March 14, 1879
Ulm, Württemberg, Germany
Died April 18, 1955
Princeton, New Jersey
Residence Germany, Italy, Switzerland, USA
Nationality German (1879-96, 1914-33)
Known for General
relativity, Special relativity
Brownian motion, Photoelectric effect
Notable Prizes Nobel Prize in Physics (1921)
(March 14, 1879
– April 18, 1955) was a German-born theoretical physicist widely
known as one of the greatest physicists of all time. He formulated
the special and general theories of relativity. In addition, he made
significant advancements to quantum theory and statistical mechanics.
While best known for the Theory of Relativity (and specifically mass-energy
equivalence, E=mc2), he was awarded the 1921 Nobel Prize for Physics
for his 1905 (his "wonderful year" or "miraculous year")
explanation of the photoelectric effect and "for his services to
Theoretical Physics". In popular culture, the name "Einstein"
has become synonymous with great intelligence and genius.
Among his many investigations
were: capillary action, his special theory of relativity which stemmed
from an attempt to reconcile the laws of mechanics with the laws of
the electromagnetic field, his general theory of relativity which extended
the principle of relativity to include gravitation, relativistic cosmology,
critical opalescence, classical problems of statistical mechanics and
problems in which they were merged with quantum theory, including an
explanation of Brownian motion, atomic transition probabilities, the
probabilistic interpretation of quantum theory, the quantum theory of
a monatomic gas, the thermal properties of light with a low radiation
density which laid the foundation of the photon theory of light, the
theory of radiation, including stimulated emission, the construction
of a unified field theory, and the geometrization of physics.Biography
Einstein was born
on March 14, 1879, around 11:30 AM LMT, to a Jewish family, in the city
of Ulm in Württemberg, Germany, about 100 km east of Stuttgart.
His father was Hermann Einstein, a salesman who later ran an electrochemical
works, and his mother was Pauline née Koch. They were married
in Stuttgart-Bad Cannstatt.
At his birth, Albert's
mother was reputedly frightened that her infant's head was so large
and oddly shaped. Though the size of his head appeared to be less remarkable
as he grew older, it's evident from photographs of Einstein that his
head was disproportionately large for his body throughout his life,
a trait regarded as "benign macrocephaly" in large-headed
individuals with no related disease or cognitive deficits.
Another more famous
aspect of Einstein's childhood is the fact that he spoke much later
than the average child. Einstein claimed that he did not begin speaking
until the age of three and only did so hesitantly, even beyond the age
of nine (see "Speculation and controversy" section). Because
of Einstein's late speech development and his later childhood tendency
to ignore any subject in school that bored him — instead focusing
intensely only on what interested him — some observers at the
time suggested that he might be "retarded", such as one of
the Einstein family's housekeepers. This latter observation was not
the only time in his life that controversial labels and pathology would
be applied to Einstein. (See again, "Speculation and controversy".)
members were all non-observant Jews and he attended a Catholic elementary
school. At the insistence of his mother, he was given violin lessons.
Though he initially disliked the lessons, and eventually discontinued
them, he would later take great solace in Mozart's violin sonatas.
When Einstein was
five, his father showed him a small pocket compass, and Einstein realized
that something in "empty" space acted upon the needle; he
would later describe the experience as one of the most revelatory events
of his life. He built models and mechanical devices for fun and showed
great mathematical ability early on.
In 1889, a medical
student named Max Talmud (later: Talmey), who visited the Einsteins
on Thursday nights for six years, introduced Einstein to key science
and philosophy texts, including Kant's Critique of Pure Reason. Two
of his uncles would further foster his intellectual interests during
his late childhood and early adolescence by recommending and providing
books on science, mathematics and philosophy.
the Luitpold Gymnasium, where he received a relatively progressive education.
He began to learn mathematics around age twelve; in 1891, he taught
himself Euclidean plane geometry from a school booklet and began to
study calculus four years later; Einstein realized the power of axiomatic
deductive reasoning from Euclid's Elements, which Einstein called the
"holy little geometry book" (given by Max Talmud). While
at the Gymnasium, Einstein clashed with authority and resented the school
regimen, believing that the spirit of learning and creative thought
were lost in such endeavors as strict memorization.
In 1894, following
the failure of Hermann Einstein's electrochemical business, the Einsteins
moved from Munich to Pavia, a city in Italy near Milan. Einstein's first
scientific work, called "The Investigation of the State of Aether
in Magnetic Fields", was written contemporaneously for one of his
uncles. Albert remained behind in Munich lodgings to finish school,
completing only one term before leaving the gymnasium in the spring
of 1895 to rejoin his family in Pavia. He quit a year and a half prior
to final examinations without telling his parents, convincing the school
to let him go with a medical note from a friendly doctor, but this meant
that he had no secondary-school certificate. That year, at the age
of 16, he performed the thought experiment known as "Albert Einstein's
mirror". After gazing into a mirror, he examined what would happen
to his image if he were moving at the speed of light; his conclusion,
that the speed of light is independent of the observer, would later
become one of the two postulates of special relativity.
Although he excelled
in the mathematics and science part of entrance examinations for the
Federal Polytechnic Institute in Zürich, today the ETH Zürich,
his failure of the liberal arts portion was a setback; his family sent
him to Aarau, Switzerland to finish secondary school, and it became
clear that he was not going to be an electrical engineer as his father
intended for him. There, he studied the seldom-taught Maxwell's electromagnetic
theory and received his diploma in September 1896. During this time,
he lodged with Professor Jost Winteler's family and became enamoured
with Sofia Marie-Jeanne Amanda Winteler, commonly referred to as Sofie
or Marie, their daughter and his first sweetheart. Einstein's sister,
Maja, who was perhaps his closest confidant, was to later marry their
son, Paul, and his friend, Michele Besso, married their other daughter,
Anna. Einstein subsequently enrolled at the Federal Polytechnic Institute
in October and moved to Zürich, while Marie moved to Olsberg, Switzerland
for a teaching post. The same year, he renounced his Württemberg
In the spring of
1896, the Serbian Mileva Maric started initially as a medical student
at the University of Zürich, but after a term switched to the Federal
Polytechnic Institute to study as the only woman that year for the same
diploma as Einstein. Maric's relationship with Einstein developed into
romance over the next few years, though his mother would cry that she
was too old, not Jewish, and physically defective.
In 1900, Einstein
was granted a teaching diploma by the Federal Polytechnic Institute.
Einstein then submitted his first paper to be published, on the capillary
forces of a drinking straw, titled "Folgerungen aus den Capillaritätserscheinungen",
which translated is "Consequences of the observations of capillarity
phenomena" (found in "Annalen der Physik" volume 4, page
513). In it, he tried to unify the laws of physics, an attempt he would
continually make throughout his life. Through his friend Michele Besso,
an engineer, Einstein was presented with the works of Ernst Mach, and
would later consider him "the best sounding board in Europe"
for physical ideas. During this time, Einstein discussed his scientific
interests with a group of close friends, including Besso and Maric.
