Albert Einstein (14 March 1879 – 18 April 1955) was a German-born scientist who studied how the universe works. He is best known for creating the theory of relativity. Einstein also helped develop quantum theory. His famous equation, E = mc², which comes from his theory of relativity, is often called "the world's most famous equation." He won the 1921 Nobel Prize in Physics for his work in theoretical physics and for discovering the photoelectric effect.

Einstein was born in the Kingdom of Württemberg, which was part of the German Empire. In 1895, he moved to Switzerland and gave up his German citizenship the next year. At 17, he began studying math and physics at a school in Zurich, graduating in 1900. He became a Swiss citizen in 1901 and later worked at the Swiss Patent Office in Bern. In 1905, he completed his PhD at the University of Zurich. In 1914, he moved to Berlin to join the Prussian Academy of Sciences and Humboldt University. He became a director of the Kaiser Wilhelm Institute for Physics in 1917 and again became a German citizen. In 1933, while visiting the United States, Adolf Hitler became leader of Germany. Einstein was shocked by the mistreatment of Jewish people and chose to stay in the U.S., becoming an American citizen in 1940. Before World War II began, he wrote a letter to President Franklin D. Roosevelt about the possibility of Germany developing nuclear weapons, which led to the Manhattan Project.

In 1905, called his "annus mirabilis" or miracle year, Einstein published four important papers. These papers explained the photoelectric effect, described Brownian motion, introduced his special theory of relativity, and showed that mass and energy are connected. In 1915, he developed the general theory of relativity, which expanded his ideas to include gravity. A paper he wrote the next year explained how general relativity affects the structure and history of the universe. It introduced the cosmological constant and is considered the first step in modern theoretical cosmology. In 1917, Einstein wrote a paper that explained spontaneous and stimulated emission. Stimulated emission is the basis for lasers and masers. His work also helped future studies in physics, such as quantum electrodynamics and quantum optics.

During the middle part of his career, Einstein made important contributions to statistical mechanics and quantum theory. He studied how light behaves as particles, later called photons. With physicist Satyendra Nath Bose, he helped create Bose–Einstein statistics. In his later years, Einstein worked on two projects that did not succeed. First, he disagreed with quantum theory's idea that the universe has randomness, saying, "God does not play dice." Second, he tried to create a unified field theory by combining gravity and electromagnetism. These efforts made him less connected to modern physics. Many things are named after him, including the element Einsteinium. In 1999, he was named Time's Person of the Century.

Life and career

Albert Einstein was born on March 14, 1879, in Ulm, which was part of the Kingdom of Württemberg in the German Empire. His parents were Hermann Einstein, a salesman and engineer, and Pauline Koch. They were Jewish people who followed secular traditions. In 1880, the family moved to Munich, where Hermann and his brother Jakob started a company called Elektrotechnische Fabrik J. Einstein & Cie. The company made electrical equipment using direct current.

When Einstein was very young, his parents were worried he might have a learning problem because he learned to speak very slowly. At age five, while he was sick in bed, his father gave him a compass. This experience sparked Einstein’s lifelong interest in electromagnetism. He later said, “Something deeply hidden had to be behind things.”

Einstein attended St. Peter’s Catholic elementary school in Munich starting at age five. At eight, he moved to the Luitpold Gymnasium, where he received education in both primary and secondary school.

In 1894, Hermann and Jakob’s company tried to win a contract to install electric lighting in Munich but failed. They could not afford to update their technology from direct current to alternating current, which was more efficient. This failure forced the family to sell their factory and move to Italy. They first went to Milan and then to Pavia, where they lived in Palazzo Cornazzani. Einstein, who was fifteen at the time, stayed in Munich to finish his schooling. His father wanted him to study electrical engineering, but Einstein struggled with the strict teaching methods at the Gymnasium. He later wrote that the school’s focus on memorization hurt creativity. After a doctor’s letter, Einstein left the school and joined his family in Pavia. While in Italy, he wrote an essay titled “On the Investigation of the State of the Ether in a Magnetic Field.”

Einstein was very skilled in physics and mathematics from an early age. By twelve, he was teaching himself algebra, calculus, and Euclidean geometry. He discovered a new proof of the Pythagorean theorem before his thirteenth birthday. A family tutor, Max Talmud, said Einstein quickly mastered a geometry textbook and then moved on to advanced math. Einstein said he learned integral and differential calculus by age fourteen. He believed nature could be understood as a “mathematical structure.”

