{PDF} Why Does E=Mc2?: (And Why Should We Care?)

WHY DOES E=MC2?: (AND WHY SHOULD WE CARE?) PDF, EPUB, EBOOK

NOOK Book. Home 1 Books 2. Add to Wishlist. Sign in to Purchase Instantly. Members save with free shipping everyday! See details. Brian Cox and Professor Jeff Forshaw go on a journey to the frontier of twenty-first century science to unpack Einstein's famous equation. Explaining and simplifying notions of energy, mass, and light-while exploding commonly held misconceptions-they demonstrate how the structure of nature itself is contained within this equation. Along the way, we visit the site of one of the largest scientific experiments ever conducted: the now-famous Large Hadron Collider, a gigantic particle accelerator capable of re-creating conditions that existed fractions of a second after the Big Bang. Jeff Forshaw is a Professor of Theoretical Physics at the University of Manchester, specializing in the physics of elementary particles. He was awarded the Institute of Physics Maxwell Medal in for outstanding contributions to theoretical physics. Related Searches. A nutritionist offers recipes and a diet program to aid in determining which foods cause View Product. Between You and Me. At the age of 87, Mike Wallace is a legendary figure in broadcast journalism. Now, after 60 years of reporting on important events around the world, he shares his personal stories about the incredible range of celebrities, newsmakers, criminals, and The authoritative guide to understanding and living with borderline personality disorder, now fully revised and The authoritative guide to understanding and living with borderline personality disorder, now fully revised and updated Millions of Americans suffer from borderline personality disorder BPD , a psychiatric condition marked by extreme emotional instability, erratic and self-destructive behavior, and tumultuous As a layman who is interested in Physics and finds some books too technical and many others lack of precision and depth, I found this book brilliant and very helpful. It is an easy-to-follow popular He has received many awards for his work promoting science, including being elected an International Fellow of the Explorers Club in , an organization whose members include NeilArmstrong and Chuck Yeager. Jeff Forshaw is professor of theoretical physics at the University of Manchester, specializing in the physics of elementary particles. He was awarded the Institute of Physics Maxwell Medal in for outstanding contributions to theoretical physics. From he worked in Professor Frank Close's group at the Rutherford Appleton Laboratory before returning to Manchester in Jeff is an enthusiastic lecturer and currently teaches Einstein's Theory of Relativity to first year undergraduates. He has co-writing an undergraduate textbook on relativity for Wiley and he is the author of an advanced level monograph on particle physics for Cambridge University Press. Cox and Forshaw began collaborating on scientific papers in , and have published on topics ranging from Pomerons to Higgs Bosons. Their most successful paper to date deals with physics at the Large Hadron Collider in the absence of a Higgs particle. Brian Cox , Jeff Forshaw. Why Does E=mc2?: (And Why Should We Care?) by Brian Cox, Jeff Forshaw, Paperback | Barnes & Noble®

Why should we not need to catalog everything in huge databases and encyclopedias? Nobody really knows why nature allows itself to be summarized in this way, and it is certainly true that this apparent underlying elegance and simplicity is one of the reasons why many physicists do what they do. While reminding ourselves that nature may not continue to submit itself to this wonderful simplification, we can at least for the moment marvel at the underlying beauty we have discovered. Highly recommended if you have the itch to scratch, but a word of warning - if you're not interested in understanding why the theory of special relativity is so important, then this is not the book for you. The authors are intentionally avoided adding to the understandable hero worship that surrounds Einstein, and this is not biography-as-science: this is a maths and physics primer, kindly and interestingly written. View 1 comment. Aug 02, Max rated it really liked it Shelves: physics. They state upfront that their book is intended to be challenging. And it is, despite simplistic analogies and explanations tucked in between some pretty dense material. Einstein noticed that Maxwell had shown that the speed of light was a constant and from this he constructed the Special Theory of Relativity. Then Einstein thought about the fact that all objects fell at the same rate as Galileo demonstrated. He turned this idea into the General Theory of Relativity. Many complex topics are addressed along the way. The authors employ high school algebra and geometry but their manipulations can be intricate. The derivation is not done historically. They note that the observer in motion and stationary observer are interchangeable. Each can perceive the other as the one moving and the one for who time slows. There is no absolute motion as Galileo validated. Time, size and distance are observer dependent but the solution must be invariant, looking the same to all observers. To achieve this space and time must be combined into a single entity with four dimensions. The authors introduce us to Minkowski space which blends space and time. In it Cox and Forshaw use a modified Pythagorean formula that avoids going back in time which would violate the principle of causality, e. To measure distance in spacetime, the constant c, is introduced to calibrate. It is the universal speed limit and the speed of light. Everything moves through spacetime at this speed. If at rest the movement is all through time. If moving through space then time slows proportionately from the point of view of a stationary observer. Thus both moving and stationary observers agree on movement through the combined spacetime and invariance is achieved. To complete their derivation the authors introduce momentum, the product of mass and velocity. Momentum is a three dimensional vector in our everyday 3D world and four dimensional in the 4D world with the added component of time. The time component of the momentum vector in 4D space is mc , mass times the universal speed limit. Momentum is a conserved quantity as is mass which is equivalent to energy. Mass and energy are different manifestations of a single underlying physical quantity. Energy, mass and momentum form a spacetime object known as the energy- momentum four-vector. The details are in the book. The foregoing is just intended to give the flavor and flow of the book. The second half of the book is easier to digest as Cox and Forshaw give a broad overview of assorted physics topics. They describe the vast amount of energy in a tiny amount of mass and how that mass is converted, not just in nuclear reactions but in chemical reactions and other everyday phenomena. The authors discuss the Higgs boson as the origin of mass, even though this was just a prediction when they wrote the book. They even go back to the Big Bang and the disparity between matter and anti-matter. They then present the equation for the Standard Model, explaining what each term represents. They discuss how the model was put together and the various contributors, Glashow, Weinberg, Salam, Feynman, and Gell-Mann. Finally such a wide ranging review would not be complete without General Relativity to which the last chapter is devoted. I enjoyed this