The men referred to themselves as the "Olympia Academy". Einstein
and Maric had a daughter out of wedlock, Lieserl Einstein, born in January
1902. Her fate is unknown; some believe she died in infancy, while others
believe she was given out for adoption.
Works and doctorate
Einstein in 1905, when he wrote the "Annus Mirabilis Papers"Einstein
could not find a teaching post upon graduation, mostly because his brashness
as a young man had apparently irritated most of his professors. The
father of a classmate helped him obtain employment as a technical assistant
examiner at the Swiss Patent Office in 1902. There, Einstein judged
the worth of inventors' patent applications for devices that required
a knowledge of physics to understand — in particular he was chiefly
charged to evaluate patents relating to electromagnetic devices.
He also learned how to discern the essence of applications despite sometimes
poor descriptions, and was taught by the director how "to express
[him]self correctly". He occasionally rectified their design errors
while evaluating the practicality of their work.
Mileva Maric on January 6, 1903. Einstein's marriage to Maric, who was
a mathematician, was both a personal and intellectual partnership: Einstein
referred to Mileva as "a creature who is my equal and who is as
strong and independent as I am". Ronald W. Clark, a biographer
of Einstein, claimed that Einstein depended on the distance that existed
in his marriage to Mileva in order to have the solitude necessary to
accomplish his work; he required intellectual isolation. Abram Joffe,
a Soviet physicist who knew Einstein, wrote in an obituary of him, "The
author of [the papers of 1905] was… a bureaucrat at the Patent
Office in Bern, Einstein-Maric" and this has recently been taken
as evidence of a collaborative relationship. However, according to Alberto
A. Martínez of the Center for Einstein Studies at Boston University,
Joffe only ascribed authorship to Einstein, as he believed that it was
a Swiss custom at the time to append the spouse's last name to the husband's
name. The extent of her influence on Einstein's work is a controversial
and debated question.
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 under Alfred Kleiner
at the University of Zürich after submitting his thesis "A
new determination of molecular dimensions" ("Eine neue Bestimmung
der Moleküldimensionen") in 1905.
During 1905, in his spare time, he wrote four articles that participated
in 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; at the time of the
award, it had the most unchallenged experimental evidence behind it,
although the Nobel committee expressed the opinion that Einstein's other
work would be confirmed in due course.
Some might regard
the award for the photoelectric effect 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.
this 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) commemorated 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", ("Über einen die Erzeugung und Verwandlung
des Lichtes betreffenden heuristischen Gesichtspunkt") was specifically
cited for his Nobel Prize. In this paper, Einstein extends Planck's
hypothesis (E = h?) of discrete energy elements to his own hypothesis
that electromagnetic energy is absorbed or emitted by matter in quanta
of h? (where h is Planck's constant and ? is the frequency of the light),
proposing a new law
to account for the photoelectric effect, as well as other properties
of photoluminescence and photoionization. In later papers, Einstein
used this law to describe the Volta effect (1906), the production of
secondary cathode rays (1909) and the high-frequency limit of Bremsstrahlung
(1911). Einstein's key contribution is his assertion that energy quantization
is a general, intrinsic property of light, rather than a particular
constraint of the interaction between matter and light, as Planck believed.
Another, often overlooked result of this paper was Einstein's excellent
estimate (6.17 1023) of Avogadro's number (6.02 1023). However, Einstein
does not propose that light is a particle in this paper; the "photon"
concept was not proposed until 1909 (see below).
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",
("Über die von der molekularkinetischen Theorie der Wärme
geforderte Bewegung von in ruhenden Flüssigkeiten 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.
Brownian motion was also explained by Louis Bachelier in 1900.
paper that year, "On the Electrodynamics of Moving Bodies"
("Zur Elektrodynamik bewegter Körper"), was published
in June 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 speculate that Mileva played
a part in its development.
A few historians
of science believe that Einstein and his wife were both aware that the
famous French mathematical physicist Henri Poincaré had already
published the equations of relativity, a few weeks before Einstein submitted
his paper. Most believe their work was independent and varied in many
crucial ways, namely, regarding the "ether" (Einstein denied
ether, Poincaré considered it superfluous). Similarly, it is
debatable if he knew the 1904 paper of Hendrik Antoon Lorentz which
contained most of the theory and to which Poincaré referred.
Most historians, however, believe that Einsteinian relativity varied
in many key ways from other theories of relativity which were circulating
at the time, and that many of the questions about priority stem from
the misleading trope of portraying Einstein as a genius working in total
isolation. Although Einstein discussed physics with Mileva, there
is no solid evidence that she made any significant contribution to his
In a fourth paper,
"Does the Inertia of a Body Depend Upon Its Energy Content?",
("Ist die Trägheit eines Körpers von seinem Energieinhalt
abhängig?"), published late in 1905, he showed that from relativity's
axioms, it is possible to deduce the famous equation which shows the
equivalence between matter and energy. The energy equivalence (E) of
some amount of mass (m) is that mass times the speed of light (c) squared:
E = mc2. However, it was Poincaré who in 1900 first published
the "energy equation" in slightly different form, namely as:
m = E / c2 — see also relativity priority dispute.
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).
During this time, Einstein described why the sky is blue in his paper
on the phenomenon of critical opalescence, which shows the cumulative
effect of scattering of light by individual molecules in the atmosphere.
In 1911, Einstein became first associate professor at the University
of Zürich, and shortly afterwards full professor at the German
language-section of the Charles University of Prague. While at Prague,
Einstein published a paper calling on astronomers to test two predictions
of his developing theory of relativity: a bending of light in a gravitational
field, measurable at a solar eclipse; and a redshift of solar spectral
lines relative to spectral lines produced on Earth's surface. A young
German astronomer, Erwin Freundlich, began collaborating with Einstein
and alerted other astronomers around the world about Einstein's astronomical
tests. In 1912, Einstein returned to Zürich in order to become
full professor at the ETH Zürich. At that time, he worked closely
with the mathematician Marcel Grossmann, who introduced him to Riemannian
geometry. 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 Prussian citizenship. From 1914 to 1933, he served
as director of the Kaiser Wilhelm Institute for Physics in Berlin. He
also held the position of extraordinary professor at the University
of Leiden from 1920 until 1946, where he regularly gave guest lectures.
In 1917, Einstein
published "On the Quantum Mechanics of Radiation" ("Zur
Quantentheorie der Strahlung," Physkalische Zeitschrift 18, 121–128).
This article introduced the concept of stimulated emission, the physical
principle that allows light amplification in the laser. He also published
a paper that year that used the general theory of relativity to model
the behavior of the entire universe, setting the stage for modern cosmology.
In this work Einstein created the cosmological constant, which he later
considered his "biggest blunder".
On May 14, 1904,
Albert and Mileva's first son, Hans Albert Einstein, was born. Their
second son, Eduard Einstein, was born on July 28, 1910. Hans Albert
became a professor of hydraulic engineering at the University of California,
Berkeley, having little interaction with his father, but sharing his
love for sailing and music. Eduard, the younger brother, intended to
practice as a Freudian analyst but was institutionalized for schizophrenia
and died in an asylum. Einstein divorced Mileva on February 14, 1919,
and married his cousin Elsa Löwenthal (born Einstein: Löwenthal
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.
