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Science with Brian Cox and Jeff Forshaw
Why Does E=mc2?
The most accessible, entertaining, and enlightening explanation of the best-known physics equation in the world, as rendered by two of todayOCOs leading scientists."
265 pages, Unknown Binding
First published January 1, 2009
1259 people are currently reading
13287 people want to read
About the author
Brian Cox
101 books2,007 followersNot to be confused with actor [Author: Brian Cox].
Brian Edward Cox, OBE (born 3 March 1968) is a British particle physicist, a Royal Society University Research Fellow, PPARC Advanced Fellow and Professor at the University of Manchester. He is a member of the High Energy Physics group at the University of Manchester, and works on the ATLAS experiment at the Large Hadron Collider (LHC) at CERN, near Geneva, Switzerland. He is working on the R&D project of the FP420 experiment in an international collaboration to upgrade the ATLAS and the CMS experiment by installing additional, smaller detectors at a distance of 420 metres from the interaction points of the main experiments.
He is best known to the public as the presenter of a number of science programmes for the BBC, boosting the popularity of subjects such as astronomy; so is a science popularizer, and science communicator. He also had some fame in the 1990s as the keyboard player for the pop band D:Ream.
Brian Edward Cox, OBE (born 3 March 1968) is a British particle physicist, a Royal Society University Research Fellow, PPARC Advanced Fellow and Professor at the University of Manchester. He is a member of the High Energy Physics group at the University of Manchester, and works on the ATLAS experiment at the Large Hadron Collider (LHC) at CERN, near Geneva, Switzerland. He is working on the R&D project of the FP420 experiment in an international collaboration to upgrade the ATLAS and the CMS experiment by installing additional, smaller detectors at a distance of 420 metres from the interaction points of the main experiments.
He is best known to the public as the presenter of a number of science programmes for the BBC, boosting the popularity of subjects such as astronomy; so is a science popularizer, and science communicator. He also had some fame in the 1990s as the keyboard player for the pop band D:Ream.
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Displaying 1 - 30 of 615 reviews
January 7, 2011
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).
'Why does E=mc2' is my fifth book from the Royal Society science book shortlist. 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 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 50,000 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:
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.
'Why does E=mc2' is my fifth book from the Royal Society science book shortlist. 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 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 50,000 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.
August 2, 2017
Cox and Forshaw pack Einstein’s theories of relativity and much more into 250 pages. 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. Their underlying premise is “From the simplest of ideas”. 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.
The first half of the book centers around a derivation of E=MC2. 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 use Pythagoras’s theorem to compute the value of time dilation, the difference in time between a stationary observer and one in motion. 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 spacetime Euclidian geometry won’t work. In it Cox and Forshaw use a modified Pythagorean formula that avoids going back in time which would violate the principle of causality, e.g. you can’t kill your parents before you were born. 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. From this the authors produce E=MC2. 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. They venture into particle physics and quantum mechanics describing the emission and absorption of photons from electrons and subsequent changes in their “orbits”. 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.
The first half of the book centers around a derivation of E=MC2. 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 use Pythagoras’s theorem to compute the value of time dilation, the difference in time between a stationary observer and one in motion. 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 spacetime Euclidian geometry won’t work. In it Cox and Forshaw use a modified Pythagorean formula that avoids going back in time which would violate the principle of causality, e.g. you can’t kill your parents before you were born. 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. From this the authors produce E=MC2. 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. They venture into particle physics and quantum mechanics describing the emission and absorption of photons from electrons and subsequent changes in their “orbits”. 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.
December 1, 2009
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" 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. I think many of the examples were well chosen, and the histories/biographies of the scientists leading up to Einstein were very interesting, but the book lacked a bit of flow and at times seemed to be lacking in proper explanation for the chosen examples until much later on (or sometimes never toward the end). 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.
Read
March 31, 2023There are countless books out there that try to make the theory of special relativity real. Brian Cox starts out his particular journey on the subject well enough, but then he quickly gets bogged down by introducing mathematics into the text. Therein lies the problem. Math does not read well. It does not translate into literary prose no matter how beautiful its predictions of realities actually are. As a reader, I want analogies, descriptions of relevancy, and practical applications. What Cox provides, however, are square roots, trigonometry, and descriptions of mathematical operations.
I did learn one mind-blowing aspect of relativity through a mention made by Cox almost in passing. Distances in space become smaller as velocity increases. I knew that time slowed down with velocity, but learning that distances became compressed as well was something new. External research revealed that this effect is known as space contraction. It was disappointing that Cox left this aspect of the theory on the ground, deciding instead to dive deeper into the math associated with time and space.
Overall, this was not the book on the subject for me...DNF
I did learn one mind-blowing aspect of relativity through a mention made by Cox almost in passing. Distances in space become smaller as velocity increases. I knew that time slowed down with velocity, but learning that distances became compressed as well was something new. External research revealed that this effect is known as space contraction. It was disappointing that Cox left this aspect of the theory on the ground, deciding instead to dive deeper into the math associated with time and space.
Overall, this was not the book on the subject for me...DNF
January 11, 2014
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.
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.
March 16, 2010
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 authors--very slowly and gently, bringing in maths only when absolutely necessary--walk the reader through the major breakthroughs in science/physics that paved the way for Einstein's e=mc2. Then, they show us how Einstein arrived at e=mc2. 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. When vectors are broken down in spacetime, e=mc2 is revealed. 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.
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.
February 25, 2018
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..
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..
May 15, 2016
Have you watched
Wonders Of The Universe
with Brian Cox? You should. And afterwards, when you’ll read this book, his voice and passion will accompany you all along.
For me it wasn’t a breakthrough experience, but if one’s not familiar with the theory of relativity and physics concepts of space and time, it will be a more than pleasant reading, for it is written in a very accessible language, with day to day examples and a bit of humor on occasion.
And you can even accompany your reading with some music:
https://www.youtube.com/watch?v=AOTA3...
