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E=MC 89

Posted by timothy
from the yessir-*squaaared*-away dept.
Michael JasonSmith (not his evil cousin Jason MichaelSmith, or the nefarious Smith MichaelJason) contributed this review of a book which treads the line between simple and complex by concentrating on that strangely simple little equation of Einstein's -- how it came to be uncovered, its history, and its ramifications.

E=mc² : A Biography of the World's Most Famous Equation
author David Bodanis
pages 324
publisher MacMillan
rating 8
reviewer Michael JasonSmith
ISBN 0802713521
summary A good discussion about the origins and impact of Einstein's famous famous equation, and a fun geek read for the lazy summer holidays.

Most people know of the equation E=mc, but how many know what it means? Sure, you know that energy equals mass times the square of the speed of light. Good for you. You may also know that it allows you to calculate the destructive capacity of the glass of Coke sitting next to you. But what many do not know is how Einstein came about the equation, how other scientists set the foundations for E=mc, and what the seemingly simple equation means in the big picture. This book sets out to rectify this in a way that does not get too bogged down with atomic weights and pictures of squashed up trains.

When I was given this book for Christmas (hi, Mum) I was a bit sceptical. I already knew what E=mc meant, and I'm not a big fan of biographies. But I was pleasantly surprised by this book. It cracks along explaining the origins of E=mc, such as how Faraday came up with the modern concept of energy, and the implications of the equation, such as the use of a German battleship to make the Galileo space probe. David Bodanis uses the conflict between young and old scientists as the main method of explaining science, so the stories are interesting even if you are aware of the formula behind them. The bigger picture is not forgotten and we are constantly reminded of modern European history, as the French Revolution and two world wars played a big part in influencing the development of science.

Those who are looking for a biography of Einstein will be disappointed as he does not play a big part in the book, despite the fact that he discovered the relationship between mass and energy. Instead the book lives up to its subtitle as a biography of the equation, from the early days of Antiube-Laurent Lavoiser in the 1700s to Subrahmanyan Chandrasekhar in the 20th Century.

I have two niggles related to this book. Firstly is the use of Imperial measurements. I don't know how heavy 5,000 pounds is, so have to stop reading, find a conversion table (or log into the net), convert the 5,000 pounds to Kilograms, find where I was up to and continue reading for a couple of lines until I get up to the next measurement. Frustrating. For some reason temperature measurements are given in Metric and Imperial, but they are the only ones. Most of the books from the UK that I have read recently have provided measurements in Metric as well as Imperial, but for some reason Bodanis and his editor of did not see fit to follow the trend.

The other problem was the notes were at the end of the book instead of at the bottom of the relevant page or the end of each chapter. If the notes were just bibliographic references I would not have minded so much, but often they were very interesting stories that I would have liked to have read in context, such as why a slow moving neutron is needed to start a chain reaction. Because the notes were at the end of the book I often forgot that they were there.

  1. Bern Patient Office, 1905
  2. E is for Energy
  3. =
  4. m is for mass
  5. c is for celeritas
  6. Einstein and the Equation
  7. Into the Atom
  8. Quiet in the Midday Snow
  9. Germany's Turn
  10. Norway
  11. America's Turn
  12. 8:16am -- Over Japan
  13. The Fires of the Sun
  14. Creating the Earth
  15. A Brahmin Lifts His Eyes Unto the Sky

You can purchase this book at Fatbrain.

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  • by Fatal0E (230910) on Thursday January 18, 2001 @05:40AM (#499079)
    I think Stephen Hawkings A Brief History Of Time [] is the best summation/applied theory of Einsteins theorys. Hawking gives Einstein mad props throughout the book and Hawkings respect for the guy shines through. After reading A Brief History I think that as a layman the applications of E=MC^2 are more interesting the then the nuts 'n bolts of the theory itself.
    "Me Ted"
  • by Bonker (243350) on Thursday January 18, 2001 @05:46AM (#499080)
    The best book I have ever read about Einstein's theories was 'Relativity Visualized' by Lewis Epstein.

    It gives a semi-complete history of the developments of relativistic science, going through the discovery of Newtonian motion and covering the dismissal of the 'Cosmic Aether' theory. It then goes in to explaining how relativity works in both simple terms that my Dad could get and then gives more explicit examples, complete with 'da math. This was the first book that made me really understand how time works in gravitational field.

    Good reading for the expert and the casual intelectual.
  • by omarius (52253) <omar&allwrong,com> on Thursday January 18, 2001 @05:47AM (#499081) Homepage Journal
    Hawking's Brief History is the one thing I would get back, IF I had the power to receive one item out of all the tings I have ever lost to ex-girlfriends.


  • E=mc2 is a nice equation and all, but people often forget that it was a side not to his other works (Einstein himself published it as just an insight from his 1905 paper "On the Electrodynamics of Moving Objects") - the paper that ushered in the theory of special relativity where special meant constant velocity, no acceleration. Most of Einsteins work that has been applied to other problems is his much later General Theory of Relativity, where he concludes that light must follow a bent path because people "fall" when elevators accelerate upwards and therefore space itself is bent. For a more thorough acccount of Einstein I highly recommend Albert Einstein: A Biography []

  • by powlette (198002) on Thursday January 18, 2001 @05:55AM (#499083) Homepage
    Although it was interesting, there is absolutely no focus on the science of the equation. The author would have you believe that the equation came about simply by a thought experiment in einstien's head. I got a more in-depth explaination in my freshman physics course.

    If you're interested in a history lesson of all things leading up to and including the atom bomb in WW2. This book is for you.

  • Three names. Michael, Jason, Smith.
    Three positions for each name.