book. However the presentation was a bit disjointed. The authors write for readers at varying levels bouncing back and forth between simple explanations and more difficult detailed ones. They insert apologies to those for who the material might be too complicated and for those who might get bored. While the math itself was not overly difficult, following it in terms of the concepts it represented was more demanding. Still I applaud the effort to put some accessible math behind concepts that are deep and not intuitive. Regardless of level this is a book for a non-scientist reader with a strong interest in the subject. Cox and Forshaw said the book was meant to be a challenge. It was and that made it worthwhile. View 2 comments. Nov 30, Danielle rated it liked it Shelves: science-technology , biography , nonfiction , history. I was expecting, from the first few paragraphs of the book, that I was going to breeze right through this. It didn't really happen that way. I had to take college physics, which included the basics of relativity and quantum theories, so I probably have a bit more knowledge than the average non- physicist. All the same, there were areas of this book that just did not seem to click at all, even after reading paragraphs over and over again. Usually the parts that didn't click were the "easy" example I was expecting, from the first few paragraphs of the book, that I was going to breeze right through this. Usually the parts that didn't click were the "easy" examples such as how the distance between the moon and the Earth get further apart as the spin of the Earth slows. For anyone that doesn't know about conservation of rotational momentum, this is not an easy thing to figure out. Especially since they don't even mention momentum until 5 chapters later. The end of the book definitely seemed a little bit rushed, mainly due to the "just take our word for it" approach for what they deemed hard to understand topics. I understand this was attempting to make Einstein's theories accessible to lay people, but I feel it felt a little bit short. I would love to say that I understood every word and every example of this book, but unfortunately there were many times I felt like the concepts were far too complicated for me. I'm not an unintelligent person but my math and physics knowledge is rather old and rusty. I'll give it another 2 or 3 read through before making any firm judgements on the books. I feel I have learned something from this book I just don't know what it is I've learned.. Jun 22, C rated it did not like it. Absolutely senseless. If he ever gets close to talking about the matter at hand, another long passage about a motorcyclist will pop up to "explain things" Look. The reason you use so many horrible analogies is because you are a horrible explainer! Convey it the first time, don't waddle about. View all 5 comments. Feb 24, Kristin rated it really liked it. On a good day, high school physics class used to leave me feeling kind of for lack of a better word high. This book brought back that old, familiar feeling, but in an even better way. In the end, I walked away with a much clearer understanding of Einstein's theories of special and general relativity than I ever achieved slogging through high school physics. I think our teacher must have been unable to articulate and synthesize the underlying questions that the equations sought to answer. The On a good day, high school physics class used to leave me feeling kind of for lack of a better word high. This process is broken down into a few key steps: 1 an understanding that the speed of light is constant and therefore space and time must be "variables"; 2 the mathematical definition of spacetime and the formula needed to relate events within it; and 3 the definition of vectors in spacetime. It really is as simple as that. With an understanding of these key relationships, the elegance, beauty, and profound repercussions of the equation become crystal clear, even for those of us who never pursued physics beyond high school. I did struggle with a few sections, particularly the bits about electromagnetism, the conservation of rotational momentum, and--I hate to say it--the "tiny physicists in elevators" analogy. In spite of my mushy understanding of those parts, I was still able to "go there" with the authors in the end. The English major in me was a little miffed when they had a go at Murray Gell-Mann for taking his inspiration for the name "quark" from Finnegan's Wake , but otherwise I enjoyed the authors' playful, easygoing tone. You should. Enjoy Jan 13, Trevor rated it liked it Shelves: science. The best of this is how well they explain why it is not possible to travel faster than light — a really quite nice geometrical proof they offer. There are also some rather veiled digs made at Creationism and Intelligent Design which might have been better being said out loud rather than the curious sotto voce chosen here. My problem has been in trying to understand why the twin paradox happens? The twin paradox is where you have a pair of twins and you stick one of them in a spacecraft and her brother gets left here on earth. The twin in the spacecraft zaps off at near light speed for a few years and when she returns her brother has been dead for a million years or so. This was something nearly explained in The Fabric of the Cosmos , I think, although, not as well as is done here. In that book he talks about being in a spinning box in the middle of the universe and seeing the stars turning around you — how do you know it is you that is moving and not the stars. When you think about it this is an amusing example, given Ptolemy, but his point is that you can tell you are moving and not the sky moving around you. If a body is experiencing an accelerating force it therefore experiences the universe differently from one that is experiencing a lesser force. I might have missed it here, though, perhaps they did explain it. Why should accelerating make time slow down? View all 8 comments. Feb 29, Bob Nichols rated it it was ok. For those trying to nudge themselves into Einstein's world a little more, this book's title has great appeal. At some very general level, the equivalence of energy and mass can be understood, but the role of light "c" and light squared remains a challenge. In the reverse, energy adds to mass. When energy heat is added to mass, mass For those trying to nudge themselves into Einstein's world a little more, this book's title has great appeal. When energy heat is added to mass, mass increases because energy itself has mass. At the heart of the understanding of reality, the authors make it clear that mass and energy are the same thing. They are not "disconnected entitites. This all prompts one to wonder what underlies and connects these two disconnected entities and why does conversion from one to the other occur. Is the "pull - push" phenomena related in the sense that mass pulls energy into itself and energy seeks to escape mass? Is concentrated energy in mass gravity? Is energy escaping mass "liberation"? If, as the authors note, the sun loses 4 million tons of mass every second in the form of radiated energy, does this mean that the earth is gaining some mass from that energy? While the authors are quite lucid here and there, their discussion of the role of light in Einstein's equation was frustratingly opaque. Intriguingly, they seem to suggest that the speed of light is not the central factor. It is, rather, a way to measure distance in a time direction, but it is not