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In Our Time: Relativity

Thursday 6 June 2013, 17:28

Melvyn Bragg Melvyn Bragg

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Editor's note: In Thursday's programme Melvyn Bragg and his guests discussed Relativity. As always the programme is available to listen to online or to download and keep.

Relativity Relativity

Hello

Well, I got through it. People who know more about physics than I do (most of you) will have realised again and again how thin the ice was on which I was attempting to skate. Nevertheless, once again, those who contributed to the programme were not only a safety net and a cradle, but considerate enough to let me say a few words along the way. Martin Rees said afterwards how difficult it was to do this sort of programme without illustrations. "That's why we kept waving our arms around," he said. He also spoke about the number of letters he gets from people who are very interested in physics who sometimes begin "Even Newton was wrong..." Roger Penrose's letters include those that begin by saying how much they admire his books, but then attempt to explain why he's wrong. As a young man apparently Einstein was very dapper and beautifully dressed in the annus mirabilis of 1905, when he produced four papers while not working inside a university or a scientific community – four papers which changed the understanding of the universe. As an older man, the scruffy and bemused-looking mop top (the model for the first Dr Who?). He could have been a refugee from the Marx Brothers. Both Roger Penrose and the producer, Tom Morris, had personal anecdotes transmitted to them down their respective families that although Einstein loved to play the violin, especially in string quartets, and his name commanded only the best people to play with him, he had one grave fault. He couldn't count.

Ruth Gregory said that four dimensions were nothing like as complicated as we thought they were. When we came across a crowd of people and worked out how to navigate our way through them, we were using four dimensions. Martin said that the reason why Einstein's greater theory lay dormant for about forty years at the beginning of the twentieth century was that there were only very crude ways of testing their veracity. They could only come within 10% of establishing the truth. Now they can come within 1/100,000.

Doing this from the train, on the way to Carlisle, to give a talk about my novel in the town in which I was born. The event is being laid on by Gwenda Matthews, an independent bookseller, valiantly and, I hope, successfully continuing in her increasingly lovely occupation. I think it's 400 independent bookshops that have closed down over the last two or three years.

Tunnel, tunnel, tunnel... back in the light again. When I was at a grammar school I used to go into Carlisle sometimes to traipse around the independent bookshops. There was one second-hand bookshop, dug into the castle wall, which was wonderfully ripe for looting, with an extremely benevolent bookseller practically giving them away. Anyway, good luck to Gwenda Matthews and all who share her determination to stay independent.

It's been a John Ball week - filming a BBC documentary on this extraordinary fourteenth century preacher who helped inspire and amplify what has too long been miscalled the Peasants' Revolt. We've been whirling around Kent and Essex; at a wonderful sheep market in Colchester which has been there since at least the twelfth century, to abbey ruins which again – the abbey, that is – date from the twelfth century. Into Chelmsford for an unusual lunch break (i.e. not a sandwich in a car park), beside a river, and young Chelmsford folk wandering in the sunshine while cricket was being played nearby. In and out of churches beside the Essex Marshes, England past and present delighted by the appearance of the sun and leaping out to lap it up.

Best wishes

Melvyn Bragg

 

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  • rate this
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    Comment number 1.

    I think not enough emphasis was given to the fact that special relativity was a team effort. In fact, according to Max Born, special relativity should not be connected with a single name or with a single date. It was in the air around 1900. "in 1905 Einstein based the theory on very general principles of a philosophical character". As pointed out by Roger Penrose, the theory was given its final form by Minkowski.The other point perhaps not emphasized enough is that Einstein realized that special relativity and gravity were incompatible. Rather than modifying special relativity he made the revolutionary step of getting rid of gravity as a separate force.That was perhaps his single greatest achievement.

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    Comment number 2.

    What a wonderfully interesting programme earlier today with a magnificent panel! I was hooked from start to finish, the time simply flew by but then it is after all only relative.

  • rate this
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    Comment number 3.

    On a different subject (but interesting in its own right) Melvyn Bragg's programme on Tyndale last night was brilliant - clarity of thought and presentation revealed Tyndale's importance to the English language and democracy. Well worth watching.

  • rate this
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    Comment number 4.

