Feynman at Caltech - John Preskill and Kip Thorne - 5/11/2018

so cap we both knew dick Feynman as a colleague but for those who didn't know him personally it's hard to explain what a remarkable scientist he was yeah it really is it's amazing because he would sometimes come up with these astounding insights seemingly on the spur of the moment how was he able to do that yeah I really don't know but I do remember I really do remember one occasion of this in 1963 just after hit Martin Schmidt here at Cal Tech had discovered quasars in the sky and people physicists and astronomers all around the world they were trying to figure out what these quasars were and here at Cal Tech really Fowler together with Fred Hoyle who was visiting from Cambridge at the time they invented a theory of quasars it was based on supermassive stars stars that wait a million times what the Sun weighs and they gave a seminar about their theory and in the middle of the seminar Richard Feynman stood up and objected he said those stars of yours they're going to be unstable because of general relativity they're going to collapse and destroy themselves and everybody in the room was just flabbergasted they were just amazed at this insight well I bet Fowler in the foil were the most fun of all they were indeed Willy used to go around telling the story of this he loved to tell the story in retrospect after they'd figured out how to deal with it yeah and then just a few months later Chandrasekhar at the University of Chicago published a paper that explained this relativistic instability that nobody had ever known about before so this became part of the Fineman legend somehow Fineman just knew this instinctively but Chandrasekhar had to work hard to discover it you know and so when I came back here on the faculty a few years later I asked dick about I said dick how did you know and Dick said I'll show you and so he went home and he brought back the next day 40 pages of handwritten calculations in which he had been working out the details of the collapse of a star month before they Hoyle Fowler theory he'd been doing this because Johnny wheeler who is his meandering mine Johnny wheeler at Princeton had been challenging everybody to understand the collapse of things to form what later became to be called black holes and so driven by his intellectual curiosity dick had worked all of this out for himself he must have had to solve those equations numerically I supposedly used a slide rule indeed he did I saw the slide roll calculations step after step after step but once he'd done the calculations he went and put the calculations away in his desk drawer and didn't think much more about it he figured well other people know about this and okay now I understand I'm happy and then in the middle of the Hoyle Fowler seminar he suddenly realized because of the calculations these things are going to be unstable and so what to everybody in the audience seemed like a remarkable insight was after the result of very hard work done driven by his own intellectual curiosity well that explains a lot he must have had a lot of secrets in that drawer of his I think he did I think he did did I ever tell you about the first time I encountered Richard Fineman oh well trying to guess how old I was I don't know twenty one way off I was nine really and when I was nine I read this remarkable book a wonderful book called the world of science by Jane Huerta Watson and what especially captured my attention in this book was the chapter on theoretical physics and it begins with the story of a small boy who has a red wagon with a ball in the back and he notices that when he pulls the wagon forward the ball rolls to the back and when he stops pulling the ball rolls to the front so he asked his father why does that happen and his father said well that's called inertia but nobody knows why and so I thought what's going on when I saw interview years later this interview with Christopher Seitz this great interview called the pleasure of finding things out and finally tells the same story I thought this guy stole that story from the book I read when I was good but then I looked at the book hadn't looked at it in years and I realized what had happened Jane Werner Watson had based every chapter of the book on interviews with Caltech faculty so that cleared up one mystery though others remain yeah like why is dick wearing a bowtie and where are Marie gell-mann's glasses exactly I don't know I can't explain it I don't really care but you're right you always puts me down it's it's an enduring mystery and what was really terrific about this book is it described a discovery that had just been made in 1957 a year before the book was published which was that the laws of nature actually know the difference between left and right and that's what Simon and gell-mann were working on at the time and I thought that was so exciting it got me interested in physics which eventually led me to Caltech where I'd joined Fineman on the faculty 21 years later Wow they're going in another direction you know it was in the early 1960s that Richard Feynman revitalized revamped our introductory course on physics freshman sophomore physics and he wrote up his lectures in three volumes and that came to be called the final lectures on physics three volumes that had tremendous tremendous insights because of his tremendous physical intuition his great pedagogical power those lectures have sold a million and a half copies in the English language alone and they are the most influential set of books on physics I think that the world has ever seen the most widely influential that's right and for a lot of the students who attended those lectures looking back they consider fineman's lectures to be their most memorable experience of their college years Simon loved an audience he loved to perform so every class was like a meticulously prepared performance he had notes like you can see on the table but he didn't look at them every lecture was almost perfectly timed even the use of the chalkboards was very precisely Corian it was really remarkable and even today the so many decades later these lectures are of enormous value and interest to physicists mature physicists and novices alike they're being read by people all around the world and thanks to the heroic efforts of