    That's six. Expressed mathematically, it is :

    3! = 3 * 2 * 1 = 6
    You have three names, so any three can go in the first spot, after that, any of the remaining two..and so on.

    If you had 4 names, it would be 4!=24, or 24 permutations.

    Got it?
    Class dismissed.
  • People who haven't studied this stuff often don't realize that "E=mc^2" is deceptively simple. It's only part of the equation. The whole thing is more like "E=((mc^2)/(sqrt(1 - (v^2/c^2)))", where v is the velocity of the mass in question.

    "E=mc^2" is what the equation simplifies to when the mass is at rest (v = 0). When you put an object in motion -- especially if you achieve speeds that are statistically significant percentages of c -- the rest of the equation comes into play. And the denominator of that equation is also where relativistic effects such as time dilation come into play.

    And if you don't think this stuff is important, well, don't come crying to me if you get stuck near the event horizon of a black hole.

    And remember, E=mc^3 at some point just before you reach c :)
    Ernest MacDougal Campbell III / NIC Handle: EMC3

  • If you don't get it, it's a reference to a GREAT Far Side cartoon. Anyone got a link? I've seen some notices from Larson asking that his work not be put on the Net so it may not be out there.
  • My favorite Einstein book is (barnes and noble link) Einstein for Beginners [], from the quite excellent "Beginners" series you have probably seen in the philosophy or science racks at the bookstore.

    This book makes no assumptions about your physics acumen, and the explanation of relativity is one of the best I have read - it is accessible to almost anyone with a high-school level education.

  • Wasn't Einstein's Nobel for his work on Brownian motion?
    MailOne []
  • > Most people know of the equation E=mc, but how many know what it means? Sure, you know that energy equals mass times the square of the speed of light. Good for you. You may also know that it allows you to calculate the destructive capacity of the glass of Coke sitting next to you.

    That's not strictly true. E=mc2 is only accurate on a subatomic level. Thus in a reaction where Uranium decays, the energy released can be calculated from the mass of the components. The energy is considerably less than e=mc2 for the Uranium atom itself because you have to take the overall result - energy in and energy out. Thus although e=mc2 is true for Coke, the overall energy released will probably be negative, because you've got to put more energy in than you get out in order to split the atom.
  • by Anonymous Coward on Thursday January 18, 2001 @06:27AM (#499090)
    Because your superscripted 2 is a Microsoft centric character that not everyone can see. Didn't you read your own article [] yesterday on the dangers of the web losing its feature of browser neutrality? If you must use non-ASCII, at least use honest to God Unicode.
  • Yeah, for some reason I read through these books in 1 or 2 evening, as his storytelling is very addictive indeed. And that was just the translation of his english book.

    He succeeds brilliantly in explaining clearly how anti matter and quarks, hawking radiation, black holes and space time deformations are all logically tied into the mechanics of relativistic or quantum mechanic processes, without holding back important quirks in the theories or over emphasizing importance of certain details. He invites you to play with notions of timetravel, spacewarps and baby universes, as if you could reach out and touch the essence of these concepts in your mind. His books are among the best, and certainly a good suggestion for people who are curious about the Grand Theory of All, or just interested in reading up from the point where they dropped out of physics classes.

  • by Anonymous Coward

    Let me get this straight. If I don't properly take into account the full equation, I'll be stuck near two really stupid sci-fi films:
    "Event Horizon" and "The Black Hole"?

    Oh, the horror

  • Einstein won his prize "for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect" - see the relevant page [] on the Nobel [] website.
  • The last time it matched it was this [] article.
  • If you're interested in a history lesson of all things leading up to and including the atom bomb in WW2

    You seem to imply the myth that E = mc^2 was necessary or useful in the design of the atom bomb. It was neither. The bomb was designed using basic results from nuclear physics, ingenuity, and a lot of engineering and hard work. The discoveries of Chadwick (the neutron) and Fermi (nuclear fission) were far more relevant to bomb design than Einstein's theory of special relativity. Special relativity is simply unneeded if one is engineering a nuclear weapon.

    Read "The Making of the Atomic Bomb" by Richard Rhodes if you want to learn more. Also recommended is "The Los Alamos Primer" by Robert Serber. Einstein did play a political role in the making of the bomb (he wrote a very important letter to Roosevelt), but he did not work on the Manhattan Project.

  • The physical and natural science section of my personal library is composed completely of books from ex-boyfriends. The way I see it, the more crappy poetry I am forced to listen to, the more books I keep. However, my copy of Brief History of Time I bought all by myself. This has nothing to do with the topic, but keep in mind - the ratio of books you lose to ex-girlfriends is directly related to every crappy poem you made her read, about 1:3 respectively.
  • by peter303 (12292) on Thursday January 18, 2001 @06:46AM (#499097)
    The book basically explains the origin of the
    symbol in each equation, from the oldest, the
    equals sign, to the most recent, the speed of

    I would present it differently.
    I would assume a knowledge of high school physics,
    which is basically simplified Newtonian and
    absolute reference frame, then qualitatively
    introduce special relativity.

    The best quantitative book I've seen is William
    French's "Special Relativity". It only uses
    high school algebra and physics, but is usually
    is offered as an enrichment appendix to second
    semester physics (E&M) at MIT.
  • No, it was for his work on the photoelectric effect. It was awarded in 1921, six years after he published "On the electrodynamics of moving bodies" and its corollary, which deduced from the results of the first paper that light must carry away inertia. Later this turned into the E=mc formula. Here [] is a good bunch of links to follow for details on the Nobel.

