First, despite his great contributions to quantum mechanics, he opposed what it evolved into, objecting that nature “does not play dice”. Second, he attempted to devise a unified field theory by generalizing his geometric theory of gravitation to include electromagnetism. As a result, he became increasingly isolated from the mainstream of modern physics.
In 1933, while Einstein was visiting the United States, Adolf Hitler came to power. Einstein did not return to Germany because he objected to the policies of the newly elected Nazi-led government. He settled in the United States and became an American citizen in 1940.
On the eve of World War II, he endorsed a letter to President Franklin D. Roosevelt alerting him to the potential German nuclear weapons program and recommending that the US begin similar research. Einstein supported the Allies, but he generally denounced the idea of nuclear weapons.
On 17 April 1955, Einstein experienced internal bleeding caused by the rupture of an abdominal aortic aneurysm, which had previously been reinforced surgically by Rudolph Nissen in 1948. He took the draft of a speech he was preparing for a television appearance commemorating the state of Israel’s seventh anniversary with him to the hospital, but he did not live to complete it.
Einstein refused surgery, saying, “I want to go when I want. It is tasteless to prolong life artificially. I have done my share; it is time to go. I will do it elegantly.” He died in Princeton Hospital early the next morning at the age of 76, having continued to work until near the end.
*14 March 1879, Ulm, Kingdom of Württemberg, German Empire.
†18 April 1955, Princeton, New Jersey, U.S.
Albert Einstein was a German-born theoretical physicist, widely acknowledged to be one of the greatest physicists of all time. Einstein is known widely for developing the theory of relativity, but he also made important contributions to the development of the theory of quantum mechanics.
Einstein developed an appreciation for music at an early age. In his late journals he wrote: “If I were not a physicist, I would probably be a musician. I often think in music. I live my daydreams in music. I see my life in terms of music… I get most joy in life out of music.”
His mass–energy equivalence formula E = mc2, which arises from relativity theory, has been dubbed “the world’s most famous equation”. His work is also known for its influence on the philosophy of science.
Einstein was born in the German Empire, but moved to Switzerland in 1895, forsaking his German citizenship the following year. In 1901, he acquired Swiss citizenship, which he kept for the rest of his life.
In 1905 Einstein published four groundbreaking papers. These outlined the theory of the photoelectric effect, explained Brownian motion, introduced special relativity, and demonstrated mass-energy equivalence. Einstein thought that the laws of classical mechanics could no longer be reconciled with those of the electromagnetic field, which led him to develop his special theory of relativity. In this year was Einstein also awarded a PhD by the University of Zurich.
He then extended the theory to gravitational fields; he published a paper on general relativity in 1916, introducing his theory of gravitation. In 1917, he applied the general theory of relativity to model the structure of the universe. He continued to deal with problems of statistical mechanics and quantum theory, which led to his explanations of particle theory and the motion of molecules.
He also investigated the thermal properties of light and the quantum theory of radiation, which laid the foundation of the photon theory of light. However, for much of the later part of his career, he worked on two ultimately unsuccessful endeavors.
At Google’s Zeitgeist Conference in 2011, Hawking said that “philosophy is dead”. He believed that philosophers “have not kept up with modern developments in science” and that scientists “have become the bearers of the torch of discovery in our quest for knowledge”.
In 2006 Hawking expressed concern that life on Earth is at risk from a sudden nuclear war, a genetically engineered virus, global warming, or other dangers humans have not yet thought of. Hawking viewed spaceflight and the colonisation of space as necessary for the future of humanity.
Hawking achieved commercial success with several works of popular science in which he discussed his theories and cosmology in general. His book A Brief History of Time appeared on the Sunday Times bestseller list for a record-breaking 237 weeks.
Hawking was a Fellow of the Royal Society, a lifetime member of the Pontifical Academy of Sciences, and a recipient of the Presidential Medal of Freedom, the highest civilian award in the United States.
He died on 14 March 2018 at the age of 76, after living with motor neurone disease for more than 50 years.
*8 January 1942, Oxford, England.
†14 March 2018, Cambridge, England.
Stephen Hawking was an English theoretical physicist, cosmologist, and author who was director of research at the Centre for Theoretical Cosmology at the University of Cambridge at the time of his death. He was the Lucasian Professor of Mathematics at the University of Cambridge between 1979 and 2009.
