Albert Einstein (14 March 1879 – 18 April 1955) was a German-born
theoretical physicist. He is best known for his theory of relativity and
specifically mass - energy equivalence, expressed by the equation E = mc
Einstein received the 1921 Nobel Prize in Physics "for his services to
Theoretical Physics, and especially for his discovery of the law of the
photoelectric effect. ".
Einstein's many contributions to physics include his special theory of
relativity, which reconciled mechanics with electromagnetism, and his
general theory of relativity, which was intended to extend the principle of
relativity to non-uniform motion and to provide a new theory of gravitation.
His other contributions include advances in the fields of relativistic
cosmology, capillary action, critical opalescence, classical problems of
statistical mechanics and their application to quantum theory, an explanation
of the Brownian movement of molecules, atomic transition probabilities, the
quantum theory of a monatomic gas, thermal properties of light with low
radiation density, a theory of radiation including stimulated emission, the
conception of a unified field theory, and the geometrization of physics.
Einstein published over 300 scientific works and over 150 non-scientific works. In 1999 Time magazine named
him the "Person of the Century". In wider culture the name "Einstein" has become synonymous with genius, and
he has since been regarded as one of the most influential people in human history.
Youth and schooling
Albert Einstein was born into a Jewish family in Ulm, in the Kingdom of
Wurttemberg in the German Empire on 14 March 1879. His father was
Hermann Einstein, a salesman and engineer. His mother was Pauline Einstein.
In 1880, the family moved to Munich, where his father and his uncle founded a
company, Elektrotechnische Fabrik J. Einstein & Cie, that manufactured
The Einsteins were not observant of Jewish religious practices, and Albert
attended a Catholic elementary school. Although Einstein had early speech
difficulties, he was a top student in elementary school.
When Einstein was five, his father showed him a pocket compass. Einstein
realized that there must be something in the space, previously thought to be
empty, that was moving the needle and later stated that this experience made "a
deep and lasting impression". At his mother's insistence, he took violin lessons
starting at age six, and although he disliked them and eventually quit, he later
took great pleasure in Mozart's violin sonatas. As he grew, Einstein built
models and mechanical devices for fun, and began to show a talent for
In 1889, family friend Max Talmud, a medical student, introduced the ten-year-old Einstein to key science,
mathematics, and philosophy texts, including Kant's Critique of Pure Reason and Euclid's Elements.
From Euclid, Einstein began to understand deductive reasoning, and by the age of twelve, he had learned
Euclidean geometry. Soon thereafter he began to investigate infinitesimal calculus.
In his early teens, Einstein attended the progressive Luitpold Gymnasium. His father intended for him to pursue
electrical engineering, but Einstein clashed with authorities and resented the school regimen. He later wrote that
the spirit of learning and creative thought were lost in strict rote learning.
In 1894, when Einstein was fifteen, his father's business failed, and the Einstein family moved to Italy, first to
Milan and then, after a few months, to Pavia.
During this time, Einstein wrote his first scientific work, "The Investigation of the State of Aether in Magnetic
Fields". Einstein had been left behind in Munich to finish high school, but in the spring of 1895, he withdrew to
join his family in Pavia, convincing the school to let him go by using a doctor's note.
Rather than completing high school, Einstein decided to apply directly to the ETH Zurich, the Swiss Federal
Institute of Technology in Zurich, Switzerland. Lacking a school certificate, he was required to take an entrance
examination, which he did not pass, although he got exceptional marks in mathematics and physics. Einstein
wrote that it was in that same year, at age 16, that he first performed his famous thought experiment visualizing
traveling alongside a beam of light.
The Einsteins sent Albert to Aarau, Switzerland to finish secondary school. While lodging with the family of
Professor Jost Winteler, he fell in love with the family's daughter, Marie. In Aarau, Einstein studied Maxwell's
electromagnetic theory. At age 17 he graduated, renounced his German citizenship to avoid military service ,
and finally enrolled in the mathematics program at ETH. Marie moved to Olsberg, Switzerland for a teaching
In 1896, Einstein's future wife, Mileva Maric, also enrolled at ETH, as the only woman studying mathematics.
During the next few years, Einstein and Maric's friendship developed into romance. Einstein graduated in 1900
from ETH with a degree in physics. That same year, Einstein's friend Michele Besso introduced him to the work
of Ernst Mach. The next year, Einstein published a paper in the prestigious Annalen der Physik on the capillary
forces of a straw. On 21 February 1901, he gained Swiss citizenship, which he never revoked.
Following graduation, Einstein could not find a teaching post. After almost two
years of searching, a former classmate's father helped him get a job in Berne, at
the Federal Office for Intellectual Property, the patent office, as an assistant
examiner. His responsibility was evaluating patent applications for
electromagnetic devices. In 1903, Einstein's position at the Swiss Patent Office
was made permanent, although he was passed over for promotion until he
"fully mastered machine technology".
With friends he met in Berne, Einstein formed a weekly discussion club on
science and philosophy, jokingly named "The Olympia Academy". Their
readings included Poincare, Mach, and Hume, who influenced Einstein's
scientific and philosophical outlook.