clear how time spacetime relates to the discussion that energy and matter are equivalent. The authors are clear that time and space are one thing, and that light years a unit of time can be used to measure distance. The authors seem to say that "c" is relevant because particles of light are massless. Elsewhere, the authors say that spacetime is like "cosmic maple syrup" with some mass Higgs field? When that happens, does light pick up mass? The authors say other things about light that are also unlcear: that there's a cosmic speed limit and that there is such a thing as "allocated speed" and a cosmic "speed quota," and that everything hurtles through spacetime at the same speed. All of this is somehow related to the "c" in the Einstein equation. At this point, it's an achievement for the lay reader to simply identify what he or she does not understand. This is all challenging stuff. Perhaps the real problem is the inability to transfer our earth-bound perspective as that has evolved to be into these cosmic realms that operate on such vastly different scales. View all 12 comments. Dec 26, Merilee rated it it was amazing. Superb review of latest in particle physics and spacetime. Cox explains things as clearly as possible, but I believe I will need to reread this before I could begin to explain any of it to anyone else. Dec 07, Blair rated it really liked it Shelves: science-physics. The challenge of writing any popular science book is that the audience has different levels of knowledge. The author needs to choose the appropriate level of knowledge to aim the writing at. To understand my perspective, you should know my background: A long time ago I completed first year university science before switching into computers. I have since read a number of popular science books on relativity and quantum mechanics. I am presently taking on-line university physics courses to get a deeper understanding. I have thus seen many of the ideas in this book before, and understand the mathematics. Frequently they give a hokey apology I got very tired of chalk dust and then present complex mathematics in prose. Important steps are often skipped. I can tell you that I had to read much of this book several times, and do the math on paper to try to understand it. Following Einstein, the authors devote a chapter to this subject. This is fine with me, because I am taking my electricity course for precisely this reason. Briefly, experiments in the 19th century showed that a moving magnetic field generates electric current, and an electric current generates a magnetic field. These mutually reinforcing forces create an energy wave, which can be described by a wave equation. This equation gives us the speed at which the wave must travel, which turns out to be the same as the speed of light. Thus light is just another type of electromagnetic wave. Einstein assumed all movement is relative, and that the laws of physics are always the same no matter what is perceived to be doing the moving. His genius was to take this result literally, and conclude that the speed of light must always be constant no matter how it is measured. The book claims on page 27 the speed of light is determined by the ratio of the strengths of the electric and magnetic fields. That looks like a product to me, which makes intuitive sense if they are reinforcing each other. But this stuff is over my head, so did they oversimplify, or do I have it wrong? Riding the Relativity Railroad with Pythagoras Now we get to the classic thought experiment of measuring the relative passage of time on a train from the perspective of an observer on the platform. The passenger measures time by shining a light from one position to another one meter above it. The observer on the platform sees the light taking a longer path because the light pulse is moving along with the train. We can use the Pythagorean theorem to calculate the rate at which time appears to slow down, known as time dilation. While it is cool that such basic math can be used to derive relativity, for some reason the author chooses not to call this by its usual name of Lorentz factor. This stuff seems to make sense when I read it, then I wake up in the middle of the night and it does not make sense any more. For example, I wondered if the above result is only true at the exact moment when the train passes the observer. No, it turns out that time dilation does not depend on the direction of motion. This is still not obvious to me, and I could have used an explanation in the book. I find it easy to get confused about which clock is running slower. I have to remind myself of what I call the Spoiled Princess Principle: You are the center of the universe. You do not move, everything else moves relative to you. Your clock always runs at the same rate. Stretching time does not seem as strange as the fact that space contracts in front of you when you are moving. The example he gives is that if we go fast enough, we can get to the Andromeda galaxy, which is three million light years away, in fifty years of our time. Are we going faster than light? No, my spoiled princess, remember that is only how it appears to you. How it looks to the people who sent you is coming up next. According to the equation, light, which goes the speed of light, takes no time at all to reach its destination. It suggests that a photon traveling between you and Andromeda is everywhere on its path simultaneously. Does this not mess with causality? Is there any connection with wave nature of particles in quantum mechanics? The Imaginary Single Speed in Minkowski Space-time I was aware that travelling in space means that you also travel in time, and nothing can go faster than light. But the introduction of Minkowski space-time was a revelation. It begins with the observation we just made that distance in space changes depending on the relative motion of the observer. This violates causality, which means this model does not work. But, of course, he knows the answer in advance. He then constructs a hyperbolic curve to demonstrate this relationship. It solves the causality problem, but visually the arithmetic is clearly false. Squaring it gives a negative number, hence the minus sign. Now it makes mathematical sense, but why did he not explain this? Anyway, the amazing result is that the speed of light is not just a limit, it is the only possible speed! When we think we are standing still, we are zooming through the time dimension at the speed of light. When we move in space we have to slow down our movement through time to compensate. The Mystery of the Time Travelling Twins I think the twin paradox is the key mystery in special relativity. One twin takes a round trip to Andromeda on a fast spaceship while his sister remains behind on Earth. When the travelling twin returns, he thinks it took one hundred years, but the Earth, including his sister, is now six million years older. After all the work we have done, I thought I was finally going to understand it. But at the end we are told the whole calculation fails because it does not take into account the acceleration required to turn the spaceship around. How can he do this to me? Lets jump ahead to the final chapter on General Relativity. We learn that acceleration and gravitational attraction are equivalent. We also learn that clocks run faster in weaker gravitational fields. This must mean that clocks run slower under higher acceleration. It started well, but when the maths kicked in i got lost. You Do have to have more than a basic understanding of