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 a new theory of gravity,
known as general relativity. The final lecture ended with his introduction
of an equation that replaced Newton's law of gravity, the Einstein field
equation. This theory considered all observers to be equivalent,
not only those moving at a uniform speed. In general relativity, gravity
is no longer a force (as it is in Newton's law of gravity) but is a
consequence of the curvature of space-time.
papers on general relativity were not available outside of Germany due
to the war. News of Einstein's new theory reached English-speaking astronomers
in England and America via Dutch physicists Hendrik Antoon Lorentz and
Paul Ehrenfest and their colleague Willem de Sitter, Director of Leiden
Observatory. Arthur Stanley Eddington in England, who was Secretary
of the Royal Astronomical Society, asked de Sitter to write a series
of articles in English for the benefit of astronomers. He was fascinated
with the new theory and became a leading proponent and popularizer of
relativity. Most astronomers did not like Einstein's geometrization
of gravity and believed that his light bending and gravitational redshift
predictions would not be correct. In 1917, astronomers at Mt. Wilson
Observatory in southern California published results of spectroscopic
analysis of the solar spectrum that seemed to indicate that there was
no gravitational redshift in the Sun. In 1918, astronomers at Lick
Observatory in northern California obtained photographs at a solar eclipse
visible in the United States. After the war ended, they announced results
claiming that Einstein's general relativity prediction of light bending
was wrong; but they never published their results due to large probable
In May, 1919 during
British solar-eclipse expeditions (carried out in Sobral, Ceará,
Brazil, as well as on the island of Principe, at the west coast of Africa)
Arthur Eddington supervised measurements of the bending of star light
as it passed close to the Sun, resulting in star positions appearing
further away from the Sun. This effect is called gravitational lensing
and the positions of the stars observed were twice that which would
be predicted by Newtonian physics.  These observations match that
predicted by the Field Equation of general relativity. Eddington announced
that the results confirmed Einstein's prediction and The Times reported
that confirmation on November 7 of that year, with the headline: "Revolution
in science – New theory of the Universe – Newtonian ideas
overthrown". Nobel laureate Max Born viewed General Relativity
as the "greatest feat of human thinking about nature"; fellow
laureate Paul Dirac called it "probably the greatest scientific
discovery ever made". These comments and resulting publicity
cemented Einstein's fame. He became world-famous – an unusual
achievement for a scientist.
were still unconvinced for various reasons ranging from the scientific
(disagreement with Einstein's interpretation of the experiments, belief
in the ether or that an absolute frame of reference was necessary) to
the psycho-social (conservatism, anti-Semitism). In Einstein's view,
most of the objections were from experimentalists with very little understanding
of the theory involved. Einstein's public fame which followed the
1919 article created resentment among these scientists, some of which
lasted well into the 1930s.
On March 30, 1921,
Einstein went to New York to give a lecture on his new Theory of Relativity,
the same year he was awarded the Nobel Prize. Though he is now most
famous for his work on relativity, it was for his earlier work on the
photoelectric effect that he was given the Prize, as his work on general
relativity was still disputed. The Nobel committee decided that citing
his less-contested theory in the Prize would gain more acceptance from
the scientific community.
Einstein and Niels Bohr sparred over quantum theory during the 1920s.
Photo taken by Paul Ehrenfest during their visit to Leiden in December
1925In 1909, Einstein presented a paper (Über die Entwicklung unserer
Anschauungen über das Wesen und die Konstitution der Strahlung,
available in its English translation The Development of Our Views on
the Composition and Essence of Radiation) to a gathering of physicists
on the history of aether theories and, more importantly, on the quantization
of light. In this and an earlier 1909 paper, Einstein showed that the
energy quanta introduced by Max Planck also carried a well-defined momentum
and acted in many respects as if they were independent, point-like particles.
This paper marks the introduction of the modern "photon" concept
(although the term itself was introduced much later, in a 1926 paper
by Gilbert N. Lewis). Even more importantly, Einstein showed that light
must be simultaneously a wave and a particle, and foretold correctly
that physics stood on the brink of a revolution that would require them
to unite these dual natures of light. However, his own proposal for
a solution — that Maxwell's equations for electromagnetic fields
be modified to allow wave solutions that are bound to singularities
of the field — was never developed, although it may have influenced
Louis de Broglie's pilot wave hypothesis for quantum mechanics.
Beginning in the mid-1920s, as the original quantum theory was replaced
with a new theory of quantum mechanics, Einstein voiced his objections
to the Copenhagen interpretation of the new equations. His opposition
in this regard would continue all his life. The majority see the reason
for his objection in terms of the view that he was a rigid determinist
(see determinism). They would cite a 1926 letter to Max Born, where
Einstein made the remark which history recalls the most:
is certainly imposing. But an inner voice tells me it is not yet the
real thing. The theory says a lot, but does not really bring us any
closer to the secret of the Old One. I, at any rate, am convinced that
He does not throw dice.
To this, Bohr, who
sparred with Einstein on quantum theory, retorted, "Stop telling
God what He must do!" The Bohr-Einstein debates on foundational
aspects of quantum mechanics happened during the Solvay Conferences.
Another important part of Einstein's viewpoint is the famous 1935 paper
written by Einstein, Podolsky, and Rosen. Some physicists see this work
as further supporting the notion that Einstein was a determinist.
There is a case
to be made, however, for a quite different view of Einstein's objections
to quantum orthodoxy. Einstein himself made further statements beyond
that just given, and an emphatic comment on the matter was made by his
contemporary Wolfgang Pauli. The above 'God does not play dice' quotation
was something stated quite early, and Einstein's later statements were
concerned with other issues. The Wolfgang Pauli quotation is as follows:
…I was unable
to recognize Einstein whenever you talked about him in either your letter
or your manuscript. It seemed to me as if you had erected some dummy
Einstein for yourself, which you then knocked down with great pomp.
In particular Einstein does not consider the concept of `determinism'
to be as fundamental as it is frequently held to be (as he told me emphatically
many times) …he disputes that he uses as a criterion for the admissibility
of a theory the question "Is it rigorously deterministic?"…
he was not at all annoyed with you, but only said that you were a person
who will not listen.
(emphasis due to Pauli)
The Albert Einstein Memorial, Washington DC at the National Academy
of Sciences in Washington, DC.Many of Einstein's comments indicate his
belief that quantum mechanics is 'incomplete'. This was first asserted
in the famous 1935 Einstein, Podolsky, Rosen (EPR paradox) paper,
and it appears again in the 1949 book Albert Einstein, Philosopher-Scientist.
The "EPR" paper — entitled "Can Quantum Mechanical
Description of Physical Reality Be Considered Complete?" —
concluded: "While we have thus shown that the wave function does
not provide a complete description of the physical reality, we left
open the question of whether or not such a description exists. We believe,
however, that such a theory is possible."