Hawking was born in Oxford into a family of doctors. Hawking began his university education at University College, Oxford in October 1959 at the age of 17, where he received a first-class BA degree in physics. He began his graduate work at Trinity Hall, Cambridge in October 1962, where he obtained his PhD degree in applied mathematics and theoretical physics, specialising in general relativity and cosmology in March 1966.
During this period in 1963 Hawking was diagnosed with an early-onset slow-progressing form of motor neurone disease that gradually paralysed him over the decades. After the loss of his speech, he was able to communicate through a speech-generating device—initially through use of a handheld switch, and eventually by using a single cheek muscle.
Hawking’s scientific works included a collaboration with Roger Penrose on gravitational singularity theorems in the framework of general relativity and the theoretical prediction that black holes emit radiation, often called Hawking radiation. Initially, Hawking radiation was controversial.
Hawking was an atheist and believed that “the universe is governed by the laws of science”. He stated: “There is a fundamental difference between religion, which is based on authority and science, which is based on observation and reason. Science will win because it works.”
After the war, Bohr called for international cooperation on nuclear energy. He was involved with the establishment of CERN and the Research Establishment Risø of the Danish Atomic Energy Commission and became the first chairman of the Nordic Institute for Theoretical Physics in 1957.
Heisenberg said of Bohr that he was “primarily a philosopher, not a physicist”. Bohr read the 19th-century Danish Christian existentialist philosopher, Søren Kierkegaard. Richard Rhodes argued in The Making of the Atomic Bomb that Bohr was influenced by Kierkegaard through Høffding. In 1909, Bohr sent his brother Kierkegaard’s Stages on Life’s Way as a birthday gift.
In the enclosed letter, Bohr wrote, “It is the only thing I have to send home; but I do not believe that it would be very easy to find anything better … I even think it is one of the most delightful things I have ever read.” Bohr enjoyed Kierkegaard’s language and literary style, but mentioned that he had some disagreement with Kierkegaard’s philosophy. Some of Bohr’s biographers suggested that this disagreement stemmed from Kierkegaard’s advocacy of Christianity, while Bohr was an atheist.
*7 October 1885, Copenhagen, Denmark.
†18 November 1962, Copenhagen, Denmark.
Niels Henrik David Bohr was a Danish physicist who made foundational contributions to understanding atomic structure and quantum theory, for which he received the Nobel Prize in Physics in 1922. Bohr was also a philosopher and a promoter of scientific research.
Bohr was educated at Gammelholm Latin School, starting when he was seven. In 1903, Bohr enrolled as an undergraduate at Copenhagen University. His major was physics, which he studied under Professor Christian Christiansen, the university’s only professor of physics at that time. He also studied astronomy and mathematics under Professor Thorvald Thiele, and philosophy under Professor Harald Høffding, a friend of his father.
Bohr developed the Bohr model of the atom, in which he proposed that energy levels of electrons are discrete and that the electrons revolve in stable orbits around the atomic nucleus but can jump from one energy level (or orbit) to another. Although the Bohr model has been supplanted by other models, its underlying principles remain valid.
He conceived the principle of complementarity: that items could be separately analysed in terms of contradictory properties, like behaving as a wave or a stream of particles. The notion of complementarity dominated Bohr’s thinking in both science and philosophy.
Bohr founded the Institute of Theoretical Physics at the University of Copenhagen, now known as the Niels Bohr Institute, which opened in 1920. Bohr mentored and collaborated with physicists including Hans Kramers, Oskar Klein, George de Hevesy, and Werner Heisenberg. He predicted the existence of a new zirconium-like element, which was named hafnium, after the Latin name for Copenhagen, where it was discovered. Later, the element bohrium was named after him.
During the 1930s Bohr helped refugees from Nazism. After Denmark was occupied by the Germans, he had a famous meeting with Heisenberg, who had become the head of the German nuclear weapon project. In September 1943 word reached Bohr that he was about to be arrested by the Germans, and he fled to Sweden. From there, he was flown to Britain, where he joined the British Tube Alloys nuclear weapons project, and was part of the British mission to the Manhattan Project.
Richard Phillips Feynman
Along with his work in theoretical physics, Feynman has been credited with pioneering the field of quantum computing and introducing the concept of nanotechnology. He held the Richard C. Tolman professorship in theoretical physics at the California Institute of Technology.