    I was struck by how much said about relativity was wrong. Yet again, the twins paradox was wrongly stated on the show. The paradox is one that Einstein admitted contradicted the principle of relativity, which is based on the principle of symmetry between frames: whatever happens to the one twin, motion-wise, must happen to the other, so they end up both being younger than the other: a paradox (indeed, a logical contradiction).

    Key issues are addressed in Guy Burniston Brown's classic 1967 article in the Bulletin of the Institute of Physics, What it Wrong with Relativity (Googlable). It begins "Genuine physicists—that is to say, physicists who make observations and experiments as well as theories—have always felt uneasy about 'relativity'". It goes on to show how Einstein assumed the Newtonian principles, then proceeded to modify them -- an exercise that is fundamentally offensive to the logician. It also myth-busts many things to do with the history of the theory, such as the emergence of E=mc^2, which was plagiarised -- along with Poincare's work outlining the essential principles of SR -- by Einstein, and (at first, wrongly) derived from classical, not relativistic principles (which is how it was derived by DePretto in 1904).

    The article gives some history of the 1919 eclipse experiments. They were obtained by discarding all photographic plates for which deviation from what was the expected - according to relativity - values were discarded. It says "This must be one of the most extraordinary self-deceptions in the whole history of science (see Poor 1930)".

    All the experiments using clocks that purport to confirm relativity, in fact serve to *disprove* it, because they demonstrate that so-called time dilation is objectively recordable, and not purely relative to frame.

    In the above-cited article, Brown says
    'The general theory has been well summed up by Fock: "It is... incorrect to call Einstein's theory of gravitation a 'General theory of relativity' all the more since 'The general principle of relativity' is impossible under any physical condition."'
    He also says, following a critique of the principle of equivalence (which is easily shown to be false),

    'This contact with the physical world having gone we are left in the general theory only with the principle of covariance—that the laws of physics must be expressed in a form independent of the coordinate system, and the mathematical development of this condition which Einstein did with Grossmann and others. Unfortunately, given sufficient ingenuity, almost any law of physics can be expressed in covariant form, so that the principle imposes no necessary restriction on the nature of these laws. The principle is therefore barren, and Einstein had to regard it as merely of heuristic significance (by considering only the simplest laws in accord with it (Einstein 1959, p. 39)). Also the number of problems which can be completely formulated, let alone solved, is extremely small. Some relativists look on it rather as an encumbrance (Fock 1959).'

    Length contraction can be shown to violate thermodynamics, when one imagines a physical coupling between moving bodies, itself in a rest frame, that is so influenced by the changing lengths of bodies that it becomes distorted (though not length-contracted). This requires a force, which is not considered in relativity.

    Points and co-ordinate systems do not move in mathematics. This is one example of how Einstein is,for some inexplicable reason, granted logical licence. Another is the circularity of the idea that velocity causes time dilation, while velocity is distance divided by time.

    Finally, it is also false that the GPS system uses relativity. Ronald R Hatch, former President of the Institute of Satellite Navigation (and member of the Natural Philosophy Alliance, which is highly critical of relativity), has written peer-reviewed papers explaining how both theories of relativity contradict the operations of satellite clocks. The so-called - as by, as I shall explain, a misnomer - 'equations of general relativity' (which weren't, in fact, derived by Einstein - he said he didn't understand them) themselves *are* used, in some context. However, they don't bear much resemblance to the theory itself. For one thing, they incorporate energy, a phenomenon that causes nothing but trouble -- with issues of energy conservation having to be cast aside -- when used in association with theory of relativity. (To call E=m^2 'relativistic' is, as I have already implied, also a misnomer.)

    All in all, I was sorry that this programme was broadcast in the form it took. It is time to move away from the plethora of fallacies that characterise mainstream physics.

  • rate this
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    Comment number 5.

    Rest Assured that ProllyMathic is very much a minority view. To take the case of the twins: it is not a paradox because the situation is not symmetric. One twin has to travel at a certain speed, then turn round, involving accelerations, and come back. He feels these inertial forces, whereas the other twin does not.
    As far as Einstein assuming Newtonian principles, the fact is that it was Newton who assumed (he called it a universal law) that throughout the entire universe, inertial frames of reference move uniformly with respect to each other. That's a big and unwarranted assumption that Einstein aimed to eliminate with General Relativity. Here inertial frames are those where Special Relativity holds. (I assume that even ProllyMathic accepts SR, it has been verified by countless thousands of experiments) . I could go on but I don't have the time.