In the Schilpp book,
Einstein sets up a fascinating experimental proposal somewhat similar
to Schrödinger's cat. He begins by addressing the problem of the
radioactive decay of an atom. If one begins with an undecayed atom and
one waits a certain time interval, then quantum theory gives the probability
that the atom has undergone the transformation of radioactive decay.
Einstein then imagines the following system as a means to detect the
Rather than considering
a system which comprises only a radioactive atom (and its process of
transformation), one considers a system which includes also the means
for ascertaining the radioactive transformation — for example,
a Geiger-counter with automatic registration mechanism. Let this include
a registration-strip, moved by a clockwork, upon which a mark is made
by tripping the counter. True, from the point of view of quantum mechanics
this total system is very complex and its configuration space is of
very high dimension. But there is in principle no objection to treating
this entire system from the standpoint of quantum mechanics. Here too
the theory determines the probability of each configuration of all coordinates
for every time instant. If one considers all configurations of the coordinates,
for a time large compared with the average decay time of the radioactive
atom, there will be (at most) one such registration-mark on the paper
strip. To each co-ordinate- configuration must correspond a definite
position of the mark on the paper strip. But, inasmuch as the theory
yields only the relative probability of the thinkable coordinate-configurations,
it also offers only relative probabilities for the positions of the
mark on the paperstrip, but no definite location for this mark.
…If we attempt
[to work with] the interpretation that the quantum-theoretical description
is to be understood as a complete description of the individual system,
we are forced to the interpretation that the location of the mark on
the strip is nothing which belongs to the system per se, but that the
existence of that location is essentially dependent upon the carrying
out of an observation made on the registration-strip. Such an interpretation
is certainly by no means absurd from a purely logical point of standpoint;
yet there is hardly anyone who would be inclined to consider it seriously.
For, in the macroscopic sphere it simply is considered certain that
one must adhere to the program of a realistic description in space and
time; whereas in the sphere of microscopic situations, one is more readily
inclined to give up, or at least to modify, this program."
(emphasis due to Einstein)
Einstein never rejected
probabilistic techniques and thinking, in and of themselves. Einstein
himself was a great statistician, using statistical analysis in
his works on Brownian motion and photoelectricity and in papers published
before 1905; Einstein had even discovered Gibbs ensembles. According
to the majority of physicists, however, he believed that indeterminism
constituted a criteria for strong objection to a physical theory. Pauli's
testimony contradicts this, and Einstein's own statements indicate a
focus on incompleteness, as his major concern.
More recent times
have given us another twist to this business. John Stewart Bell discovered
further interesting results (Bell's Theorem and Bell's inequality) in
his researches on the Einstein, Podolsky, and Rosen paper. There is
a divergence in thinking as to the conclusions derivable from this,
in conjunction with the EPR analysis. According to Bell, quantum nonlocality
has been established, while others see the death of determinism.
Whatever his inner convictions, Einstein agreed that the quantum theory
was the best available, but he looked for a more "complete"
explanation, i.e., either more deterministic or one that could more
fundamentally explain the reason for probabilities in a logical way.
He could not abandon the belief that physics described the laws that
govern "real things", nor could he abandon the belief that
there are no explanations that contain contradictions, which had driven
him to his successes explaining photons, relativity, atoms, and gravity.
In 1924, Einstein received a short paper from a young Indian physicist
named Satyendra Nath Bose describing light as a gas of photons and asking
for Einstein's assistance in publication. Einstein realized that the
same statistics could be applied to atoms, and published an article
in German (then the lingua franca of physics) which described Bose's
model and explained its implications. Bose-Einstein statistics now describe
any assembly of these indistinguishable particles known as bosons. The
Bose-Einstein condensate phenomenon was predicted in the 1920s by Bose
and Einstein, based on Bose's work on the statistical mechanics of photons,
which was then formalized and generalized by Einstein. The first such
condensate in alkali gases was produced by Eric Cornell and Carl Wieman
in 1995 at the University of Colorado at Boulder, though Bose-Einstein
Condensation has been observed in superfluid Helium-4 since the 1930s.[citation
needed] Einstein's original sketches on this theory were recovered in
August 2005 in the library of Leiden University.
Einstein also assisted
Erwin Schrödinger in the development of the quantum Boltzmann distribution,
a mixed classical and quantum mechanical gas model although he realized
that this was less significant than the Bose-Einstein model and declined
to have his name included on the paper.
Einstein and Szilárd's patent diagram for the Einstein refrigerator.In
1926, Einstein and former student Leó Szilárd co-invented
the Einstein refrigerator. On November 11, 1930, U.S. Patent 1,781,541
was awarded to Albert Einstein and Leó Szilárd for the
refrigerator. The patent covered a thermodynamic refrigeration cycle
providing cooling with no moving parts, at a constant pressure, with
only heat as an input. The refrigeration cycle used ammonia, butane,
World War II
When Adolf Hitler came to power in January 1933, Einstein was a guest
professor at Princeton University, a position which he took in December
1932, after an invitation from the American educator, Abraham Flexner.
In 1933, the Nazis passed "The Law of the Restoration of the Civil
Service," which forced all Jewish university professors out of
their jobs. Throughout the 1930s, a campaign to label Einstein's work
as "Jewish physics"—in contrast with "German"
or "Aryan physics"—was led by Nobel laureates Philipp
Lenard and Johannes Stark. With the assistance of the SS, the Deutsche
Physik supporters worked to publish pamphlets and textbooks denigrating
Einstein's theories and attempted to politically blacklist German physicists
who taught them, notably Werner Heisenberg. Einstein renounced his Prussian
citizenship and stayed in the United States, where he was given permanent
residency. He accepted a position at the newly founded Institute for
Advanced Study in Princeton, New Jersey, where he concentrated on developing
a unified field theory (see below). Einstein became an American citizen
in 1940, though he still retained Swiss citizenship.
In 1939, under the
encouragement of Szilárd, Einstein sent a letter to President
Franklin Delano Roosevelt urging the study of nuclear fission for military
purposes, under fears that the Nazi government would be first to develop
nuclear weapons. Roosevelt started a small investigation into the matter
which eventually became the massive Manhattan Project. Einstein himself
did not work on the bomb project, however, and, according to Linus Pauling,
he later regretted having signed this letter.
Rescue Committee was founded in 1933 at the request of Albert Einstein
to assist opponents of Adolf Hitler.
In 1948, Einstein served on the original committee which resulted in
the founding of Brandeis University. A portrait of Einstein was taken
by Yousuf Karsh on February 11 of that same year. In 1952, the Israeli
government proposed to Einstein that he take the post of second president.
He declined the offer, and is believed to be the only United States
citizen ever to have been offered a position as a foreign head of state.
Einstein's refusal might have stemmed from his disapproval of some of
the Israeli policies during the war of independence. In a letter he
signed, along with other Jewish leaders in the U.S., he criticised the
Freedom Party under the leadership of Menachem Begin for "Nazi
and Fascist" methods and philosophy. On March 30, 1953, Einstein
released a revised unified field theory.