Enjoy :)
For me it wasn’t a breakthrough experience, but if one’s not familiar with the theory of relativity and physics concepts of space and time, it will be a more than pleasant reading, for it is written in a very accessible language, with day to day examples and a bit of humor on occasion.
And you can even accompany your reading with some music:
https://www.youtube.com/watch?v=AOTA3...
Enjoy :)
January 21, 2012
I’ve got rather mixed feelings about this one. I think writing a simple account of very difficult material is hard to achieve and so every such effort should be praised wherever it is found – but there is a fine line between simple and patronising and I’m not sure this one respects that line all of the time.
It is clear these guys know their stuff, but I found it hard to concentrate on parts of this book as they would go into a longish chat about how hard the maths is and so how they have made the maths easier to understand than it should have been and by the time I’d drifted back to paying attention I felt I might have missed something along the way. I read this book, rather than listened to an audio book – where drifting off is more excusable - so I wouldn’t have expected drifting off to have been an issue. It also hasn’t helped that I started this and then spent three weeks in New Zealand with only having 30 pages left to read. I’m telling you all this because my problems with this book may have been related to my drifting off while reading it and with the long break in the middle of reading it.
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. They also give a really nice discussion of the Higgs field and why finding the Higgs Boson is quite so important and why some physicists might choose to call it the ‘God Particle’.
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.
All the same the bit I enjoyed the most was the part of Einstein’s special theory of relativity that has troubled me for years and I’ve never had a satisfactory answer to. This book doesn’t really answer all of my concerns – I’ve a feeling I would need to learn lots of maths and lots of physics to really understand what happens, but this book has been the best explanation I’ve found so far. 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. My problem with this has always been the ‘relativity’ part of it. If she is travelling off at near light speed and he is here drinking coffee at earth speed, why shouldn’t she consider him to be as moving off from her at near light speed and her not really moving at all?
The answer, I’ve been told here and also told by Paul Davies in How to Build a Time Machine is that if she was going at near light speed the whole time then there would be no difference in their relative times and no way for either to know who was moving or who was still – but to get to those speeds she would need to accelerate and in coming back she would need to decelerate and it is those changes that make their relativity no longer work and for her to age effectively more slowly than someone left on earth. 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.) I think this all relates to Newton’s first law, the law of inertia. If a body is experiencing an accelerating force it therefore experiences the universe differently from one that is experiencing a lesser force. But I don’t think anyone ever really has explained to me why this might be the case. I might have missed it here, though, perhaps they did explain it. If they did I still don’t really get it. All of this stuff makes my head spin and so no matter how simply people seem to be able to write about it I still feel like I’m caught in some twisted logic I can’t quite follow. Why should accelerating make time slow down?
All the same, the authors have gone out of their way to make this book as clear as they can – if I still don’t quite follow it is probably my own fault.
It is clear these guys know their stuff, but I found it hard to concentrate on parts of this book as they would go into a longish chat about how hard the maths is and so how they have made the maths easier to understand than it should have been and by the time I’d drifted back to paying attention I felt I might have missed something along the way. I read this book, rather than listened to an audio book – where drifting off is more excusable - so I wouldn’t have expected drifting off to have been an issue. It also hasn’t helped that I started this and then spent three weeks in New Zealand with only having 30 pages left to read. I’m telling you all this because my problems with this book may have been related to my drifting off while reading it and with the long break in the middle of reading it.
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. They also give a really nice discussion of the Higgs field and why finding the Higgs Boson is quite so important and why some physicists might choose to call it the ‘God Particle’.
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.
All the same the bit I enjoyed the most was the part of Einstein’s special theory of relativity that has troubled me for years and I’ve never had a satisfactory answer to. This book doesn’t really answer all of my concerns – I’ve a feeling I would need to learn lots of maths and lots of physics to really understand what happens, but this book has been the best explanation I’ve found so far. 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. My problem with this has always been the ‘relativity’ part of it. If she is travelling off at near light speed and he is here drinking coffee at earth speed, why shouldn’t she consider him to be as moving off from her at near light speed and her not really moving at all?
The answer, I’ve been told here and also told by Paul Davies in How to Build a Time Machine is that if she was going at near light speed the whole time then there would be no difference in their relative times and no way for either to know who was moving or who was still – but to get to those speeds she would need to accelerate and in coming back she would need to decelerate and it is those changes that make their relativity no longer work and for her to age effectively more slowly than someone left on earth. 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.) I think this all relates to Newton’s first law, the law of inertia. If a body is experiencing an accelerating force it therefore experiences the universe differently from one that is experiencing a lesser force. But I don’t think anyone ever really has explained to me why this might be the case. I might have missed it here, though, perhaps they did explain it. If they did I still don’t really get it. All of this stuff makes my head spin and so no matter how simply people seem to be able to write about it I still feel like I’m caught in some twisted logic I can’t quite follow. Why should accelerating make time slow down?
All the same, the authors have gone out of their way to make this book as clear as they can – if I still don’t quite follow it is probably my own fault.
August 14, 2021
“Why does E=MC2?” is one of the most thorough and concentrated science books I have read. Brian Cox picks a small area and gets deeply into if. I'll be reading it again.
December 30, 2022
Original 2012 review edited: The authors do a good job of describing how mass converts to energy (heat/photons/light carry away mass; when wood burns, energy is released and mass is reduced). In the reverse, energy adds to mass. 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 entities." Matter is, in short, "capable of popping into and out of existence" but (presumably) continues to exist as energy.
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 (push itself away from) mass? Is concentrated energy in mass, gravity? Is energy escaping mass, "liberation"? [The authors make a few references to "liberated energy"].
December 2022 review, upon a re-read:
The authors define force as “the amount by which something is pushed or pulled.” Stated in this way, force is confusing: One body’s state is affected by an accelerating (gravitational) body that either pushes it (hits it, as in the body that hit the earth creating the moon) it or pulls it via gravitational (attractive) force. The authors’ definition tracks that of Newton.