  • rate this
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    Comment number 6.

    May I ask those of you who understand these things whether the phenomenon of the clock going slower when moving at great speed would equally apply to any piece of clockwork equipment, eg a child's toy train. After all, a clockwork clock is nothing more special than any other piece of clockwork equipment. Or does the phenomenon occur with battery-powered clocks too ? Given that Einstein was coming up with his theories at a time when almost all clocks would have been mechanical, I'm suprised that this question never seems to come up.

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    Comment number 7.

    Tony Chinnery writes



    Geniune physics is not done by a show of hands. (But mainstream theoretical physics is done by a show of cash, as Martin Rees, I think admits -- he - admirably - called for a big discussion, among top minds, on the current crisis in physics.)



    Yes but the Principle of relativity has it that it *should* be symmetric. The motion of one twin is supposedly indistinguishable from the motion of the other, as recorded in the respective frame.



    Apart from my above reply, you obviously didn't read the Guy Burniston Brown article, which deals with this (very easily) a third the way through. You can make the journey sufficiently long that these differences are negligible.

    >

    Same here.

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    Comment number 8.

    In answer to Tony Chinnery: I don't accept SR for one moment. As I have said, it has never been validated, and if you scrutinse the results from the point of view of the supposed reciprocity of relativistic effects between frames, it has always been falsified by experiment (as I imply in my first post).
    Also, your concept of an inertial frame is off the mark. An inertial frame is one that is undergoing natural motion, so it will indeed be accelerating in the Newtonian system (under the influence of gravity).

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    Comment number 9.

    In reply to Billip: the relativists will tell you that all time-keeping devices will be affected; but why they assume this is entirely obscure. They take time to be a physical process, and just assume that all time flows in accordance with rate of atomic resonance. But time, as you seem to have realised, isn't just a physical process; rather, it's metaphysical.

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    Comment number 10.

    ProllyMathic's comments above exhibit a very high degree of tinfoilhattery. He bases his argument on a journal article almost half a century old, written long before a host of observations which agree to a high degree of accuracy with predictions made by SR and ER. He cites the single prominent satellite-navigation expert who disputes the truth of relativity while ignoring the legion who don't - including the theorists and engineers whose relativistic calculations are incorporated into GPS and make it work! His definition of an inertial frame is straightforwardly wrong and displays ignorance of the basics of relativity. I'm slightly amazed that anybody can take such a position and keep a straight face. SR and GR have been thoroughly tested both theoretically and by observation and have yet to be found wanting. PS time is 'metaphysical'??? Ergo so is movement, any type of change or process. If time is metaphysical, science is pointless and I'm a Dutchman.

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    Comment number 11.

    To reply to billip1: clocks do not go more slowly when traveling at speed, but to an observer moving uniformly with respect to you they appear to. Not only clocks but all physical processes. So you do not notice these changes (in any case speed is relative. To you, you are stationary). Its the other guy's measurements that change. In an airplane moving uniformly you cannot tell you are moving, and your clocks go at the normal speed. However, if an observer on the earth could look through a window in the airplane and observe your watch, it would appear to go a tiny bit more slowly than when it was at rest. Not only your watch, but your entire metabolism, if he could only measure it.

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    Comment number 12.

    I was expecting the kind of rant that appeared, from mantuesday . I will address it rant-bit by rant-bit.
    The Brown article's reasoning is no less true than it has ever been. I am concerned with the logic of theory of relativity, and no 'experimental confirmation of a theory' (an oxymoron in many scholars' books) of the theory will change flawed logic.

    Even Roger Penrose said, in the broadcast, that he had found something amiss in SR.

    Incidentally, I always find it interesting the way that professors will come on the TV and begin presenting their documentary by saying that relativity has been confirmed many times over, and end by saying there's something not quite right about it (SR and GR, that is).

    The so-called 'confirmations' have always been a mix of fudging beneath the noise level, misrepresenting the conceptual components of the theory (as with the way the twin paradox has been quietly changed these past few years, so that it no longer looks like a glaring contradiction) and using relativity to prove relativity (see the online article by Marmet & Couture 'Relativistic Deflection of Light Near the Sun etc...' -- the authors show that standard relativistic corrections were never taken out of the co-ordinate data when the results were analysed - hardly surprising there was a relativistic deflection of precisely the predicted magnitude), which is an unacceptable procedure from the point of view of physics, and taking concepts that are casually termed 'relativistic' out of context.