maths to get this. As a layman who is interested in Physics and finds some books too technical and many others lack of precision and depth, I found this book brilliant and very helpful. It is an easy-to-follow popular He has received many awards for his work promoting science, including being elected an International Fellow of the Explorers Club in , an organization whose members include NeilArmstrong and Chuck Yeager. Jeff Forshaw is professor of theoretical physics at the University of Manchester, specializing in the physics of elementary particles. He was awarded the Institute of Physics Maxwell Medal in for outstanding contributions to theoretical physics. From he worked in Professor Frank Close's group at the Rutherford Appleton Laboratory before returning to Manchester in Jeff is an enthusiastic lecturer and currently teaches Einstein's Theory of Relativity to first year undergraduates. He has co-writing an undergraduate textbook on relativity for Wiley and he is the author of an advanced level monograph on particle physics for Cambridge University Press. Cox and Forshaw began collaborating on scientific papers in , and have published on topics ranging from Pomerons to Higgs Bosons. Why Does E=mc²? by Brian Cox

Jeff Forshaw is a Professor of Theoretical Physics at the University of Manchester, specializing in the physics of elementary particles. He was awarded the Institute of Physics Maxwell Medal in for outstanding contributions to theoretical physics. Related Searches. A nutritionist offers recipes and a diet program to aid in determining which foods cause View Product. Between You and Me. At the age of 87, Mike Wallace is a legendary figure in broadcast journalism. Now, after 60 years of reporting on important events around the world, he shares his personal stories about the incredible range of celebrities, newsmakers, criminals, and The authoritative guide to understanding and living with borderline personality disorder, now fully revised and The authoritative guide to understanding and living with borderline personality disorder, now fully revised and updated Millions of Americans suffer from borderline personality disorder BPD , a psychiatric condition marked by extreme emotional instability, erratic and self-destructive behavior, and tumultuous Psychotherapist and trauma survivor Jasmin Lee Cori offers new insight into trauma-related difficulties including PTSD, depression, substance abuse , provides self-care tools, candor about therapy and medications, and addresses spiritual issues. While there are many different approaches to healing trauma, few On September 1, , Adolph Hitler inaugurated a new style of warfare-blitzkrieg- that terrorized Europe for On September 1, , Adolph Hitler inaugurated a new style of warfare-blitzkrieg-that terrorized Europe for half a decade. This lightning war provoked panic in millions and led to the downfall of entire nations: Poland, Denmark, Norway, Belgium, Holland and, one Hope's Boy. From the moment he was born, Andrew Bridge and his mother, Hope, shared a love From the moment he was born, Andrew Bridge and his mother, Hope, shared a love so deep that it felt like nothing else mattered. Trapped in desperate poverty and confronted with unthinkable tragedies, all Andrew ever wanted was to be The English major in me was a little miffed when they had a go at Murray Gell-Mann for taking his inspiration for the name "quark" from Finnegan's Wake , but otherwise I enjoyed the authors' playful, easygoing tone. You should. Enjoy Jan 13, Trevor rated it liked it Shelves: science. The best of this is how well they explain why it is not possible to travel faster than light — a really quite nice geometrical proof they offer. There are also some rather veiled digs made at Creationism and Intelligent Design which might have been better being said out loud rather than the curious sotto voce chosen here. My problem has been in trying to understand why the twin paradox happens? The twin paradox is where you have a pair of twins and you stick one of them in a spacecraft and her brother gets left here on earth. The twin in the spacecraft zaps off at near light speed for a few years and when she returns her brother has been dead for a million years or so. This was something nearly explained in The Fabric of the Cosmos , I think, although, not as well as is done here. In that book he talks about being in a spinning box in the middle of the universe and seeing the stars turning around you — how do you know it is you that is moving and not the stars. When you think about it this is an amusing example, given Ptolemy, but his point is that you can tell you are moving and not the sky moving around you. If a body is experiencing an accelerating force it therefore experiences the universe differently from one that is experiencing a lesser force. I might have missed it here, though, perhaps they did explain it. Why should accelerating make time slow down? View all 8 comments. Feb 29, Bob Nichols rated it it was ok. For those trying to nudge themselves into Einstein's world a little more, this book's title has great appeal. At some very general level, the equivalence of energy and mass can be understood, but the role of light "c" and light squared remains a challenge. In the reverse, energy adds to mass. When energy heat is added to mass, mass For those trying to nudge themselves into Einstein's world a little more, this book's title has great appeal. When energy heat is added to mass, mass increases because energy itself has mass. At the heart of the understanding of reality, the authors make it clear that mass and energy are the same thing. They are not "disconnected entitites. This all prompts one to wonder what underlies and connects these two disconnected entities and why does conversion from one to the other occur. Is the "pull - push" phenomena related in the sense that mass pulls energy into itself and energy seeks to escape mass? Is concentrated energy in mass gravity? Is energy escaping mass "liberation"? If, as the authors note, the sun loses 4 million tons of mass every second in the form of radiated energy, does this mean that the earth is gaining some mass from that energy? While the authors are quite lucid here and there, their discussion of the role of light in Einstein's equation was frustratingly opaque. Intriguingly, they seem to suggest that the speed of light is not the central factor. It is, rather, a way to measure distance in a time direction, but it is not clear how time spacetime relates to the discussion that energy and matter are equivalent. The authors are clear that time and space are one thing, and that light years a unit of time can be used to measure distance. The authors seem to say that "c" is relevant because particles of light are massless. Elsewhere, the authors say that spacetime is like "cosmic maple syrup" with some mass Higgs field? When that happens, does light pick up mass? The authors say other things about light that are also unlcear: that there's a cosmic speed limit and that there is such a thing as "allocated speed" and a cosmic "speed quota," and that everything hurtles through spacetime at the same speed. All of this is somehow related to the "c" in the Einstein equation. At this point, it's an achievement for the lay reader to simply identify what he or she does not understand. This is all challenging stuff. Perhaps the real problem is the inability to transfer our earth- bound perspective as that has evolved to be into these cosmic realms that operate on such vastly different