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Einstein 1905. and the birth of modern physics. Einstein Year. Einstein 1905 Nature of Light Atomic Theory Special Theory of Relativity. Early Years. Born in Ulm ( D ) 1879 Primary and secondary school ( MUC ) Family move to Milan 1894 Aarau Gymnasium ( SCH ) 1895
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Einstein 1905 and the birth of modern physics
Einstein Year Einstein 1905 • Nature of Light • Atomic Theory • Special Theory of Relativity
Early Years • Born in Ulm (D) 1879 • Primary and secondary school (MUC) • Family move to Milan 1894 • Aarau Gymnasium (SCH) 1895 • ETH (ZUR) 1896
Student Years • Not a model student • Lack of interest • Diploma in maths and physics 1900 • Unable to find University assistantship • Temporary schoolteaching
Bern 1901- 1905 • Tech expert in Swiss Patent Office (Bern) • Swiss citizenship in 1901 • Daughter with Mileva Maric in 1902 • Adoption • Married in 1903 • Son in 1904
Bern 1901-1905 • Engineering problems (day) • Fundamental physics problems (night) • Olympia Academy of Philosophy • Arrival of Micheal Besso • Five scientific papers on thermodynamics
Contemporary Physics • Mechanics F = ma Law of Gravity • Electromagnetism Elec +Mag =EM Light = electromagnetic wave • Radiation Planck’s Law • Radioactivity Energy mystery
Einstein 1905 • The Nature of Light (cornerstone of quantum theory) • Atomic Theory (reality of atoms) • Special Theory of Relativity (physics of relative motion)
I Atomic Theory • Greeks – matter composed of atoms • Dalton – atoms of the chemical elements differ • Avogadro –atoms and molecules • Mendeleev – Periodic Table • Maxwell – Kinetic theory of gases No direct evidence
Einstein and Atomic Theory • Molecular dimensions in liquids • Well received • Statistics of molecular motion in liquids • Fluctuations • Effect on immersed particle - Brownian motion • Mean free path calculation
Einstein and Atomic Theory • 1906-08 Perrin’s Brownian Motion experiments • 1908 : Confirmation of Einstein predictions Atomic theory = reality • Role of probability and statistics in nature • Einstein established • Nobel Prize for Perrin
II Problems with Light • Radiation studies • Ultraviolet Catastrophe • Planck’s Radiation Law (1900) “Radiation emitted/absorbed in chunks (quanta)” • Mathematical artefact • Applies only to oscillators
Einstein and Light • Einstein : inconsistency in Planck’s Law • Einstein : new statistical approach (1905) “Light itself behaving like particles (quanta)” • Explained Planck’s law, Photoelectric Effect • Conflict with wave theory of light • Rejected for 17 years
III Relativity • Galileo: Principle of Relativity • Laws of mechanics independent of uniform motion • Impossible to detect motion internally • No absolute frame of reference for motion • Newton : absolute space
Relativity and Electromagnetism • Maxwell : electromagnetic theory • Radiation = electromagnetic waves (speed 3x108 m/s) light = em wave of speed 3x108 m/s • Speed relative to ether ? • Absolute frame of reference for light ? • Experiments
Einstein’s Relativity 1905 • Relativity applies to all laws of physics (includes electromagnetism) • Speed of light = universal constant (general principle) Implication: time and distance not absolute
Implications of Special Relativity • Length of a body • Time interval • Mass of a body
Implications of SR • Time is relative • Time + space = spacetime • Mass is a form of energy E = mc2
Response to relativity • Controversy (1905-08) • Kaufmann experiments (1908) • Bucherer experiments (1909) By 1911 Special Relativity accepted
Career Progress • 1905 PhD (ETH) • 1908 Privatdozent (Univ Bern) • 1909 Assoc Prof (Univ Zurich) • 1911 Prof (Univ Prague) • 1912 Prof (ETH Zurich) • 1914 Prof (Univ Berlin), Director (FWInstitute) • 1913 Separation
Middle Years (1908-1916) • Relativity and accelerated bodies (1908-15) • Principle of Equivalence • General Relativity (1915) “Gravity = curvature of space-time” • Bending of light by gravity • Slowing of time by gravity • Cosmological implications
After the War • 1916 Photoelectric effect (Millikan) • 1919 Evidence for GR (Eddington) 1921 Nobel Prize (Photoelectric effect) • 1923 Compton Effect (light quanta) • 1925 Electron waves (quantum duality)
Between Wars • 1919 Remarried • 1920s Anti-semitism in Germany Einstein’s work attacked • 1930-33 Rise of Nazi Party • 1930-33 Visiting Prof at Caltech (US) • 1933 Hitler assumes power • 1933 Flight to Princeton (US)
Princeton Years (1933-55) • Hero’s Welcome • American Icon • Letter to Roosevelt (1939) • Manhattan Project • Regret at Hiroshima (1944) • Nuclear disarmament (1940s) • McCarthyism (1950s)
Princeton Years (1933-55) • Interpretation of quantum theory • Relativity and electromagnetism Unified Field Theory • Evidence for relativity (1950s) • New York Times Iconic figure
Einstein Today Atomic Theory Reality of atoms Stat. applications Quantum Theory Wave/particle duality Applications Special Relativity Particle physics Nuclear fission and fusion
Einstein Today General Relativity Underlies cosmology Evolution of Universe Unified Field Theory Still not solved Holy grail of physics