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.
Article by: J J O'Connor and
E F Robertson