Walter Maurice Elsasser (March 20, 1904 – October 14, 1991) was a German-born American

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

, a developer of the presently accepted

dynamo theory In physics, the dynamo theory proposes a mechanism by which a celestial body such as Earth or a star generates a magnetic field. The dynamo theory describes the process through which a rotating, convecting, and electrically conducting fluid can ...

as an explanation of the

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

's magnetism. He proposed that this magnetic field resulted from electric currents induced in the fluid outer core of the Earth. He revealed the history of the Earth's magnetic field by the study of the magnetic orientation of

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2 ...

s in rocks. He was also the first to suggest that the wave-like nature of matter might be investigated by electron scattering experiments using crystalline solids. The Olin Hall at the

Johns Hopkins University Johns Hopkins University (Johns Hopkins, Hopkins, or JHU) is a private research university in Baltimore, Maryland. Founded in 1876, Johns Hopkins is the oldest research university in the United States and in the western hemisphere. It consi ...

has a Walter Elsasser Memorial in the lobby.

Biography

Elsasser was born in 1904 to a Jewish family in

Mannheim Mannheim (; Palatine German: or ), officially the University City of Mannheim (german: Universitätsstadt Mannheim), is the second-largest city in the German state of Baden-Württemberg after the state capital of Stuttgart, and Germany's ...

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

. Before he became known for his geodynamo theory, while in

Göttingen Göttingen (, , ; nds, Chöttingen) is a university city in Lower Saxony, central Germany, the capital of the eponymous district. The River Leine runs through it. At the end of 2019, the population was 118,911. General information The ori ...

during the 1920s, he had suggested the experiment to test the wave aspect of

electron The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no ...

s. This suggestion of Elsasser was later communicated by his senior colleague from Göttingen (

Nobel Prize The Nobel Prizes ( ; sv, Nobelpriset ; no, Nobelprisen ) are five separate prizes that, according to Alfred Nobel's will of 1895, are awarded to "those who, during the preceding year, have conferred the greatest benefit to humankind." Alfr ...

recipient Max Born) to physicists in

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

. This explained the results of the Davisson-Germer and Thomson experiments later awarded with the

Nobel Prize in Physics ) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then " ...

. In 1935, while working in Paris, Elsasser calculated the binding energies of protons and neutrons in heavy radioactive nuclei.

Wigner Eugene Paul "E. P." Wigner ( hu, Wigner Jenő Pál, ; November 17, 1902 – January 1, 1995) was a Hungarian-American theoretical physicist who also contributed to mathematical physics. He received the Nobel Prize in Physics in 1963 "for his con ...

, Jensen and Goeppert-Mayer received the Nobel in 1963 for work developing out of Elsasser's initial formulation. Elsasser therefore came quite close to a Nobel prize on two occasions. During 1946–47, Elsasser published papers describing the first mathematical model for the origin of the

Earth's magnetic field Earth's magnetic field, also known as the geomagnetic field, is the magnetic field that extends from Earth's interior out into space, where it interacts with the solar wind, a stream of charged particles emanating from the Sun. The magnetic ...

. He conjectured that it could be a self-sustaining

dynamo "Dynamo Electric Machine" (end view, partly section, ) A dynamo is an electrical generator that creates direct current using a commutator. Dynamos were the first electrical generators capable of delivering power for industry, and the foundati ...

, powered by convection in the liquid

outer core Earth's outer core is a fluid layer about thick, composed of mostly iron and nickel that lies above Earth's solid inner core and below its mantle. The outer core begins approximately beneath Earth's surface at the core-mantle boundary and e ...

, and described a possible feedback mechanism between flows having two different geometries,

toroidal and poloidal Toroidal describes something which resembles or relates to a torus or toroid: Mathematics *Torus *Toroid, a surface of revolution which resembles a torus *Toroidal polyhedron *Toroidal coordinates, a three-dimensional orthogonal coordinate system ...

(indeed, inventing the terms). This had been developed from about 1941 onwards, partly in his spare time during his scientific war service with the

U.S. Army Signal Corps ) , colors = Orange and white , colors_label = Corps colors , march = , mascot = , equipment = , equipment_label = ...

. During his later years, Elsasser became interested in what is now called systems biology and contributed a series of articles to

Journal of Theoretical Biology The ''Journal of Theoretical Biology'' is a biweekly peer-reviewed scientific journal covering theoretical biology, as well as mathematical, computational, and statistical aspects of biology. Some research areas covered by the journal include cell ...