Feynman was a keen popularizer of physics through both books and lectures, including a 1959 talk on top-down nanotechnology called There’s Plenty of Room at the Bottom and the three-volume publication of his undergraduate lectures, The Feynman Lectures on Physics.
Feynman also became known through his semi-autobiographical books Surely You’re Joking, Mr. Feynman! and What Do You Care What Other People Think?, and books written about him such as Tuva or Bust! by Ralph Leighton and the biography Genius: The Life and Science of Richard Feynman by James Gleick.
In 1978, Feynman sought medical treatment for abdominal pains and was diagnosed with liposarcoma, a rare form of cancer. Surgeons removed a tumor the size of a football that had crushed one kidney and his spleen. Further operations were performed in October 1986 and October 1987. He was again hospitalized at the UCLA Medical Center on February 3, 1988. A ruptured duodenal ulcer caused kidney failure, and he declined to undergo the dialysis that might have prolonged his life for a few months. Watched over by his wife Gweneth, sister Joan, and cousin Frances Lewine, he died on February 15, 1988, at age 69.
* 11 May 1918, New York City, U.S.
† 15 February 1988, Los Angeles, California, U.S.
Richard Phillips Feynman was an American theoretical physicist, known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics, the physics of the superfluidity of supercooled liquid helium, as well as his work in particle physics for which he proposed the parton model. For contributions to the development of quantum electrodynamics, Feynman received the Nobel Prize in Physics in 1965 jointly with Julian Schwinger and Shin’ichirō Tomonaga.
Upon starting high school, Feynman was quickly promoted to a higher math class. An IQ test administered in high school estimated his IQ at 125—high but “merely respectable”, according to biographer James Gleick. Years later he declined to join Mensa International, saying that his IQ was too low.
When Feynman was 15, he taught himself trigonometry, advanced algebra, infinite series, analytic geometry, and both differential and integral calculus. Before entering college, he was experimenting with and deriving mathematical topics such as the half-derivative using his own notation.
He created special symbols for logarithm, sine, cosine and tangent functions so they did not look like three variables multiplied together, and for the derivative, to remove the temptation of canceling out the s in .
Feynman developed a widely used pictorial representation scheme for the mathematical expressions describing the behavior of subatomic particles, which later became known as Feynman diagrams.
During his lifetime, Feynman became one of the best-known scientists in the world. In a 1999 poll of 130 leading physicists worldwide by the British journal Physics World, he was ranked the seventh greatest physicist of all time. He assisted in the development of the atomic bomb during World War II and became known to a wide public in the 1980s as a member of the Rogers Commission, the panel that investigated the Space Shuttle Challenger disaster.
Fermi left Italy in 1938 to escape new Italian racial laws that affected his Jewish wife, Laura Capon. He emigrated to the United States, where he worked on the Manhattan Project during World War II. Fermi led the team that designed and built Chicago Pile-1, which went critical on 2 December 1942, demonstrating the first human-created, self-sustaining nuclear chain reaction.
He was on hand when the X-10 Graphite Reactor at Oak Ridge, Tennessee, went critical in 1943, and when the B Reactor at the Hanford Site did so the next year. At Los Alamos, he headed F Division, part of which worked on Edward Teller’s thermonuclear “Super” bomb. He was present at the Trinity test on 16 July 1945, where he used his Fermi method to estimate the bomb’s yield.
After the war, Fermi served under J. Robert Oppenheimer on the General Advisory Committee, which advised the Atomic Energy Commission on nuclear matters. After the detonation of the first Soviet fission bomb in August 1949, he strongly opposed the development of a hydrogen bomb on both moral and technical grounds. He was among the scientists who testified on Oppenheimer’s behalf at the 1954 hearing that resulted in the denial of Oppenheimer’s security clearance.
*29 September 1901, Rome, Kingdom of Italy
†28 November 1954, Chicago, Illinois, U.S.
Enrico Fermi was an Italian physicist and the creator of the world’s first nuclear reactor, the Chicago Pile-1. He was one of very few physicists to excel in both theoretical physics and experimental physics. Fermi was awarded the 1938 Nobel Prize in Physics for his work on induced radioactivity by neutron bombardment and for the discovery of transuranium elements.
