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Thread: The origins of this idea.......

  1. #1 The origins of this idea....... 
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    Ernest Rutherford is reputed to have stated that the idea of using nuclear reaction to generate useful power was "moonshine".

    His exact quote was:

    "The energy produced by the atom is a very poor kind of thing. Anyone who expects a source of power from the transformation of these atoms is talking moonshine."

    LOL - Poor Ernest!

    Hey, as for what I mean by, 'the origins of this idea' - - does anyone know who came up with the idea that atoms could be a tremendous source of energy? And why did they think that?

    It's strange how someone as bright as Rutherford could be so opposed to the ideas of another apparently bright physicist.

    When you consider the disagreement, it just shows how highly ambiguous and theoretical physics was back in the 30's.


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  3. #2 Re: The origins of this idea....... 
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    Quote Originally Posted by remit
    Ernest Rutherford is reputed to have stated that the idea of using nuclear reaction to generate useful power was "moonshine".

    His exact quote was:

    "The energy produced by the atom is a very poor kind of thing. Anyone who expects a source of power from the transformation of these atoms is talking moonshine."

    LOL - Poor Ernest!

    Hey, as for what I mean by, 'the origins of this idea' - - does anyone know who came up with the idea that atoms could be a tremendous source of energy? And why did they think that?

    It's strange how someone as bright as Rutherford could be so opposed to the ideas of another apparently bright physicist.

    When you consider the disagreement, it just shows how highly ambiguous and theoretical physics was back in the 30's.


    In answer to YOUR question it was Albert Einstein who proposed the idea what E=MC^2. So HE was the one who proposed initially that from a small amount of mass you could get a lrage amount of energy.


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    to make it even more clear
    he did not directly propose the idea of e=mc² but the special relativity theory in wich the e=mc² formula can be derived
    I am zelos. Destroyer of planets, exterminator of life, conquerer of worlds. I have come to rule this uiniverse. And there is nothing u pathetic biengs can do to stop me

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  5. #4  
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    Quote Originally Posted by Zelos
    to make it even more clear
    he did not directly propose the idea of e=mc² but the special relativity theory in wich the e=mc² formula can be derived
    Oh yes he did, Zelos, explicitly, in 1905. As to the OP's question "why did he think that {atoms could be a tremendous source of energy}?", Einstein himself didn't think the bit in parentheses. That realization apparently had to wait till the 1930's (I'm quoting A. Pais's excellent biography of Einstein)
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    Listen to the words of the great man himself, and Zealos pay attention, mass is not energy and enregy is not mass, they are equivalent but NOT identical.


    http://www.aip.org/history/einstein/voice1.htm
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    there is no a in my name
    mega if the equation says E=M then mass and energy is the same, right? i´ll tell you my point after youve answered
    I am zelos. Destroyer of planets, exterminator of life, conquerer of worlds. I have come to rule this uiniverse. And there is nothing u pathetic biengs can do to stop me

    On the eighth day Zelos said: 'Let there be darkness,' and the light was never again seen.

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  8. #7  
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    Quote Originally Posted by Zelos
    there is no a in my name
    mega if the equation says E=M then mass and energy is the same, right? i´ll tell you my point after youve answered
    But the equation does not say E=M.

    It says E=MC^2.
    The hand of time rested on the half-hour mark, and all along that old front line of the English there came a whistling and a crying. The men of the first wave climbed up the parapets, in tumult, darkness, and the presence of death, and having done with all pleasant things, advanced across No Man's Land to begin the Battle of the Somme. - Poet John Masefield.

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  9. #8  
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    As I'm bored, I'll see if I can remember how the derivation goes, but I'm flying a bit blind here.

    Suppose (says Einstein) there is some massive body B that emits a certain quantity of light L for some fixed period of time t. Then tL is the energy withdrawn from B during this period. Let the energy of B before emission = E<sub>initial</sub>, and after emission E<sub>final</sub>, and set E<sub>initial</sub> - E<sub>final</sub> = δE. Then δE = tL (this should of course be big delta, but I can't do that here.

    Now compare this with the case of B' moving with uniform velocity relative to B. We will have δE' = t'L.

    Recall that t' = t(1 - (v/c)<sup>2</sup>)<sup>-1/2</sup>. Lets call that ß for now.

    So δE' = ßtL and, independent of the time of emission, δE' - δE = ßL - L = L(ß - 1). Expanding (1 - (v/c)<sup>2</sup>)<sup>-1/2</sup> as a power series and ignoring terms in (v/c) of fourth order and higher, yields 1 + ½(v/c)<sup>2</sup>. So one has

    δE' - δE = L(1 + ½(v/c)<sup>2</sup> -1) = L(½(v/c)<sup>2</sup>) = ½(L/c<sup>2</sup>)v<sup>2</sup>

    Note, says Einstein, that the equation above refers to the difference between the light energy withdrawn from a body in motion and that withdrawn from the same body at rest.

    But, says he, in general the energy differential between a body in motion and the same body at rest is its kinetic energy KE = ½mv<sup>2</sup>, so that δE' - δE can differ from KE only by an irrelevant additive constant, so ½(L/c<sup>2</sup>)v<sup>2</sup> = ½mv<sup>2</sup> ==> L/c<sup>2</sup> = m, and L = mc<sup>2</sup>.

    But L is light energy by supposition, hence E = mc<sup>2</sup>

    Um, I wonder if I got that right. Any thoughts?
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