Albert Einstein was one of the greatest scientists of all time. He is best known for his theory of relativity, which he first advanced when he was only 26. He also made many other contributions to science.

Relativity. Einstein's relativity theory revolutionized scientific thought with new conceptions of time, space, mass, motion, and gravitation. He treated matter and energy as exchangeable, not distinct. In so doing, he laid the basis for controlling the release of energy from the atom.

Thus, Einstein was one of the fathers of the nuclear age. Einstein's famous equation, E equals m times c-squared (energy equals mass times the velocity of light squared), became a foundation stone in the development of nuclear energy. Einstein developed his theory through deep philosophical thought and through complex mathematical reasoning. The great scientist was once reported to have said that only a dozen people in the world could understand his theory. However, Einstein always denied this report.

Urged atomic research. On Aug. 2, 1939, Einstein wrote a letter to President Franklin D. Roosevelt, explaining that it might be possible to build an atomic bomb. Einstein urged the President to provide governmental help for the study of the release of nuclear energy. Einstein also warned the President that Nazi Germany might already be trying to build an atomic bomb. His letter helped set the United States on the long, difficult, and costly path that finally led to the production of an atomic bomb in 1945.

Early years. Einstein was born on March 14, 1879, in Ulm, Wurttemberg, Germany, the son of Hermann and Paulina Koch Einstein. When Einstein was five years old,his father showed him a pocket compass. The little boy was deeply impressed by the mysterious behavior of the compass needle, which kept pointing in the same direction no matter which way the compass was turned. He later said he felt then that "something deeply hidden had to be behind things."

After attending elementary and secondary schools in Munich and in Aarau, Switzerland, Einstein studied mathematics and physics at the Swiss Polytechnic Institute in Zurich. He graduated in 1900. From 1902 to 1909, Einstein worked as an examiner at the Swiss Patent Office in Bern. This job as patent examiner allowed him much free time, which he spent in scientific investigations. Einstein became a Swiss citizen in 1905.

The papers of 1905. During this time, Einstein made three of his greatest contributions to scientific knowledge. The year 1905 was an epoch-making one in the history of physical science, because Einstein contributed three papers to Annalen der Physik (Annals of Physics,) a German scientific periodical. Each of them became the basis of a new branch of physics.

In one of the papers, Einstein suggested that light could be thought of as a stream of tiny particles. This idea forms an important part of the quantum theory. In 1900, the German physicist Max K. E. L. Planck had proposed that the radiation of light occurred in packets of energy, called quanta. Einstein extended this idea by arguing that light itself consisted of quanta, which were later called photons.

Scientists before Einstein had discovered that a bright beam of light striking a metal caused the metal to release electrons, which could form an electric current. They called this phenomenon the photoelectric effect. But scientists could not explain the phenomenon as long as they assumed that light traveled only in waves. Using his theory of quanta, Einstein explained the photoelectric effect. He showed that when quanta of light energy strike atoms in a metal, the quanta force the atoms to release electrons.

Einstein's paper established the theoretical basis for the photoelectric cell, or "electric eye." This device made possible sound motion pictures, television, and many other inventions. Einstein received the 1921 Nobel Prize in physics for this paper on quanta.

In a second paper, titled The Electrodynamics of Moving Bodies, Einstein presented the special theory of relativity. In this paper, he showed how the theory demonstrated the relativity of time, a previously unimaginable idea. Einstein's name is most widely known for this theory. In 1944, a manuscript copy of Einstein's famous electrodynamics paper brought a pledge to invest $61/2 million in war bonds at an auction in Kansas City. The paper was later sent to the Library of Congress in Washington, D.C. In a study published in 1905, Einstein showed the equivalence of mass and energy, expressed in the famous equation E equals m times c-squared.

The third major paper of 1905 concerned Brownian motion, an irregular motion of microscopic particles suspended in a liquid or gas. It confirmed the atomic theory of matter.