With his colleagues, Fermi filed several patents related to the use of nuclear power, all of which were taken over by the US government. He made significant contributions to the development of statistical mechanics, quantum theory, and nuclear and particle physics.
Fermi’s first major contribution involved the field of statistical mechanics. After Wolfgang Pauli formulated his exclusion principle in 1925, Fermi followed with a paper in which he applied the principle to an ideal gas, employing a statistical formulation now known as Fermi–Dirac statistics. Today, particles that obey the exclusion principle are called “fermions”. Pauli later postulated the existence of an uncharged invisible particle emitted along with an electron during beta decay, to satisfy the law of conservation of energy. Fermi took up this idea, developing a model that incorporated the postulated particle, which he named the “neutrino”.
His theory, later referred to as Fermi’s interaction and now called weak interaction, described one of the four fundamental interactions in nature. Through experiments inducing radioactivity with the recently discovered neutron, Fermi discovered that slow neutrons were more easily captured by atomic nuclei than fast ones, and he developed the Fermi age equation to describe this.
After bombarding thorium and uranium with slow neutrons, he concluded that he had created new elements. Although he was awarded the Nobel Prize for this discovery, the new elements were later revealed to be nuclear fission products.
Dirac was known among his colleagues for his precise and taciturn nature. His colleagues in Cambridge jokingly defined a unit called a “dirac”, which was one word per hour. When Niels Bohr complained that he did not know how to finish a sentence in a scientific article he was writing, Dirac replied, “I was taught at school never to start a sentence without knowing the end of it.”
In 1975, Dirac gave a series of five lectures at the University of New South Wales which were subsequently published as a book, Directions in Physics (1978). He donated the royalties from this book to the university for the establishment of the Dirac Lecture Series. The Silver Dirac Medal for the Advancement of Theoretical Physics is awarded by the University of New South Wales to commemorate the lecture.
In 1984, Dirac died in Tallahassee, Florida.
Immediately after his death, two organizations of professional physicists established annual awards in Dirac’s memory. The Institute of Physics, the United Kingdom’s professional body for physicists, awards the Paul Dirac Medal for “outstanding contributions to theoretical (including mathematical and computational) physics”.
* 8 August 1902 Bristol, England
† 20 October 1984 Tallahassee, Florida, U.S.
Paul Adrien Maurice Dirac was an English theoretical physicist who is regarded as one of the most significant physicists of the 20th century. He was the Lucasian Professor of Mathematics at the University of Cambridge, was a member of the Center for Theoretical Studies, University of Miami, and spent the last decade of his life at Florida State University.
Dirac made fundamental contributions to the early development of both quantum mechanics and quantum electrodynamics. Among other discoveries, he formulated the Dirac equation which describes the behaviour of fermions and predicted the existence of antimatter. Dirac shared the 1933 Nobel Prize in Physics with Erwin Schrödinger “for the discovery of new productive forms of atomic theory”. He also made significant contributions to the reconciliation of general relativity with quantum mechanics.
Dirac was educated first at Bishop Road Primary School and then at the all-boys Merchant Venturers’ Technical College, where his father was a French teacher. The school was an institution attached to the University of Bristol, which shared grounds and staff. It emphasised technical subjects like bricklaying, shoemaking and metal work, and modern languages. This was unusual at a time when secondary education in Britain was still dedicated largely to the classics, and something for which Dirac would later express his gratitude.
Dirac studied electrical engineering on a City of Bristol University Scholarship at the University of Bristol’s engineering faculty, which was co-located with the Merchant Venturers’ Technical College. Shortly before he completed his degree in 1921, he sat for the entrance examination for St John’s College, Cambridge. He passed and was awarded a £70 scholarship, but this fell short of the amount of money required to live and study at Cambridge.
Despite his having graduated with a first class honours Bachelor of Science degree in engineering, the economic climate of the post-war depression was such that he was unable to find work as an engineer. Instead, he took up an offer to study for a Bachelor of Arts degree in mathematics at the University of Bristol free of charge. He was permitted to skip the first year of the course owing to his engineering degree.
Dirac was regarded by his friends and colleagues as unusual in character. In a 1926 letter to Paul Ehrenfest, Albert Einstein wrote of Dirac, “I have trouble with Dirac. This balancing on the dizzying path between genius and madness is awful.” In another letter he wrote, “I don’t understand Dirac at all (Compton effect).”