    The 'single satellite-navigation expert', Ron R Hatch, just happened to be the world's greatest knowledge -- or one of such of a tiny handful -- on the subject. There are very large numbers of engineers (including many from NASA), professional mathematicians (note that the Chair of the Natural Philosophy Alliance is the mathematical physicist, Professor Domina Eberle Spencer) and whatnot who reject relativity and just don't get their work published in mainstream journals; Paul Marmet even lost his job as a physics professor for being so bold as to question the accepted 'wisdom'; editors know they'll get rant-like comeback - within the academic community - of precisely the kind mantuesday gives. There was a bit of a liberalisation, however, in the late 1960's and early 70's (eg. check out the online Science at the Crossroads by Professor Sir Herbert Dingle).

    An inertial frame is one in which the motion of the bodies in the frame cannot be detected from the physical condition of those bodies -- i.e., it's in natural motion (freefall). (There is, in fact, no such thing as a perfectly inertial frame, as all bodies undergo tidal forces.) Tell me how I am wrong.

    And it remains absurd to speak of a co-ordinate system (frame of reference) 'moving'. It's not mathematical.

    Yes, I agree movement is metaphysical. Leibniz would agree too. But I don't want to get into that; I was just using 'metaphysical' to distinguish physical process from *gauging* of physical process. Time is the gauge within which physics operates. That makes science pointless?

  • rate this
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    Comment number 13.

    MB's blog note on Einstein's interest in/relationship with clothes is strengthened by a great anecdote in 'From Birdland to Broadway' by jazz bassist Bill Crow, page 124. Have a look on Google Books.

  • rate this
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    Comment number 14.

    In reply billip1 (#6), I would like to emphasise what is said in Tony Chinnery’s reponse (#1)1. All four forces known to physics at the present time behave the same way as far as relativity is concerned. All the ways of measuring time rely on processes governed by those laws and therefore all the ways of measuring time (“clocks”) exhibit time dilation. The human body, including the mind, is governed by the same four forces (at least as far as modern medicine is concerned) and therefore human experience of time also conforms to the time dilation phenomenon. Some people believe in a “soul” which they think continues after death. It is not obvious that the operation of the “soul” depends on (one or more of) the four forces, so the “soul” might be an exception.

    It’s worth noting, I think, that the laws of physics (the four forces) are different for objects that move at different speeds from one another (Einstein worked how they are different for electromagnetism and gravity and the other two forces discovered subsequently behave the same way). So if you start with two clocks at rest with respect each other and then start one of them moving, you can calculate from the laws of physics that apply to the moving clock that it registers less time than the one which remains at rest. Starting with two rods originally at rest, the same applies to the contraction of a rod set moving with respect to the rod remaining at rest.

    It is helpful not to mix up what happens when comparing clocks or rods moving at different speeds to each other (which is the easier case) with the case of two different observers observing the same clock or rod. The latter is more complicated because the different observers are using measuring instruments which behave differently (because the measuring instruments are moving at different speeds). Obviously the different results (in their respective terms) of the two different observers have nothing to do with any change in the (single) object which is being observed. What can cause confusion is that the mathematical expressions relating the different observations of two observers observing a single object are the same as the mathematical expressions relating the different times and lengths of two objects moving with respect to each other. When you think about it, the mathematical relations must be the same because the two different observers get their results from physical objects (measuring instruments) which are moving with respect to each other. Nevertheless, I think that it is important to keep in mind the differences between two objects moving with respect to each other (which are “real” differences) and the differences between the observations of two observers moving with respect to each other (which are due to the different perspectives of the two observers and not a change in the object observed).

  • rate this
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    Comment number 15.

    If ProllyMathic does not accept even SR, I wonder what part of it he is denying. SR is based on the principle of inertia (from Galileo via Newton) and the constant value of the speed of light, both of which have been verified in thousands of experiments. Perhaps for him it is a giant conspiracy. But where would he go back to? The ether theory (light being the vibration of an invisible fluid filling the universe)? What about phlogiston whilst we are at it? Is he perhaps a flat earther?

  • rate this
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    Comment number 16.