  • Is another magic equation that encapsulates
    mathematics through the first half of the 19th century.
    I've seen books on individual symbols,
    but don't know if anyone has done all five (or seven).
    I. Shah has done 1, *, =, 0, and -1, and refers
    to this equation. There are dozens of history
    books on pi and a couple on natural logorithms.
    "Want to be a Millionaire" quaestion: what is the
    historical ordering of these symbols (first printed usage)?
    What is the historical ordering of the concepts
    behind the symbols (different answer)?
    The trick answer is that zero is one of the
    latest understood, even though today it
    is one of the first taught.

  • >theory of special relativity where special meant
    >constant velocity, no acceleration.

    Wrong. "Special" does not mean no acceleration. Special Relativity is quite capable of handling acceleration, using a little calculus. The "special" means "flat spacetime", i.e. the absence of any (significant) spacetime curvature (a.k.a. "gravity") due to the presence of large nearby masses. Flat spacetime is the assumption under which the Two Postulates of Special Relativity [1. Principle of Relativity -- all inertial frames are created equal. 2. Law of Propagation of Light -- light's speed is a constant independent of the motion of its source] are made.

    General Relativity is the extension of Special Relativity that handles GRAVITY (not acceleration). Don't overestimate the signifigance of the Equivalence Principle -- it applies only locally. That's why SR+calculus can handle acceleration, but gravity requires GR. SR is a special case of GR, in the low-mass limit. That's the difference.

  • by rezn (222056) on Thursday January 18, 2001 @07:10AM (#499101)
    I'm a physicist and I don't have the intentions of putting anyone but. However, if you want to learn some physics, stop reading these fairy tell books and grab a real physics book. Any book you get from Hawkings pr abpit Einstein and relativity is about as informative as a two year old when it comes down to real physics. I've seen some of you talk about E=mc^2 but yet none seem to have any true grasp on what it is, how it is applied, etc.. I only see thoughts that it is, cool, and "the applications of E=MC^2 are more interesting the then the nuts 'n bolts of the theory itself" which is complete rubish. The nuts and bolts of E=mc^2 defines everything in modern physics. We would not understand nuclear reactions, nuclear binding energies, etc... without E=mc^2. Radioactive Nuclear Structure just so happens to be what I do research on. Anyway, the "nuts and bolts" of E=mc^2 is by far the most important thing. As far as quantum mechanics, your view on what quantum mechanics is will do a 180 when you take a real class in it. Reading what Stephen Hawkings has to say is a lot different than reading pure quantum mechanics and working out real problems. Hell, if you haven't at least had every calculus, differential equations, and analysis, there is no way you can even attempt to do quantum mechanics. Part of understanding a large bit of quantum mecanics is directly related to your understanding of the math behind it. Anyway, my point is for many of you guys to stop reading such books for learning physics and read some real textbooks instead.
  • First Gavin Bong, and now this! "Michael JasonSmith" what sort of a name is that?
  • Wrong. "Special" does not mean no acceleration. Special Relativity is quite capable of handling acceleration, using a little calculus.

    Sorry, but you're wrong. Special relativity applies only to inertial frames, where there is no acceleration. This is the limitation that made Einstein start towards General Relativity. He then came up with the Principle of Equivalence stating that every acceleration has an equivalent gravitational field and vice versa, hence they are the same thing. So yes, special relativity doesn't work in gravitational fields, but this also means it doesn't work for an accelerating frame of reference either.

  • where m is the invariant (sometimes known as "rest")

    But later it was changed to "The Professor and Mary Ann."

  • This one [] is good too. Not too scientific, but it definitally makes one think.

    _14k4 ( /
  • Duh. He wasn't asking about permutations in general, he was asking what the reason was for doing it with this guy's name.

  • For people that are interested in learning more about Einstein's other theories, another great book is Clifford Will's "Was Einstein Right?". A great discussion of the general theory of relativity and the experiments that have put it to the test since it was created, written by a distinguished researcher in the field.
  • no offense but this original post gets a score of 4? There isn't a single thing said that is true. A brief history of time doesn't even scratch einstein's theories. Also, the statement that "the applications of E=MC^2 are more interesting the then the nuts 'n bolts of the theory itself" is completely ridiculous. This person obviously has no grasp of eintein's theories. However, like always, slashdot tends to give incorrect posts the highest score or the posts that conform to their own thoughts. Besides, if a physics book isn't 60% math, it's no good. Words and contexts of blackholes, etc.... doesn't teach you a thing about physics. I probably seem a bit pissed over this and I am. It really pisses me off when I see slashdot people comment over physics related subjects because everytime they do, Hawkings is always brought up. Well let me tell you, in the physics community, no one gives a shit about Hawkins and his books. It's like the National Enquirer to us. On top of that, trying to even understand space-time, blackholes, etc... without the fundamentals of physics is like trying to crank up the car without gas in it.
  • by JWhitlock (201845) <.John-Whitlock. .at.> on Thursday January 18, 2001 @07:44AM (#499109)
    I agree that you can't say you really understand what's going on until you try it out (apply E=mc&sup2 to real physics problems). But to say that we should stop reading these books, and instead read physics textbooks?

    Have you looked at a physics textbook recently? Entry level books go about half the way - it takes a born-physicist to understand what is going on with only the textbook. It almost requires a teacher to demonstrate the math, to get feedback on what the student is doing wrong.

    Plus, they are too expensive. Like most educational materials, it is overpriced, because people are buying them with government funding (schools), or are forced to buy them (college students). There appears to be little competition, or at least little competition that results in a better product.

    Then, you say to truly appreciate this stuff, you need the equvalent of 3 years of a physics major. Calculus, Diff Eq., Quantum Mechanics - you could do it in two years, but probably not if you were working at the same time. In other words, only students can appreciate it.