Frank Donald Drake
He is one of the pioneers of the modern field of the search for extraterrestrial intelligence with Giuseppe Cocconi, Philip Morrison, Iosif Shklovsky, and Carl Sagan.
Drake co-designed the Pioneer plaque with Carl Sagan in 1972, the first physical message sent into space. The plaque was designed to be understandable by extraterrestrials should they encounter it. He later supervised the creation of the Voyager Golden Record. He was elected to the American Academy of Arts and Sciences in 1974.
Drake is a member of the National Academy of Sciences where he chaired the Board of Physics and Astronomy of the National Research Council (1989–1992). He also served as President of the Astronomical Society of the Pacific. He was a Professor of Astronomy at Cornell University (1964–1984) and served as the Director of the Arecibo Observatory. As of 2010, he was involved in “The Carl Sagan Center for the Study of life in the Universe” at the SETI Institute.
He is Emeritus Professor of Astronomy and Astrophysics at the University of California at Santa Cruz where he also served as Dean of Natural Sciences (1984–1988). He serves on the Board of Trustees of the SETI Institute.
Drake Planetarium at Norwood High School in Norwood, Ohio is named for Drake and linked to NASA.
*18 May 1930, Chicago, Illinois
Frank Donald Drake is an American astronomer and astrophysicist. He is involved in the search for extraterrestrial intelligence, including the founding of SETI, mounting the first observational attempts at detecting extraterrestrial communications in 1960 in Project Ozma, developing the Drake equation, and as the creator of the Arecibo Message, a digital encoding of an astronomical and biological description of the Earth and its lifeforms for transmission into the cosmos.
Born on May 28, 1930, in Chicago, Illinois, as a youth Drake loved electronics and chemistry. He reports that he considered the possibility of life existing on other planets as an eight-year-old, but never discussed the idea with his family or teachers due to the prevalent religious ideology.
He enrolled at Cornell University on a Navy Reserve Officer Training Corps scholarship. Once there he began studying astronomy. His ideas about the possibility of extraterrestrial life were reinforced by a lecture from astrophysicist Otto Struve in 1951. After college, he served briefly as an electronics officer on the heavy cruiser USS Albany. He then went on to graduate school at Harvard to study radio astronomy.
Drake’s hobbies include lapidary and the cultivation of orchids.
Although explicitly linked with modern views on the likelihood and detectability of extraterrestrial civilizations, Drake started his career undertaking radio astronomical research at the National Radio Astronomy Observatory (NRAO) in Green Bank, West Virginia, and later the Jet Propulsion Laboratory. He conducted key measurements which revealed the presence of a Jovian ionosphere and magnetosphere.
In the 1960s, Drake spearheaded the conversion of the Arecibo Observatory to a radio astronomical facility, later updated in 1974 and 1996. As a researcher, Drake was involved in the early work on pulsars. In this period, Drake was a professor at Cornell University and Director of the National Astronomy and Ionosphere Center (NAIC) – the formal name for the Arecibo facility. In 1974 he wrote the Arecibo message.
J. Robert Oppenheimer
In his first year, he was admitted to graduate standing in physics on the basis of independent study, which meant he was not required to take the basic classes and could enroll instead in advanced ones. He was attracted to experimental physics by a course on thermodynamics that was taught by Percy Bridgman. He graduated summa cum laude in three years.
After the war ended, Oppenheimer became chairman of the influential General Advisory Committee of the newly created United States Atomic Energy Commission. He used that position to lobby for international control of nuclear power to avert nuclear proliferation and a nuclear arms race with the Soviet Union. He opposed the development of the hydrogen bomb during a 1949–1950 governmental debate on the question and subsequently took stances on defense-related issues that provoked the ire of some factions in the U.S. government and military.
During the Second Red Scare, those stances, together with past associations Oppenheimer had with people and organizations affiliated with the Communist Party, led to him suffering the revocation of his security clearance in a much-written-about hearing in 1954. Effectively stripped of his direct political influence, he continued to lecture, write and work in physics. Nine years later, President John F. Kennedy awarded him with the Enrico Fermi Award as a gesture of political rehabilitation.
