Ludwig Boltzmann
Born:
20 Feb 1844 in Vienna, Austria
Died: 5 Oct 1906 in Duino (near Trieste), Austria (now Italy)
Ludwig Boltzmann's father was a taxation official. Boltzmann was awarded
a doctorate from the University of Vienna in 1866 for a thesis on the kinetic
theory of gases supervised by Josef Stefan. After obtaining his doctorate, he
became an assistant to his teacher Josef Stefan.Boltzmann taught at Graz,
moved to Heidelberg and then to Berlin. In these places he studied under Bunsen,
Kirchhoff and Helmholtz.
In 1869 Boltzmann was appointed to a chair of theoretical
physics at Graz. He held this post for four years then, in 1873, he accepted the
chair of mathematics at Vienna. He did not stay very long in any place and after
three years he was back in Graz, this time in the chair of experimental physics.
Boltzmann, at least half jokingly, used to say that the reason he moved around
so much was that he was born during the dying hours of a Mardi Gras ball. It was
only half joking since he did feel that his nature made him subject to rapid swings
between happiness and sadness. His personality certainly had a major impact on
the direction that his career took and personal relationships, where he was always
very soft-hearted, played a big part. He suffered from an alternation of depressed
moods with elevated, expansive or irritable moods. Indeed his physical appearance,
being short and stout with curly hair, seemed to fit his personality. His fiancée
called him her "sweet fat darling".
After another three years, in 1894, Boltzmann
moved back to Vienna, this time to the chair of theoretical physics which became
vacant on the death of his teacher Josef Stefan. However, the following year Ernst
Mach was appointed to the chair of history and philosophy of science at Vienna.
Boltzmann had many scientific opponents but, to Boltzmann, Mach was more than
a scientific opponent as the two were on bad personal terms.
In 1900, because
of his dislike of working with Mach, Boltzmann moved to Leipzig but here he became
a colleague of his strongest scientific opponent Wilhelm Ostwald. Despite their
scientific differences Boltzmann and Ostwald were on good personal terms. Despite
this, depressed by scientific arguments with Ostwald which are described below
Boltzmann unsuccessfully attempted suicide during his time in Leipzig.
In 1901
Mach retired from Vienna due to ill health, and because of this Boltzmann's reason
for moving from Vienna had gone. In 1902 he returned to Vienna to his chair of
theoretical physics which had not been filled in the intervening period. In addition
to his teaching in mathematical physics, Boltzmann was given Mach's philosophy
course to teach. His philosophy lectures quickly became famous with the audience
soon being too large for the biggest lecture hall available. In fact because of
the fame of these lectures Boltzmann was invited to the Palace of Franz Josef.
Boltzmann's fame is based on his invention of statistical mechanics. This
he did independently of Willard Gibbs. Their theories connected the properties
and behaviour of atoms and molecules with the large scale properties and behaviour
of the substances of which they were the building blocks.
Boltzmann obtained
the Maxwell-Boltzmann distribution in 1871, namely the average energy of motion
of a molecule is the same for each direction. He was one of the first to recognise
the importance of Maxwell's electromagnetic theory.
In 1884 the work of Josef
Stefan was developed by Boltzmann who showed how Josef Stefan's empirical T4
law for black body radiation, formulated in 1879, could be derived from the principles
of thermodynamics.
Boltzmann worked on statistical mechanics using probability to describe how
the properties of atoms determine the properties of matter. In particular his
work relates to the Second Law of Thermodynamics which he derived from the principles
of mechanics in the 1890s.
The equations of Newtonian mechanics are reversible
in time and Poincaré proved that if a mechanical system is in a given state it
will return infinitely often to a state arbitrarily close to the given one. Zermelo
deduced that the Second Law of Thermodynamics is impossible in a mechanical system.
Boltzmann asserted that entropy increases almost always, rather than always. However
he believed that Poincaré's result, although correct in theory, was in practice
impossible to observe since the time before a system returns to near its original
state was too long.
Boltzmann's ideas were not accepted by many scientists.
In 1895, at a scientific meeting in Lübeck, Wilhelm Ostwald presented a paper
in which he stated:-
The actual irreversibility of natural phenomena
thus proves the existence of processes that cannot be described by mechanical
equations, and with this the verdict on scientific materialism is settled.
Sommerfeld, who was at the meeting, described the resulting battle
between Ostwald and Boltzmann. Sommerfeld wrote:-
... Boltzmann
was seconded by Felix Klein. The battle between Boltzmann and Ostwald resembled
the battle of the bull with the supple fighter. However, this time the bull was
victorious ... . The arguments of Boltzmann carried the day. We, the young mathematicians
of that time, were all on the side of Boltzmann ... .
Ostwald
led the opposition to Boltzmann's ideas which were opposed by many European scientists,
they misunderstood them, not fully grasping the statistical nature of his reasoning.
However some, including Mach, thought the arguments were too violent, and this
certainly appeared to be the case when Boltzmann attempted suicide while a colleague
of Ostwald.
In 1904 Boltzmann visited the World's Fair in St Louis, USA. He
lectured on applied mathematics and then went on to visit Berkeley and Stanford.
Unfortunately he failed to realise that the new discoveries concerning radiation
that he learnt about on this visit were about to prove his theories correct.
Boltzmann
continued to defend his belief in atomic structure and in a 1905 publication Populäre
Schriften he tried to explain how the physical world could be described by
differential equations which
represented the macroscopic view without representing the underlying atomic structure.
:-
May I be excused for saying with banality that the forest hides
the trees for those who think that they disengage themselves from atomistics by
the consideration of differential equations.
Attacks on his work
continued and he began to feel that his life's work was about to collapse despite
his defence of his theories. Depressed and in bad health, Boltzmann committed
suicide just before experiment verified his work.
On holiday with his wife
and daughter at the Bay of Duino near Trieste, he hanged himself while his wife
and daughter were swimming. However the cause of his suicide may have been wrongly
attributed to the lack of acceptance of his ideas. We will never know the real
cause which may have been the result of mental illness causing his depression.
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