Albert Einstein

Albert Einstein was without doubt one of the world's greatest scientists. Aside from his scientific endeavors, he was a social activist who spoke out against war and supported nuclear disarmament.

Intelligence in question

Einstein was born on March 14, 1879, to a businessman and his wife. He was slow to talk and did not utter a world until he was three years old. Even then, it took several years before his speech was fluent. So poorly did he perform in school that his parents and others suspected he was mentally challenged. In fact, he simply preferred to learn on his own; as a scientist, he would continue to study independently.

Einstein graduated from a German college in 1900 with a degree in physics. He landed a job in 1902 as a technical expert with the Swiss Patent Office. In his spare time, he conducted his own research and applied his work toward a doctorate at the University of Zurich. Einstein married and had three children but he was divorced in 1919. He later married his cousin Elsa.

Becomes a published scientist

Einstein published a series of papers in 1905. The first in this three-part series was concerned with Brownian motion. Scottish botanist Robert Brown (1773–1858) had reported in 1827 that tiny particles move about in a random zigzag motion when placed in liquid. Einstein's hypothesis was that the visible motion of particles was caused by the random movement of molecules that comprised the liquid. He figured out a mathematical formula to predict the distance traveled by the particles and their relative speed. The formula was proven correct in 1908, and Einstein was credited with providing the first experimental evidence of the existence of molecules.

The next topic covered in the series was the photoelectric effect. This phenomenon involves the release of electrons from a metal that occurs when light shines on that metal. What puzzled scientists was that the number of electrons released was not a function of the light's intensity but of the color—or wavelength—of the light.

Einstein assumed light travels in tiny bundles of energy known as quanta. The energy of any given light quantum, he believed, is determined by its wavelength. When light falls on metal, electrons in the metal absorb specific quanta of energy, giving them enough energy to escape the metal's surface. The number of electrons released will depend on the light's energy (wavelength), not on the number of quanta (or intensity of light). His hypothesis was proven and laid the foundation for the fields of quantitative photoelectric chemistry and quantum mechanics. Einstein received the Nobel Prize in physics in 1921 for his work.

Theory of relativity

The final paper in the 1905 series was responsible for making the physicist famous. It discussed the relationship between measurements made by observers in two separate systems moving at a constant speed with respect to each other. This is known as relativity, and scientists had been studying the concept for several years.

Although those before him had contributed to the field of study, Einstein gave the most complete analysis of the subject. He began by making two assumptions. The first was that the laws of physics are the same in all frames of reference. Second, the velocity (or speed) of light is always the same, no matter what the conditions. He developed a mathematical relationship between the length of an object and its velocity. Einstein's theory of relativity was groundbreaking because it established that measurable properties will vary depending on the relative motion of the observer. Prior to his theory, scientists believed that measurable entities such as time, mass, and length remained the same in all frames of reference.

Einstein wrote other papers in 1905. In one, he discussed his belief that the energy and mass of a body are interrelated. In 1907, he constructed a formula to illustrate that relationship: E = mc², which states that energy equals mass times the speed of light squared.

Einstein earned his Ph.D. from the University of Zurich in 1905 and held various teaching jobs before accepting a position as the director of scientific research at the Kaiser Wilhelm Institute for Physics in Berlin, Germany, in 1913. He remained in that post for thirty years.

General theory of relativity

Einstein extended his theory of relativity to a broader context. The general theory of relativity applied to motions that are not uniform and relative velocities that are not constant. He wrote mathematical expressions describing the relationships between measurements made in any two systems in motion relative to each other, even if the motion changes in one or both. A basic feature of this general theory is the concept of a space-time continuum in which space is curved.

Einstein's theory was not accepted right away. Pioneering physicist Isaac Newton's (1642–1727) theory of gravity had been the accepted theory for two hundred years; Einstein's theory would replace Newton's, and it was not easy for an entire scientific community to accept that it had been wrong. Einstein proved the accuracy of his general theory, however, and it was accepted as truth in 1919.

Jersey boy

Einstein had been a vocal opponent of war since the outbreak of World War I (1914–18). He even traveled throughout Europe, lecturing on his views. As the Nazi Party began its rise to power in the 1930s, Einstein decided the time was right to leave his native country. As a Jew and a pacifist (someone who opposes violence), he would not be safe in Germany.

Einstein accepted a position at the Institute for Advanced Studies in New Jersey , and he remained at that job until his death. He continued to lecture and write about peace. Despite his views, in 1939 he signed his name to a letter informing President Franklin D. Roosevelt (1882–1945; served 1933–45) of the possibility that an atomic bomb could be developed. Einstein's earlier work on relativity was key to the development of the atomic bomb, but he himself did not help.

In World War II (1939–45), the United States dropped two atomic bombs on Japan, killing and maiming hundreds of thousands of people, mostly civilians. At war's end, Einstein publicly denounced nuclear warfare and called for nuclear disarmament. He also supported the Zionist movement, in which Jews hoped to create a Jewish homeland in Palestine.

For his scientific achievements, Einstein was awarded countless honors. He died of an aortic aneurysm in his home on April 18, 1955, at the age of seventy-six.