    I think you can transmit some of the wonder of physics in a format that the average person can understand. I believe you can even convey some of the theory to the mathematically inclined - some of the best authors have done it. But to say, don't study it unless you study the pure stuff - I can't agree with that. That leads to members of congress, who have been told they can't even comprehend particle physics, making funding decisions on the superconducting supercolider. We need the lower-level stuff to communicate the promise of science to the non-scientific public.

    That being said, it is fairly ignorant to start speculating on practical uses when you don't understand the theory. Ignorant, or good engineering, depending on the result.

    And, it's fairly unforgivable to use Imperial units to the exclusion of scientific units. I can forgive both being given, since I think in Imperial units most of the time, but doing physics in Imperial units? It gives me nightmares of thermodynamics classes.

  • ....When you specialize in your desired field you spend most of your time working and learning in said field. We do not have enough time in our lives to learn everything about everything. This is why it is nice to be able to pick up a book on a certain subject (in this case Hawkings' A Brief History Of Time) without having any prior knowledge of that subject, read it, and hopefully have a much better understanding of that subject - even if that understanding is not comprehensive.

    For example, after reading A Brief History Of Time, I now consider that I have a basic understanding of black holes. Unless you are suggesting that black holes are not: Places where gravity is so strong that light (i.e. photons) cannot escape. If that is not true then I stand corrected....and could you please tell me what they are?

  • one could make a nuclear weapon without e=mc^2 but purely by luck. The true understanding of what is happening is from e=mc^2. When you have nucleons binding through nuclear forces, you have a binding energy related to that. That binding energy is what causes the weight per nucleon go up with increasing nucleons. That binding energy is directly related to e=mc^2. If you look at the mass differences, my oh my, the binding energy is mc^2 where m is the mass difference. This is just the cover of what e=mc^2 is.
  • e^(pi*i)+1=0

    Euler's [] relationship.
  • Ahem, a pound = 2.2 Kg. Why would you have to constantly refer back to the conversion table after the first time? It's a little more than doubled. You can't double a number in your head?

    Now, if it was Fahrenheit to Celsius conversions, I could understand... that's a little trickier.

    But still, why do you even need to know the exact measurement? The book is not a reference book. All you need to know is that "5000 pounds" is a lot of weight. Why would it matter exactly how much it is?


  • by Anonymous Coward
    What the heck do you mean, "the real equation"? There is more than one expression for energy, and expressing it in terms of momentum is not intriniscally better (or different) than expressing it in terms of velocity for massive particles.
  • >Special relativity applies only to inertial frames

    No. The POSTULATES of Special Relativity apply only to inertial frames. But these postulates allow you to DERIVE results for accelerated frames, provided that spacetime is flat in the region under consideration.

    And no, gravity and acceleration are not the same thing. They are *locally* indistinguishable, meaning only in small regions of spacetime. In an accelerated coordinate system, the pseudo-gravitational field lines are all parallel. In real gravitational fields, they radiate out of the mass source.

    You're simply wrong about special relativity not working for an accelerated frame of reference. Granted, the POSTULATES don't apply, and therefore accelerated frames cannot be treated as simply as inertial frames, but accelerated frames *can* be handled using Special Relativity and calculus to integrate over the continuum of inertial frames in the worldline of an accelerated object.

    For further details, please see the Usenet Relativity FAQ here []. Note specifically the question about whether SR can handle accelerated frames []

    Hope this helps.

    Christopher R. Volpe

  • by Fatal0E (230910) on Thursday January 18, 2001 @08:24AM (#499116)
    Thats a bunch of shit.

    First of all, General and Special Relativity are explained. They aren't proofed, just run-down. One of the running themes of the book is that w/o at least a superficial understanding special relativity the rest of the book will be lost upon the reader.

    Words and contexts of blackholes, etc.... doesn't teach you a thing about physics. ...Besides, if a physics book isn't 60% math, it's no good.

    Then I guess we don't have any quarrel since the book is more about celestial anomolies and only touches the physics aspect superficially. I personally didn't read it to learn about physics and didn't think I would, I read because I was curious about how space and time interact.

    It really pisses me off when I see slashdot people comment over physics related subjects because everytime they do, Hawkings is always brought up. Well let me tell you, in the physics community, no one gives a shit about Hawkins and his books. It's like the National Enquirer to us.

    What you equate his popular work to aside, the fact that he's publishing something you already know in a "for dummies" format doesn't surprise me as being offensive to you. Having said that I honestly don't care what you or your so called community thinks of his work. He brought me closer to understanding to nature of the universe as it pertains to me and that can't be anything less then good thing.

    This is not a flame

    "Me Ted"
  • That's all well and good, but what about people like me, who don't know physics, and don't want to read physics textbooks but would like to read about E=mc^2 in laymens terms?
  • one of my points was that space time is so complicated that it's impossible to grasp it from reading a book like that of stephen hawkings. When I've studied space-time relativity, the making up of the theories were so complex, so mathamatically in depth, etc... that any ideas or knowledge you do get from a book from stephen hawkins is so limited that it isn't worth reading. On top of that, you are forced to take it all for granted. As far as blackholes goes, the true nature of blackholes can't even be put into words that would make a valid argument.
  • I always prefer e^(2*pi*i)-1=0.

    That equation contains and links 0,1,2,e,pi and i. Maybe the original poster meant this as well, but he just dropped the 2 accicentally.
  • You seem to imply the myth that E = mc^2 was necessary or useful in the design of the atom bomb.

    Whether that's true or not is irrelevant, since I don't think he was making such a point. His implication was towards the handling of the subject matter (making of the atom bomb) in part of this book. There is certainly more history than science to be found in it.
  • ...but in fact a Kg is 2.2 pounds!