Oppenheimer was a chain smoker who was diagnosed with throat cancer in late 1965. After inconclusive surgery, he underwent unsuccessful radiation treatment and chemotherapy late in 1966. He fell into a coma on February 15, 1967, and died at his home in Princeton, New Jersey, on February 18, aged 62.
Oppenheimer’s achievements in physics included the Born–Oppenheimer approximation for molecular wave functions, work on the theory of electrons and positrons, the Oppenheimer–Phillips process in nuclear fusion, and the first prediction of quantum tunneling. With his students he also made important contributions to the modern theory of neutron stars and black holes, as well as to quantum mechanics, quantum field theory, and the interactions of cosmic rays.
As a teacher and promoter of science, he is remembered as a founding father of the American school of theoretical physics that gained world prominence in the 1930s. After World War II, he became director of the Institute for Advanced Study in Princeton, New Jersey.
* 22.4 1904, New York City, New York, U.S.
† 18.2 1967, Princeton, New Jersey, U.S.
J. Robert Oppenheimer was an American theoretical physicist and professor of physics at the University of California, Berkeley. Oppenheimer was the wartime head of the Los Alamos Laboratory and is among those who are credited with being the “father of the atomic bomb” for their role in the Manhattan Project, the World War II undertaking that developed the first nuclear weapons. The first atomic bomb was successfully detonated on July 16, 1945, in the Trinity test in New Mexico.
Oppenheimer later remarked that it brought to mind words from the Bhagavad Gita: “Now I am become Death, the destroyer of worlds.” In August 1945, the weapons were used in the atomic bombings of Hiroshima and Nagasaki.
Oppenheimer was initially educated at Alcuin Preparatory School; in 1911, he entered the Ethical Culture Society School. Oppenheimer was a versatile scholar, interested in English and French literature, and particularly in mineralogy. He completed the third and fourth grades in one year and skipped half the eighth grade. During his final year, he became interested in chemistry.
He entered Harvard College one year after graduation, at age 18, because he suffered an attack of colitis while prospecting in Joachimstal during a family summer vacation in Europe. To help him recover from the illness, his father enlisted the help of his English teacher Herbert Smith who took him to New Mexico, where Oppenheimer fell in love with horseback riding and the southwestern United States.
Oppenheimer majored in chemistry, but Harvard required science students to also study history, literature, and philosophy or mathematics. He compensated for his late start by taking six courses each term and was admitted to the undergraduate honor society Phi Beta Kappa.
In 2010, Penrose reported possible evidence, based on concentric circles found in Wilkinson Microwave Anisotropy Probe data of the cosmic microwave background sky, of an earlier universe existing before the Big Bang of our own present universe.
He mentions this evidence in the epilogue of his 2010 book Cycles of Time, a book in which he presents his reasons, to do with Einstein’s field equations, the Weyl curvature C, and the Weyl curvature hypothesis (WCH), that the transition at the Big Bang could have been smooth enough for a previous universe to survive it. He made several conjectures about C and the WCH, some of which were subsequently proved by others, and he also popularized his conformal cyclic cosmology (CCC) theory.
In simple terms, he believes that the singularity in Einstein’s field equation at the Big Bang is only an apparent singularity, similar to the well-known apparent singularity at the event horizon of a black hole. The latter singularity can be removed by a change of coordinate system, and Penrose proposes a different change of coordinate system that will remove the singularity at the big bang. One implication of this is that the major events at the Big Bang can be understood without unifying general relativity and quantum mechanics, and therefore we are not necessarily constrained by the Wheeler–DeWitt equation, which disrupts time. Alternatively, one can use the Einstein–Maxwell–Dirac equations.
* 8 August 1931, Colchester, England, UK
Sir Roger Penrose OM FRS is a British mathematical physicist, mathematician, philosopher of science and Nobel Laureate in Physics. He is Emeritus Rouse Ball Professor of Mathematics at the University of Oxford, an emeritus fellow of Wadham College, Oxford, and an honorary fellow of St John’s College, Cambridge, and University College London.
Penrose has made contributions to the mathematical physics of general relativity and cosmology. He has received several prizes and awards, including the 1988 Wolf Prize in Physics, which he shared with Stephen Hawking for the Penrose–Hawking singularity theorems, and one half of the 2020 Nobel Prize in Physics “for the discovery that black hole formation is a robust prediction of the general theory of relativity”.
