Max Planck (April 23, 1858 –
October 4, 1947) was a German
physicist. He is considered to be the
founder of the
quantum theory, and
thus one of the most important physicists of the twentieth century.
Planck was awarded the
Nobel
Prize in Physics in 1918.
Biography
Planck came from a traditional, intellectual family.
His paternal
great-grandfather and grandfather were both theology professors in
Göttingen
, his father was a law professor
in Kiel
and Munich
, and his pater uncle was a
judge.
Max Planck's signature at ten years of
age.
Planck was
born in Kiel
, Holstein, to Johann Julius Wilhelm Planck and his
second wife, Emma Patzig. He was baptised with the name of
Karl Ernst Ludwig Marx Planck; of his given names,
Marx (a now obsolete variant of
Markus or maybe
simply an error for
Max, which is actually short for
Maximilian) was indicated as the
primary name. However,
by the age of ten he signed with the name
Max and used
this for the rest of his life.
He was the sixth child in the family, though two of his siblings
were from his father's first marriage.
Among his earliest
memories was the marching of Prussian
and Austrian
troops into
Kiel during the Danish-Prussian
war of 1864. In 1867 the family moved to Munich
, and Planck
enrolled in the Maximilians gymnasium school, where he came under the
tutelage of Hermann Müller, a
mathematician who took an interest in
the youth, and taught him astronomy and
mechanics as well as mathematics.
It was from Müller that Planck first learned the principle of
conservation of energy. Planck graduated early, at age 17. This is
how Planck first came in contact with the field of physics.
Planck was gifted when it came to
music. He
took singing lessons and played
piano,
organ and
cello,
and composed
songs and
operas. However, instead of music he chose to study
physics.
Planck as a young man, 1878
The Munich physics professor
Philipp
von Jolly advised Planck against going into physics, saying,
"in this field, almost everything is already discovered, and all
that remains is to fill a few holes."
Planck replied that he
did not wish to discover new things, only to understand the known
fundamentals of the field, and began his studies in 1874 at the
University of
Munich
. Under Jolly's supervision, Planck performed
the only experiments of his scientific career, studying the
diffusion of
hydrogen through heated
platinum, but transferred to
theoretical physics.
In 1877 he
went to Berlin
for a year of study with physicists Hermann von Helmholtz and Gustav Kirchhoff and the mathematician
Karl Weierstrass. He wrote
that Helmholtz was never quite prepared, spoke slowly,
miscalculated endlessly, and bored his listeners, while Kirchhoff
spoke in carefully prepared lectures which were dry and monotonous.
He soon became close friends with Helmholtz. While there he
undertook a program of mostly self-study of
Clausius's writings, which led him to choose
heat theory as his field.
In October 1878 Planck passed his qualifying exams and in February
1879 defended his dissertation,
Über den zweiten Hauptsatz der
mechanischen Wärmetheorie (
On the second fundamental
theorem of the mechanical theory of
heat). He briefly taught mathematics and physics at his
former school in Munich.
In June 1880 he presented his
habilitation thesis,
Gleichgewichtszustände
isotroper Körper in verschiedenen Temperaturen
(
Equilibrium states of isotropic bodies at different
temperatures).
Academic career
With the completion of his habilitation thesis, Planck became an
unpaid private lecturer in Munich, waiting until he was offered an
academic position. Although he was initially ignored by the
academic community, he furthered his work on the field of
heat theory and discovered one after another
the same
thermodynamic formalism as
Gibbs without realizing it.
Clausius's ideas on
entropy occupied a
central role in his work.
In April
1885 the University of
Kiel appointed Planck as associate professor of theoretical physics. Further work
on entropy and its treatment, especially as applied in
physical chemistry, followed. He proposed
a thermodynamic basis for
Svante
Arrhenius's theory of
electrolytic
dissociation.
Within four years he was named the successor to Kirchhoff's
position at the University of Berlin — presumably thanks to
Helmholtz's intercession — and by 1892 became a full professor.
In 1907
Planck was offered Boltzmann's
position in Vienna
, but turned
it down to stay in Berlin. During 1909, as University of Berlin
professor, eight of his lectures were used by the Ernest Kempton
Adams Fund for Physical Research in Theoretical Physics at Columbia University in New York City
for a series of lectures translated by Columbia
University professor A. P. Wills. He retired from Berlin on
January 10, 1926, and was succeeded by
Erwin Schrödinger.