scales. View all 12 comments. Dec 26, Merilee rated it it was amazing. Superb review of latest in particle physics and spacetime. Cox explains things as clearly as possible, but I believe I will need to reread this before I could begin to explain any of it to anyone else. Dec 07, Blair rated it really liked it Shelves: science-physics. The challenge of writing any popular science book is that the audience has different levels of knowledge. The author needs to choose the appropriate level of knowledge to aim the writing at. To understand my perspective, you should know my background: A long time ago I completed first year university science before switching into computers. I have since read a number of popular science books on relativity and quantum mechanics. I am presently taking on-line university physics courses to get a deeper understanding. I have thus seen many of the ideas in this book before, and understand the mathematics. Frequently they give a hokey apology I got very tired of chalk dust and then present complex mathematics in prose. Important steps are often skipped. I can tell you that I had to read much of this book several times, and do the math on paper to try to understand it. Following Einstein, the authors devote a chapter to this subject. This is fine with me, because I am taking my electricity course for precisely this reason. Briefly, experiments in the 19th century showed that a moving magnetic field generates electric current, and an electric current generates a magnetic field. These mutually reinforcing forces create an energy wave, which can be described by a wave equation. This equation gives us the speed at which the wave must travel, which turns out to be the same as the speed of light. Thus light is just another type of electromagnetic wave. Einstein assumed all movement is relative, and that the laws of physics are always the same no matter what is perceived to be doing the moving. His genius was to take this result literally, and conclude that the speed of light must always be constant no matter how it is measured. The book claims on page 27 the speed of light is determined by the ratio of the strengths of the electric and magnetic fields. That looks like a product to me, which makes intuitive sense if they are reinforcing each other. But this stuff is over my head, so did they oversimplify, or do I have it wrong? Riding the Relativity Railroad with Pythagoras Now we get to the classic thought experiment of measuring the relative passage of time on a train from the perspective of an observer on the platform. The passenger measures time by shining a light from one position to another one meter above it. The observer on the platform sees the light taking a longer path because the light pulse is moving along with the train. We can use the Pythagorean theorem to calculate the rate at which time appears to slow down, known as time dilation. While it is cool that such basic math can be used to derive relativity, for some reason the author chooses not to call this by its usual name of Lorentz factor. This stuff seems to make sense when I read it, then I wake up in the middle of the night and it does not make sense any more. For example, I wondered if the above result is only true at the exact moment when the train passes the observer. No, it turns out that time dilation does not depend on the direction of motion. This is still not obvious to me, and I could have used an explanation in the book. I find it easy to get confused about which clock is running slower. I have to remind myself of what I call the Spoiled Princess Principle: You are the center of the universe. You do not move, everything else moves relative to you. Your clock always runs at the same rate. Stretching time does not seem as strange as the fact that space contracts in front of you when you are moving. The example he gives is that if we go fast enough, we can get to the Andromeda galaxy, which is three million light years away, in fifty years of our time. Are we going faster than light? No, my spoiled princess, remember that is only how it appears to you. How it looks to the people who sent you is coming up next. According to the equation, light, which goes the speed of light, takes no time at all to reach its destination. It suggests that a photon traveling between you and Andromeda is everywhere on its path simultaneously. Does this not mess with causality? Is there any connection with wave nature of particles in quantum mechanics? The Imaginary Single Speed in Minkowski Space-time I was aware that travelling in space means that you also travel in time, and nothing can go faster than light. But the introduction of Minkowski space-time was a revelation. It begins with the observation we just made that distance in space changes depending on the relative motion of the observer. This violates causality, which means this model does not work. But, of course, he knows the answer in advance. He then constructs a hyperbolic curve to demonstrate this relationship. It solves the causality problem, but visually the arithmetic is clearly false. Squaring it gives a negative number, hence the minus sign. Now it makes mathematical sense, but why did he not explain this? Anyway, the amazing result is that the speed of light is not just a limit, it is the only possible speed! When we think we are standing still, we are zooming through the time dimension at the speed of light. When we move in space we have to slow down our movement through time to compensate. The Mystery of the Time Travelling Twins I think the twin paradox is the key mystery in special relativity. One twin takes a round trip to Andromeda on a fast spaceship while his sister remains behind on Earth. When the travelling twin returns, he thinks it took one hundred years, but the Earth, including his sister, is now six million years older. After all the work we have done, I thought I was finally going to understand it. But at the end we are told the whole calculation fails because it does not take into account the acceleration required to turn the spaceship around. How can he do this to me? Lets jump ahead to the final chapter on General Relativity. We learn that acceleration and gravitational attraction are equivalent. We also learn that clocks run faster in weaker gravitational fields. This must mean that clocks run slower under higher acceleration. Then why did he not make the connection? Well, lets go ask Mr. Yikes, you would think this would have been figured out by now, but apparently not. The most common view is that, contrary to this book, the acceleration is irrelevant. Apparently the special relativity formula is correct, and there are ways to explain it with simple math. It would have been nice if he did this for us. So then, why do the effects of General Relativity make no additional difference? Ah, forget it, nobody answers my dumb questions. So wow, we can go anywhere in space as quickly as we want, and travel far into the future! The problem is that we are not photons — we have mass. Why does he not mention that it takes an ever increasing amount of energy to accelerate mass? Near the speed of light the energy required becomes infinite. Lose some weight first like all of it. Then we realize that a momentum vector in space does not work in relativity, so we must find an equivalent in space-time. The now familiar distance vector in space-time is transformed into a momentum vector, which is mass times velocity. To get there, we multiply by mass and by the velocity of light, then divide out