More on Trotsky on nukes....

Les Schaffer schaffer at
Fri Feb 7 19:12:22 MST 2003

1926 was too early in the development of nuclear physics for Trotsky
to be doing any more than following the speculative lead of the time:
that the fantastic energies involved in an E=mc^2 could __somehow__ be

the trick was to find mechanisms whereby the transformation from
matter to energy could occur. this is why calculating the equivalent
energy of a drop of water is fairly spurious, that awe inspiring.

i was impressed tho with trotsky's speech, he had a good feel for the
physics of the time and its odd mix of theory, experiment, and
interpretation. and what a time it was: 1926 marks the great leap
forward (by Heisenberg and others) to a quantum __mechanics__.

from Abraham Pais' "Inward Bound: of matter and forces in the physical
world", Chapter 6, "Radioactivity's three early puzzles",

   Radioactivity was doscovered in 1896, the atomic nucleus in
   1911. Thus even the simplest qualitative statements --
   radioactivity is a nuclear phenomenon -- could not be made until
   fifteen years after radioactivity was first observed. The
   connection between nuclear binding energy and nuclear stability was
   not made until 1920. Thus some twenty-five years would pass before
   one could understand why some, and only some, elements are
   radioactive. The concept of decay probability was not properly
   formulated until 1927. UNtil that time, it had to remain a mystery
   why radioactive substances have a characteristic lifetime. Clearly
   then, radioactive phenomena had to be a cause of considerable
   bafflement during the early decades following their first


   With the help of Einstein's discovery of the mass-energy
   equivalence some of the questions related to the origins of
   radioactive energy release could have been answered, at least in
   principle. However, as a matter of historical fact this did not
   come to pass in the period under discussion. There appear to be
   three reasons for this: 1.) The precepts of relativity were
   assimilated rather slowly. 2.) The level of accuracy of mass
   measurements was not adequate during this period. Thus in his 1921
   review of relativity theory, Pauli noted that 'perhaps the theorem
   of the equivalence of mass and energy can be checked __at some
   future date__ by observations on the stability of nuclei'. 3.) The
   lifetime question had to remain unresolved until the advent of
   quantum mechanics, when it was possible for the first time to
   understand the mechanisms of radioactive decay. ...

David quoting Eddington:

> "The main store of energy in a star cannot be used for radiation
> unless the matter composing the star is being annihilated."

or some fraction of the matter annihilated...

> "It has, for example been objected that the temperature of the stars
> is not great enough for the transmutation of hydrogen into helium --
> so ruling out one source of energy. But helium exists, and it is not
> much use for the critic to urge that the stars are not hot enough
> for its formation unless he is prepared to show us a hotter place.'

measured/observed surface temperature of the surface of the Sun (its
"photosphere":                    approx 6000 degrees K

infered temperature of its core:  approx 16 million degrees K

time for released energy (photon)
 to travel from core to surface:  approx a few hundred thousand years

that last number tells you that the sun is optically dense and why one
couldnt observe interior Sun's temperatures without gudance from

the mechanism for release of fission energy wasnt really worked out
till the late '30s, primarily by Lise Meitner and colleagues. it came
upon Lise one evening while walking in the snow that if one could
strike a uranium nucleus sufficiently hard, its nuclear core would
start to undulate with increasing instability until the point when it
tore itself apart into two pieces or fairly equal positive charge --
much like a drop of water which wobbles and breaks apart when
struck. at that point the intense repulsion of the electric field
would accelerate the two broken pieces apart at such a rate that by
the time they were widely seperated, they contained enormous kinetic
energy of motion.

the amount seemed so incomprehenively high that Meitner returned to
her house and worked out the E=mc^2 thing __as a check of the
calculation__. it worked extremely well and she published the result
soon after on Jan 16, 1939.

tho its rarely acknowledged in either popular or textbook physics,
Einstein's mass-energy theorem was used as a check on a theory -- a
theory almost classical in nature -- and not, as often believed, that
Einstein's theory lead directly somehow to understanding of mechanism
of nuclear energy release.

it should be clear then that at the time Trotsky spoke, scientists
were only just beginnning to understand the possibilities of "nuclear
energy" at even the fundamental level.

les schaffer

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