Search This Blog

Sunday, 11 March 2012

The Einstein Misconception

A few months ago I submitted a “Mythconception” to Fortean Times concerning what I described at the time as “a very tenacious myth about Einstein”. After much conferring, they decided it was too abstruse and too open to debate to go into the magazine. They were probably right -- but I still think my original point was valid, so I’m going to inflict it on the world anyway.

As I originally stated it, the Mythconception concerns “the idea that Einstein’s 1905 theory of relativity, with its famous equation E = mc2, laid the theoretical groundwork for the atomic bomb -- which, the myth claims, works by converting small quantities of matter (atoms) into large quantities of energy. This view is repeated ad nauseam by the media, but it’s wrong. There is no annihilation of matter in a nuclear weapon, only the release of nuclear binding energy.”

To be even more pedantic, E = mc2 doesn’t describe the conversion of one thing into another, but the absolute equivalence of energy and mass... with c2 as the constant of proportionality. A cannonball may have a mass of 10 kg when it’s sitting in the cannon, but when it’s flying through the air it has a very slightly greater mass due to its additional kinetic energy. This extra energy/mass came from the chemical binding energy released by the exploding gunpowder. If you could collect all the combustion products together again, their combined mass would be just slightly less than that of the original gunpowder.

So even a mediaeval cannon obeys E = mc2 -- you don’t need an atom bomb! You might argue that a nuclear weapon is qualitatively different from a cannon, but it isn’t really. There’s a quantitative difference, in that the “slight” changes in mass in the case of a cannon are so slight as to be immeasurable, whereas they’re appreciably bigger in the nuclear case. But they’re still very small. The difference is that the energy released in this case is nuclear binding energy, not chemical binding energy.

The basic nuclear reaction involves the fission of an unstable heavy nucleus (such as Uranium 235) into lighter nuclei. This is commonly described as “splitting the atom”, which is accurate, and “annihilation of the atom”, which is journalistic bollocks. Nothing is annihilated. The fission products have just as many nucleons (protons and neutrons) as there were to start with. But because they’re stable, they have less binding energy -- hence less total mass. That missing energy/mass went into the X megatons of explosive energy.

The archetypal Cold War weapon was a “thermonuclear” device that produced additional energy from the fusion of heavy hydrogen into helium. Again, the number of nucleons remains the same, and the energy released comes from binding energy. If people want to say that matter is “destroyed” in a fission reaction, then they might as well say it is “created” in a fusion reaction!

I know I’m being pedantic -- it all comes down to what you mean by “matter”. I’m using the term to mean “nucleons”... and what I’m saying is that nucleons are neither created or destroyed in a nuclear reaction. But if by “matter” you mean the rest-mass of a macroscopic chunk of matter, then a measurable part of that comes from the nuclear binding energy, some of which is lost (in both fission and fusion reactions). But—coming back to Einstein—that’s a consequence of quantum theory, not the theory of relativity! E = mc2 merely describes one effect of the nuclear reaction, not its ultimate cause.

When you get down below the scale of nucleons, things get even more blurred. Protons and neutrons are made up of three quarks each, but if you could separate the quarks out they’d hardly have any mass at all -- most of the mass you’re aware of in the real world is the binding energy holding the quarks together!

4 comments:

julianpenrod said...

I have mentioned this in blogs repeatedly for awhile now. One of, frankly, the many inconsistencies of "special relativity". This may create great antipathy among those who follow the unconventional, but the people at Fortean Times were either too limited academically or even intellectually to correctly appraise your statements, but unwilling to admit it, or too much a part of the New World Order that insists on foisting things like "special relativity" on the public. Either way, they seem unlikely to voice any kind of questioning about it. Of course, you could give them the benefit of the doubt that that being a conventional science issue, not a matter of the anomalous. But, if they didn't mention that in their reply, it can be considered at best unlikely.
In fact, yes, when atoms "split", the energy released is the binding energy. It is represented after the fact as "the difference in the mass of the nucleus and the released particles", but there does not seem ever to have been an assay performed to compare the teo amounts. And few question how the binding energy could express itself as energy and yet also represent an "equivalent mass".
But that's only one aspect of it. In fact, "relativistic mass" is a myth. If you follow the derivation of "relativistic kinetic energy", and understand things, you will see the fault. In one derivation, integrating from the "relativistic momentum" to the kinetic energy, you see the gamma factor, which includes the square of light, initially used to tranform time into relativistic time divorced from the velocity term and married artificially and illegitimately to the mass term! A separate derivation includes the m0c^2 value as an artifact of converting the gamma term into an infinite algebraic series. In that sense, the m0c^2 acts only as a reference value, a number which, if subtracted, leaves the supposed observable kinetic energy. In that way, then, it's canonical, but not an actual manifestation.
But all of "special relativity" is fraudulent in the extreme, in terms of derivation. Among other things, "special relativity", unlike other disciplines, cannot analyze all situations from fundamental tenets. Supposed you have a platform with a light emitter aimed at a receiver, the two of them a distance l apart, both set to speak to leave a trail on a paper tape sitting unmoving next to the platform. And assume the platform is in movement at speed v. When light is emitted from one receiver to the other, how far apart will the sparks be on the paper tape? "Special relativity" does not answer that directly. You have to derive the transforms, which come from only one special set of experiments, and then require that you believe they apply to all ciscumstances, then apply them.
In fact, the very derivation of the fundamental rule of "special relativity", that thge speed of light is the same with respect to all observers, shows flaws. Invoking only the Michelson-Morley Experiment, which, itself has been shown to display seasonal variations in the speed of light as the earth supposedly moves in different directions throught the aether, the idea of the constancy of the observed speed of light comes from a misperception. The "speed of light" is also the value derived when you take the inverse of the square root of the product of the electrostatic permittivity of the vacuum and the magnetic pemeability of the vacuum. If, somehjow, deep within the structure of an experiment, the measurement of those two constants in involved, you would get the same value even if the actual movement of light varied with respect to you.

Andrew said...

Thanks for the detailed comment. I think you're being too hard on Fortean Times - their point was essentially that Relativity is a can of worms, and it would be invidious and confusing to mention just one aspect in a small column like Mythconceptions. And the various points you go on to make prove just what a can of worms Relativity really is!

alanborky said...

Andrew I suggest a better image for making your point is the simple bullet.

No matter how hard I throw a bullet at you the most I'm likely to do is bruise you.

So if I were to place that bullet on your brow while you're sleeping nothing'd happen of course - unless I were to place a ten ton weight atop it.

But since I can't lift a ten ton weight it'd be more convenient to convert the bullet itself to a ten ton weight by imparting the energetic equivalent of ten tons into it - which is of course what we're doing when we use explosives to launch projectiles.

That's all we're doing when we set off say a handgrenade: inputting energy and accelerating time - only in a highly chaotic way.

My own particular beef with E = mc2 is it depends on squaring the speed of light when Einstein's quite adamant c can't be exceeded.

In fact I suggest E = mc (even without the squared) implies matter (m) travelling at the speed of light (c) behaves like or becomes energy (E).

Andrew said...

Interesting points - thanks.