. The final version of his thoughts on this subject can be found in his book ''Reflections on a Theory of Organisms'', published in 1987 and again posthumously with a new foreword by Harry Rubin in 1998. Elsasser died in 1991 in

Baltimore Baltimore ( , locally: or ) is the List of municipalities in Maryland, most populous city in the U.S. state of Maryland, fourth most populous city in the Mid-Atlantic (United States), Mid-Atlantic, and List of United States cities by popula ...

Maryland Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean to ...

, US.

Biotonic laws

A biotonic law, a phrase invented by Elsasser, is a principle of nature which is not contained in the principles of physics. Biotonic laws may also be considered as local instances of global organismic or organismal principles, such as the Organismic Principle of Natural Selection. Some, but not all, of Elsasser's theoretical biology work is still quite controversial, and in fact may disagree with several of the basic tenets of current systems biology that he may have helped to develop. Basic to Elsasser's biological thought is the notion of the great complexity of the cell. Elsasser deduced from this that any investigation of a causative chain of events in a biological system will reach a "terminal point", where the number of possible inputs into the chain will overwhelm the capacity of the scientist to make predictions, even with the most powerful computers. This might seem like a counsel of despair, but in fact Elsasser was not suggesting the abandonment of biology as a worthwhile research topic, but rather for a different kind of biology such that molecular causal chains are no longer the main focus of study. Correlation between supra-molecular events would become the main data source. Moreover, the heterogeneity of logical classes encompassed by all biological organisms without exception is an important part of Elsasser's legacy to both Complex systems biology and Relational Biology.

Publications

* ''The Physical Foundation of Biology. An Analytical Study'', (1958), Pergamon Press, London * ''Atom and Organism. A New Approach to Theoretical Biology'', (1966) Princeton University Press * ''The Chief Abstractions of Biology'', (1975), North Holland, Amsterdam. * ''Memoirs of a Physicist in the Atomic Age'', (1978) * ''The role of individuality in biological theory'', (1970) in ''Towards a Theoretical Biology vol.3'' Edinburgh University Press * ''Reflections on a Theory of Organisms. Holism in Biology'', (1998) Johns Hopkins University Press (JHU).

Awards

Elsasser was elected to the National Academy of Sciences in 1957. From the

American Geophysical Union The American Geophysical Union (AGU) is a 501(c)(3) nonprofit organization of Earth, atmospheric, ocean, hydrologic, space, and planetary scientists and enthusiasts that according to their website includes 130,000 people (not members). AGU's a ...

he received the William Bowie Medal, its highest honor, in 1959; and the

John Adam Fleming John Adam Fleming, (January 28, 1877 – July 29, 1956) was an American geophysicist interested in the magnetosphere and the atmospheric electricity. Fleming worked first at the U.S. Coast and Geodetic Survey with his superior Louis Agricola Ba ...

Medal (for contributions to geomagnetism) in 1971. He received the

Penrose Medal The Penrose Medal was created in 1925 by R.A.F. Penrose, Jr., as the top prize awarded by the Geological Society of America. Originally created as the Geological Society of America Medal it was soon renamed the Penrose Medal by popular assent of t ...

from the

Geological Society of America The Geological Society of America (GSA) is a nonprofit organization dedicated to the advancement of the geosciences. History The society was founded in Ithaca, New York, in 1888 by Alexander Winchell, John J. Stevenson, Charles H. Hitch ...

in 1979 and the Gauss Medal from Germany in 1977. In 1987, he was awarded the USA's

National Medal of Science The National Medal of Science is an honor bestowed by the President of the United States to individuals in science and engineering who have made important contributions to the advancement of knowledge in the fields of behavioral and social scienc ...

"for his fundamental and lasting contributions to physics, meteorology, and geophysics in establishing quantum mechanics, atmospheric radiation transfer, planetary magnetism and plate tectonics."

References

External links

Oral history interview transcript with Walter Elsasser on 29 May 1962, American Institute of Physics, Niels Bohr Library & Archives

Oral history interview transcript with Walter Elsasser on 21 November 1985, American Institute of Physics, Niels Bohr Library & Archives

Elsasser's photo
{{DEFAULTSORT:Elsasser, Walter M. 1904 births 1991 deaths 20th-century American physicists 20th-century German physicists Jewish emigrants from Nazi Germany to the United States Scientists from Mannheim People from the Grand Duchy of Baden Systems biologists Theoretical biologists Heidelberg University alumni Ludwig Maximilian University of Munich alumni University of Göttingen alumni National Medal of Science laureates Scientists from Baltimore Jewish American scientists Jewish physicists Fellows of the American Physical Society