the distance. Figuring this out from the text took a lot of work on my part. By trying to simplify, he actually made it a lot more difficult than it needed to be. Now he makes an approximation for the Lorentz factor, which is reasonably accurate at low speeds. At zero velocity, we still have energy in the mass. We have just achieved the stated goal of the book. So far I have been feeling sorry for the scientifically challenged trying to read this book, but now I experienced being one of them. The verbal description made sense, but without knowing what the symbols or operators mean, constantly referring back to the equation just got in the way. I think this book could have been better if they accepted they are writing for two different levels of knowledge. The equations could then be presented properly in a text box, accompanied by a text description of what they mean, followed by a philosophical summary for the non-mathematical reader. Better still, they could provide supplementary material on the web to answer my questions. I suppose this review is really a long confession of ignorance. I learned a lot from this book, and more from the research to make sense of it. Actual Rating: 3. The writing of science books is a difficult task. On one hand, you have a ready market of science nerds that will instantly pick up your book an easy sale , but they want hard facts, maths and challenging concepts. On the other hand you have a large mass market audience wanting desperately to learn more about science but if you dive in with the hard facts, maths and challenging concepts you are possibly going to lose some of them along the way and turn them off scienc Actual Rating: 3. On the other hand you have a large mass market audience wanting desperately to learn more about science but if you dive in with the hard facts, maths and challenging concepts you are possibly going to lose some of them along the way and turn them off science. So what do you do? Brian Cox has made a living on bring science to the masses and having heard him speak a few times now when he has been in Australia it is always such a delight to see the diverse crowds that rock up to see him talk. If any-one was able to please both groups - I would put money on it being him. While I found this book to be a really solid read and will definitely read it a second time , I unfortunately think the audience of the book is unclear. The book starts out quite gently with some very easy to get your head around concepts about space and time, the speed of light and special theory. I was speeding through these chapters feeling pretty confident with everything I was reading and coming up with a few good examples to incorporate into my work. Then there is a sudden switch to spacetime momentum vectors that had me trying to recall study from years ago and wishing desperately that I had a pen and paper note: next time bring pen and paper. So just when you go "yes The jumping back and forth between baby steps and elephant steps just made me feel a little confused and dizzy. I also wonder if the authors solo wrote specific chapters as the voice way of explaining did seem to change throughout and that also mixed up my rhythm with the book a little and added to the dizzy. So hats off to them both. So if you are a hard-core physics geek, maybe skip the book and grab a textbook. If you are totally new to this field If you are in the middle, bring pen and paper and enjoy the bumps. He is incredibly intelligent to state the obvious , but gets across ideas in an accessible and easily understood way, and has a great sense of humour to boot. Probably a book I'll read again to try to cement my understandings. Very much enjoyed it. May 10, Ana rated it it was amazing Shelves: science. Omg I had no idea how shallow my understanding of relativity was!! A bit difficult to follow at times and I still have a few technical questions that I'll need to look-up myself, but I still learned a lot! While the progress we've made is astounding, I can't help but feel a bit of despair at the thought of how this progress was achieved sometimes see the Minkowski spacetime "why not try Pythagora's theorem with a minus sign??? Jun 17, Carlos Martinez rated it really liked it Shelves: science. An entertaining and not-entirely-impossible guide to Einstein's physics. I enjoyed reading it, but it'll take me at least one more go to master the main concepts. Plan on going back to this, and crunching the numbers. View all 3 comments. Aug 15, Bruno Espadana rated it really liked it Shelves: ebook , popular-science , non-fiction , read Which, in this case, is probably most of us. And it works. You might feel a bit lost at times, but things will fall into place. I never say this, but thank goodness I read this book in Hungarian. It was difficult enough without having to try and decipher what are the Hungarian equivalents of all the terms. My main motivation to read this book was Brian Cox I never say this, but thank goodness I read this book in Hungarian. For a long time I considered myself devoid of any kind of scientific interest, but then I had to realize that everything is interesting if explained properly — and I think this book is further proof of my theory. The authors certainly try and explain even simple concepts, e. I have to admit that a significant part of this book went over my head, despite all the best efforts of Messrs. Jan 08, Rebecca rated it it was ok. Well, thank the gods that's over! I bought this as further reading on an iTunes U course I'm doing, thinking that it would offer further insight. The first half of the book is so patronising that I could barely bring myself to claw through it but unfortunately I have a Magnus Magnusson approach to reading. B e c a u s e Well, thank the gods that's over! The over-use of analogies in an attempt to "simplify" the mathematics, theories, discoveries etc, does nothing but confuse you, and I would recommend, if you do decide to read this book, that you skip anything referring to motorbike riders, billiard balls, cannon balls, or anything that starts to look like an apology for teaching you something in a book about science, that you have chosen to read. On the upside however, once you reach the apex so to speak, and your tiny, limited little brain has been gently guided through all the scary bits that lead to Einstein's equation, then things get kind of interesting, and much less patronising. Chapters 6 and 7 were much more enjoyable and far easier to understand once the authors felt they could trust you not to dissolve into a quivering wreck of unteachable mush. So all in all, a bit of a disappointment, but there are nuggets of lovely knowledge in this book which I'm glad I've discovered. Now on to my next challenge! Jun 29, John rated it it was ok. It was an enormous ask, and Cox and Forshaw were never going to deliver. It is easy reading, but unless you understand maths you won't get it at all. When I read on page 77 "although we did not prove the maths " I began to feel cheated, and then they tried to explain in several thousand words space-time vectors, which could have been done in two lines of maths, then I thought to myself it would have been much easier if they had used the maths throughout, and dispensed with all those words and all that repetition. It is not a bad read, but I wouldn't want to read it twice. Mar 28, JJ Coetzer rated it really liked it. Cox and Forshaw say this at some point halfway through the book, but it might as well be applied to my feelings when finishing it.

