Influential Atomic and Nuclear Physicists of the 20th Century
*Denotes Nobel Laureate

Date
Pre 1900











1900









1910







1920







1930






1940








1950









1960









1970
Key Events
1873, Equations of Electromagnetism-J. Maxwell



1877, Discovery of Radio Waves-Heinrich Hertz

1887, Michelson-Morley experiment

11/8/1895, Discovery of X-Rays-Wilhelm Roentgen

1897, Discovery of the Electron-J.J. Thomson


12/14/1900
, Definition of the energy quanta and e=hv- M. Planck
3/1905, Solution to the Photoelectric effect-theorize photons as light quanta-Albert Einstein.
5/1905, Theory of Special Relativity-Albert Einstein






3/7/1911
, Discovery of the atomic nucleus-definition of atomic classical theory-E. Rutherford
1913, Theory of quantum structure of the atom-discrete levels of electron orbits-Niels Bohr
1915, Theory of General Relativity-Albert Einstein
1915, Discovery of the Proton-E. Rutherford
1919, Eddington’s proof of General Relativity
1924, Paper on Particle Pilot Waves- L. de Broglie
7/9/25, Development of Matrix Mechanics-W. Heisenberg
1/1926, Development of Wave Mechanics-E. Schrodinger
1/1926, Exclusion Principle-Wolfgang Pauli
1926, Inclusion of probability into Quantum
Physics-M. Born
9/1927, Complimentarity Principle-Niels Bohr
1927, Solvay Conference, Brussels (& 1933)



2/27/32
, Discovery of the Neutron-J. Chadwick
8/2/32, Discovery of the Positron-C. Anderson
12/1938, Discovery of Nuclear Fission-O. Hahn*- F. Strassmann*- (L. Meitner)

12/2/42, First Man-made sustaining nuclear
reaction (U. Chicago, Met Lab)

7/6/45, First nuclear fission explosion (Trinity site)

6/1-3/1947, Shelter Island Conference

Max Karl Ernst Ludwig Planck* (1858-1947)
4/23/1858, Born, Kiel, Germany. Came from a family of academics. Father, Julius Wilhelm, Professor of Law, U. Kiel and later, Gottingen.
1867, Family moved to Munich. Attended secondary school, Maximilian Gymnasium.
1874-77, U. Munich, studied physics.
1877-78, U. Berlin, (Kirchkoff).
1878-1879, U. Munich, Ph.D.
1880-1885, U. Munich, Privatdozent
1885-1889, U. Kiel, Assoc. Professor.
1889-1927, U. Berlin, Chair, Theoretical Physics (succeeded Kirchkoff). At the time, the highest academic position in Germany
12/14/1900, Before the German Physical Society, introduced Planck radiation formula that described radiation energy in “quanta” or discrete units for each frequency as opposed to the classical interpretation of a continuous amount. It solved the dilemma between observed phenomena and the results of classical theory.



1912-1943, Permanent Secretary of the Prussian Academy of Science.
1913, Bohr’s use of Planck’s equation to describe the atom created a general acceptance of the quantum idea.
1918, Nobel Prize, “for advancement of physics by his discovery of energy quanta”.
1918, Lost his oldest son in WWI.









1930-1937, President, Kaiser Wilhelm Institute










1945-46, President, Kaiser Wilhelm Institute
1945, Erwin, youngest son, assassinated for plotting to kill Hitler.
1945, Home completely destroyed by bombing in Berlin
10/4/47, Died Gottingen, Germany (89)


Planck was a true “Classical “ physicist rooted in the rigid academic culture of 19th century Germany who created a major turning point in the history of physics without immediately understanding or believing what he had done. He spent a number of years attempting to reconcile his quantum concept of energy and action with the classical underpinnings of Newton but to no avail and only later began to understand what he had accomplished when others started to use his concepts to further develop quantum theory. After his 1900 paper, he contributed very little to the further development of the quantum theory and its explosive revolution in physical thought. As opposed to most theoretical physicists who usually make fundamental discoveries at an early age, Planck was 42 when  he produced his most creative endeavor. He also was a gifted pianist who thought at one time of becoming a professional musician.


Back Next