Einstein made incredible discoveries, but was still a very human and feeling man, and this simply added to his importance and influence in the world of physics. One of Einstein's most famous discoveries is the Theory of Relativity, which he first developed in 1905, and which many people call "the birth of modern physics" (Infeld 37). Relativity Theory seems complicated, and it is. Einstein was criticized when he first made his theory public and it became known because other scientists felt very few people could actually understand it. Writer Infeld describes the theory in more understandable terms. He writes, "It [Relativity Theory] deduces that energy is not weightless, but has a definite mass. If the amount of energy changes, so does its mass. Energy has mass and mass has energy" (Infeld 38). This explanation is simplified for non-scientists, and seems rather tame today. However, Einstein's theory revolutionized the world of physics, and changed the way the entire scientific world viewed physics and energy in general. Relativity Theory gave the world Einstein's famous equation: "E = mc2 (energy equals mass multiplied by the square of the speed of light)" (Einstein 287). One writer explains Einstein's theory this way.

According to classical physics, a moving body has kinetic energy just because it moves. This energy, like all energy, is weightless, or let us say the same thing differently: the mass of a moving body does not change. But in relativity theory mass must change with speed, or, to put it differently, kinetic energy must have mass, however small (Infeld 40).

Thus, Einstein's theory reformulated classical physics, and physicists along with it. He changed the way science views mass and energy, and because of this, innovation and change was possible.

Einstein was a modest, reclusive man. Amazingly, he did not take full credit for his theory of Relativity. Biographer Pais continues, "He [Einstein] deprecated the idea that the new principle was revolutionary. It was, he told his audience, the direct outcome and, in a sense, the natural completion of the work of Faraday, Maxwell, and Lorentz. Moreover there was nothing specially, certainly nothing intentionally, philosophical about it....'" (Pais 30). He remained low-key about his accomplishments throughout his life and was continually working on new projects and ideas. None of them would ever bring him as much acclaim and notoriety as his theories on Relativity and Quantum physics.

Einstein also helped to develop Quantum Theory, which "deals with the laws that describe how matter is built out of these elementary particles and what the forces are between them as revealed in spectral lines, in radioactive phenomena, or in the process of fission. The story of modern physics is in great part that of quantum theory" (Infeld 85). The use of Quantum Theory and continued study into it by other scientists eventually led to the development of atomic fission, and later, the development of the atomic and bomb. Einstein always regretted the part he played in the development of the bomb, as he was a lifelong pacifist. In fact, he co-wrote a famous book, "Why War?" with Sigmund Freud in 1932 that became classic anti-war literature. Another writer states, "The 'Why War?' letters, organized by Einstein, were written at the behest of the International Institute of Intellectual Co-operation, a committee of the League of Nations" (Dunn 112). Einstein saw the potential of harnessing atomic principles to create nuclear power,...

He spent the remainder of his life studying many different projects. One however, eluded him. Another scientist writes, "Einstein, who had already united space, time and gravity in his theories, certainly believed this and spent the latter half of his life seeking -- unsuccessfully -- 'a theory of everything' that would combine quantum physics and relativity" (Mckie). That work today is evolving into another theory of physics - string theory, which shows his influence is still felt around the world today.
Einstein did not work on the project to develop the atomic bomb, even though many people believe he did. In fact, he urged President Roosevelt not to use the bomb to end the World War II with Japan. However, Einstein was instrumental in getting the President's attention about nuclear development, and in securing the uranium necessary to conduct the nuclear experiments that led to the development of the atomic bomb. Einstein wrote several letters to the president mentioning nuclear work going on in Germany, and he recognized the world's danger if Germany developed the technology first. They would have dominated the world while owning technology that would wipe out millions of people. Another Einstein publication notes, "The Advisory Committee on Uranium was organized by the President as an immediate result of Einstein's intervention and was the germinal body from which the whole huge atomic effort developed" (Einstein 301). Thus, Einstein did not play a role in the actual development of the bomb, but without him and his intervention, the work could not have continued, and ultimately the war might have turned out far differently.

In conclusion, Albert Einstein may be one of the world's greatest physicists and scientists. His discoveries led to some of the most innovative and controversial inventions in the world, but more than that, his theories changed the way people literally view the world. Another author writes, "The harvest of Einstein's ideas in this century was one of the richest that any man has ever brought to science. From relativity theory as formulated in 1905, a road forward was possible, and much of it was later traversed under the leadership of Einstein" (Infeld 35). Without Einstein, the world today would be a far different place, and so would our understanding of it.