At thirteen, Einstein’s interests expanded to include music and philosophy. Talmud introduced him to Kant’s Critique of Pure Reason, which became Einstein’s favorite philosophy. Talmud noted that even though Kant’s work was hard for most people to understand, Einstein seemed to grasp it easily.

In 1895, at sixteen, Einstein took an exam for a school in Zurich, Switzerland. He did not meet the requirements for the general part of the test but performed well in physics and mathematics. He completed his secondary education at a school in Aarau, Switzerland, graduating in 1896. While living there, he fell in love with Marie Winteler, the daughter of a family he stayed with. His sister, Maja, later married Marie’s brother, Paul.

In January 1896, with his father’s approval, Einstein gave up his citizenship in the Kingdom of Württemberg to avoid being drafted into the military. He graduated with high marks in history, physics, algebra, geometry, and descriptive geometry. At seventeen, he enrolled in a four-year program at the federal polytechnic school in Zurich. He became friends with Marcel Grossmann, who helped him despite his irregular study habits. Marie Winteler later became a teacher in Olsberg, Switzerland.

In 1896, Einstein met Mileva Marić, a twenty-year-old Serbian woman who was one of only a few women in his class. The two shared a strong interest in physics and spent time discussing topics not covered in school. Einstein wrote that working with Mileva made studying more enjoyable than reading alone. Over time, they became close friends and then lovers.

Historians debate how much Mileva contributed to Einstein’s scientific breakthroughs. Some believe she influenced his ideas, while others think her impact was minimal. Letters between Einstein and Mileva, discovered in 1987, revealed they had a daughter named Lieserl. She was born in early 1902 while Mileva was visiting her family. When Mileva returned to Switzerland, Lieserl was no longer with her. Einstein later wrote that the girl may have been adopted or died of scarlet fever as an infant.

Einstein and Mileva married in 1903. Their son, Hans Albert, was born in Bern, Switzerland, in 1904. Their son, Eduard, was born in Zurich in 1910. In letters before Eduard’s birth, Einstein described his love for Mileva as “misguided” and expressed sadness about the life he imagined he might have had with Marie Winteler instead.

In 1912, Einstein began a relationship with Elsa Löwenthal, who was his first cousin on his mother’s side and his second cousin on his father’s. When Mileva learned of this, she moved back to Zurich with their children. Einstein and Mileva divorced in 1919 after living apart for five years. As part of the divorce, Einstein agreed to give any Nobel Prize money to Mileva. He won the prize in 1921.

Einstein married Elsa Löwenthal in 1919. In 1923, he began a relationship with a secretary named Betty Neumann. Despite this, Elsa remained loyal to him and accompanied him when he moved to the United States in 1933. Elsa was diagnosed with heart and kidney problems in 1935 and died in December 1936.

A collection of Einstein’s letters published in 2006 revealed he had relationships with other women, including Margarete Lebach and Estella Katzenellenbogen.

Scientific career

Albert Einstein wrote hundreds of books and articles during his lifetime. He published over 300 scientific papers and 150 non-scientific ones. On December 5, 2014, universities and archives announced the release of Einstein’s papers, which included more than 30,000 unique documents. In addition to his individual work, Einstein also worked with other scientists on projects such as Bose–Einstein statistics, the Einstein refrigerator, and others.

Einstein’s first paper, sent to the Annalen der Physik journal in 1900, was about capillary attraction. It was published in 1901 with the title "Folgerungen aus den Capillaritätserscheinungen," which means "Conclusions from the capillarity phenomena." Two papers he published between 1902 and 1903 (about thermodynamics) tried to explain atomic behavior using statistics. These papers helped form the basis of his 1905 paper on Brownian motion, which showed that the movement of tiny particles in a liquid proves that molecules exist. His research in 1903 and 1904 focused on how the size of atoms affects diffusion.

Einstein returned to the topic of thermodynamic fluctuations, studying how density changes in a fluid at its critical point. Normally, density changes are controlled by the second derivative of free energy related to density. At the critical point, this derivative becomes zero, causing large density changes. These changes scatter light of all wavelengths, making the fluid look milky white. Einstein connected this to Rayleigh scattering, which explains why the sky appears blue. He calculated how critical opalescence happens due to density changes and showed that both effects come from the atomic structure of matter.