He died at 1:15
AM in Princeton hospital in Princeton, New Jersey, on April
18, 1955 at the age of 76 from internal bleeding, which was caused by
the rupture of an aortic aneurism, leaving the Generalized Theory of
Gravitation unsolved. The only person present at his deathbed, a hospital
nurse, said that just before his death he mumbled several words in German
that she did not understand. He was cremated without ceremony on the
same day he died at Trenton, New Jersey, in accordance with his wishes.
His ashes were scattered at an undisclosed location.
An autopsy was performed
on Einstein by Dr. Thomas Stoltz Harvey, who removed and preserved his
brain. Harvey found nothing unusual with his brain, but in 1999 further
analysis by a team at McMaster University revealed that his parietal
operculum region was missing and, to compensate, his inferior parietal
lobe was 15% wider than normal. The inferior parietal region is
responsible for mathematical thought, visuospatial cognition, and imagery
of movement. Einstein's brain also contained 73% more glial cells than
the average brain.
Einstein was an Honorary Associate of the Rationalist Press Association
beginning in 1934, and was an admirer of Ethical Culture. He served
on the advisory board of the First Humanist Society of New York.
Quotations on religion
I came — though the child of entirely irreligious (Jewish) parents
— to a deep religiousness, which, however, reached an abrupt end
at the age of twelve.
I do not think that
it is necessarily the case that science and religion are natural opposites.
In fact, I think that there is a very close connection between the two.
Further, I think that science without religion is lame and, conversely,
that religion without science is blind. Both are important and should
A Jew who sheds
his faith along the way, or who even picks up a different one, is still
As an adult, he called his religion a "cosmic religious sense".
In The World As
I See It he wrote:
You will hardly
find one among the profounder sort of scientific minds without a peculiar
religious feeling of his own. But it is different from the religion
of the naive man.
For the latter God
is a being from whose care one hopes to benefit and whose punishment
one fears; a sublimation of a feeling similar to that of a child for
its father, a being to whom one stands to some extent in a personal
relation, however deeply it may be tinged with awe.
But the scientist
is possessed by the sense of universal causation. The future, to him,
is every whit as necessary and determined as the past. There is nothing
divine about morality, it is a purely human affair. His religious feeling
takes the form of a rapturous amazement at the harmony of natural law,
which reveals an intelligence of such superiority that, compared with
it, all the systematic thinking and acting of human beings is an utterly
In response to the
telegrammed question of New York's Rabbi Herbert S. Goldstein in 1929:
"Do you believe in God? Stop. Answer paid 50 words." Einstein
replied "I believe in Spinoza's God, Who reveals Himself in the
lawful harmony of the world, not in a God Who concerns Himself with
the fate and the doings of mankind." Note that Einstein replied
in only 25 (German) words. Spinoza was a naturalistic pantheist.
In the "Copenhagen Interpretation" section (1.3.2) above,
reference was made to the disagreement regarding Einstein's actual position
regarding the quantum theory. The famous quotation "God does not
play dice" is often used to support the majority view that he disliked
the theory due to its indeterminism.
Others make the
case for a different view. They note that the 1926 "Dice"
quotation occurred when the quantum theory was just in its first year
of discovery and in the subsequent 30 years of his life, one would be
hard pressed to find a similar comment from the man. Instead Einstein
focused on the conceptually independent subject of 'incompleteness'.
This attention is shown both in his 1935 "EPR" paper, and
in his 1949 Geiger counter registration strip thought-experiment (see
section 22.214.171.124). Further evidence against the "Einstein-determinist"
view is W. Pauli's quotation: "he (Einstein) disputes that he uses
as a criterion for the admissibility of a theory the question 'Is it
In favor of the
deterministic view are the following statements of Einstein:
But the scientist
is possessed by the sense of universal causation. The future, to him,
is every whit as necessary and determined as the past. and:
People like us,
who believe in physics, know that the distinction between past, present,
and future is only a stubbornly persistent illusion. His devotion
to Schopenhauer can be cited:
I do not believe
in freedom of the will. Schopenhauer's words: “Man can do what
he wants, but he cannot will what he wills ” accompany me in all
situations throughout my life and reconcile me with the actions of others
even if they are rather painful to me. This awareness of the lack of
freedom of will preserves me from taking too seriously myself and my
fellow men as acting and deciding individuals and from losing my temper.
Einstein believed that true theorists always take some position on the
metaphysics behind what they do:
I believe that every
true theorist is a kind of tamed metaphysicist, no matter how pure a
'positivist' he may fancy himself. The metaphysicist believes that the
logically simple is also the real. The tamed metaphysicist believes
that not all that is logically simple is embodied in experienced reality,
but that the totality of all sensory experience can be 'comprehended'
on the basis of a conceptual system built on premises of great simplicity.
The following general assessment was given by his colleague Nathan
I think that the
things which impressed me most were the simplicity of his thinking and
his faith in the ability of the human mind to understand the workings
of nature. Throughout his life, Einstein believed the human reason was
capable of leading to theories that would provide correct descriptions
of physical phenomena. In building a theory, his approach had something
in common with that of an artist; he would aim for simplicity and beauty
(and beauty for him was, after all, essentially simplicity). The crucial
question that he would ask, when weighing an element of a theory was:
"Is it reasonable?" No matter how successful a theory appeared
to be, if it seemed to him not to be reasonable (the German word that
he used was "vernunftig"), he was convinced that the theory
could not provide a really fundamental understanding of nature.
.Einstein considered himself a pacifist and humanitarian, and
in later years, a committed democratic socialist. He once said, "I
believe Gandhi's views were the most enlightened of all the political
men of our time. We should strive to do things in his spirit: not to
use violence for fighting for our cause, but by non-participation of
anything you believe is evil." Deeply influenced by Gandhi, Einstein
once said of Gandhi, "Generations to come will scarce believe that
such a one as this ever in flesh and blood walked upon this earth."
Einstein's views were sometimes controversial. In a 1949 article entitled
"Why Socialism?", Albert Einstein described the "predatory
phase of human development", exemplified by a chaotic capitalist
society, as a source of evil to be overcome. He disapproved of the totalitarian
regimes in the Soviet Union and elsewhere, and argued in favor of a
democratic socialist system which would combine a planned economy with
a deep respect for human rights. Einstein was a co-founder of the liberal
German Democratic Party and a member of the AFL-CIO-affiliated union
the American Federation of Teachers.
Einstein was very
much involved in the Civil Rights movement. He was a close friend of
Paul Robeson for over 20 years. Einstein was a member of several civil
rights groups (including the Princeton chapter of the NAACP) many of
which were headed by Paul Robeson. He served as co-chair with Paul Robeson
of the American Crusade to End Lynching. When W.E.B. DuBois was frivolously
charged with being a communist spy during the McCarthy era while he
was in his 80s, Einstein volunteered as a character witness in the case.
The case was dismissed shortly after it was announced that he was to
appear in that capacity. Einstein was quoted as saying that "racism
is America's greatest disease".