    One fascinating topic not covered in the program is the connection between Einstein's work on special relativity, and his work on the photoelectric effect, which earned him the Nobel prize. For his enunciation of the principles on which SR should be based eliminated the ether as a medium for light and made electromagnetic waves different from all other known waves as traveling through empty space. In other words, electromagnetic waves have an independent existence, they do not rely on a vibrating medium. In his 1905 paper on the photoelectric effect he uses the Planck hypothesis to turn these free waves into particles: when a wave packet hits a metal target, the energy instead of being spread out in space as one would expect, is entirely absorbed by just one electron in the metal target. The combination of these two papers created the photon and laid the basis for quantum mechanics.

  • rate this
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    Comment number 17.

    Billip1: Time dilation in moving systems was explained very neatly by Richard Feynman in a thought experiment he invented. In a spacecraft traveling at uniform speed, a clock is synchronized to a beam of light bouncing between two mirrors placed on an axis perpendicular to the direction of motion (so that the distance between them remains invariant). To the people in the spacecraft the light is traveling up and down, and using the number c (the velocity of light) and the distance between the mirrors, they can calibrate their clock. To the people on earth looking at the apparatus through a telescope, the light travels through a zig-zag path, as the mirrors move forward in space with the ship. In other words, the path the light travels is longer than for the people in the ship, and as the speed of light is always the same, the time taken for the light to travel from one mirror to the other is increased. So the ticks of the clock in the spaceship (synchronized to the light hitting a mirror) are further apart in time: in other words, the clock appears to have slowed down to the people on earth. But the important thing to bear in mind is that for the people in the spaceship nothing has changed. Their frame of reference is just as valid as that of the people on earth, as long as the spaceship is not accelerating.

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    Comment number 18.

    There is little point in arguing with a crank, since they will always have the last word. The organisation ProllyMathic is so keen on, the Natural Philosophy Alliance, last year gave a lifetime achievement award to a man who claims to be able to extract energy 'from the vacuum'. This is the 21st-century version of the perpetual motion machine - pseudoscientific mumbo-jumbo, in other words.

  • rate this
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    Comment number 19.

    In reply to Tony Chinnery (#15):

    As I have repeatedly said, the principle of symmetry between frames is easily shown to be flawed. See the online Burniston Brown article, 1/3rd the way through; or Science at the CrossRoads by Dingle, a link to which is at the top of the article [BTW you click on the blue bit of Russian to get to the chapters, and you have to scroll through some more Russian to get to the English-language chapter headings]. Dingle (who used to write the entries on relativity for the Encyclopaedia Brittanica) says

    "It is ironical that, in the very field in which Science has claimed superiority to Theology, for example - in the abandoning of dogma and the granting of absolute freedom to criticism - the positions are now reversed. Science will not tolerate criticism of special relativity, while Theology talks freely about the death of God, religionless Christianity, and so on."

    Ether theory is undergoing a resurgence of interest (though I don't myself, subscribe to any conventional notion of an ether - not a physical one, anyway). (So are steady-state type theories, BTW, as big bang theory is every bit as flawed as relativity, and cosmologists know it.) Some proponents question the validity of the Michelson-Morley results, and others conceive ether in such a way that it doesn't contradict the M-M experiment. The satellite expert Ron R Hatch has his own 'Modified Lorentz Ether Theory', and (as I recall) uses a sun-based GPS frame. If you are asking what ideas I would develop to form a picture of nature, it's not these, but the metaphysics of Kant and various others.

    In your the 'constant value of the speed of light' you omit to append the crucial SR qualification 'with respect to the observer'. The (online) work of Bryan G. Wallace (as well as simple logic, BTW) shows that you are wrong about this. Further, the Shapiro effect is well-known for demonstrating how the claims about the speed of light as made in GR are inconsistent with the claims about the speed of light as made in SR.

    Also, particles have been accelerated to 99.99... etc. % of the speed of light with no sign of becoming hugely massive (and certainly not approaching infinite mass), so the signs are very much - and this is widely acknowledged - that the mass transformation of SR does not hold.


    To mantuesday (#18):


    Well I don't responded to name-callers, as they always get the most ludicrous word, if not the last one. But, as for the NPA award, extracting energy from the vacuum is an old one. It's well-known, even by mainstream physicists, that if you put any two plates close together in a vacuum, you get a potential between them. Pseudoscientific?

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    Comment number 20.

    One further thing -- proponents of SR never seem to realise that physics doesn't deal in illusions.

 

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