During this period Einstein had almost no personal contact with the physics
community. Much of his work at the patent office related to questions about
transmission of electric signals and electrical-mechanical synchronization of
time: two technical problems that show up conspicuously in the thought
experiments that eventually led Einstein to his radical conclusions about the nature of light and the fundamental
connection between space and time.
Marriage and family life
Einstein and Mileva Maric had a daughter, Lieserl Einstein, born in early 1902. Her fate is unknown.
Einstein married Mileva on 6 January 1903, although his mother had objected to the match because she had a
prejudice against Serbs and thought Maric "too old" and "physically defective." Their relationship was for a
time a personal and intellectual partnership. In a letter to her, Einstein called Maric "a creature who is my equal
and who is as strong and independent as I am." There has been debate about whether Maric influenced Einstein's
work, however, most historians do not think she made major contributions. On 14 May 1904, Albert and
Mileva's first son, Hans Albert Einstein, was born in Berne, Switzerland. Their second son, Eduard, was born in
Munich on 28 July 1910.
Albert and Maric divorced on 14 February 1919, having lived apart for five years. On 2 June of that year,
Einstein married Elsa Lowenthal, who had nursed him through an illness. Elsa was Albert's first cousin
maternally and his second cousin paternally. Together the Einsteins raised Margot and Ilse, Elsa's daughters
from her first marriage. Their union produced no children.
Annus Mirabilis and special relativity
Albert Einstein, 1905
In 1905, while he was working in the patent office, Einstein had four papers published
in the Annalen der Physik, the leading German physics journal. These are the papers
that history has come to call the Annus Mirabilis Papers:
•His paper on the particulate nature of light put forward the idea that certain
experimental results, notably the photoelectric effect, could be simply
understood from the postulate that light interacts with matter as discrete
"packets" of energy, an idea that had been introduced by Max Planck in 1900
as a purely mathematical manipulation, and which seemed to contradict
contemporary wave theories of light. This was the only work of Einstein's that
he himself called "revolutionary."
•His paper on Brownian motion explained the random movement of very small objects as direct evidence
of molecular action, thus supporting the atomic theory.
•His paper on the electrodynamics of moving bodies introduced the radical theory of special relativity,
which showed that the observed independence of the speed of light on the observer's state of motion
required fundamental changes to the notion of simultaneity. Consequences of this include the time-space
frame of a moving body slowing down and contracting (in the direction of motion) relative to the frame
of the observer. This paper also argued that the idea of a luminiferous aether - one of the leading
theoretical entities in physics at the time—was superfluous.
•In his paper on mass–energy equivalence (previously considered to be distinct concepts), Einstein
deduced from his equations of special relativity what has been called the twentieth century's most well
known equation: E = mc
. This suggests that tiny amounts of mass could be converted into huge amounts
of energy and presaged the development of nuclear power.
All four papers are today recognized as tremendous achievements—and hence 1905 is known as Einstein's
"Wonderful Year". At the time, however, they were not noticed by most physicists as being important, and
many of those who did notice them rejected them outright. Some of this work—such as the theory of light
quanta—remained controversial for years.
At the age of 26, having studied under Alfred Kleiner, Professor of Experimental Physics, Einstein was awarded
a PhD by the University of Zurich. His dissertation was entitled A New Determination of Molecular Dimensions.
Light and general relativity
One of the 1919 eclipse photographs taken during Arthur Stanley Eddington's
expedition, which confirmed Einstein's predictions of the gravitational bending of
In 1906, the patent office promoted Einstein to Technical Examiner Second Class,
but he had not given up on academia. In 1908, he became a privatdozent at the
University of Bern. In 1910, he wrote a paper on critical opalescence that described
the cumulative effect of light scattered by individual molecules in the atmosphere,
i.e., why the sky is blue.
During 1909, Einstein published "Uber die Entwicklung unserer Anschauungen
uber das Wesen und die Konstitution der Strahlung", on the quantization of light. In
this and in an earlier 1909 paper, Einstein showed that Max Planck's energy quanta
must have well-defined momenta and act in some respects as independent, point-
like particles. This paper introduced the photon concept and inspired the notion of
wave–particle duality in quantum mechanics.
In 1911, Einstein became an associate professor at the University of Zurich. However, shortly afterward, he
accepted a full professorship at the Charles University of Prague. While in Prague, Einstein published a paper
about the effects of gravity on light, specifically the gravitational redshift and the gravitational deflection of
light. The paper appealed to astronomers to find ways of detecting the deflection during a solar eclipse. German
astronomer Erwin Finlay-Freundlich publicized Einstein's challenge to scientists around the world.
In 1912, Einstein returned to Switzerland to accept a professorship at his alma mater, the ETH. There he met
mathematician Marcel Grossmann who introduced him to Riemannian geometry and more generally differential
geometry, and at the recommendation of Italian mathematician Tullio Levi-Civita, Einstein began exploring the