The U.S. FBI kept
a 1,427 page file on his activities and recommended that he be barred
from immigrating to the United States under the Alien Exclusion Act,
alleging that Einstein "believes in, advises, advocates, or teaches
a doctrine which, in a legal sense, as held by the courts in other cases,
'would allow anarchy to stalk in unmolested' and result in 'government
in name only'", among other charges. They also alleged that Einstein
"was a member, sponsor, or affiliated with thirty-four communist
fronts between 1937 and 1954" and "also served as honorary
chairman for three communist organizations". Many of the documents
in the file were submitted to the FBI, mainly by civilian political
groups, and not written by the FBI.
In 1939, Einstein
signed a letter, written by Leó Szilárd, to President
Roosevelt arguing that the United States should start funding research
into the development of nuclear weapons.Einstein opposed tyrannical
forms of government, and for this reason (and his Jewish background),
opposed the Nazi regime and fled Germany shortly after it came to power.
Einstein initially favored construction of the atomic bomb, in order
to ensure that Hitler did not do so first, and even sent a letter to
President Roosevelt (dated August 2, 1939, before World War II broke
out, and probably written by Leó Szilárd) encouraging
him to initiate a program to create a nuclear weapon. Roosevelt responded
to this by setting up a committee for the investigation of using uranium
as a weapon, which in a few years was superseded by the Manhattan Project.
After the war, though,
Einstein lobbied for nuclear disarmament and a world government: "I
do not know how the Third World War will be fought, but World War IV
will be fought with sticks and stones."
A 5 Israeli pound
note from 1968 with the portrait of Einstein.While Einstein was a supporter
of Zionism in the cultural sense, he often expressed reservations regarding
its application in terms of nationalism. During a speech at the Commodore
Hotel in New York, he told the crowd "My awareness of the essential
nature of Judaism resists the idea of a Jewish state with borders, an
army, and a measure of temporal power, no matter how modest. I am afraid
of the inner damage Judaism will sustain." He also signed an
open letter published in the New York Times condemning Menachem Begin
and his nationalistic Herut party, especially for the treatment of the
indigenous Arabs at Deir Yassin by Herut’s predecessor Irgun.
Despite these reservations,
he was active in the establishment of the Hebrew University in Jerusalem,
which published (1930) a volume titled About Zionism: Speeches and Lectures
by Professor Albert Einstein, and to which Einstein bequeathed his papers.
In later life, in 1952, he was offered the post of second president
of the newly created state of Israel, but declined the offer, saying
that he lacked the necessary people skills. However, Einstein was deeply
committed to the welfare of Israel and the Jewish people for the rest
of his life.
was closely associated with plans for what the press called "a
Jewish-sponsored non-quota university," from August 19, 1946, with
the announcement of the formation of the Albert Einstein Foundation
for Higher Learning, Inc. until June 22, 1947, when he withdrew support
and barred the use of his name by the foundation. The university opened
in 1948 as Brandeis University.
with Albert Schweitzer and Bertrand Russell, fought against nuclear
tests and bombs. As his last public act, and just days before his death,
he signed the Russell-Einstein Manifesto, which led to the Pugwash Conferences
on Science and World Affairs.
Einstein was born a German citizen. At the age of 17, on January 28,
1896, he was released from his German citizenship by his own request
and with the approval of his father. He remained stateless for five
years. On February 21, 1901, he gained Swiss citizenship, which he never
revoked. Einstein obtained Prussian citizenship in April 1914 when he
entered the Prussian civil service, but due to the political situation
and the persecution of Jewish people in Nazi Germany, he left civil
service in March 1933 and thus also lost the Prussian citizenship. On
October 1, 1940, Einstein became an American citizen. He remained both
an American and a Swiss citizen until his death on April 18, 1955.
Popularity and cultural
According to "A Ranking of the Most Influential Persons in History",
Einstein is "the greatest scientist of the twentieth century and
one of the supreme intellects of all time". His popularity
has also led to widespread use of Einstein's image in advertising and
merchandising, including the registration of "Albert Einstein"
as a trademark.
Albert Einstein has been the subject of and inspiration for a number
of novels, films and plays, including Jean-Claude Carrier's 2005 French
novel, Einstein S'il Vous Plait (Please Mr Einstein), Nicolas Roeg's
film Insignificance, Fred Schepisi's film I.Q. (where he was portrayed
by Walter Matthau), Alan Lightman's collection of short stories Einstein's
Dreams, and Steve Martin's comedic play Picasso at the Lapin Agile.
He was the subject of Philip Glass's groundbreaking 1976 opera Einstein
on the Beach. His humorous side is also the subject of Ed Metzger's
one-man play Albert Einstein: The Practical Bohemian.
He is often used
as a model for depictions of mad scientists and absent-minded professors
in works of fiction; his own character and distinctive hairstyle suggest
eccentricity, or even lunacy, and are widely copied or exaggerated.
TIME magazine writer Frederic Golden referred to Einstein as "a
cartoonist's dream come true."
On Einstein's 72nd
birthday in 1951, the UPI photographer Arthur Sasse was trying to persuade
him to smile for the camera. Having done this for the photographer many
times that day, Einstein stuck out his tongue instead. The image
has become an icon in pop culture for its contrast of the genius scientist
displaying a moment of levity. Yahoo Serious, an Australian film maker,
used the photo as an inspiration for the intentionally anachronistic
movie Young Einstein. The image is also used in a poster used in the
UK as part of dyslexia education, which has a string of posters showing
great scientists, thinkers and artists and talks about the unfounded
(not specified within the posters) claims that they had/have dyslexia.
There are innumerable speculations which suggest that Einstein was a
poor student, a slow learner, or had a form of autism (such as High-functioning
autism, or Asperger syndrome), dyslexia, and/or attention-deficit hyperactivity
disorder. According to the biography by Pais (page 36, among others),
such speculations are unfounded. Some researchers have periodically
claimed otherwise, but most historians and doctors are skeptical
of retrospective medical diagnoses, especially for complex and, in the
case of ADHD, diagnostically-controversial conditions. Examinations
of Albert Einstein's brain after his death have not produced any conclusive
evidence of any particular condition.
rumor that Einstein failed in mathematics during his education is untrue.
On the contrary, Einstein always showed great talent at mathematics;
when he obtained his matura, he obtained the best mark (6/6) in algebra,
geometry, physics and history, among all of the classes that he took.
The grading system of Switzerland, where 6 is the best mark, may have
been confused with the German system, in which 1 is the best mark. As
can be seen from his Matura grades, indicated in the graphic to the
right (also found in "Einstein: A Hundred Years of Relativity"
by W. Andrew Robinson, p.27), Albert Einstein did receive poor grades
(4/6) in drawing, (both artistic- and technical) and geography. His
performance (5/6) in all other subjects studied in high school, namely
Natural history, German literature and Italian literature as well as
chemistry, was significantly above average. Einstein also completed
English studies, for which he received no grade. One may reasonably
presume that Einstein only excelled in the subjects he deemed relevant
or necessary to pursue his scientific interests.