  • hehe, algebra? Algebra can't even be put into the same sentense as quantum mechanics. :) You can give some simple expressions for momentum, energy, etc.. bu they are specific scenarios and found either through extensive derivation or from experiments.
  • sorry, I meant That binding energy is what causes the weight per nucleon to go down with increasing nucleons
  • No, special relativity means no acceleration. Gravity is an acceleration, in fact, the law of equivalence states that gravity and an acceleration are the same. It means constant velocity because of your own "all inertial frames are created equal" portion - this is true when two bodies are moving at constant velocities. However, if one accelerates you disrupt the inertial frame. Think about it: you can tell whether a train is accelerating because of its change of speed relative to the surroundings. However if the surroundings moved away from you at a constant, albeit slower, velocity and you had a constant velocity there is no test which could tell you whether you were moving or not. Special means no acceleration.

  • Ahem, a pound = 2.2 Kg

    That's what NASA thought...

  • I apologize in advance if the reviewer is from somwhere like Singapore or is a non-native speaker (with a name like Michael JasonSmith?!) who just happened to learn English really, really well (though in that case I'd still argue that knowing, more or less, what pounds, feet, etc. are is an essential part of English-language literacy).

    If you're from USA, the UK, Canada, or Australia, then -- come on, who are you trying to fool? The big English-speaking countries have adopted the SI system to varying degrees, it's true (with the US lagging far behind everyone else), but if I'm not mistaken, everyone who grows up in any of those countries encounters Imperial units often enough that 'not knowing how heavy 5000 pounds is' would be a laughable pretension (or else evidence of severe cultural illiteracy).

    Argue, if you like, that the author should, in a book about physics, use SI units. But don't claim that the use of Imperial units is an obstacle to your comprehension of the book.

    Most people reading this book, after all, can safely be presumed to have graduated from elementary school. (Sadly, in the US, I suspect that using SI units exclusively would be a hardship for at least some potential readers -- a situation I do deplore).

    Finally, even if we stipulate that a reader could start out having absolutely no idea how heavy pounds are, why would he/she have to keep referring to tables/the net/etc.? Once you have ascertained that a pound is a little less than half a kilogram, a mile is somewhat less than two kilometers, etc. I'm sure you'd know all you needed to mentally translate the measurements in the rest of the book. After all, precision is presumably not an issue for most of the numbers. All you really need to know is that 5000 pounds is a little more than 2 tonnes, or about the weight of a medium-sized truck.

    Again, if your name ('Michael JasonSmith') is unfairly leading me to believe that you grew up in the US, UK, etc. then I apologize (though I stick to my basic point, which is that fluency in English includes a basic familiarity with the peculiar units of measurement used in everyday life in the largest English-speaking countries!)

    P.S. Please don't interpret this message as being anti-SI. I am a biologist myself and, like all scientists, use SI units almost exclusively in my work (the exception being when I have to do some machining, which usually involves decimal inches). Even at home I tend to use SI units more often than Imperial ones: I weigh myself on a kg scale and I even cook with SI-graduated utensils, relics of the years I lived in Europe. But I do live in the US now, which means that when I buy (say) fish, I have to ask for it by the pound, and when I look on a road sign, I see the distance to my destination in miles. All this of necessity leads to a gut-level familiarity with the meaning of those units, just as, when I lived in Europe, I quickly got used to asking for drinks in deciliters, fish in kilograms, and fishing line in meters!
  • Hmm. If I remember correctly, at the time of the Manhattan project the nuclear physics involved in the atomic bomb were already fairly well known. Little boy, being a gun type weapon, was extreemly simple: slam two peices of Uranium together to push it over critical mass and, well, boom.
    Fatman, on the other hand, was an implosion type weapon. On the surface, the nuclear physics are again quite simple: compress a plutonium pit to the point of criticality, and watch the fireworks. The trick is the compression bit. This requires absolutely precise use of explosives and control of the gases that the explosion creates, a hugely difficult fluid dynamics/chemistry problem. It's this very problem that keeps a lot of nation-states from developing their own nuclear arsenals. Even if they get their hands on weapons grade plutonium, they need to develop a way to set it off. If the chemical explosion is not absolutely perfect, the bomb will simply scatter the plutonium all over the place and not go critical.
  • Oops... right. One should never post on Slashdot when one is not feeling well. :)


  • yes, i agree, i read it (the french translation) some years ago and it's very good.

    there's marx for beginners too, much easier to read than das kapital.

  • No, you're wrong. Read my other post on this thread, the one with the subject "Bzzzzt YOU'RE wrong". It contains a detailed explanation of the common misconception that you demonstrate, as well as links to the FAQ that addresses this and other Relativity questions.
  • When I read the Hawking's BHOT in highschool, heady with plans to start a career in physics, I wanted to believe I understood it.

    But no, I don't understand a single thing : it's utterly incomprehensible.

    Now, I _am_ actually doing physics in grad school, and understood the "nuts and bolts" a bit more, I still think that BHOT is one of the worse popular science books ever written about fundamental physics ever. It's terrible.

    Anybody who claimed they learned a great deal, or understood clearly what Hawking meant, was either (a) BS-ting for the sake of having an ego boost OR (b) a genius.

    I figured that the reason BHOT becomes a bestseller is because people are more fascinated by Hawking the Man himself than his physics (which is while of extreme high quality, is no where near as dominating as those of an Einstein or a Dirac).

    So there.

  • If you're interested in a history lesson of all things leading up to and including the atom bomb in WW2

    You seem to imply the myth that E = mc^2 was necessary or useful in the design of the atom bomb. It was neither.

    That must be why there's a chapter called "8:16 -- Over Japan". Or did the author chain up a bunch of monkeys to typewriters until they strung together a couple of words that made sense?


  • Yes there is one but why, oh why so many reviews get to the frontpage? Books are cool, but I'd like to get their headlines on the sidebar like YRO...