Why Does E=mc2?: (And Why Should We Care?) - Brian Cox, Jeff Forshaw - Google книги

Additional Product Features Dewey Edition. But here's something that training as a physicist simply can not teach: they deliver their message not only clearly, but with a deep and resonant humor. What's important about this book is not that it says something new about science. It's that it gives a primer for understanding how a certain type of scientist sees the universe. What is more, they focus on the most puzzling part: the question of what c, the speed of light, is doing in there Their arguments are so presented so clearly It is to their credit that they do not always hide the complexity nor the long history of ideas behind relativity It is also to their credit that they make the case, as Feynman and others have done before them, that, at some level, the weirdness of the universe just has to be accepted Will help school science teachers as much as it will their students. For anyone afraid of technicalities, Cox and Forshaw lead the reader by the hand through the complexity, adding in rest stops of wit and real- world examples. Even the hardest bits feel like being taken on an army assault course by the two friendliest drill sergeants in the world. You may have to read some bits twice but, boy, will you feel better for it once the insights become clear. In the process of exposing the science, the authors do a good job of showing how the hard end of research works: abandon all assumptions and re-build everything from scratch. By going one step at a time, the buildup ensures each chuck is absorbed slowly rather than all at once. We were delighted to find our knowledge of equations-long forgotten since leaving school for some of us-reinvigorated and felt ourselves rediscovering our enjoyment of mathematics. Although the theory might be tricky, the authors show they understand readers are not on their level. We were delighted to find our knowledge of equations--long forgotten since leaving school for some of us--reinvigorated and felt ourselves rediscovering our enjoyment of mathematics. The lowest-priced brand-new, unused, unopened, undamaged item in its original packaging where packaging is applicable. Packaging should be the same as what is found in a retail store, unless the item is handmade or was packaged by the manufacturer in non-retail packaging, such as an unprinted box or plastic bag. See details for additional description. Skip to main content. About this product. Make an offer:. Stock photo. Brand new: Lowest price The lowest-priced brand-new, unused, unopened, undamaged item in its original packaging where packaging is applicable. In other words, how the very fabric of our world is constructed. See all 2 brand new listings. Buy It Now. Add to cart. Brian Cox and Professor Jeff Forshaw go on a journey to the frontier of twenty-first century science to unpack Einstein's famous equation. Explaining and simplifying notions of energy, mass, and light,while exploding commonly held misconceptions,they demonstrate how the structure of nature itself is contained within this equation. Along the way, we visit the site of one of the largest scientific experiments ever conducted: the now-famous Large Hadron Collider, a gigantic particle accelerator capable of re-creating conditions that existed fractions of a second after the Big Bang. Additional Product Features Dewey Edition. But here's something that training as a physicist simply can not teach: they deliver their message not only clearly, but with a deep and resonant humor. Community Reviews. Showing Average rating 4. Rating details. More filters. Sort order. Sep 16, Courtney Johnston rated it really liked it Shelves: borrowed , science , big-ideas-made-accessible. I loved this book, and it wasn't just that cheeky Brian Cox going on all the time about being covered in tweed and chalkdust somebody please hand me a fan. If Marcus Chown is magical cellulite cream, this is physics bootcamp - no corners cut, no let's-take-it-easy-today-shall-we. Cox and Forshaw don't just want to explain this equation - they want you to understand it, to understand its power predictive and descri I loved this book, and it wasn't just that cheeky Brian Cox going on all the time about being covered in tweed and chalkdust somebody please hand me a fan. Cox and Forshaw don't just want to explain this equation - they want you to understand it, to understand its power predictive and descriptive and understand how, despite being just a diminutive collection of letters and symbols, it underpins nearly a century of contemporary science, and captures some of the most fundamental characteristics of the universe. I feel like the target market for this book - a person who gave up on maths in fourth form, and stumbled through sixth form physics before escaping the next year to classics class, my natural home. Cox and Forshaw are punctilious in their care for the mathematically challenged, to the point where even I wished they'd quit apologising for bringing the maths in to it - because for once, I was following it. I'll need to read the book at least one more time to really get to grips with the subject. But I started to feel the magic tingle of understanding when I read sentences like 'temperature is essentially nothing more than a measure of the average speed of things', or when I looked up from the book and listened to the waves breaking and thought of them as energy, drawn from the moon's gravitational force, dispersing itself through friction and sound yep - an unusual beach read, I'll concede, but perhaps that suggests the book's measured pace and gentle writing. I felt my usual moment of cosmic connectedness when I read in here about the Super-Kamiokande experiment in Hida, Japan, where neutrinos are 'seen' passing through a cylinder filled with 50, tonnes of pure water at the bottom of a mine shaft. Knowing that every second every part of my body, everthing I can see - everything I can't see - is being lanced through by innumerable particles spat out from the sun fills me with a sense of wonder that is the nearest I come to a religious sensation. In addition to their explication of the equation, Cox and Forshaw do a good job of describing the sense of wonder physicists themselves feel, not just at the deep movements of the world, but at the almost magical way that mathematics can be used to describe them. Writing about the master equation that lies at the heart of the Standard Model of Particle Physics and sums up - well, basically everything - they note: It is certainly impressive that we can shoehorn so much physics into one equation. It speaks volumes for Wigner's "unreasonable effectiveness of mathematics". Why should the natural world not be far more complex? Why do we have the right to condense so much physics into one equation like that. Why should we not need to catalog everything in huge databases and encyclopedias? Nobody really knows why nature allows itself to be summarized in this way, and it is certainly true that this apparent underlying elegance and simplicity is one of the reasons why many physicists do what they do. While reminding ourselves that nature may not continue to submit itself to this wonderful simplification, we can at least for the moment marvel at the underlying beauty we have discovered. Highly recommended if you have the itch to scratch, but a word of warning - if you're not interested in understanding why the theory of special relativity is so important, then this is not the book for you. The authors are intentionally avoided adding to the understandable hero worship that surrounds Einstein, and this is not biography-as-science: this is a maths and physics primer, kindly and interestingly written. View 1 comment. Aug 02, Max rated it really liked it Shelves: physics. They state upfront that their book is intended to be challenging. And it is, despite simplistic analogies and explanations tucked in between some pretty dense material. Einstein noticed that Maxwell had shown that the speed of light was a constant and from this he constructed the Special Theory of Relativity. Then Einstein thought about the fact that all objects fell at the same rate as Galileo demonstrated. He turned this idea into the General Theory of Relativity. Many complex topics are addressed along the way. The authors employ high school algebra and geometry but their manipulations can be intricate. The derivation is not done historically. They note that the observer in motion and stationary observer are interchangeable. Each can perceive the other as the one moving and the one for who time slows. There is no absolute motion as Galileo validated. Time, size and distance are observer dependent but the solution must be invariant, looking the same to all observers. To achieve this space and time must be combined into a single entity with four dimensions. The authors introduce us to