Family
In March 1887 Planck married Marie Merck (1861-1909), sister of a
school fellow, and moved with her into a sublet apartment in Kiel.
They had four children: Karl (1888-1916), the twins Emma
(1889-1919) and Grete (1889-1917), and
Erwin (1893-1945).
After the appointment to Berlin, the Planck family lived in a villa
in Berlin-Grunewald, Wangenheimstraße 21. Several other professors
of Berlin University lived nearby, among them theologian
Adolf von Harnack, who became a close
friend of Planck. Soon the Planck home became a social and cultural
centre. Numerous well-known scientists, such as
Albert Einstein,
Otto
Hahn and
Lise Meitner were frequent
visitors. The tradition of jointly performing music had already
been established in the home of
Helmholtz.
After several happy years the Planck family was struck by a series
of disasters. In July 1909 Marie Planck died, possibly from
tuberculosis. In March 1911 Planck
married his second wife, Marga von Hoesslin (1882-1948); in
December his third son Hermann was born.
During
the First World War Planck's second
son Erwin was taken prisoner by the French in 1914, while his
oldest son Karl was killed in action at Verdun
. Grete died in 1917 while giving birth to
her first child. Her sister died the same way two years later,
after having married Grete's widower. Both granddaughters survived
and were named after their mothers. Planck endured these losses
stoically.
In January 1945,
Erwin, to whom he had
been particularly close, was sentenced to death by the
Nazi Volksgerichtshof because of his
participation in the
failed attempt to
assassinate Hitler in July 1944. Erwin was executed on 23
January 1945.
- Wives: Marie Merck (m. 1887), Marga von Hoesslin (m. 1910)
- Children: Karl (1888-1916), twins Emma (1889-1919) and Grete
(1889-1917), Erwin (1893-1945), Hermann
(b. 1911)
Professor at Berlin University
In Berlin, Planck joined the local Physical Society. He later wrote
about this time: "In those days I was essentially the only
theoretical physicist there, whence things were not so easy for me,
because I started mentioning entropy, but this was not quite
fashionable, since it was regarded as a mathematical spook". Thanks
to his initiative, the various local Physical Societies of Germany
merged in 1898 to form the German Physical Society (
Deutsche Physikalische
Gesellschaft, DPG); from 1905 to 1909 Planck was the
president.
Planck started a six-semester course of lectures on theoretical
physics, "dry, somewhat impersonal" according to
Lise Meitner, "using no notes, never making
mistakes, never faltering; the best lecturer I ever heard"
according to an English participant,
James R. Partington, who continues: "There were
always many standing around the room. As the lecture-room was well
heated and rather close, some of the listeners would from time to
time drop to the floor, but this did not disturb the lecture".
Planck did not establish an actual "school"; the number of his
graduate students was only about 20, among them:
- 1897 Max Abraham (1875 - 1922)
- 1904 Moritz Schlick (1882 -
1936)
- 1906 Walther Meißner (1882
- 1974)
- 1906 Max von Laue (1879 -
1960)
- 1907 Fritz Reiche (1883 -
1960)
- 1912 Walter Schottky (1886 -
1976)
- 1914 Walther Bothe (1891 -
1957)
Black-body radiation
In 1894 Planck turned his attention to the problem of
black-body radiation. He had been commissioned by
electric companies to create maximum light from
lightbulbs with minimum energy. The problem had
been stated by Kirchhoff in 1859: how does the intensity of the
electromagnetic radiation emitted by a
black
body (a perfect absorber, also known as a cavity radiator)
depend on the
frequency of the radiation
(e.g., the color of the light) and the temperature of the body? The
question had been explored experimentally, but no theoretical
treatment agreed with experimental values.
Wilhelm Wien proposed
Wien's law, which correctly predicted the
behaviour at high frequencies, but failed at low frequencies. The
Rayleigh-Jeans law, another
approach to the problem, created what was later known as the
"
ultraviolet catastrophe",
but contrary to many textbooks this was not a motivation for
Planck.