With the emphasis on gravitational mass and its effects, this sidesteps the role that inertial mass plays in the interaction between two bodies. Per Einstein’s equivalence principle (1), inertial mass (a body of mass-energy) and gravitational mass are the same. In the former instance, a body remains at rest or persists in straight-line motion unless acted upon, and resists deviation from either state. The effects of either this rest state or this straight-line motion creates accelerating effects, i.e. gravity, thus gravitational mass. Seen this way, inertial mass is itself a force that has accelerating (pulling or pushing) effects on other inertial masses and, alternatively, inertial mass is also a resisting force via-a-vis other inertial masses (in their own rest state or straight-line motion), which is a reacting, pushing away, force. In other words, a massive body is both a resisting (pushing away) and an attractive (pulling or pushing) force, with the amount of force being directly a factor of relative mass (i.e. relative to other bodies), the inverse square law (effects of distance), and velocity (the effects of speed and escape velocity).
But then there's this curve ball that Einstein throws at us, which is given lip service while as the default discussion continues to say that gravity is one of the four fundamental forces in the cosmos, all of which engage in this pushing and pulling fashion that the authors highlight. (2) Einstein says that inertial mass is only indirectly (and quite so) a force as it is the warping of spacetime by massive bodies (weight in spacetime creates depression is its fabric, which means that spacetime is only, relatively, a vacuum?) that curves spacetime around itself, and this is the line (the pathway) that inertial mass follows as it moves toward a gravitational center, either within a massive body itself, or at a point of balance in spacetime among multiple massive bodies. (3) Seen this way, rather than gravitational mass, an argument could be made that inertial mass itself is a force (4) because of its persistence in resisting accelerating effects (the natural tendency to stay at rest if at rest, or to persist in straight-line motion if in motion), until a balance point is found between it and other bodies, and because this inertial state or movement has gravitational effects (depresses space time and creates spacetime curvature that mass-energy follows as it moves toward the gravitational center). (5)
But, then a question is begged. Inertial mass moves in a straight-line but why this is, is not clear. (6) Is this the aftermath of the big bang explosion that sent mass-energy outward, setting matter in motion that is then subject to all sorts of accelerating effects by gravitational masses that curve straight-line motion? Unlike light, which is mass converted to pure energy, matter does not seem to have the power of self-propulsion, unless there is some initial explosive force that sends it outward (like some deist Prime Mover), unless inertial rest or movement can be construed as some sort of "self-propulsion."
1. Among writers on physics, the principle of equivalence seems to have multiple uses/meanings that is confusing. Unfortunately, for such a key term, the authors do not have it listed in their index.
2. Russell noted the problem accurately - gravity was not a force but it was too complicated to talk about it in Einstein’s geometric way, so by default, writers revert shorthand, referring to gravity as a force.
3. The balance among multiple bodies occurs, simultaneously, either by a pushing (itself) away as a resisting force or pulling other bodies toward itself as an attractive force that, collectively, constitutes a gravitational center.
4. Of the four fundamental forces, electro-magnetic and strong nuclear force exhibit push (away) and pull (together) qualities, along with inertial mass. Gravitational force only indirectly pulls mass-energy toward itself, per Einstein. It’s not clear how the weak force is a push-pull force. It seems more like Einstein’s E=mc squared law in operation, i.e. the release of energy from its bound state in mass.
5. The expression free fall is confusing (as in the Einstein example of a person in a space capsule who experiences weightlessness). The free part I understand (as in a free floating), but the fall part is less understandable because there is no absolute reference point to indicate whether one is going up, down, or sideways. On the other hand, with the movement toward a gravitational center, the notion of “falling” makes sense.
6. Newton took this question off the table as he was only focused on changes in motion and what caused these (versus what causes motion). That the authors state that “Energy has no direction” is a problem: straight-line motion is a direction, and inertia (resistance to deviation from a state of rest or from straight-line movement) is very much a directive property of mass-energy (as constituted in matter).
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 (push itself away from) mass? Is concentrated energy in mass, gravity? Is energy escaping mass, "liberation"? [The authors make a few references to "liberated energy"].
December 2022 review, upon a re-read:
The authors define force as “the amount by which something is pushed or pulled.” Stated in this way, force is confusing: One body’s state is affected by an accelerating (gravitational) body that either pushes it (hits it, as in the body that hit the earth creating the moon) it or pulls it via gravitational (attractive) force. The authors’ definition tracks that of Newton.
With the emphasis on gravitational mass and its effects, this sidesteps the role that inertial mass plays in the interaction between two bodies. Per Einstein’s equivalence principle (1), inertial mass (a body of mass-energy) and gravitational mass are the same. In the former instance, a body remains at rest or persists in straight-line motion unless acted upon, and resists deviation from either state. The effects of either this rest state or this straight-line motion creates accelerating effects, i.e. gravity, thus gravitational mass. Seen this way, inertial mass is itself a force that has accelerating (pulling or pushing) effects on other inertial masses and, alternatively, inertial mass is also a resisting force via-a-vis other inertial masses (in their own rest state or straight-line motion), which is a reacting, pushing away, force. In other words, a massive body is both a resisting (pushing away) and an attractive (pulling or pushing) force, with the amount of force being directly a factor of relative mass (i.e. relative to other bodies), the inverse square law (effects of distance), and velocity (the effects of speed and escape velocity).
