The physicist Albert Einstein was one of the greatest geniuses in the history of science. His theories led to new ways of thinking about space, time, matter, energy, and gravity. However, his work also had a destructive result—the development of nuclear weapons.

Early life

Albert Einstein was born to Jewish parents in Ulm, Germany, on March 14, 1879. He went to elementary school in Munich. Albert did not do well in school, but he did become interested in mathematics and science. Later he studied physics and mathematics at a technical college in Zürich, Switzerland.

After graduating in 1900, Einstein became a citizen of Switzerland. He moved to Bern, the capital, and took a job in the government office that gave patents for new inventions. Meanwhile he continued studying physics on his own.

Scientific breakthroughs

Einstein's great year was 1905, when he published five major research papers. The papers forever changed the way people think about the universe.

One of Einstein's papers helped to explain how light works. Light is a form of energy. Most scientists up to that time believed that light energy traveled in a continuous flow. Einstein disagreed. He argued that light is made up of individual packets of energy, which are called quanta or photons. Einstein received the Nobel prize for physics in 1921 mainly for this work.

In another paper Einstein presented what is now called the special theory of relativity. Before Einstein, physicists believed that measurements of space (the distance between objects) and time were always the same throughout the universe. Again Einstein disagreed. He said that measurements of space and time are relative—that is, they change when taken by observers who are moving at different speeds. This idea was entirely new.

The special theory of relativity also changed how scientists thought about matter and energy. Earlier scientists believed that matter and energy were completely different from each other. Einstein argued that matter and energy are closely related, that matter could change to energy and energy could change to matter. He described this idea with his famous equation E = mc²: E is energy, m is mass (a measure of matter), and c² is the speed of light squared, a huge number. According to the equation, small amounts of mass can be changed into enormous amounts of energy.

Einstein's papers of 1905 made him well known to other scientists. In 1909 he left the patent office and took up teaching. In 1916, while at the University of Berlin, he published a new theory—the general theory of relativity. It expanded his special theory of relativity to include gravity. When other scientists confirmed the theory in 1919, Einstein became famous worldwide.

Later years

In 1933 the Nazi Party took over Germany. The Nazis hated the Jews, so Einstein decided to leave Germany. He eventually settled in the United States.

Throughout his life Einstein was passionately concerned with world affairs. He often spoke out against war and violence. He supported the movement to set up a Jewish homeland in Palestine. During World War II he wrote a letter to U.S. President Franklin D. Roosevelt warning him that German scientists might be working to create an atomic bomb. The letter urged the president to begin atomic bomb research in the United States in case such a weapon was needed to defeat the Nazis. The research program that resulted, called the Manhattan Project, created the first atomic bomb in 1945. Einstein, however, did not work to develop the bomb, and after World War II he tried to prevent any future use of atomic weapons. Einstein died in Princeton, New Jersey, on April 18, 1955.