Planck's first proposed solution to the problem in 1899 followed
from what Planck called the "principle of elementary disorder",
which allowed him to derive
Wien's law
from a number of assumptions about the entropy of an ideal
oscillator, creating what was referred-to as the
Wien-Planck law. Soon it was found that
experimental evidence did not confirm the new law at all, to
Planck's frustration. Planck revised his approach, deriving the
first version of the famous
Planck black-body radiation
law, which described the experimentally observed black-body
spectrum well. It was first proposed in a meeting of the DPG on
October 19, 1900 and published in 1901. This first derivation did
not include energy quantisation, and did not use
statistical mechanics, to which he
held an aversion. In November 1900, Planck revised this first
approach, relying on
Boltzmann's
statistical interpretation of the
second law of thermodynamics as
a way of gaining a more fundamental understanding of the principles
behind his radiation law. As Planck was deeply suspicious of the
philosophical and physical implications of such an interpretation
of Boltzmann's approach, his recourse to them was, as he later put
it, "an act of despair ... I was ready to sacrifice any of my
previous convictions about physics."
The central assumption behind his new derivation, presented to the
DPG on 14 December 1900, was the supposition, now known as the
Planck postulate, that
electromagnetic energy could be emitted only in
quantized form, in other words, the
energy could only be a multiple of an elementary unit E = h \nu,
where h is
Planck's constant, also
known as Planck's action quantum (introduced already in 1899), and
\nu is the frequency of the radiation.
At first Planck considered that quantisation was only "a purely
formal assumption ... actually I did not think much about it...";
nowadays this assumption, incompatible with
classical physics, is regarded as the
birth of
quantum physics and the
greatest intellectual accomplishment of Planck's career (
Ludwig Boltzmann had been discussing in a
theoretical paper in 1877 the possibility that the energy states of
a physical system could be discrete). Further interpretation of the
implications of Planck's work was advanced by
Albert Einstein in 1905 in connection with
his work on the
photoelectric
effect—for this reason, the philosopher and historian of
science
Thomas Kuhn argued that Einstein
should be given credit for quantum theory more so than Planck,
since Planck did not understand in a deep sense that he was
"introducing the quantum" as a real physical entity. Be that as it
may, it was in recognition of Planck's monumental accomplishment
that he was awarded the
Nobel
Prize in Physics in 1918.
The discovery of Planck's constant enabled him to define
a new universal set of physical units (such as
the
Planck length and the
Planck mass), all based on fundamental
physical constants.
Subsequently, Planck tried to grasp the meaning of energy quanta,
but to no avail. "My unavailing attempts to somehow reintegrate the
action quantum into classical theory extended over several years
and caused me much trouble." Even several years later, other
physicists like
Rayleigh,
Jeans, and
Lorentz set Planck's constant to zero in
order to align with classical physics, but Planck knew well that
this constant had a precise nonzero value. "I am unable to
understand Jeans' stubbornness — he is an example of a theoretician
as should never be existing, the same as
Hegel
was for philosophy. So much the worse for the facts, if they are
wrong."
Max Born wrote about Planck: "He was by
nature and by the tradition of his family conservative, averse to
revolutionary novelties and skeptical towards speculations. But his
belief in the imperative power of logical thinking based on facts
was so strong that he did not hesitate to express a claim
contradicting to all tradition, because he had convinced himself
that no other resort was possible."
Einstein and the theory of relativity
In 1905 the three epochal papers of the hitherto completely unknown
Albert Einstein were published in
the journal
Annalen der
Physik. Planck was among the few who immediately
recognized the significance of the
special theory of relativity.
Thanks to his influence this theory was soon widely accepted in
Germany. Planck also contributed considerably to extend the special
theory of relativity.
Einstein's hypothesis of light
quanta (
photons), based on
Philipp
Lenard's 1902 discovery of the
photoelectric effect, was initially
rejected by Planck. He was unwilling to discard completely
Maxwell's theory of
electrodynamics. "The theory of light would
be thrown back not by decades, but by centuries, into the age when
Christian Huygens dared to fight
against the mighty emission theory of
Isaac
Newton ..."
In 1910 Einstein pointed out the anomalous behavior of
specific heat at low temperatures as another
example of a phenomenon which defies explanation by classical
physics. Planck and
Nernst, seeking
to clarify the increasing number of contradictions, organized the
First
Solvay Conference (Brussels
1911). At this meeting Einstein was able to convince Planck.
Meanwhile Planck had been appointed dean of Berlin University,
whereby it was possible for him to call Einstein to Berlin and
establish a new professorship for him (1914). Soon the two
scientists became close friends and met frequently to play music
together.