But then there's this curve ball that Einstein throws at us, which is given lip service while as the default discussion continues to say that gravity is one of the four fundamental forces in the cosmos, all of which engage in this pushing and pulling fashion that the authors highlight. (2) Einstein says that inertial mass is only indirectly (and quite so) a force as it is the warping of spacetime by massive bodies (weight in spacetime creates depression is its fabric, which means that spacetime is only, relatively, a vacuum?) that curves spacetime around itself, and this is the line (the pathway) that inertial mass follows as it moves toward a gravitational center, either within a massive body itself, or at a point of balance in spacetime among multiple massive bodies. (3) Seen this way, rather than gravitational mass, an argument could be made that inertial mass itself is a force (4) because of its persistence in resisting accelerating effects (the natural tendency to stay at rest if at rest, or to persist in straight-line motion if in motion), until a balance point is found between it and other bodies, and because this inertial state or movement has gravitational effects (depresses space time and creates spacetime curvature that mass-energy follows as it moves toward the gravitational center). (5)
But, then a question is begged. Inertial mass moves in a straight-line but why this is, is not clear. (6) Is this the aftermath of the big bang explosion that sent mass-energy outward, setting matter in motion that is then subject to all sorts of accelerating effects by gravitational masses that curve straight-line motion? Unlike light, which is mass converted to pure energy, matter does not seem to have the power of self-propulsion, unless there is some initial explosive force that sends it outward (like some deist Prime Mover), unless inertial rest or movement can be construed as some sort of "self-propulsion."
1. Among writers on physics, the principle of equivalence seems to have multiple uses/meanings that is confusing. Unfortunately, for such a key term, the authors do not have it listed in their index.
2. Russell noted the problem accurately - gravity was not a force but it was too complicated to talk about it in Einstein’s geometric way, so by default, writers revert shorthand, referring to gravity as a force.
3. The balance among multiple bodies occurs, simultaneously, either by a pushing (itself) away as a resisting force or pulling other bodies toward itself as an attractive force that, collectively, constitutes a gravitational center.
4. Of the four fundamental forces, electro-magnetic and strong nuclear force exhibit push (away) and pull (together) qualities, along with inertial mass. Gravitational force only indirectly pulls mass-energy toward itself, per Einstein. It’s not clear how the weak force is a push-pull force. It seems more like Einstein’s E=mc squared law in operation, i.e. the release of energy from its bound state in mass.
5. The expression free fall is confusing (as in the Einstein example of a person in a space capsule who experiences weightlessness). The free part I understand (as in a free floating), but the fall part is less understandable because there is no absolute reference point to indicate whether one is going up, down, or sideways. On the other hand, with the movement toward a gravitational center, the notion of “falling” makes sense.
6. Newton took this question off the table as he was only focused on changes in motion and what caused these (versus what causes motion). That the authors state that “Energy has no direction” is a problem: straight-line motion is a direction, and inertia (resistance to deviation from a state of rest or from straight-line movement) is very much a directive property of mass-energy (as constituted in matter).
January 6, 2012
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. Check out Cox's (who's a prof at Manchester U and a scientist at CERN, working on the Large Hadron Collider) wonderful videos on YouTube.
September 8, 2011
It was so good, I ended it re-reading half of it right I after I finished it the first time. Many gems in the book and now I do understand special relativity.
May 20, 2024
This book was a great reminder that I'm not as smart as I thought I was.
January 1, 2021
har jeg læst den her, ord for ord, og nærstuderet hver en graf, hver en formel, hvert et græsk symbol? yes. forstår jeg hvorfor mc^2 gir E? nej. dette skyldes ikke bogen, men 100% min manglende evne til at begribe matematik når det er skrevet på engelsk. "math is the same in every language" er mean girls propaganda
August 15, 2019
Einstein’s theory of special relativity for dummies. Which, in this case, is probably most of us.
It will be hard for someone to come up with a simpler way to explain Einstein’s work - if you’re well versed on maths or physics, you will probably find this annoying or maybe too dumbed down. But this isn’t for you - it’s for all people that are curious about Einstein and our universe, can follow a logical discussion, but are not technical enough to follow a more detailed explanation. Not that this isn’t detailed, but Cox and Forshaw go to great lengths to hold your hand along the way and explain it all, using analogies and not a lot of maths to make their point.
And it works. You might feel a bit lost at times, but things will fall into place. And hopefully you will also be able to appreciate the beauty of Einstein’s ideas.
It will be hard for someone to come up with a simpler way to explain Einstein’s work - if you’re well versed on maths or physics, you will probably find this annoying or maybe too dumbed down. But this isn’t for you - it’s for all people that are curious about Einstein and our universe, can follow a logical discussion, but are not technical enough to follow a more detailed explanation. Not that this isn’t detailed, but Cox and Forshaw go to great lengths to hold your hand along the way and explain it all, using analogies and not a lot of maths to make their point.
And it works. You might feel a bit lost at times, but things will fall into place. And hopefully you will also be able to appreciate the beauty of Einstein’s ideas.
July 1, 2012
Why is E=mc^2? 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.
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.
August 28, 2021
Physics is often neglected by many people for its deep connections to math. In this book, the authors expose the main concepts behind modern physics using only Pythagoras theorem. They make you realize that the genius of heros like Einstein comes out of pondering the trivial implications of our universe rather than solving crazy equations. I would highly recommend this book to any victim of the fallacy that physics is for gifted minds.
July 2, 2016
Who was this Adventure in Space-Time Written For?
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. It follows that the reader’s appreciation of the book depends on what they know. 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.
The book begins with the claim, “We do not assume any prior scientific knowledge.” While the language is often simplistic, and they even explain the meaning of a divide sign, I think this is a compromise that does not really work. 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.
Electricity and Magnetism Dance at the Speed of Light
Einstein’s insight into the special role of the speed of light derives from Maxwell’s equations of electricity and magnetism. 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. Maxwell’s equations give us the speed of light without mentioning the motion of the source or the observer. 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. But peeking into the actual wave equation, I see that c = 1 / √(ε*μ), where ε and μ are the electrical “permittivity” and magnetic “permeability” constants respectively. 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. As the speed of light is constant, the passenger’s clock must therefore appear to be running slower. 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. It is everybody else’s clock that is different.