  • by nphinit (36616)

    it's e=mc^2, morons.

  • there is absolutely no focus on the science of the equation. The author would have you believe that the equation came about simply by a thought experiment in einstien's head.

    Einstein's "thought experiment" (actually a primitive form of Image Streaming []) lasted something like 10 years. The equation was just a final step putting all the pictures Einstein had going through his head into mathmatics. Throughout history, revolutionary scientists haven't used the scientific method. My two copies of The Einstein Factor [] are out on loan, otherwise I'd site specific examples. (Offhand: Tesla, Farraday and others)

  • OK, before I start, I will say that I'm working in Astrophysics. I have taken multiple General Relativity classes, and read many difficult books on the subject. I've even taught special relativity. OK, here is how it goes. SPecial relativity is done in flat space time. As you are taught in beginning classes, you are limited to NO accelerations. However, when you take a more advanced course, they develop the idea of an instantaneous rest frame, and how you can use an integral over proper time to work with this acceleration. Granted, since gravity is not a force (in the GR picture it results from an extremum path in spacetime), we can't use this idea of acceleration for calcualtions. For people that disagree, they obviously haven't taken more than special relativity for engineers. It isn't meant as an insult, mearly to let you know your place. ;)
  • Thank you for clearing this up. Without benefit of a text explaining how it could be done I had suspected that SR, as presented in simplified form, could be generalized to handle acceleration. A statement you make, however, addresses a matter that still has me scratching my head.
    gravity is not a force (in the GR picture it results from an extremum path in spacetime)
    On several "ask the expert" type physics boards I posted a query saying almost exactly that, (did I err in using "geodesic" rather than "extremum path"), and went on to wonder if there could really be a quantum theory of a pseudo-force. I know that the search is on for a quantum theory of gravity, but is it possible that there is actually no such thing? So far, nobody has had a reply for me.

  • Rezn, don't be a jerk. Some of us don't have the time to pick up a physics degree. That doesn't mean we don't find it interesting; it also doesn't mean we think we know it all if we read a physics book targeted at the general population.
    It's Hawking, not Hawkings, and I'm skeptical of taking you at your word regarding his standing in the physics community. After all, you don't hear about Rezn radiation...

    Personally, my background is in music. The composer Aaron Copland wrote a book called "What to Listen for in Music" for the general populace. Do I listen for the same things that he talks about? No, I listen for more things because I know more about music than the general populace. Does someone who knows nothing about music gain from reading the book? Absolutely; just because his explanations are geared down a little doesn't hurt. The reader comes away with a richer understanding of something exciting than they had before they picked up the book. That's what I get out of books like the one reviewed here, and that's what I get out of Brief History.

    If you've got to feel smug about something, then go research something about Radioactive Nuclear Structures, find something new. Maybe it'll be something interesting enough to get you your own /. news item.

    In the meantime, I'll be over here telling people they don't know jack about music until they've read all of Arnold Schoenberg's books on form and harmonic structure and spent a couple of years analyzing sonata form. That way, I can feel smug too! Do we have a deal?
  • Hawking said in BHOT that someone told him that every equation in the book would cut the readership by half. IIRC, there was only one equation in the whole thing.

    You obviously have no idea how things work. Hawking is a big name in physics. Just because you don't care for him (and, by the way, his name is Hawking, not Hawkins or Hawkings) doesn't mean that other people don't respect him and his theories.

    Besides, BHOT wasn't meant as a textbook. Textbooks are useless without equations and mathematics. Books for the common people, as BHOT was, do worse by having equations in them.
  • Quarks: They're the dreams stuff is made of
    Kris "dJOEK" Vandecruys
  • Bull.
    Anything that can be written in mathamatical equations, can be put into words, and that's easily provable.
  • Well let me tell you, in the physics community, no one gives a shit about Hawkins and his books.

    You're a troll, of course, and a bad liar. Black holes are just a part of what Hawking has studied, documented, and explained. But I suppose "you physicists" (yeah, right) just call it Hawking radiation for no good reason, though.

  • Sorry, you're wrong. There is no 2. The guy was right. This equation comes from the fact that e^(i) = cos() + isin(). Therefore, since cos() = -1 and sin() = 0, e^(i) = -1, or restated, e^(i) + 1 = 0.
  • Another ok book on Einstein is Azel's God's Equation []. (Though the equation in that is the Einsten field equation E=8piT, not E=mc^2.)


  • geeze, if I ever had a GF who would steal Brief History, I don't think I'd let her go!

  • a troll? No, I just get aggrevated by cs people acting like they know everything about everything. Yes, Hawking is a important person in the physics world but not that important. He is viewed as more of a fiction writer than anything else. If any of you where physicists, you would know that speculating things from pure theory is usually 99% wrong and take be taken as true. The lack of experiemental data is the reason his views are not held high. Also, for you of those that think all of this can be understood by reading his book, you are just lying to yourself. As I said before, you guys are getting ahead of yourself. It would be like a newbie programmer trying to write a game before he even knows how to us malloc. Hell, I bet most of you can't even work simple gravitational field problems much less the electrodynamics, quantum relativity, and other materials needed to actually piece together possibilities of blackholes. I'm not trying to bash anyone for not being a physics guru but many people talk a lot of shit about blackholes, etc... with no real knowledge about it. It is about as annoying as a linux guru seeing linux being called a company by some tech reporter, etc... You get the point.
  • So I don't know anything about physics because I spelled his name wrong? Give me a break.
  • I'm not snickering. I have taken both Quantum mechanics 1 and Quantum mechanics 2. Have you taken any? I believe I know what math is involved in quantum mechanics and the little alegbra involved, is trival. 99% of quantum mechanics is differentials, and eigenfunctions or hamiltonians.
  • actually, Einstein came up with relativity after noticing the differences between classical mechanics and electro dynamics. Amazily, everything we've known about electro statics, and electro dynamics has been relativistically correct. Einstein noticed this and began to question the classical dynamics which lead him to deduce relativity.
  • If any of you where physicists, ...

