Lost Lecture by Feynman - Book Report/Review Example

Assignment Book Review – Feynman’s Lost Lecture Introduction Goldstein and Goldstein have taken rather an innovative approach while writing the book on Feynman’s research and inferences over a particular topic of physics. As the book is called Feynman’s Lost Lecture: The Motion of Planets and the Sun, a reader might expect that it would contain some complicated treatise on certain topics and attributes of astronomy, physics, and mathematics. However, Goldstein and Goldstein have selected a subject that deals a highly complex problem of physics in an unexpectedly simple manner. Feynman’s lecture was predominantly about deducing Kepler’s First Law with the help of Newtonian Mechanics. And how did the distinguished scientist do this? He did this using only high school level trigonometry and algebra! Summary Goldstein and Goldstein have written the book keeping in mind that the topic can be read and understood by a lot more reader even outside the scientific community. However, this factor makes their task more challenging. The authors must explain the significance of Feynman’s deduction in such a way that even a person with average knowledge of physics can understand the charm of the subject all the more. The book starts with a concise introduction with much focus on planetary motions and why they are so important in the context of general physics. In the next section, the authors try to develop a relevant history of scientific enquiry regarding planetary and solar motions. The authors have mentioned that how old and elegant this topic has been from the era of ancient Babylonians and Greeks. Although Ptolemy’s research and inferences have not been discussed intricately, it is understood that the universe was thought to be geocentric according as the observations of this ancient era Greek scientist. The main discussion starts from explaining the contributions of Copernicus, and then somewhat criticizing him! Copernicus’s area of research had been picked up by Tycho Brahe. Copernicus’s model of universe was heliocentric, while Tycho’s universe was again geocentric. In order to show the significance of Tycho’s contribution, Goldstein and Goldstein write: “To the modern eye, the Tychonic universe seems to be a compromise between Aristotle and Copernicus, but in his own time Tycho’s cosmos was in some ways an even more audacious departure from Aristotle than Copernicus’s had been, because it smashed the crystal spheres that were supposed to fill the heaven regardless of whether the Earth or the Sun was at the center.” (26) The historic discovery of telescope by Galileo (an event that occurred almost after a decade from the death of Tycho) revolutionized astronomy forever. Galileo’s observations were scientifically enough to establish the heliocentric model of solar system and prove that Earth revolves around Sun. Moreover, Kepler’s formulation of the laws of planetary motion further simplified the mystery of cosmology. By the end of 17th century, Newton formulated a number of physical laws that furthered this process of scientific enquiry. In the context of Astronomy, he propounded the Universal Law of Gravitation which helped the world to better understand Kepler’s model of universe (37-41). He also propounded three other laws to explain motions as observed in the physical world. One of these laws, the Principle of Inertia, is again tremendously important in understanding (or misunderstanding) cosmology as a whole. After explaining the history of cosmological models up to the era of Newton, the authors adopt a more entertaining and generalized story telling approach. Hence the chapter titled “Feynman: A Reminiscence” (45). In this part of the book, most of the introductory discussion on Feynman’s scientific perspectives can be found. After a brief introduction to the scientist, his life and his works, the authors then focus on his proof of the Law of Ellipses (this is placed as the first one of Kepler’s three laws explaining planetary motion). In the next chapter, the authors finally discuss the historic lecture of Feynman delivered on 13th March, 1964. This lecture had been delivered to first year college students. Although the lecture directly dealt with some profound mysteries of physics, it had an astonishingly simple approach which utilized only high school level knowledge of physics and simple mathematical techniques. Next, the reader arrives at the section of Epilogue. In this section, the authors have explained that how Newton’s Laws fail to give a complete explanation of the physical phenomena as observed in our world and beyond. From Newtonian perspective, there cannot be concepts like absolute rest or absolute motion. “But James Clerk Maxwell had shown that light has a definite speed – a speed that can be found in the fundamental forces between magnets and between electric charges.” (173) In sum, from an expert level understanding in the subject, it can be well understood that Feynman had just hinted toward some extremely complicated enigmas of physics. Although his lecture as delivered on 13th March, 1964 utilized simple facts and techniques of high school level physics and mathematics, the importance of this lecture remains phenomenal and historic. The Key Steps The key steps of Feynman’s deduction involve and are supported by some basic explanations and techniques. Although the Lost Lecture was not all about this deduction, the major portions of the lecture notes involved it. The main aim was to develop a geometry based demonstration of the fact that Kepler’s Law of Ellipses is actually a result that follows from the Law of Areas and the Law of Periods. After a brief note on the history of this topic, Feynman started his phenomenal deduction: Step 1: Overview of some characteristic features of ellipses. This involved a reference to the “circle construction of an ellipse” (see Hall and Higson 3). The concept shows that how a tangent can be drawn to an ellipse and what is its geometric significance. Step 2: At any point of its orbit, the orbiting planet would fly off in a tangential path. This follows from Newton’s Principle of Inertia. However, the planet cannot fly off because a force acts upon it perpendicularly with respect to that tangential path. This is understood with the help of Newton’s First Law of motion and the concept of external force. (Goldstein and Goldstein 71-89) Step 3: This step can be viewed as an extension of Step 2. The technique of finding vector sum is applied. One of the vectors is the planet’s genuine motion, not caused by the Sun. The other vector is the force of attraction exerted by the Sun. At every point in its path, the planet moves along the resultant of these two forces at that point. Now with the help of basic trigonometry of triangles, Feynman proves Kepler’s Second Law or the Law of Areas. Step 4: Newton’s Law of Universal Gravitation is applied at this stage of the deduction (Hall and Higson 5). Accordingly, the gravitational pull of the Sun varies inversely as the square of its distance from the planet. Now applying simple geometry of vector summation, Feynman derives the Law of Periods. Step 5: Now Feynman demonstrates that the velocity of the orbiting planet changes due to a combined effect of its inertial force and the gravitational force as exerted by the Sun. Next, with the help of Fano’s theorem, Feynman shows that these velocity alterations culminate at a pure elliptical shape of the planet’s trajectory. In other words, the Law of Ellipses is derived. (Goldstein and Goldstein 117-130) Works Cited Goldstein, David .L. and Judith R. Goldstein. Feynman’s Lost Lecture: The Motion of Planets around the Sun. New York: Norton, 2000. Print. Hall, Rachel W. and Nigel Higson. ‘Paths of the Planet.’ Lecture notes and supporting material for MATH 235: Mathematical Models and Their Analysis. The University of Vermont: Burlington, 1998. Web. 26 September 2013. Read More