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Friedrich Hasenöhrl (November 30, 1874 
October 7, 1915), was an AustroHungarian
physicist.
Friedrich Hasenöhrl was born in Vienna, Austria
(AustriaHungary) in 1874. His father was a lawyer and his mother
belonged to a prominent aristocratic family. After his elementary
education, he studied natural science and mathematics at the
University of Vienna under Stephan and Boltzmann. He worked under
H. A.
Lorentz in Leiden at the low temperature laboratory.
In 1907 he became Boltzmann's successor at the University of
Vienna as the head of the Department of Theoretical Physics. He had
a number of illustrious pupils there and had an especially
significant impact on Erwin Schrödinger, who later won the
Nobel Prize for Physics for his
contributions to Quantum
Mechanics.
When the war broke out in 1914, he volunteered at once into the
AustriaHungarian army. He fought as Oberleutnant against the
Italians in Tyrol. He was wounded, recovered and
returned to the front. He was then killed by a grenade in an attack
on Mount Plaut on October 7, 1915 at the age of 40.
Cavity
Radiation
Since J. J.
Thomson in 1881, many physicists like Wilhelm Wien (1900), Max Abraham (1902), and
Hendrik
Lorentz (1904) used equations equivalent to
for the so called "electromagnetic mass", which expresses how
much electromagnetic energy contributes to the mass of bodies. And
Henri
Poincaré (1900) implicitly used the expression
m=E/c^{2} for the mass of electromagnetic
energy.
Following this line of thought, Hasenöhrl (1904, 1905) published
several papers on the inertia of a cavity containing radiation.
This was an entirely classical derivation (no use of special
relativity) and used Maxwell's equation for the pressure of
light. Hasenöhrl specifically associated the "apparent" mass
via inertia with the energy concept through the equation
 ,
where hε_{0} is the radiation energy. He also concluded
that this result is valid for all radiating bodies, i.e. for all
bodies whose temperature is > 0°K. For this result Hasenöhrl was
awarded the Haitinger prize of the Austrian Academy of
Sciences. However, it was shown by Abraham that Hasenöhrl's
calculation for the apparent mass was incorrect, so he published
another paper in 1905, where he presented Abraham's criticism and
corrected his formula to:
This was the same relation (as Hasenöhrl noted himself) which
was already known from the electromagnetic mass. If he had included
the shell in his calculations in a way consistent with relativity,
the prefactor of 4/3 would have been 1, so yielding m = E /
c^{2}. He could not have done this, since
he did not have relativistic mechanics, with which he could model
the shell.
Hasenöhrl's results (concerning apparent mass and
thermodynamics) by using cavity radiation was further elaborated
and criticized by Kurd von Mosengeil (1906/7) who
already incorporated Albert Einstein's theory of
relativity in his work. A broad outline of relativistic
thermodynamics and massenergy
equivalence using cavity radiation was given by Max Planck in 1907.^{[1]}^{[2]}^{[3]}
In some additional papers (1907, 1908) Hasenöhrl elaborated
further on his 1904work and concluded that his new results were
now in accordance to the theories of Mosengeil and Planck. However,
he complained about the fact that Planck (1907) did not mention his
earlier 1904results (like the dependency of apparent mass on
temperature). Eventually, in 1908 Planck wrote that the results of
Hasenöhrl's new approach from 1907 were indeed equivalent to those
of relativity.^{[4]}
Hasenöhrl and Einstein
The formulas for electromagnetic
mass (like those of Hasenöhrl's) were similar to the famous
equation for mass–energy equivalence:
published by Albert Einstein in September 1905 in
the Annalen der Physik —a few editions after Hasenöhrl
published his results on cavity radiation. The similarity between
those formulas led some critics of Einstein, up until the 1930's,
to claim that he plagiarized the formula from Hasenöhrl,
often in connection with the antisemitic Deutsche
Physik.
As an example, Phillip Lenard published a paper in 1921 in
which he gave priority for "E=mc²" to Hasenöhrl (Lenard also gave
credit to Johann Georg von Soldner and
Paul Gerber in
relation to some effects of general relativity).^{[5]}
However, Max von
Laue quickly rebutted those claims by saying that the inertia
of electromagnetic energy was long known before Hasenöhrl,
especially by the works of Henri Poincaré (1900) and Max Abraham (1902),
while Hasenöhrl only used their results for his calculation on
cavity radiation. Laue continued by saying that credit for
establishing the inertia of all forms of energy (the
real massenergy equivalence) goes to Einstein, who was
also the first to understand the deep implications of that
equivalence in relation to relativity. ^{[6]}
See also
Publications
 Hasenöhrl's papers on cavity radiation and thermodynamics
 Zur Theorie
der Strahlung bewegter Körper. (Sitzungsberichte der
mathematischnaturwissenschaftlichen Klasse der kaiserlichen
Akademie der Wissenschaften, Wien. 113 IIa, 1039,
1904)
 Zur
Theorie der Strahlung in bewegten Körpern. (Annalen der Physik
15, 344370, 1904),

Zur Theorie der Strahlung in bewegten Körpern. Berichtigung
(Annalen der Physik 16, 589592, 1905).
 Zur
Thermodynamik bewegter Systeme (Sitzungsberichte der
mathematischnaturwissenschaftlichen Klasse der kaiserlichen
Akademie der Wissenschaften, Wien. 116 IIa (9): 13911405,
1907)
 Zur
Thermodynamik bewegter Systeme (Fortsetzung) (Sitzungsberichte
der mathematischnaturwissenschaftlichen Klasse der kaiserlichen
Akademie der Wissenschaften, Wien. 117 IIa (2): 207215,
1908).
Notes and
References
 ^
Miller, Arthur I. (1981). Albert
Einstein’s special theory of relativity. Emergence (1905) and early
interpretation (1905–1911). Reading: Addison–Wesley.
pp. 359–374. ISBN
0201046792.
 ^
Mosengeil, Kurd von (1907). "Theorie
der stationären Strahlung in einem gleichförmich bewegten
Hohlraum". Annalen der Physik 327 (5):
867–904.
 ^
Planck, Max (1907). "Zur Dynamik
bewegter Systeme". Sitzungsberichte der
KöniglichPreussischen Akademie der Wissenschaften, Berlin
Erster Halbband (29): 542–570.
 ^
Planck, Max (1908). "
Bemerkungen zum Prinzip der Aktion und Reaktion in der allgemeinen
Dynamik". Physikalische Zeitschrift 9
(23): 828–830.
 ^
Lenard, P. (1921). "Vorbemerkung
Lenards zu Soldners: Über die Ablenkung eines Lichtstrahls von
seiner geradlinigen Bewegung durch die Attraktion eines
Weltkörpers, an welchem er nahe vorbeigeht;". Annalen der
Physik 65: 593–604. doi:10.1002/andp.19213701503.
 ^
Laue, M.v. (1921). "Erwiderung auf
Hrn. Lenards Vorbemerkungen zur Soldnerschen Arbeit von 1801".
Annalen der Physik 66: 283–284. doi:10.1002/andp.19213712005.
Further
reading
 Lenard, Philipp, Great Men of Science. Translated from
the second German edition, G. Bell and sons, London (1950) ISBN
083691614X
 Moore, Walter "Schrödinger: Life and Thought" University of
Cambridge (1989) ISBN 0521437679.
External
links