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. I don’t know why they don’t talk more about this. 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. We can add a fourth dimension in time such that some quantity (distance “s”) is invariant no matter what speed the observer is moving. This new dimension is multiplied by the speed of light (c*t), so it becomes expressed in the same distance units as the other dimensions. But if we assume this is a Euclidean space, so that the Pythagorean triangle relationship
s^2 = x^2 + (c*t)^2
holds, we can get events that finish before they start. This violates causality, which means this model does not work. He then tells us “there is no other option” than to assume that
s^2 = x^2 - (c*t)^2
Not true, it is only one of many possibilities. 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.
I had to hunt around to discover that Minkowski space-time uses an (unfortunately so-called) “imaginary” time dimension, meaning a multiple of the square root of -1. Squaring it gives a negative number, hence the minus sign. Now it makes mathematical sense, but why did he not explain this? I still do not understand why, given that it is the time dimension that is “imaginary”, he subtracting the space dimension instead.
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. The apparent speed-up in space is compensated by a vast increase in elapsed time, at least from someone’s point of view.
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. Is this why the travelling twin’s clock slowed down while he was turning around? Then why did he not make the connection?
Well, lets go ask Mr. Internet. I’m back! 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. I think of it as all the energy is going into moving in time rather than space, but I can’t connect this thought to what I learned about Minkowski space-time. Anyway, don’t expect to book your sci-fi trip anytime soon. Lose some weight first (like all of it).
The Energy of Momentum in Space-Time
To introduce the concept of momentum, we get a crash course on vectors, mass, Newton’s second law, and energy. 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. In the end, we get of the standard momentum component (mass * velocity) in the space direction, and mass times the speed of light (m*c) in the time direction, both multiplied by the Lorentz factor (γ).
Because the total momentum must be conserved, the time direction (γ*m*c) must also be conserved. Therefore γ*m*c^2 is also conserved. Now he makes an approximation for the Lorentz factor, which is reasonably accurate at low speeds. The result is:
m*c^2 + (1/2)*m*v^2
This is interpreted as the sum of the energy contained in the mass (m*c^2) plus its kinetic energy. At zero velocity, we still have energy in the mass. We have just achieved the stated goal of the book. But what happens if we don’t cheat on the math? I can’t help thinking there is an important consequence at high speeds, such as what happens when you accelerate mass?
A Good Learning Experience with Room for Improvement
After proving that E = m*c^2 he cannot resist going on to presenting the Entire Standard model, with its master equation that shows how every particle reacts with every other particle. 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. While I still don’t completely get it, this journey into the mystery of space and time was well worth it.
April 30, 2020
Actual Rating: 3.5 Stars.
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 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...we are ramping this up a little" it then switches to quite inane topics again (let me explain scientific notation to you....hmmm...if I got through spacetime diagrams and spacetime momentum vectors I think I got scientific notation and why scientists use such big numbers). 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).
Overall, I think the authors did an admirable job on a difficult topic/market. 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 ...jump in but be prepared for a shaky journey. If you are in the middle, bring pen and paper and enjoy the bumps.
Reading Challenge
Aussie Reader's 2020 April Opposites Challenge: Read a book of fiction and a book of non-fiction
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 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...we are ramping this up a little" it then switches to quite inane topics again (let me explain scientific notation to you....hmmm...if I got through spacetime diagrams and spacetime momentum vectors I think I got scientific notation and why scientists use such big numbers). 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).
Overall, I think the authors did an admirable job on a difficult topic/market. 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 ...jump in but be prepared for a shaky journey. If you are in the middle, bring pen and paper and enjoy the bumps.
Reading Challenge
Aussie Reader's 2020 April Opposites Challenge: Read a book of fiction and a book of non-fiction
January 22, 2020
2020 TBR Challenge: Read a book you don't remember why you added or bought
I really enjoy Brian Cox, I watched his series Wonders of Life ages ago, and I've always liked seeing him on various panel shows etc. 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.
This all extends to Why Does E=mc²? - I still don't think I fully grasp any of the concepts explored in it, I have never had a brain that is wired in the right way to 'get' physics intuitively like some people I know, but this book certainly got me the closest, and inspired me to do some research off my own back to see if I can at least say I understand something.
Why Does E=mc²? regularly made me laugh out loud with some of its analogies and turns of phrase, which are a fantastic and welcome break after several pages of frowning, squinting at the page, and grappling to understand relativity.
Probably a book I'll read again to try to cement my understandings. Very much enjoyed it.
I really enjoy Brian Cox, I watched his series Wonders of Life ages ago, and I've always liked seeing him on various panel shows etc. 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.
This all extends to Why Does E=mc²? - I still don't think I fully grasp any of the concepts explored in it, I have never had a brain that is wired in the right way to 'get' physics intuitively like some people I know, but this book certainly got me the closest, and inspired me to do some research off my own back to see if I can at least say I understand something.
Why Does E=mc²? regularly made me laugh out loud with some of its analogies and turns of phrase, which are a fantastic and welcome break after several pages of frowning, squinting at the page, and grappling to understand relativity.
Probably a book I'll read again to try to cement my understandings. Very much enjoyed it.
May 10, 2019
Omg I had no idea how shallow my understanding of relativity was!! Eye opening & exciting read. 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???") and all the "forced" assumptions we've made when shaping our theories (e.g. the demands of causality when shaping up the spacetime "rules")
Definitely recommend it!
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???") and all the "forced" assumptions we've made when shaping our theories (e.g. the demands of causality when shaping up the spacetime "rules")
Definitely recommend it!
June 17, 2019
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.
May 14, 2021
It has been 12 years since I read this book and I thought I would try it again to see if I better understood it than the last time. Although I have a HNC in physical sciences I have always found the maths of the subject challenging and this was the case of this book.
I found it frustrating to constantly having to re-read and re-look at diagrams to digest what was being said.
The authors do make a commendable job of trying to explain things in lay man's terms and I did enjoy the sections of the book which looked at the subject of physics in a historical context.
The explanation of why nothing can travel faster than the speed of light, and the chapter on gravity and space-time were particularly well done.
One of those books due to the nature of change in scientific theories and discoveries, may in another 12 years be out of date.
