properties. That they can be a conductor of electrons in some ways and and semiconductors like consisted. In others see people have begun to exploit using these. Structure that says. That scrapping those things to begin to think about that that the caller was asking does. As switches to begin to think about making the world's smallest. Piece of a computer. And these are hopeless dream in the same ethnicity. Which is more than just step to a science fiction but at the moment not realize supposed to actually be able to. Make these circuits and we've begun to people have begun to make. Pieces of circuits small circuits at this tiny bell and eventually to think that combine them into. That kind of computation as we can only hope words today because. All right -- circuits and -- studies they are still very -- does that. The dream and they are it is true that these carbon -- when there wound up in certain ways sometimes act like. Says that this is sometimes like kind of -- good wire. We've got that -- that I've got about a minute left limit texting -- question I do want to ask you is religion diametrically opposed to physics. -- is religion. Diametrically opposed to physics are they diametrically opposite. And historically. I would say no. That there have been many times when physicists in different list. Have been actually inspired by ideas from religion. The idea of the big bang and the debates around that we're connected with certain religious views Newton brought that religion tremendously Einstein had a kind of -- at this sticker pants he has stick view that in order in the universe I I believe you would never do physics if you didn't think that there was some. -- behind all these things that he thought of this kind of spiritual. But not personified. God. That's not to say they're people who oppose -- six on the grounds of religion but I think the stated categorically religion and science are opposites would be. Huge historical mistake. You know wanna thank you I know who overstayed there welcome a little bit and I thank you feel forbearance and classic -- -- always been and I wish you wonderfully here. Thank you ashamed -- thanks for being with us this afternoon. Professor Peter Cal's -- of Harvard university. Of physics philosophy if there's a history of physics. Back on the other side with more mundane subjects of politics don't go away among Nelson.