    I'm not a Physicist, but I know some, and none of them have expressed anything but reverence for Hawking. Kip Thorne, who I would consider fitting any definition of True Physicist, seems to regard Hawking as a Real Physicist. But I suppose you're going to say Kip Thorne is equally crap? Rai Weiss? Vladimir Braginsky? Eanna Flanagan? I don't know. I've never heard your particular view of it and it's not as if I've never met a physicist or talked about Hawking with a verifiable physicist before. Given that, I'm still inclined to believe you're a troll.

  • For a start, E=mc^2 isn't true in Imperial units; you have to say E=kmc^2, where k is a constant that depends on the units you used for E, m and c.

    For a second, there are so many conversion factors that just because you've seen the conversion factor once doesn't mean that you've automatically memorised it. And that's not even thinking about conversions within Imperial. Quick, off the top of your head: how many chains in a league?

  • Books which can give the public some comprehension of factual matters about various branches of science are a valuable counterforce to the dumbing down of the US population which goes on continuously.

    Just listen to the TV weather readers talking foolishly about "normal" temperatures and rainfall rather than "average". They pick up an attitudinal "should be" mental state and make stupid comments that wouldn't occur if "average" was the term used.

    Few people will have the opportunity to acquire the mathematical tools to work with or even truly understand physics. Some may be incapble of such learning, although I am not convinced that this has been proven.

    In any event, don't denigrate the "fairy tale" books which treat of science. They are of great value to the general public and, if read when one is young enough, might even result in significant career choices in later life.

    I did take appropriate math and quantum mechanics courses a half century ago. Never made my living that way, but I can read books on science at various levels with some critical facility and appreciation.

  • claims that "... Carezani has described an experiment to prove Autodynamics correct and Special Relativity wrong." Ok, this isn't about E=MC^2, but I tried to submit this as a Slashdot question and I guess someone didn't like the idea. Anyway, I consider myself only of slightly above average intelligence, Master of Slack, and definitely of lower intelligence than the collective brain power of Slashdot. Anyway, please will someone read it and tell us where/why Autodynamics is incorrect? or not. "evolution is progress toward the elimination of all limitations."
  • To turn a Coke into pure energy all you have to do is turn every other atom into its antimatter counterpart. Then it will "spontaneously dissasemble" having become ~450 grams of pure energy. A mini_big-bang, if you will. This is more energy than that released by _all_ the nukes we ever used, plus tunguska, plus that meteor that killed the dinosaurs. (Kinetic energy is big; much bigger that the nuke term in this. Matter-antimatter is just biggerer.)
    This is about enough energy to significantly change earth's orbit, let alone dust all life on earth.
    If you could figure out how to rearrange the quarks in matter without disrupting it, and 'flipping' it into antimatter, you could usher in the age of limitless power, at least until humanity converted our entire universe into heat.
  • by Sara Chan (138144) on Friday January 19, 2001 @12:35AM (#499155)
    Not everyone agrees that you need a really high level of math. Richard Feynman, one of greatest physicists ever, had this fairly simple explanation:
    Newton's Second Law, which we have expressed by the equation

    F = d(mv)/dt,

    was stated with the tacit assumption that m is a constant, but we now kinow that this is not true, and that the mass of a body increases with velocity. In Einstein's corrected formula m has the value

    m = m0/sqrt(1 - v^2/c^2),

    where the "rest mass" m0 represents the mass of a body that is not moving and c is the speed of light.... For those who want to learn just enough about it so they can solve problems, that is all there is to the theory of relativity --it just changes Newton's laws by introducing a correction factor to the mass.

    --R. P. Feynman, The Feynmann Lectures On Physics, vol. I, ch. 15 (emphasis added)

    Newton's Second Law is more commonly expressed as F = ma, where a is acceleration: a = d(v)/dt.

  • E=mc2 is only accurate on a subatomic level.

    It is accurate on macroscopic level, too. It's just an effect far too small to notice.

    For instance, because of the energy they store, the batteries of your notebook are in fact heavier when full -- by about 10^-16 kg. So you won't really feel the difference :-)

    In high energy physics (admittedly subatomic), the effect is enormous. By cranking up the energy (read: velocity) of e.g. an electron, we can produce particles like muons which are 200x heavier than electrons. E=mc^2 applied. (Where m is of course the relativistic mass...)
  • Hhhhmmmmm... your opinion or Stephen Hawking's which is better in relation to physics theory?
  • How can this be modded down for being "redundant" when nobody in the 32 posts in front of me made a reference to this M.C. Hawking rap song???

    Please read the moderator's FAQ before moderating, if you don't know how to be an effective moderator, then please opt not to moderate.

  • Sorry, wrong. The character '' is a fully-paid up member of ISO 8859-1 [], the default charset on the Web. You can spell it &sup2; as well. The worst offenders are the "smart quotes" and various dashes.
  • I saved a quote from /. the other day for just such a message as yours: "That was the most over-generalized, "This is what I have seen in my infinitesimal experience of the world, therefore it is true the universe over" statement I have ever seen." (Thanks to DaPhreaker.)

    There are other English-speaking countries than the big four you mentioned. Where I grew up, I remember going to the store for pints of milk when I was about 6. But it all switched to SI shortly after that, milk switched to liters, pounds to kilograms, etc. The only Imperial unit I retained any kind of intuitive appreciation of was the pint. (Comes in handy in bars!)