I found it frustrating to constantly having to re-read and re-look at diagrams to digest what was being said.
The authors do make a commendable job of trying to explain things in lay man's terms and I did enjoy the sections of the book which looked at the subject of physics in a historical context.
The explanation of why nothing can travel faster than the speed of light, and the chapter on gravity and space-time were particularly well done.
One of those books due to the nature of change in scientific theories and discoveries, may in another 12 years be out of date.
April 26, 2020
Plan on going back to this, and crunching the numbers.
Read
June 13, 2015(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.)
I have been meaning to read this book every since it came out in Hungarian, but now it seemed like just the light summer read I needed… which, of course, it isn’t, but I’m fairly certain that I’d find some parts of it very complicated even in winter, so what the hell. My main motivation to read this book was Brian Cox himself (I know, I’m that shallow), because I’ve been fascinated with his lectures and telly programmes, and since I had my fair share of brilliant and brilliantly mediocre science teachers in my time, I had to realize how important presentation actually is. 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.
Interesting, however, doesn’t necessarily mean easily accessible. The authors certainly try and explain even simple concepts, e. g. what exponentiation means, but let’s be real, if someone meets exponentiation here for the first time, best of luck with the rest. In any case, the authors make it clear that if you don’t want to bother with the maths, you can skip the hardcore parts and still enjoy the rest – which is true, but sometimes I felt my brain bent in ways it doesn’t usually bend, but it was a nice experience, I missed it. I have noticed that several readers criticized this book for either talking down to the audience or for being to complicated, but once again, let’s be real, this is what happens when you try to talk to a wide range of people with heterogeneous backgrounds. You can’t please everyone, but I think the authors handled these challenged as well as they could be handled.
I have to admit that a significant part of this book went over my head, despite all the best efforts of Messrs. Cox and Forshaw, but I don’t think that’s a problem. It challenged my views, I have learnt a lot and it definitely raised my interest and inspired me to learn more, so I got everything out of this book that I’d hoped for.
I have been meaning to read this book every since it came out in Hungarian, but now it seemed like just the light summer read I needed… which, of course, it isn’t, but I’m fairly certain that I’d find some parts of it very complicated even in winter, so what the hell. My main motivation to read this book was Brian Cox himself (I know, I’m that shallow), because I’ve been fascinated with his lectures and telly programmes, and since I had my fair share of brilliant and brilliantly mediocre science teachers in my time, I had to realize how important presentation actually is. 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.
Interesting, however, doesn’t necessarily mean easily accessible. The authors certainly try and explain even simple concepts, e. g. what exponentiation means, but let’s be real, if someone meets exponentiation here for the first time, best of luck with the rest. In any case, the authors make it clear that if you don’t want to bother with the maths, you can skip the hardcore parts and still enjoy the rest – which is true, but sometimes I felt my brain bent in ways it doesn’t usually bend, but it was a nice experience, I missed it. I have noticed that several readers criticized this book for either talking down to the audience or for being to complicated, but once again, let’s be real, this is what happens when you try to talk to a wide range of people with heterogeneous backgrounds. You can’t please everyone, but I think the authors handled these challenged as well as they could be handled.
I have to admit that a significant part of this book went over my head, despite all the best efforts of Messrs. Cox and Forshaw, but I don’t think that’s a problem. It challenged my views, I have learnt a lot and it definitely raised my interest and inspired me to learn more, so I got everything out of this book that I’d hoped for.
January 30, 2014
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). This merely added to the annoying impression that the authors are explaining all the n a s t y, d i f f i c u l t s c i e n c e y - w i e n c e y v e r y s l o w l y t o y o u. B e c a u s e y o u ' r e s t u p i d.
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!
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!
March 19, 2013
The first book on Relativity/Quantum theory I've read that explains spacetime in a sensible way, in that it doesn't hide the (not particularly complex) mathematics. It makes it so much easier to understand if you have a passing knowledge of Pythagoras.
Loved the explanations of how the counter-intuitive properties of the universe were derived from simple rules. Lots of 'ah-ha!' moments for me, especially when talking about "everything travels at the speed of light", and "distances are smaller at faster speeds".
A really enlightening book, although I was only just hanging onto the maths at the end when pulling apart the Standard Model equation.
Loved the explanations of how the counter-intuitive properties of the universe were derived from simple rules. Lots of 'ah-ha!' moments for me, especially when talking about "everything travels at the speed of light", and "distances are smaller at faster speeds".
A really enlightening book, although I was only just hanging onto the maths at the end when pulling apart the Standard Model equation.
December 25, 2019
Dlaczego E=mc2 (i dlaczego powinno nas to obchodzić)
No właśnie, dlaczego nas to powinno obchodzić?
Powodów jest wiele, mianowicie...bo...
1. Energia i masa są wymienne, jak waluta, którą wymieniam w kantorze, to tak jak wymiana Euro na PLN, lub PLN na Euro.
2. W masie drzemie niewyobrażalna ilość energii, czystej energii, jeśli uda nam się ja uwolnić ludzkość rozwiąże problem energetyczny.
3. Masa bierze sie z energii, jesli na początku, 13,7 miliarda lat temu nic nie było, nie było masy, to co wtedy było --- logiczna odpowiedzą wydaje sie być energia
4. Proces wymiany masy na energię powiązany jest ze stała, którą jest prędkość światła, bez tej stałej świat by nieistniał, nie byłoby nas
5. Nasz świat to czasoprzestrzeń, pojęcie czasu i przestrzeni jest nierozłączne.
6. Świat zbudowany jest z 12 podstawowych cząsteczek, światem rządzą 4 siły.
7. To, ze masa istnieje, zawdzięczamy zjawisku zwanemu mechanizmem Higgsa, polu Higgsa. (Tu dodam ze w momencie napisania książki, była to teoria, na dzień dzisiejszy została potwierdzona eksperymentem).
8. Słońce ma jeszcze około 4,5 miliarda lat istnienia przed sobą, jesli w rym czasie człowiek nie znajdzie innego miejsca zamieszkania we wszechświecie, ludzkość przestanie istnieć.