World War and Weimar Republic
At the onset of the
First World War
Planck was not immune to the general excitement of the public: "...
besides of much horrible also much unexpectedly great and
beautiful: the swift solution of the most difficult issues of
domestic policy through arrangement of all parties... the higher
esteem for all that is brave and truthful..." Admittedly, he
refrained from the extremes of nationalism. He voted successfully
for a scientific paper from Italy receiving a prize from the
Prussian Academy of
Sciences in 1915 (Planck was one of its four permanent
presidents), although at that time Italy was about to join the
Allies. The infamous "
Manifesto of the 93
intellectuals", a polemic pamphlet of war propaganda, was also
signed by Planck, while Einstein retained a strictly pacifistic
attitude which almost led to his imprisonment (he was saved by his
Swiss citizenship). But in 1915
Planck revoked (after several meetings with Dutch physicist
Lorentz) parts of the Manifesto, and
in 1916 he signed a declaration against German annexationism.
In the turbulent post-war years, Planck, now the highest authority
of German physics, issued the slogan "persevere and continue
working" to his colleagues. In October 1920 he and
Fritz Haber established the
Notgemeinschaft der
Deutschen Wissenschaft (Emergency Organization of German
Science), aimed at providing support for destitute scientific
research. A considerable portion of the monies they distributed
were raised abroad. In this time Planck held leading positions also
at Berlin University, the Prussian Academy of Sciences, the German
Physical Society and the
Kaiser-Wilhelm-Gesellschaft (which
in 1948 became the
Max-Planck-Gesellschaft). Under such
conditions he was hardly able to conduct research.
He became a member of the Deutsche Volks-Partei (
German People's Party), the party of
Nobel Peace Prize laureate
Gustav
Stresemann, which aspired to liberal aims for domestic policy
and rather revisionistic aims for international politics. He
disagreed with the introduction of
universal suffrage and later expressed
the view that the Nazi dictatorship resulted from "the ascent of
the rule of the crowds".
Quantum mechanics
At the end of the 1920s
Bohr,
Heisenberg and
Pauli had worked out the
Copenhagen interpretation of
quantum mechanics, but it was rejected by Planck, as well as
Schrödinger,
Laue, and
Einstein. Planck expected that
wave mechanics would soon render quantum
theory—his own child—unnecessary. This was not to be the case,
however. Further work only cemented quantum theory, even against
his and Einstein's philosophical revulsions. Planck experienced the
truth of his own earlier observation from his struggle with the
older views in his younger years: "A new scientific truth does not
triumph by convincing its opponents and making them see the light,
but rather because its opponents eventually die, and a new
generation grows up that is familiar with it."
Nazi dictatorship and The Second World War
When the Nazis seized power in 1933, Planck was 74. He witnessed
many Jewish friends and colleagues expelled from their positions
and humiliated, and hundreds of scientists emigrated from Germany.
Again he tried the "persevere and continue working" slogan and
asked scientists who were considering emigration to remain in
Germany.He hoped the crisis would abate soon and the political
situation would improve. There was also a deeper argument against
emigration. Emigrating German non-Jewish scientists would need to
look for academic positions abroad, but these positions better
served Jewish scientists, who had no chance of continuing to work
in Germany.
Hahn asked Planck to gather well-known
German professors in order to issue a public proclamation against
the treatment of Jewish professors, but Planck replied, "If you are
able to gather today 30 such gentlemen, then tomorrow 150 others
will come and speak against it, because they are eager to take over
the positions of the others." Under Planck's leadership, the
Kaiser-Wilhelm-Gesellschaft
(KWG) avoided open conflict with the Nazi regime, except concerning
Fritz Haber. Planck tried to discuss the
issue with
Adolf Hitler but was
unsuccessful. In the following year, 1934, Haber died in
exile.
One year later, Planck, having been the president of the KWG since
1930, organized in a somewhat provocative style an official
commemorative meeting for Haber. He also succeeded in secretly
enabling a number of Jewish scientists to continue working in
institutes of the KWG for several years. In 1936, his term as
president of the KWG ended, and the Nazi government pressured him
to refrain from seeking another term.
As the political climate in Germany gradually became more hostile,
Johannes Stark, prominent exponent of
Deutsche Physik ("German Physics",
also called "Aryan Physics") attacked Planck,
Sommerfeld and Heisenberg for continuing
to teach the theories of
Einstein,
calling them "white Jews." The "Hauptamt Wissenschaft" (Nazi
government office for science) started an investigation of Planck's
ancestry, but all they could find out was that he was "1/16
Jewish."