    I live in the US now and have had to absorb a knowledge of pounds, etc. but when I first came over, I found the units meaningless. Multiplying by a factor in your head is a poor substitute for an intuitive understanding of what a number representing a weight means. I know exactly what Michael JasonSmith means, and would find it similarly annoying to read a book about topics like physics which wasn't in SI units.

    which is that fluency in English includes a basic familiarity with the peculiar units of measurement used in everyday life in the largest English-speaking countries

    I find this a truly astonishing position to take. You might as well say that fluency in English requires a familiarity with the structure of the British aristocracy. Or a familiarity with the vocabulary of Chaucer. WTF???

    Are you sure your position isn't just one of "I had to learn these dumb units so everyone else should do the same"?

  • There was a much publicized flap [] over the use of the word "niggardly" not that long ago. It was a similar situation - a perfectly innocent word that happened to sound similar to "nigger". (We're all grownups, we can say it.)

    The interesting upshot of all this, though, is that when you get right down to it, to be politically correct one has to avoid not just racism, but the appearance of racism. Which means avoiding words like niggle and niggardly, at least in the U.S., is probably a good idea.

    It's a form of social oppression, but that's one of the less onerous consequences of ones ancestors having enslaved people.

  • >Speculating things from pure theory is usually 99% wrong

    Correct me if (as I'm sure I am) wrong, but isnt that the whole thing about theory? You can't be sure what's right or wrong about it.
    Anyway, for the most part people aren't claiming a comprehensive understanding of theoretical astrophysics or quantum mechanics, but Hawkings work is very interesting to those of us without any knowledge of Einsteins field equations or anything like that. Its in laymans terms, and for physics to be taken seriously in the wider world, thats important, surely.
    As for lack of experimental data (and the views not being held high as a result) again, that's why it's called theory.

    You say you're not trying to bash anyone for not being a physics guru, then why do you bring it up? I am willing to bet that people reading these books with no prior knowledge on the matter will come away with at least a few ideas of whats going on in that field of research/thought/whatever. It's not like they're willing to give a lecture on why wormholes in curved space can/cant be used (theoretically) as a form of time travel.
    Sorry, What was the point?
  • &gt The whole thing is more like "E=((mc^2)/(sqrt(1 - (v^2/c^2)))", where v is the velocity of the mass in question.

    And if v &gt c, then the sqrt becomes negative. Doesn't this show that we can't travel faster then light (since it would take an infinite amount of engery) ?
  • Actually, the problems in the US public education system, particularly with regard to the quality of education African Americans are receiving. If they don't know what "niggardly" means, but they know full well what the other word means, what are we teaching our children? To paraphrase the NAACP official fropm your link, someone is being niggardly with their education.

    It also reminds me of another tragedy regarding the story "The Legend of Sleepy Hollow." In the original story, "an old Negro" played a fiddle at the party where the story of the headless horseman is told to Ichabod Crane. In the more politically correct versions of the story this character is "an old man" because it is not thought important to mention his blackness.

    Of course this story is rich in detail and changing even one word changes a lot in the story. In this case, it results in most illustrations of the story, the classic Disney film, and even the recent movie all being devoid of black characters, because there aren't any in the politically correct version of this story. Certainly this is a step in the direction of racial parity!

    In general it is unwise for us to consider the course of treating all African Americans as if they were uneducated buffoons incapable of any more than a third grade vocabulary as a remedy to the prior sins of Indo-European conquest and more specifically the slavery and racism perpetuated in America. And it is not necessary in all circles to assume everyone has suffered the general ignorance which is teh American way of life. It is clear from the story that the mayor, who happens to be of African American descent, knew full well what the word meant. In fact it is even possible that the man who originally lodged the complaint knew what it meant as well, since he had motivation for playing the "race card" (he wanted the white official's job and knew the mayor was taking flak fro not having more blacks in important positions).

    Perpetuating ignoprance helps no one. Only through clearer understanding, the free dissemination of information and a better education of ourselves, beyond improvements in the system through which we educate others, can we even begin to find the methods through which we might solve the problems not only of our own nations and backyards, but of the world as a whole.

  • E = mc^2 is true in Imperial units if you use Imperial units consistently (i.e., for E, m, and c).

    Can you give an example of three Imperial units (one each for E, m, c) for which this is the case? I couldn't think of any.

    For metric, it's true for the most obvious choice: m in kilograms, c in metres per second, E in joules ('cos joules are really kg.m^2.s^-2).

  • In general it is unwise for us to consider the course of treating all African Americans as if they were uneducated buffoons incapable of any more than a third grade vocabulary as a remedy to the prior sins of Indo-European conquest and more specifically the slavery and racism perpetuated in America.


    Perpetuating ignoprance helps no one.

    I agree, in general. However, I think one can reasonably make the argument that the negative connotations associated with the word "nigger" are such that similar words should be avoided, not only in the interests of humoring the less well-educated, but also to avoid any appearance of having deliberately chosen a word that evokes another, more insulting word.

    I'm not a big fan of "political correctness", but I do recognize that it serves a purpose as a kind of mindless set of rules for people who may not be intimately familiar with all the issues in a given situation and able to decide on their own what is and isn't politically appropriate in that situation. I did say that "to be politically correct one has to avoid not just racism, but the appearance of racism", and I think that's true. If one is ignoring political correctness, though, in favor of following one's own conscience, then the logic you've laid out applies.

  • No - they all wrote poetry before I dated them, and I, at the time, was an English tutor, and had no qualms about giving them straight criticism. That might have turned them gay, but I think the human female population is the better for it.

FORTUNE'S FUN FACTS TO KNOW AND TELL: #44 Zebras are colored with dark stripes on a light background.