On May 14, 1904, the couple's first son, Hans Albert Einstein, was born. In 1903, Einstein's position at the Swiss Patent Office had been made permanent, though he was passed over for promotion until he had "fully mastered machine technology". He obtained his doctorate after submitting his thesis "A new determination of molecular dimensions" ("Eine neue Bestimmung der Molek?ldimensionen") in 1905.
That same year, he wrote four articles that provided the foundation of modern physics, without much scientific literature to which he could refer or many scientific colleagues with whom he could discuss the theories. Most physicists agree that three of those papers (on Brownian motion, the photoelectric effect, and special relativity) deserved Nobel Prizes. Only the paper on the photoelectric effect would be mentioned by the Nobel committee in the award. This is ironic, not only because Einstein is far better-known for relativity, but also because the photoelectric effect is a quantum phenomenon, and Einstein became somewhat disenchanted with the path quantum theory would take. What makes these papers remarkable is that, in each case, Einstein boldly took an idea from theoretical physics to its logical consequences and managed to explain experimental results that had baffled scientists for decades.
Max Planck and Einstein
Annus Mirabilis Papers
For more details on this topic, see Annus Mirabilis Papers.
Einstein submitted the series of papers to the "Annalen der Physik". They are commonly referred to as the "Annus Mirabilis Papers" (from Annus mirabilis, Latin for 'year of wonders'). The International Union of Pure and Applied Physics (IUPAP) is commemorating the 100th year of the publication of Einstein's extensive work in 1905 as the 'World Year of Physics 2005'.
The first paper, named "On a Heuristic Viewpoint Concerning the Production and Transformation of Light", ("?ber einen die Erzeugung und Verwandlung des Lichtes betreffenden heuristischen Gesichtspunkt") proposed that "energy quanta" (which are essentially what we now call photons) were real, and showed how they could be used to explain such phenomena as the photoelectric effect. This paper was specifically cited for his Nobel Prize. Max Planck had made the formal assumption that energy was quantized in deriving his black-body radiation law, published in 1901, but had considered this to be no more than a mathematical trick.
His second article in 1905, named "On the Motion-Required by the Molecular Kinetic Theory of Heat-of Small Particles Suspended in a Stationary Liquid", ("?ber die von der molekularkinetischen Theorie der W?rme geforderte Bewegung von in ruhenden Fl?ssigkeiten suspendierten Teilchen") covered his study of Brownian motion, and provided empirical evidence for the existence of atoms. Before this paper, atoms were recognized as a useful concept, but physicists and chemists hotly debated whether atoms were real entities. Einstein's statistical discussion of atomic behavior gave experimentalists a way to count atoms by looking through an ordinary microscope. Wilhelm Ostwald, one of the leaders of the anti-atom school, later told Arnold Sommerfeld that he had been converted to a belief in atoms by Einstein's complete explanation of Brownian motion.
Einstein's third paper that year, "On the Electrodynamics of Moving Bodies" ("Zur Elektrodynamik bewegter K?rper"), was published in September 1905. This paper introduced the special theory of relativity, a theory of time, distance, mass and energy which was consistent with electromagnetism, but omitted the force of gravity. While developing this paper, Einstein wrote to Mileva about "our work on relative motion", and this has led some to ask whether Mileva played a part in its development.
A fourth paper, "Does the Inertia of a Body Depend Upon Its Energy Content?", ("Ist die Tr?gheit eines K?rpers von seinem Energieinhalt abh?ngig?") published late in 1905, showed one further deduction from relativity's axioms, the famous equation that the energy of a body at rest (E) equals its mass (m) times the speed of light (c) squared: E = mc2 .
Einstein at the 1911 Solvay Conference.
In 1906, Einstein was promoted to technical examiner second class. In 1908, Einstein was licensed in Bern, Switzerland, as a Privatdozent (unsalaried teacher at a university). Einstein's second son, Eduard, was born on July 28, 1910. In 1911, Einstein became first associate professor at the University of Zurich, and shortly afterwards full professor at the (German) University of Prague, only to return the following year to Zurich in order to become full professor at the ETH Zurich. At that time, he worked closely with the mathematician Marcel Grossmann. In 1912, Einstein started to refer to time as the fourth dimension (although H.G. Wells had done this earlier, in 1895 in The Time Machine).
In 1914, just before the start of World War I, Einstein settled in Berlin as professor at the local university and became a member of the Prussian Academy of Sciences. He took German citizenship. His pacifism and Jewish origins irritated German nationalists. After he became world-famous, nationalistic hatred of him grew and for the first time he was the subject of an organized campaign to discredit his theories. From 1914 to 1933, he served as director of the Kaiser Wilhelm Institute for Physics in Berlin, and it was during this time that he was awarded his Nobel Prize and made his most groundbreaking discoveries. He was also an extraordinary professor at the Leiden University from 1920 until officially 1946, where he regularly gave guest lectures.
Einstein divorced Mileva on February 14, 1919, and married his cousin Elsa L?wenthal (born Einstein:L?wenthal was the surname of her first husband, Max) on June 2, 1919. Elsa was Albert's first cousin (maternally) and his second cousin (paternally). She was three years older than Albert, and had nursed him to health after he had suffered a partial nervous breakdown combined with a severe stomach ailment; there were no children from this marriage. The fate of Albert and Mileva's first child, Lieserl, is unknown. Some believe she died in infancy, while others believe she was given out for adoption. They later had two sons: Eduard and Hans Albert. Eduard intended to practice as a Freudian analyst but was institutionalized for schizophrenia and died in an asylum. Hans Albert, his older brother, became a professor of hydraulic engineering at the University of California, Berkeley, having little interaction with his father.
"Einstein theory triumphs," declared the New York Times on November 10, 1919.
In November 1915, Einstein presented a series of lectures before the Prussian Academy of Sciences in which he described his theory of general relativity. The final lecture climaxed with his introduction of an equation that replaced Newton's law of gravity. This theory considered all observers to be