As for Einstein's
childhood trait of delayed speech development, a few have speculated
that Einstein had elective mutism and may have refused to speak until
he could do so in complete sentences. Though this concept fits with
a profile of a sensitive perfectionist (when Einstein did begin to speak,
he would often softly "rehearse" what he meant to say before
uttering the statement outright), it is somewhat dated insofar as selective
mutism- as it is now known- is no longer considered to be a matter of
willful silence: it presently refers to individuals with verbal ability
who cannot speak in certain social circumstances. This would not
apply to Einstein, who could not speak at all until the time that he
According to neuroscientist
Steven Pinker, the autopsy of Einstein's brain exhibited a more likely
possibility that Einstein, as a child, had been displaying a lesser
known type of speech delay relating to extraordinary and rapid prenatal
development of areas of the brain responsible for spatial and analytical
reasoning which, in competing for "brain real estate", had
temporarily robbed resources from functions of the brain responsible
for speech development.  Pinker and others have extended this speculation
to explain the asynchronous development of other famously gifted late-talkers,
such as mathematician Julia Robinson, pianists Arthur Rubinstein and
Clara Schumann, and physicists Richard Feynman and Edward Teller, to
name a few, who were also said to have shared several of Einstein's
other childhood peculiarities, such as monumental tantrums, rugged individualism
and highly selective interests. A syndrome — the "Einstein
syndrome" — was even coined by journalist and economist Thomas
Sowell as a non-pathologizing means to describe this series of traits
seen in a small percentage (though how small is debatable) of late-talking
children who go on to develop into analytically advanced and socially
conscious adults without (or in spite of) intense therapeutic intervention.
Letters written by Einstein to his relatives and kept at the Hebrew
University of Jerusalem, have revealed that during the course of his
life, he had a dozen lovers, two of whom he married. Barbara Wolff
of the Hebrew University's Albert Einstein Archives has made public
about 3,500 pages of correspondence including letters to his first and
second wives and children between the years 1912–1955. In letters
to his second wife Elsa and her daughter Margot he claimed that he had
been showered with unwanted attention from women. One of his lovers,
a Berlin socialite Ethel Michanowski, "followed me [to England],
and her chasing me is getting out of control." His son Eduard's
schizophrenia troubled Einstein greatly, and he often expressed the
idea that it would have been better if Eduard had not been born. He
adored his stepdaughter and in a letter to Elsa in 1924, he writes:
"I love her [Margot] as much as if she were my own daughter, perhaps
even more so, since who knows what kind of brat she would have become
[had I fathered her]." The letters have been claimed as evidence
to dispel myths that Einstein was cold toward his family.
Einstein bequeathed his estate, as well as the use of his image (see
personality rights), to the Hebrew University of Jerusalem. Einstein
actively supported the university during his life and this support continues
with the royalties received from licensing activities. The Roger Richman
Agency licences the commercial use of the name "Albert Einstein"
and associated imagery and likenesses of Einstein, as agent for the
Hebrew University of Jerusalem. As head licensee the agency can control
commercial usage of Einstein's name which does not comply with certain
standards (e.g., when Einstein's name is used as a trademark, the ™
symbol must be used). As of May, 2005, the Roger Richman Agency
was acquired by Corbis.
Einstein on the cover of TIME as Person of the Century.Einstein has
received a number of posthumous honors. For example:
In 1999, he was
named Person of the Century by TIME magazine. Also in 1999, Gallup Poll
recorded him as the fourth most admired person of the 20th century.
The year 2005 was designated as the "World Year of Physics"
by UNESCO for its coinciding with the centennial of the "Annus
Mirabilis" papers. The National Academy of Sciences commissioned
the "Albert Einstein Memorial", a monumental bronze sculptor
by Robert Berks, at its Washington, D.C. campus, adjacent to the National
many namesakes are:
a unit used
in photochemistry, the einstein.
the chemical element 99, einsteinium.
the asteroid 2001 Einstein.
the Albert Einstein Award.
the Albert Einstein Peace Prize.
the Albert Einstein College of Medicine of Yeshiva University opened
the Albert Einstein Medical Center in Philadelphia, Pennsylvania.
physicist Albert Einstein, b. Ulm, Germany, Mar. 14, 1879, d. Princeton,
N.J., Apr. 18, 1955, contributed more than any other scientist to the
20th-century vision of physical reality. In the wake of World War I,
Einstein's theories--especially his theory of relativity--seemed to
many people to point to a pure quality of human thought, one far removed
from the war and its aftermath. Seldom has a scientist received such
public attention for having cultivated the fruit of pure learning.
Einstein's parents, who were nonobservant Jews, moved from Ulm to Munich
when Einstein was an infant. The family business was the manufacture
of electrical apparatus; when the business failed (1894), the family
moved to Milan, Italy. At this time Einstein decided officially to relinquish
his German citizenship. Within a year, still without having completed
secondary school, Einstein failed an examination that would have allowed
him to pursue a course of study leading to a diploma as an electrical
engineer at the Swiss Federal Institute of Technology (the Zurich Polytechnic).
He spent the next year in nearby Aarau at the cantonal secondary school,
where he enjoyed excellent teachers and first-rate facilities in physics.
Einstein returned in 1896 to the Zurich Polytechnic, where he graduated
(1900) as a secondary school teacher of mathematics and physics.
After a lean two
years he obtained a post at the Swiss patent office in Bern. The patent-office
work required Einstein's careful attention, but while employed (1902-09)
there, he completed an astonishing range of publications in theoretical
physics. For the most part these texts were written in his spare time
and without the benefit of close contact with either the scientific
literature or theoretician colleagues. Einstein submitted one of his
scientific papers to the University of Zurich to obtain a Ph.D. degree
in 1905. In 1908 he sent a second paper to the University of Bern and
became privatdocent, or lecturer, there. The next year Einstein received
a regular appointment as associate professor of physics at the University
By 1909, Einstein
was recognized throughout German-speaking Europe as a leading scientific
thinker. In quick succession he held professorships at the German University
of Prague and at the Zurich Polytechnic. In 1914 he advanced to the
most prestigious and best-paying post that a theoretical physicist could
hold in central Europe: professor at the Kaiser-Wilhelm Gesellschaft
in Berlin. Although Einstein held a cross-appointment at the University
of Berlin, from this time on he never again taught regular university
courses. Einstein remained on the staff at Berlin until 1933, from which
time until his death (1955) he held an analogous research position at
the Institute for Advanced Study in Princeton, N.J.
The 1905 Papers
In the first of
three seminal papers published in 1905, Einstein examined the phenomenon
discovered by Max Planck, according to which electromagnetic energy
seemed to be emitted from radiating objects in quantities that were
ultimately discrete. The energy of these quantities--the so-called light-quanta--was
directly proportional to the frequency of the radiation. This circumstance
was perplexing because classical electromagnetic theory, based on Maxwell's
equations and the laws of thermodynamics, had assumed that electromagnetic
energy consisted of waves propagating in a hypothetical, all-pervasive
medium called the luminiferous ether, and that the waves could contain
any amount of energy no matter how small. Einstein used Planck's quantum
hypothesis to describe visible electromagnetic radiation, or light.