9. Bez E=mc2 nie działałby GPS…. Z którego często korzystam, który sprawia, że mogę odkrywać i poznawać nieznane miejsca na naszej planecie.
Co jeszcze wiemy i jaki jest stan nauki? Mianowicie.... (Upraszczam, pewnie prawdziwy fizyk mógłby uznać moje podsumowanie poniżej jako błędne, ale postaram sie we własnych słowach podsumować to jak zrozumiałem powstanie masy, pierwiastków chemicznych, skał, planet, życia).
Na początku była energia, zaczęła przeistaczać sie w elementarne cząsteczki, mające masę, kwarki, te zaczęły łączyć się w protony, neutrony, te zaczęły za pomocą silnej siły łączyć się w jądra wodoru, jądra wodoru unosząc się w przestrzeni za pomocą siły grawitacyjnej zaczęły tworzyć gęste obłoki gazowe, do tego stopnia gęste, ze w pewnym momencie uruchomiła sie reakcja łańcuchowa i wodór zaczął spalać sie i za pomocą reakcji jądrowej fuzji zaczął powstawać Hel. Następnie w piecu gwiazdy w odpowiednich sprzyjających warunkach sporadycznie zaczęły powstawać atomy węgla. Zjawisko to odkryte przez astronoma Hoyla --- o tyle przełomowe, bo przecież węgiel to podstawa życia, a z samego wodoru i Helu życie nie powstaje. W momencie powstania węgla drzwi do powstawania dalszych pierwiastków zostały otwarte. I tak życiodajny pierwiastek węgla powstawał w piecach energetycznych gwiazd. Zaczęły tworzyć sie skaly, te zaczęły tworzyć planety, księżyce, w galaktyce drogi mlecznej gdzieś tam w powstała sobie planeta o jądrze zbudowanym z żelaza, musiała sie ochłodzić, skorupa zastygła, na skorupie powstały oceany, wielkie zbiorniki wodne. Itd.
To wszystko, tak się wydaje, powstało z energii.
Książkę słuchałem jako audiobook w jeż angielskim. Koncówki słuchałem jadąc autem. W momencie kiedy skończyłem słuchać załączyłem muzykę i z głośników popłynęła niespodziewanie muzyka Stinga pt. "If I ever loose my faith..."
Dla mojej psychiki okazała się to być ciężka mieszanka, istny koktajl Mołotowa. Oto skończyłem słuchać książkę tłumacząca istnienie świata według aktualnego stanu wiedzy nauki, no i tu pojawia sie nagle tekst "if I ever loose my faith..."
"You could say I lost my sense of direction....."
.....
"Some would say I was a lost men in a last world..."
Zaraz, zaraz.... Myśle sobie jednak i zadaję sobie pytanie, dlaczego nie radzę sobie z poznawaniem tego świata? Autorzy książki wskazują na sam koniec i zamykające słowa książki wskazując, ze jest jeszcze tyle do poznania, tyle do odkrycia. Teorie naukowe które znamy dzisiaj nie tłumaczą przecież w całości wszystkich zjawisk, człowiek ma tyle jeszcze ważnych problemów do rozwiązania. Postęp ludzkości przecież zależy od tego aby dalej poznawać świat i go dalej odkrywać. A tutaj nagle taki hamulec ręczny się włącza… Jakiś mały krasnoludek siedzący w mojej głowie ciągnie za hamulec bezpieczeństwa. Na szczęście pojawia się konduktor i wyraża gotowość wlepienia mandatu za zatrzymanie pociągu.
....i w dodatku pojawia się instynkt zwątpienia i patetyczności. Ale pociąg rusza znowu, maszynista dorzuca węgla do pieca, i lokomotywa, powili jak żółw ociężale zaczyna się rozpędzać,
Nawiazując do książki o Keplerze którą niedawno przeczytałem myśle sobie, przecież wychowałem sie w duchu kulturowym który przez setki lat potępiał postęp, dzieła Kopernika były oficjalnie na liście ksiąg zakazanych do 19wieku, Kepler był prześladowany, i wykluczony przez kościół protestancki (nie tylko kościół katolicki ma w tym względzie za uszami). Sam Galileo w Rzymie musiał wyrzec się swoich odkryć. W XX wieku Einstein musiał uciekać przed Holocaustem z Europy, ze względu ze był Żydem nie traktowano go poważnie. Groziła mu śmierć. I tak mozna wyliczać. Tyle duchów przeszłości się kryje w naszych szafach, tak ciężki jest nasz bagaż przeszłości, że hamuje nas to w rozwoju. Jako jednostki i jako ludzkość.
Dzięki Ci Brianie Coxie i Jeffie Forshaw za świetny opis trudnej do zrozumienia teorii, za udowodnienie jak ważne jest odpowiednie podejście, podejście odkrywcze do naszego świata.
No i w międzyczasie.... lokomotywa osiągnęła znowu pełną prędkość....
"A dokąd? A dokąd? A dokąd? Na wprost!"
....
"I koła turkocą, i puka, i stuka to:
Tak to to, tak to to, tak to to, tak to to!… "
No właśnie, dlaczego nas to powinno obchodzić?
Powodów jest wiele, mianowicie...bo...
1. Energia i masa są wymienne, jak waluta, którą wymieniam w kantorze, to tak jak wymiana Euro na PLN, lub PLN na Euro.
2. W masie drzemie niewyobrażalna ilość energii, czystej energii, jeśli uda nam się ja uwolnić ludzkość rozwiąże problem energetyczny.
3. Masa bierze sie z energii, jesli na początku, 13,7 miliarda lat temu nic nie było, nie było masy, to co wtedy było --- logiczna odpowiedzą wydaje sie być energia
4. Proces wymiany masy na energię powiązany jest ze stała, którą jest prędkość światła, bez tej stałej świat by nieistniał, nie byłoby nas
5. Nasz świat to czasoprzestrzeń, pojęcie czasu i przestrzeni jest nierozłączne.
6. Świat zbudowany jest z 12 podstawowych cząsteczek, światem rządzą 4 siły.