Minkowski space which blends space and time. In it Cox and Forshaw use a modified Pythagorean formula that avoids going back in time which would violate the principle of causality, e. To measure distance in spacetime, the constant c, is introduced to calibrate. It is the universal speed limit and the speed of light. Everything moves through spacetime at this speed. If at rest the movement is all through time. If moving through space then time slows proportionately from the point of view of a stationary observer. Thus both moving and stationary observers agree on movement through the combined spacetime and invariance is achieved. To complete their derivation the authors introduce momentum, the product of mass and velocity. Momentum is a three dimensional vector in our everyday 3D world and four dimensional in the 4D world with the added component of time. The time component of the momentum vector in 4D space is mc , mass times the universal speed limit. Momentum is a conserved quantity as is mass which is equivalent to energy. Mass and energy are different manifestations of a single underlying physical quantity. Energy, mass and momentum form a spacetime object known as the energy-momentum four-vector. The details are in the book. The foregoing is just intended to give the flavor and flow of the book. The second half of the book is easier to digest as Cox and Forshaw give a broad overview of assorted physics topics. They describe the vast amount of energy in a tiny amount of mass and how that mass is converted, not just in nuclear reactions but in chemical reactions and other everyday phenomena. The authors discuss the Higgs boson as the origin of mass, even though this was just a prediction when they wrote the book. They even go back to the Big Bang and the disparity between matter and anti-matter. They then present the equation for the Standard Model, explaining what each term represents. They discuss how the model was put together and the various contributors, Glashow, Weinberg, Salam, Feynman, and Gell-Mann. Finally such a wide ranging review would not be complete without General Relativity to which the last chapter is devoted. I enjoyed this book. However the presentation was a bit disjointed. The authors write for readers at varying levels bouncing back and forth between simple explanations and more difficult detailed ones. They insert apologies to those for who the material might be too complicated and for those who might get bored. While the math itself was not overly difficult, following it in terms of the concepts it represented was more demanding. Still I applaud the effort to put some accessible math behind concepts that are deep and not intuitive. Regardless of level this is a book for a non-scientist reader with a strong interest in the subject. Cox and Forshaw said the book was meant to be a challenge. It was and that made it worthwhile. View 2 comments. Nov 30, Danielle rated it liked it Shelves: science-technology , biography , nonfiction , history. I was expecting, from the first few paragraphs of the book, that I was going to breeze right through this. It didn't really happen that way. I had to take college physics, which included the basics of relativity and quantum theories, so I probably have a bit more knowledge than the average non-physicist. All the same, there were areas of this book that just did not seem to click at all, even after reading paragraphs over and over again. Usually the parts that didn't click were the "easy" example I was expecting, from the first few paragraphs of the book, that I was going to breeze right through this. Usually the parts that didn't click were the "easy" examples such as how the distance between the moon and the Earth get further apart as the spin of the Earth slows. For anyone that doesn't know about conservation of rotational momentum, this is not an easy thing to figure out. Especially since they don't even mention momentum until 5 chapters later. The end of the book definitely seemed a little bit rushed, mainly due to the "just take our word for it" approach for what they deemed hard to understand topics. I understand this was attempting to make Einstein's theories accessible to lay people, but I feel it felt a little bit short. I would love to say that I understood every word and every example of this book, but unfortunately there were many times I felt like the concepts were far too complicated for me. I'm not an unintelligent person but my math and physics knowledge is rather old and rusty. I'll give it another 2 or 3 read through before making any firm judgements on the books. I feel I have learned something from this book I just don't know what it is I've learned.. Jun 22, C rated it did not like it. Absolutely senseless. If he ever gets close to talking about the matter at hand, another long passage about a motorcyclist will pop up to "explain things" Look. The reason you use so many horrible analogies is because you are a horrible explainer! Convey it the first time, don't waddle about. View all 5 comments. Feb 24, Kristin rated it really liked it. On a good day, high school physics class used to leave me feeling kind of for lack of a better word high. This book brought back that old, familiar feeling, but in an even better way. In the end, I walked away with a much clearer understanding of Einstein's theories of special and general relativity than I ever achieved slogging through high school physics. I think our teacher must have been unable to articulate and synthesize the underlying questions that the equations sought to answer. The On a good day, high school physics class used to leave me feeling kind of for lack of a better word high. This process is broken down into a few key steps: 1 an understanding that the speed of light is constant and therefore space and time must be "variables"; 2 the mathematical definition of spacetime and the formula needed to relate events within it; and 3 the definition of vectors in spacetime. It really is as simple as that. With an understanding of these key relationships, the elegance, beauty, and profound repercussions of the equation become crystal clear, even for those of us who never pursued physics beyond high school. I did struggle with a few sections, particularly the bits about electromagnetism, the conservation of rotational momentum, and--I hate to say it--the "tiny physicists in elevators" analogy. In spite of my mushy understanding of those parts, I was still able to "go there" with the authors in the end. The English major in me was a little miffed when they had a go at Murray Gell-Mann for taking his inspiration for the name "quark" from Finnegan's Wake , but otherwise I enjoyed the authors' playful, easygoing tone. You should. Enjoy Jan 13, Trevor rated it liked it Shelves: science. The best of this is how well they explain why it is not possible to travel faster than light — a really quite nice geometrical proof they offer. There are also some rather veiled digs made at Creationism and Intelligent Design which might have been better being said out loud rather than the curious sotto voce chosen here. My problem has been in trying to understand why the twin paradox happens? The twin paradox is where you have a pair of twins and you stick one of them in a spacecraft and her brother gets left here on earth. The twin in the spacecraft zaps off at near light speed for a few years and when she returns her brother has been dead for a million years or so. This was something nearly explained in The Fabric of the Cosmos , I think, although, not as well as is done here. In that book he talks about being in a spinning box in the middle of the universe and seeing the stars turning around you — how do you know it is you that is moving and not the stars. When you think about it this is an amusing example, given Ptolemy, but his point is that you can tell you are moving and not the sky moving around you. If a body is experiencing an accelerating force it therefore experiences the universe differently from one that is experiencing a lesser force. I might have missed it here, though, perhaps they did explain it. Why should accelerating make time slow down? View all 8 comments. Feb 29, Bob Nichols rated it it was ok. For those trying to nudge themselves into Einstein's world a little more, this book's title has great appeal. At some very general level, the equivalence of energy and mass can be understood, but the role of light "c" and light squared remains a challenge. In the reverse, energy adds to mass. When energy heat is added to mass, mass For those trying to nudge themselves into Einstein's world a little more, this book's title has great appeal. When energy heat is added to mass, mass increases because energy itself has mass. At the heart of the understanding of reality, the authors make it clear that mass and energy are the same thing.

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