On March 14, 1879, Albert Einstein is born, the son of a Jewish
electrical engineer in Ulm, Germany. Einstein’s theories of special and
general relativity drastically altered man’s view of the universe, and
his work in particle and energy theory helped make possible quantum
mechanics and, ultimately, the atomic bomb.
After a childhood in Germany and Italy, Einstein studied physics and
mathematics at the Federal Polytechnic Academy in Zurich, Switzerland.
He became a Swiss citizen and in 1905 was awarded a Ph.D. from the
University of Zurich while working at the Swiss patent office in Bern.
That year, which historians of Einstein’s career call the annus mirabilis–the
“miracle year”–he published five theoretical papers that were to have a
profound effect on the development of modern physics.
In the first of these, titled “On a Heuristic Viewpoint Concerning
the Production and Transformation of Light,” Einstein theorized that
light is made up of individual quanta (photons) that demonstrate
particle-like properties while collectively behaving like a wave. The
hypothesis, an important step in the development of quantum theory, was
arrived at through Einstein’s examination of the photoelectric effect, a
phenomenon in which some solids emit electrically charged particles
when struck by light. This work would later earn him the 1921 Nobel
Prize in Physics.
In the second paper, he devised a new method of counting and
determining the size of the atoms and molecules in a given space, and in
the third he offered a mathematical explanation for the constant
erratic movement of particles suspended in a fluid, known as Brownian
motion. These two papers provided indisputable evidence of the existence
of atoms, which at the time was still disputed by a few scientists.
Einstein’s fourth groundbreaking scientific work of 1905 addressed
what he termed his special theory of relativity. In special relativity,
time and space are not absolute, but relative to the motion of the
observer. Thus, two observers traveling at great speeds in regard to
each other would not necessarily observe simultaneous events in time at
the same moment, nor necessarily agree in their measurements of space.
In Einstein’s theory, the speed of light, which is the limiting speed of
any body having mass, is constant in all frames of reference. In the
fifth paper that year, an exploration of the mathematics of special
relativity, Einstein announced that mass and energy were equivalent and
could be calculated with an equation, E=mc2.
Although the public was not quick to embrace his revolutionary
science, Einstein was welcomed into the circle of Europe’s most eminent
physicists and given professorships in Zýrich, Prague, and Berlin. In
1916, he published “The Foundation of the General Theory of Relativity,”
which proposed that gravity, as well as motion, can affect the
intervals of time and of space. According to Einstein, gravitation is
not a force, as Isaac Newton had argued, but a curved field in the
space-time continuum, created by the presence of mass. An object of very
large gravitational mass, such as the sun, would therefore appear to
warp space and time around it, which could be demonstrated by observing
starlight as it skirted the sun on its way to earth. In 1919,
astronomers studying a solar eclipse verified predictions Einstein made
in the general theory of relativity, and he became an overnight
celebrity. Later, other predictions of general relativity, such as a
shift in the orbit of the planet Mercury and the probable existence of
black holes, were confirmed by scientists.
During the next decade, Einstein made continued contributions to
quantum theory and began work on a unified field theory, which he hoped
would encompass quantum mechanics and his own relativity theory as a
grand explanation of the workings of the universe. As a world-renowned
public figure, he became increasingly political, taking up the cause of
Zionism and speaking out against militarism and rearmament. In his
native Germany, this made him an unpopular figure, and after Nazi leader
Adolf Hitler became chancellor of Germany in 1933 Einstein renounced
his German citizenship and left the country.
He later settled in the United States, where he accepted a post at
the Institute for Advanced Study in Princeton, New Jersey. He would
remain there for the rest of his life, working on his unified field
theory and relaxing by sailing on a local lake or playing his violin. He
became an American citizen in 1940.
In 1939, despite his lifelong pacifist beliefs, he agreed to write to
President Franklin D. Roosevelt on behalf of a group of scientists who
were concerned with American inaction in the field of atomic-weapons
research. Like the other scientists, he feared sole German possession of
such a weapon. He played no role, however, in the subsequent Manhattan
Project and later deplored the use of atomic bombs against Japan. After
the war, he called for the establishment of a world government that
would control nuclear technology and prevent future armed conflict.
In 1950, he published his unified field theory, which was quietly
criticized as a failure. A unified explanation of gravitation, subatomic
phenomena, and electromagnetism remains elusive today. Albert Einstein,
one of the most creative minds in human history, died in Princeton in
1955