Michael Gottlieb really five-four and others they're available today online in HTML format of the Fineman lectures website it's so great that they're available for free to anybody in the world because the lectures are amazing I still dip into them every once in a while you know just for fun and it's always a great experience to reread them I bet you do too I do I do I've got them sitting in my office at home right well you know that time he taught the Fineman lectures for two years that was the only time in his career at Caltech that Fineman officially taught an undergraduate course but he was involved in undergraduate education and one way was an unofficial course that was called physics ax and it was early just Fineman standing in front of a classroom saying ask me anything he wanted the students to ask him questions about trying to understand something and then he and the students would try to work it out together with Fineman standing at the blackboard do you remember physics s oh I remember it well I was a freshman here in 1958-59 and this course physics X was something you heard about by word of mouth it was not in the Caltech catalog of courses you didn't get credit for it it wasn't advertised anywhere that you could read about and I remember vividly one of the sessions of physics X we all went we all I and a number of my freshman friends went to the rumored classroom at the rumored time and hope that phiman would show up firemen did show up he looked around the class of freshmen and said why do you want to talk about today and somebody said I want to know about water waves on Mars it's pretty cold on Mars it's pretty cold on Mars and that's what firemen said we'll be frozen there'll be no waves next question and and so so one of the really smart kids said okay let's pretend do it go Donkin experiment pretend that we warm the surface of Mars up okay now you've got now you've got real water you've got real water waves and so how fast are these waves going to propagate and so Fineman then argued things through together with us the waters crest gets pulled down into a trough by gravity but the pull of gravity on Mars is three times weaker than the pull on earth so surely the waves are going to prop more propagate more slowly and so let's go through and calculate it out and figure it out together and hand-in-hand together we worked at it to hold the whole class with phiman and figured out that it propagates square root of 3 times more slowly on mars and on earth and then the question was and how bigger the waves going to be and so we speculated together with him what causes the waves how do how did they get generated and finally he explained it's the turbulent pounding of air on the surface of the water that generates the waves but the density of the air is going to be lower on Mars a lot lower than it is on the surface if 'van on the earth and so the county will be a lot weaker the waves would be a lot smaller and we went through and worked out some of the details I emerged from that class that day just so mended so tremendously inspired that I remembered to this day more than half a century later so not a whole lot of fun surfing on Mars time not a whole lot of land that's you're one of those little itty bitty mark right well I guess he was trying to drive home a couple of lessons one is that physics should be fun yes and the other is that everything in science can be interesting if you delve into it deeply yes yes well he was just such a great explainer and he loved to explain things and and that was definitely still true when I knew him in the 1980s and I remember that in 1987 the Rogers Commission was finished investigating the Challenger disaster and finally was very eager to dive back into physics and he was particularly about a new idea he had a way to describe mathematically what happens when two protons collide at very high energy but to follow through on that idea he had to learn a subject that was new for him something called integral models and he thought well it would be fun to learn this by meeting with students to discuss it and so he had a weekly meeting in his office with a small group of students and they would talk about integral models and as the year went on how Fineman was getting increasingly ill but he really looked forward to those Wednesday meetings and he never missed them it was very inspiring to the students to see how excited he was about the topic how engaged and how much fun he had discussing it and his exhortation to the students were still on his blackboard at the time he died he told them that they should know the tools of mathematical physics they should know how to solve every problem that has been solved exactly but he also emphasized that they should work out the solution they solve problems themselves they shouldn't just follow in the steps that others had followed because he said what I cannot create I do not understand but he made one exception to that which was he arranged for his notes to be shared with the students after he died and when the student saw them they were flabbergasted because these notes were so voluminous and so meticulously detailed and fireman had delved into the subject much deeper than they suspected from those discussions yes we lost Fineman on February 15 1988 there was a tremendously sad day for us all at Caltech Richard Feynman was a loved honored cherished friend of all of us he was a hero to the faculty the students and the staff alike and he was built embedded deep in the culture of this place that's for sure I remember that day and it was indeed a sad day you know it it's been 30 years and since then many students have come and gone who didn't know Fineman personally but like us they've been deeply influenced by him in many ways by scientific accomplishments by his ideas by his writing and by his playfulness so really the spirit of dick Fineman lives on among curious scientists all over the world indeed it does you know kept he won't be forgotten [Applause] [Music] [Applause]

Channel: caltech

Views: 37,174

Rating: 4.9381442 out of 5

Keywords: Caltech, science, technology, research, John Preskill, Kip Thorne, Richard Feynman, Feynman diagrams, physics, Physics X, teaching, Feynman professor

Id: UjrAsJcmblY

Length: 14min 11sec (851 seconds)

Published: Tue May 22 2018