7. To, ze masa istnieje, zawdzięczamy zjawisku zwanemu mechanizmem Higgsa, polu Higgsa. (Tu dodam ze w momencie napisania książki, była to teoria, na dzień dzisiejszy została potwierdzona eksperymentem).
8. Słońce ma jeszcze około 4,5 miliarda lat istnienia przed sobą, jesli w rym czasie człowiek nie znajdzie innego miejsca zamieszkania we wszechświecie, ludzkość przestanie istnieć.
9. Bez E=mc2 nie działałby GPS…. Z którego często korzystam, który sprawia, że mogę odkrywać i poznawać nieznane miejsca na naszej planecie.
Co jeszcze wiemy i jaki jest stan nauki? Mianowicie.... (Upraszczam, pewnie prawdziwy fizyk mógłby uznać moje podsumowanie poniżej jako błędne, ale postaram sie we własnych słowach podsumować to jak zrozumiałem powstanie masy, pierwiastków chemicznych, skał, planet, życia).
Na początku była energia, zaczęła przeistaczać sie w elementarne cząsteczki, mające masę, kwarki, te zaczęły łączyć się w protony, neutrony, te zaczęły za pomocą silnej siły łączyć się w jądra wodoru, jądra wodoru unosząc się w przestrzeni za pomocą siły grawitacyjnej zaczęły tworzyć gęste obłoki gazowe, do tego stopnia gęste, ze w pewnym momencie uruchomiła sie reakcja łańcuchowa i wodór zaczął spalać sie i za pomocą reakcji jądrowej fuzji zaczął powstawać Hel. Następnie w piecu gwiazdy w odpowiednich sprzyjających warunkach sporadycznie zaczęły powstawać atomy węgla. Zjawisko to odkryte przez astronoma Hoyla --- o tyle przełomowe, bo przecież węgiel to podstawa życia, a z samego wodoru i Helu życie nie powstaje. W momencie powstania węgla drzwi do powstawania dalszych pierwiastków zostały otwarte. I tak życiodajny pierwiastek węgla powstawał w piecach energetycznych gwiazd. Zaczęły tworzyć sie skaly, te zaczęły tworzyć planety, księżyce, w galaktyce drogi mlecznej gdzieś tam w powstała sobie planeta o jądrze zbudowanym z żelaza, musiała sie ochłodzić, skorupa zastygła, na skorupie powstały oceany, wielkie zbiorniki wodne. Itd.
To wszystko, tak się wydaje, powstało z energii.
Książkę słuchałem jako audiobook w jeż angielskim. Koncówki słuchałem jadąc autem. W momencie kiedy skończyłem słuchać załączyłem muzykę i z głośników popłynęła niespodziewanie muzyka Stinga pt. "If I ever loose my faith..."
Dla mojej psychiki okazała się to być ciężka mieszanka, istny koktajl Mołotowa. Oto skończyłem słuchać książkę tłumacząca istnienie świata według aktualnego stanu wiedzy nauki, no i tu pojawia sie nagle tekst "if I ever loose my faith..."
"You could say I lost my sense of direction....."
.....
"Some would say I was a lost men in a last world..."
Zaraz, zaraz.... Myśle sobie jednak i zadaję sobie pytanie, dlaczego nie radzę sobie z poznawaniem tego świata? Autorzy książki wskazują na sam koniec i zamykające słowa książki wskazując, ze jest jeszcze tyle do poznania, tyle do odkrycia. Teorie naukowe które znamy dzisiaj nie tłumaczą przecież w całości wszystkich zjawisk, człowiek ma tyle jeszcze ważnych problemów do rozwiązania. Postęp ludzkości przecież zależy od tego aby dalej poznawać świat i go dalej odkrywać. A tutaj nagle taki hamulec ręczny się włącza… Jakiś mały krasnoludek siedzący w mojej głowie ciągnie za hamulec bezpieczeństwa. Na szczęście pojawia się konduktor i wyraża gotowość wlepienia mandatu za zatrzymanie pociągu.
....i w dodatku pojawia się instynkt zwątpienia i patetyczności. Ale pociąg rusza znowu, maszynista dorzuca węgla do pieca, i lokomotywa, powili jak żółw ociężale zaczyna się rozpędzać,
Nawiazując do książki o Keplerze którą niedawno przeczytałem myśle sobie, przecież wychowałem sie w duchu kulturowym który przez setki lat potępiał postęp, dzieła Kopernika były oficjalnie na liście ksiąg zakazanych do 19wieku, Kepler był prześladowany, i wykluczony przez kościół protestancki (nie tylko kościół katolicki ma w tym względzie za uszami). Sam Galileo w Rzymie musiał wyrzec się swoich odkryć. W XX wieku Einstein musiał uciekać przed Holocaustem z Europy, ze względu ze był Żydem nie traktowano go poważnie. Groziła mu śmierć. I tak mozna wyliczać. Tyle duchów przeszłości się kryje w naszych szafach, tak ciężki jest nasz bagaż przeszłości, że hamuje nas to w rozwoju. Jako jednostki i jako ludzkość.
Dzięki Ci Brianie Coxie i Jeffie Forshaw za świetny opis trudnej do zrozumienia teorii, za udowodnienie jak ważne jest odpowiednie podejście, podejście odkrywcze do naszego świata.
No i w międzyczasie.... lokomotywa osiągnęła znowu pełną prędkość....
"A dokąd? A dokąd? A dokąd? Na wprost!"
....
"I koła turkocą, i puka, i stuka to:
Tak to to, tak to to, tak to to, tak to to!… "
April 23, 2013
this is a great read, very interesting, but it is not a book I would suggest to anyone who does not have a understanding of astrophysics, the book does start of easy to understand, but it does get complicated
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