The Annus Mirabilis papers are four articles Einstein published in 1905 in the Annalen der Physik journal. These papers covered the photoelectric effect (which led to quantum theory), Brownian motion, the special theory of relativity, and the equation E = mc². These works greatly influenced modern physics and changed how people understand space, time, and matter. The four papers are:

Einstein’s paper titled "Zur Elektrodynamik bewegter Körper" ("On the Electrodynamics of Moving Bodies") was received on June 30, 1905, and published on September 26, 1905. It resolved conflicts between Maxwell’s equations (laws of electricity and magnetism) and Newtonian mechanics by changing the laws of mechanics. These changes are most noticeable at very high speeds, close to the speed of light. This theory later became known as Einstein’s special theory of relativity.

This paper predicted that a clock moving at high speeds would appear to slow down when observed from a different frame of reference, and that the moving object would shrink in the direction of motion. It also argued that the idea of a luminiferous aether (a theory popular at the time) was unnecessary.

In his paper on mass–energy equivalence, Einstein showed that E = mc² results from his special relativity equations. His 1905 work on relativity was controversial for many years but was eventually accepted by leading physicists, including Max Planck.

Einstein originally described special relativity using kinematics (the study of moving objects). In 1908, Hermann Minkowski reinterpreted special relativity using geometric terms as a theory of spacetime. Einstein later used Minkowski’s ideas in his 1915 general theory of relativity.

General relativity (GR) is a theory of gravity developed by Einstein between 1907 and 1915. It explains that gravity arises from the warping of spacetime caused by mass. General relativity is now a key tool in modern astrophysics and helps scientists understand black holes, regions where gravity is so strong that not even light can escape.

Einstein later said that the development of general relativity was driven by the need for a theory that does not favor any particular state of motion, even accelerated ones. In 1907, he published an article titled "On the Relativity Principle and the Conclusions Drawn from It," arguing that free fall is similar to inertial motion and that the rules of special relativity apply to a free-falling observer. This idea is called the equivalence principle. In the same article, Einstein predicted gravitational time dilation, gravitational redshift, and gravitational lensing.

In 1911, Einstein published another article titled "On the Influence of Gravitation on the Propagation of Light," expanding on his 1907 work. He estimated how much light bends near massive objects, allowing the predictions of general relativity to be tested experimentally for the first time.

In 1916, Einstein predicted gravitational waves, which are ripples in spacetime that carry energy as gravitational radiation. General relativity allows gravitational waves because of its Lorentz invariance, which means gravity moves at a finite speed. Newtonian gravity, by contrast, assumes gravity moves infinitely fast, making gravitational waves impossible.

The first indirect detection of gravitational waves happened in the 1970s through observations of a pair of neutron stars, PSR B1913+16. Scientists saw their orbit shrinking, proving they were emitting gravitational waves. Einstein’s prediction was confirmed on February 11, 2016, when researchers at LIGO announced the first direct observation of gravitational waves, detected on September 14, 2015, nearly 100 years after the prediction.

While working on general relativity, Einstein struggled with the theory’s gauge invariance. He concluded that a fully general relativistic field theory might be impossible and shifted his focus to equations that worked under general linear transformations.

In June 1913, Einstein created the Entwurf theory, a draft of a theory that was less elegant than general relativity and included extra conditions. After years of work, he realized the hole argument was incorrect and abandoned the theory in November 1915.

In 1917, Einstein used general relativity to study the universe’s structure. He found that the equations predicted a universe that was either expanding or contracting. Since no evidence for a dynamic universe existed at the time, Einstein added the cosmological constant to the equations to allow for a static universe. This model, known as the Einstein World or Einstein’s static universe, matched his understanding of Mach’s principle during that period.

Legacy

While traveling, Einstein wrote letters to his wife Elsa and his adopted stepdaughters Margot and Ilse every day. These letters were part of the papers left to the Hebrew University of Jerusalem. Margot Einstein allowed the personal letters to be shared with the public, but she asked that this not happen until twenty years after her death (she died in 1986). Barbara Wolff, from the Albert Einstein Archives at the Hebrew University, told the BBC that there are about 3,500 pages of private letters written between 1912 and 1955.