Einstein accomplished all this before he held any academic position. But in 1909, he became professor of theoretical physics at the University of Zurich in Switzerland. In 1911 and 1912, he occupied the same position at the German University in Prague. He returned in 1912 to a similar post at the Federal Institute of Technology in Zurich.

Einstein was elected to the Prussian Academy of Sciences in Berlin in 1913. When he accepted the professorship of physics at the University of Berlin in 1914, he once more assumed German citizenship. The same year, he became director of the Kaiser Wilhelm Physical Institute in Berlin.

In 1915, Einstein announced that he had developed a general theory of relativity based on his special theory. In his general theory, he attempted to express all laws of physics by covariant equations, or equations that have the same mathematical form regardless of the system of reference to which they are applied. The general theory was published in 1916.

Unified field theory. Einstein's general theory of relativity did not completely satisfy him because it did not include electromagnetism. Beginning in the late 1920's, he tried to combine electromagnetic and gravitational phenomena in a single theory, called a unified field theory (see ELECTROMAGNETISM; GRAVITATION). Einstein failed to establish a unified field theory, though he spent the last 25 years of his life working on it. Toward the end of his life, he remarked that it would be worthwhile to show that such a theory did not exist. He worried that if he neither produced a theory nor showed that one was impossible, perhaps no one ever would.

Einstein in the United States. In 1933, while Einstein was visiting England and the United States, the Nazi government of Germany took his property and deprived him of his positions and his citizenship. Even before this misfortune occurred, however, Einstein had been invited to become a member of the staff of the newly created Institute for Advanced Study in Princeton, N.J.

Einstein accepted this position for life, and settled down in Princeton. He lived there until his death. In 1940, Einstein became an American citizen. He died on April 18, 1955.

His personal life. Although he lived a quiet personal life, Einstein maintained a vital interest in human affairs. He was fond of classical music, and played the violin. He had a deep compassion for people who were politically or economically oppressed. He supported Zionism, and was offered the presidency of the state of Israel in 1952. But he declined this honor, insisting that he was not fitted for such a position.

Until the rise of Nazism in the 1930's, Einstein was an ardent pacifist. After the war, he became an equally determined supporter of world government. He insisted that peace among nations could be maintained in the atomic age only by bringing all people together under a system of world law.

Although not well-to-do, Einstein was never concerned about money. Publishers and editors from all parts of the world offered him huge sums for an autobiography. He never considered such offers. Finally, he did write his "Autobiographical Notes" because, as he put it, "it is a good thing to show those who are striving alongside of us, how one's own striving and searching appears to one in retrospect." Those "Notes" were the only document even approaching an autobiography that Einstein ever wrote. He wrote them for a scholarly volume without asking for or getting any money in return.

Einstein was married twice. He was separated from his first wife, a physicist named Mileva Maric, soon after his arrival in Berlin. After World War I, he married his first cousin, Elsa. She died at Princeton in 1936. He had two sons and a daughter by his first wife. He gained two stepdaughters in his second marriage.

Although he was not associated with any orthodox religion, Einstein's nature was deeply religious. He felt that belief in a personal God was too specific a concept to be applicable to the Being at work in this universe, but he never believed that the universe was one of chance or chaos. The universe to him was one of absolute law and order. He once said, "God may be sophisticated, but He is not malicious."

Additional resources

Bucky, Peter A. The Private Albert Einstein. Andrews and McMeel, 1992.

Clark, Ronald W. Einstein: The Life and Times. Avon, 1992. First published in 1971.

Ireland, Karin. Albert Einstein. Silver Burdett, 1989. For younger readers.

Pais, Abraham. "Subtle Is the Lord--": The Science and Life of Albert Einstein. Oxford, 1982.

Reef, Catherine. Albert Einstein, Scientist of the 20th Century. Dillon Pr., 1991. For younger readers.

Tauber, Gerald E. Relativity: From Einstein to Black Holes. Watts, 1988. For younger readers.

SOURCE: IBM 1999 WORLD BOOK