According to Einstein's heuristic viewpoint, light could be imagined
to consist of discrete bundles of radiation. Einstein used this interpretation
to explain the photoelectric effect, by which certain metals emit electrons
when illuminated by light with a given frequency. Einstein's theory,
and his subsequent elaboration of it, formed the basis for much of quantum
The second of Einstein's
1905 papers proposed what is today called the special theory of relativity.
At the time Einstein knew that, according to Hendrik Antoon Lorentz's
theory of electrons, the mass of an electron increased as the velocity
of the electron approached the velocity of light. Einstein also knew
that the electron theory, based on Maxwell's equations, carried along
with it the assumption of a luminiferous ether, but that attempts to
detect the physical properties of the ether had not succeeded. Einstein
realized that the equations describing the motion of an electron in
fact could describe the nonaccelerated motion of any particle or any
suitably defined rigid body. He based his new kinematics on a reinterpretation
of the classical principle of relativity--that the laws of physics had
to have the same form in any frame of reference. As a second fundamental
hypothesis, Einstein assumed that the speed of light remained constant
in all frames of reference, as required by classical Maxwellian theory.
Einstein abandoned the hypothesis of the ether, for it played no role
in his kinematics or in his reinterpretation of Lorentz's theory of
electrons. As a consequence of his theory Einstein recovered the phenomenon
of time dilatation, wherein time, analogous to length and mass, is a
function of the velocity of a frame of reference ( Fitzgerald-Lorentz
contraction). Later in 1905, Einstein elaborated how, in a certain manner
of speaking, mass and energy were equivalent. Einstein was not the first
to propose all the elements that went into the special theory of relativity;
his contribution lies in having unified important parts of classical
mechanics and Maxwellian electrodynamics.
The third of Einstein's
seminal papers of 1905 concerned statistical mechanics, a field of study
that had been elaborated by, among others, Ludwig Boltzmann and Josiah
Willard Gibbs. Unaware of Gibbs' contributions, Einstein extended Boltzmann's
work and calculated the average trajectory of a microscopic particle
buffeted by random collisions with molecules in a fluid or in a gas.
Einstein observed that his calculations could account for brownian motion,
the apparently erratic movement of pollen in fluids, which had been
noted by the British botanist Robert Brown. Einstein's paper provided
convincing evidence for the physical existence of atom-sized molecules,
which had already received much theoretical discussion. His results
were independently discovered by the Polish physicist Marian von Smoluchowski
and later elaborated by the French physicist Jean Perrin.
The General Theory
After 1905, Einstein
continued working in all three of the above areas. He made important
contributions to the quantum theory, but increasingly he sought to extend
the special theory of relativity to phenomena involving acceleration.
The key to an elaboration emerged in 1907 with the principle of equivalence,
in which gravitational acceleration was held a priori indistinguishable
from acceleration caused by mechanical forces; gravitational mass was
therefore identical with inertial mass. Einstein elevated this identity,
which is implicit in the work of Isaac Newton, to a guiding principle
in his attempts to explain both electromagnetic and gravitational acceleration
according to one set of physical laws. In 1907 he proposed that if mass
were equivalent to energy, then the principle of equivalence required
that gravitational mass would interact with the apparent mass of electromagnetic
radiation, which includes light. By 1911, Einstein was able to make
preliminary predictions about how a ray of light from a distant star,
passing near the Sun, would appear to be attracted, or bent slightly,
in the direction of the Sun's mass. At the same time, light radiated
from the Sun would interact with the Sun's mass, resulting in a slight
change toward the infrared end of the Sun's optical spectrum. At this
juncture Einstein also knew that any new theory of gravitation would
have to account for a small but persistent anomaly in the perihelion
motion of the planet Mercury.
About 1912, Einstein
began a new phase of his gravitational research, with the help of his
mathematician friend Marcel Grossmann, by phrasing his work in terms
of the tensor calculus of Tullio Levi-Civita and Gregorio Ricci-Curbastro.
The tensor calculus greatly facilitated calculations in four-dimensional
space-time, a notion that Einstein had obtained from Hermann Minkowski's
1907 mathematical elaboration of Einstein's own special theory of relativity.
Einstein called his new work the general theory of relativity. After
a number of false starts, he published (late 1915) the definitive form
of the general theory. In it the gravitational field equations were
covariant; that is, similar to Maxwell's equations, the field equations
took the same form in all equivalent frames of reference. To their advantage
from the beginning, the covariant field equations gave the observed
perihelion motion of the planet Mercury. In its original form, Einstein's
general relativity has been verified numerous times in the past 60 years,
especially during solar-eclipse expeditions when Einstein's light-deflection
prediction could be tested.
When British eclipse expeditions in 1919 confirmed his predictions,
Einstein was lionized by the popular press. Einstein's personal ethics
also fired public imagination. Einstein, who after returning to Germany
in 1914 did not reapply for German citizenship, was one of only a handful
of German professors who remained a pacifist and did not support Germany's
war aims. After the war, when the victorious allies sought to exclude
German scientists from international meetings, Einstein--a Jew traveling
with a Swiss passport--remained an acceptable German envoy. Einstein's
political views as a pacifist and a Zionist pitted him against conservatives
in Germany, who branded him a traitor and a defeatist. The public success
accorded his theories of relativity evoked savage attacks in the 1920s
by the anti-Semitic physicists Johannes Stark and Philipp Lenard, men
who after 1932 tried to create a so-called Aryan physics in Germany.
Just how controversial the theories of relativity remained for less
flexibly minded physicists is revealed in the circumstances surrounding
Einstein's reception of a Nobel Prize in 1921--it was awarded not for
relativity but for his 1905 work on the photoelectric effect.
With the rise of
fascism in Germany, Einstein moved (1933) to the United States and abandoned
his pacifism. He reluctantly agreed that the new menace had to be put
down through force of arms. In this context Einstein sent (1939) a letter
to President Franklin D. Roosevelt that urged that the United States
proceed to develop an atomic bomb before Germany did. The letter, composed
by Einstein's friend Leo Szilard, was one of many exchanged between
the White House and Einstein, and it contributed to Roosevelt's decision
to fund what became the Manhattan Project.
However much he
appeared to the public as a champion of unpopular causes, such as his
objection in the 1950s to the House Committee on Un-American Activities
and his efforts toward nuclear disarmament, Einstein's central concerns
always revolved around physics. At the age of 59, when other theoretical
physicists would long since have abandoned original scientific research,
Einstein and his co-workers Leopold Infeld and Banesh Hoffmann achieved
a major new result in the general theory of relativity.
Until the end of
his life Einstein sought a unified field theory, whereby the phenomena
of gravitation and electromagnetism could be derived from one set of
equations. Few physicists followed Einstein's path in the years after
1920. Quantum mechanics, instead of general relativity, drew their attention.
For his part, Einstein could never accept the new quantum mechanics
with its principle of indeterminacy, as formulated by Werner Heisenberg
and elaborated into a new epistemology by Niels Bohr. Although Einstein's
later thoughts were neglected for decades, physicists today refer seriously
and awesomely to Einstein's dream--a grand unification of physical theory.