In his final four years, Einstein helped create the Albert Einstein College of Medicine in New York City.

In 1979, a statue called the Albert Einstein Memorial was placed outside the National Academy of Sciences building in Washington, D.C., to celebrate Einstein’s 100th birthday. The statue was made by Robert Berks. In the statue, Einstein is shown holding a paper with three of his most important equations: the one for the photoelectric effect, general relativity, and mass-energy equivalence.

In 2015, a court in California considered Einstein’s right to control how his name and image are used. At first, the court said this right had ended, but this decision was later overturned. The issues in the lawsuit were eventually resolved. The Hebrew University of Jerusalem is the only group that can control this right. Corbis, which took over from The Roger Richman Agency, manages the use of Einstein’s name and images on behalf of the university.

Mount Einstein in the Chugach Mountains of Alaska was named in 1955. Mount Einstein in New Zealand’s Paparoa Range was named after him in 1970 by the Department of Scientific and Industrial Research.

In 1999, Einstein was named Time magazine’s Person of the Century.

In 1999, a survey of the top 100 physicists ranked Einstein as the “greatest physicist ever.” A similar survey of all physicists gave Isaac Newton the top spot, with Einstein in second place.

Physicist Lev Landau ranked scientists on a special scale from 0 to 5, based on their productivity and genius. Newton received the highest score of 0, followed by Einstein with 0.5. Scientists who helped create quantum mechanics, such as Paul Dirac, Niels Bohr, and Werner Heisenberg, were ranked 1. Landau himself was ranked 2.

Science writer John G. Simmons ranked Einstein second after Newton in The Scientific 100, based on how much influence each scientist had. He noted that Einstein’s work “forms the source of twentieth-century physics.”

Physicist Eugene Wigner said that while John von Neumann had the sharpest mind he ever knew, Einstein had the more original and deep mind of the two.

The International Union of Pure and Applied Physics declared 2005 the “World Year of Physics,” also called “Einstein Year,” to honor Einstein’s “miracle year” in 1905. The United Nations also called it the “International Year of Physics.”

In popular culture

Albert Einstein became one of the most famous scientists after his general theory of relativity was confirmed in 1919. Many people did not fully understand his work, but he was still widely known and respected. Before World War II, The New Yorker magazine included a short story in its "The Talk of the Town" section that described how Einstein was so famous in America that strangers often stopped him on the street to ask him to explain "that theory." To deal with these frequent questions, Einstein began pretending to be someone else. He would say, "Pardon me, sorry! Always I am mistaken for Professor Einstein."

Einstein has appeared in or inspired many books, movies, plays, and musical works. He is often shown as a forgetful professor in stories, and his unique face and hairstyle have been frequently copied and made bigger in pictures. Time magazine writer Frederic Golden once said Einstein was "a cartoonist's dream come true." His smart ideas and creative thinking made Einstein closely linked with the idea of genius.

Many famous quotes are incorrectly said to be from Einstein.

Awards and honors

Albert Einstein received many awards and honors. In 1922, he was given the 1921 Nobel Prize in Physics for his work in theoretical physics and for discovering the law of the photoelectric effect. The 1921 prize could not be awarded because none of the nominations that year met the requirements set by Alfred Nobel, so it was given to Einstein in 1922.

In 1955, a few months after Einstein’s death, a man-made chemical element called einsteinium was named in his honor.

Publications

• Einstein, Albert; and others. (December 4, 1948). "To the editors of The New York Times." The New York Times. Saved from the original on December 17, 2007. Retrieved on May 25, 2006.
• Einstein, Albert. (May 1949). Sweezy, Paul; Huberman, Leo (editors). "Why Socialism?" Monthly Review. 1 (1): 9–15. Available at 10.14452/MR-001-01-1949-05_3.
• ————. (May 2009) [original date: May 1949]. "Why Socialism? (Reprise)." Monthly Review. New York: Monthly Review Foundation. Saved from the original on January 11, 2006. Retrieved on January 16, 2006 – via MonthlyReview.org.
• Einstein, Albert. (September 1960). Foreword to Gandhi Wields the Weapon of Moral Power: Three Case Histories. Introduction by Bharatan Kumarappa. Ahmedabad: Navajivan Publishing House. Pages v–vi. OCLC 2325889. The foreword was first written in April 1953.