In 1938 Planck celebrated his 80th birthday. The DPG held a
celebration, during which the Max-Planck medal (founded as the
highest medal by the DPG in 1928) was awarded to French physicist
Louis de Broglie. At the end of
1938 the Prussian Academy lost its remaining independence and was
taken over by Nazis (
Gleichschaltung). Planck protested by
resigning his presidency. He continued to travel frequently, giving
numerous public talks, such as his talk on Religion and Science,
and five years later he was sufficiently fit to climb 3,000-meter
peaks in the Alps.
During the
Second World War, the
increasing number of Allied bombing campaigns against Berlin forced
Planck and his wife to leave the city temporarily and live in the
countryside. In 1942 he wrote: "In me an ardent desire has grown to
persevere this crisis and live long enough to be able to witness
the turning point, the beginning of a new rise." In February 1944
his home in Berlin was completely destroyed by an air raid,
annihilating all his scientific records and correspondence.
Finally, he got into a dangerous situation in his rural retreat due
to the rapid advance of the Allied armies from both sides.
After the
end of the war he was brought to a relative in Göttingen
.
Planck endured many personal tragedies after the age of 50. In
1909, his first wife died after 22 years of marriage, leaving him
with two sons and twin daughters. Planck's oldest son, Karl, was
killed in action in 1916. His daughter Margarete died in childbirth
in 1917, and another daughter, Emma, married her late sister's
husband and then also died in childbirth, in 1919. During World War
II, Planck's house in Berlin was completely destroyed by bombs in
1944 and his youngest son,
Erwin, was
implicated in the attempt made on Hitler's life in the
July 20 plot. Consequently, Erwin died at the
hands of the Gestapo in 1945. Although it is said that Erwin could
have been spared had Planck joined the
Nazi
Party. Planck took a stand and refused to join, and as a
consequence Erwin was executed. Erwin's death destroyed Planck's
will to live. By the end of the war, Planck, his second wife and
his son by her, moved to Göttingen where he died on October 4,
1947.
Religious view
Planck was a devoted and persistent adherent of
Christianity from early life to death, but he
was very tolerant towards alternative views and
religions, and so was discontented with the Nazi
church organizations' demands for unquestioning belief.
The God in which Planck believed was an almighty, all-knowing,
benevolent but unintelligible God that permeated everything,
manifest by symbols, including physical laws. His view may have
been motivated by an opposition like
Einstein's and
Schrödinger's against the
positivist,
statistical subjective
quantum mechanics universe of
Bohr,
Heisenberg and others. Planck was
interested in truth and Universe beyond observation, and objected
to atheism as an obsession with symbols.
Planck regarded the scientist as a man of imagination and faith,
"faith" interpreted as being similar to "having a working
hypothesis". For example the
causality
principle isn't true or false, it is an act of faith. Thereby
Planck may have indicated a view that points toward
Imre Lakatos' research programs process
descriptions, where falsification is mostly tolerable, in faith of
its future removal.
Honours and awards
- "Pour le Mérite" for Science
and Arts 1915 (in 1930 he became chancellor of this order)
- Nobel Prize in Physics
1918 (awarded 1919)
- Lorentz Medal 1927
- Adlerschild des Deutschen Reiches (1928), an award
from the German Reich President
- Max Planck medal (1929,
together with Einstein)
- Copley Medal (1929)
- Planck received honorary doctorates from the universities of
Frankfurt, Munich (TH),
Rostock, Berlin (TH), Graz, Athens, Cambridge, London, and
Glasgow.
- The asteroid 1069 was named
"Stella Planckia" by the International Astronomical
Union (1938)
See also
Publications
Bibliography
- Aczel, Amir D. Entanglement, Chapter 4. (Penguin,
2003) ISBN 9780452284579
- Heilbron, J. L. The Dilemmas of an Upright Man: Max Planck
and the Fortunes of German Science (Harvard, 2000) ISBN
0674004396
- Pickover, Clifford A.
Archimedes to Hawking: Laws of Science and the Great Minds
Behind Them, Oxford University Press, 2008, ISBN
978-0195336115
- Rosenthal-Schneider, Ilse Reality and Scientific Truth:
Discussions with Einstein, von Laue, and Planck (Wayne State
University, 1980) ISBN 0-8143-1650-6
References
External links
- http://wikisource.org/wiki/Autor:Max_Planck
Biographies
Articles
Wikis
Quiz
Map
Misc
Search