Penrose spent World War II as a child in Canada where his father worked in London, Ontario. Penrose attended University College School and University College London, where he graduated with a first class degree in mathematics.
In 1955, whilst still a student, Penrose reintroduced the E. H. Moore generalised matrix inverse, also known as the Moore–Penrose inverse, after it had been reinvented by Arne Bjerhammar in 1951. Having started research under the professor of geometry and astronomy, Sir W. V. D. Hodge, Penrose finished his PhD at St John’s College, Cambridge, in 1958, with a thesis on “tensor methods in algebraic geometry” under algebraist and geometer John A. Todd.
He devised and popularised the Penrose triangle in the 1950s, describing it as “impossibility in its purest form”, and exchanged material with the artist M. C. Escher, whose earlier depictions of impossible objects partly inspired it. Escher’s Waterfall, and Ascending and Descending were in turn inspired by Penrose.
In 2004, Penrose released The Road to Reality: A Complete Guide to the Laws of the Universe, a 1,099-page comprehensive guide to the Laws of Physics that includes an explanation of his own theory. The Penrose Interpretation predicts the relationship between quantum mechanics and general relativity, and proposes that a quantum state remains in superposition until the difference of space-time curvature attains a significant level.
John Archibald Wheeler
He received a National Research Council fellowship, which he used to study under Gregory Breit at New York University in 1933 and 1934, and then in Copenhagen under Niels Bohr in 1934 and 1935. In a 1934 paper, Breit and Wheeler introduced the Breit–Wheeler process, a mechanism by which photons can be potentially transformed into matter in the form of electron-positron pairs.
During 1939 he collaborated with Bohr to write a series of papers using the liquid drop model to explain the mechanism of fission. During World War II, he worked with the Manhattan Project’s Metallurgical Laboratory in Chicago, where he helped design nuclear reactors, and then at the Hanford Site in Richland, Washington, where he helped DuPont build them. He returned to Princeton after the war ended, but returned to government service to help design and build the hydrogen bomb in the early 1950s.
Wheeler speculated that reality is created by observers in the universe. “How does something arise from nothing?”, he asked about the existence of space and time. He also coined the term “Participatory Anthropic Principle” (PAP), a version of a Strong Anthropic Principle.
In 1990, Wheeler suggested that information is fundamental to the physics of the universe. According to this “it from bit” doctrine, all things physical are information-theoretic in origin.
For most of his career, Wheeler was a professor of physics at Princeton University, which he joined in 1938, remaining until his retirement in 1976. At Princeton he supervised 46 PhD students, more than any other professor in the Princeton physics department. Wheeler’s graduate students included Jacob Bekenstein, Hugh Everett, Richard Feynman, David Hill, Bei-Lok Hu, John R. Klauder, Charles Misner, Kip Thorne, William Unruh, Robert M. Wald, Katharine Way, and Arthur Wightman.
On April 13, 2008, Wheeler died of pneumonia at the age of 96 in Hightstown, New Jersey.
* 9 July 1911, Jacksonville, Florida, United States
†13 April, 2008, Hightstown, New Jersey, United States
John Archibald Wheeler (July 9, 1911 – April 13, 2008) was an American theoretical physicist. He was largely responsible for reviving interest in general relativity in the United States after World War II.
Wheeler also worked with Niels Bohr in explaining the basic principles behind nuclear fission. Together with Gregory Breit, Wheeler developed the concept of the Breit–Wheeler process. He is best known for using the term “black hole” for objects with gravitational collapse already predicted during the early 20th century, for inventing the terms “quantum foam”, “neutron moderator”, “wormhole” and “it from bit”, and for hypothesizing the “one-electron universe”.
Wheeler grew up in Youngstown, Ohio, but spent a year in 1921 to 1922 on a farm in Benson, Vermont, where Wheeler attended a one-room school. After they returned to Youngstown he attended Rayen High School.
After graduating from the Baltimore City College high school in 1926, Wheeler entered Johns Hopkins University with a scholarship from the state of Maryland. He published his first scientific paper in 1930, as part of a summer job at the National Bureau of Standards. He earned his doctorate in 1933. His dissertation research work, carried out under the supervision of Karl Herzfeld, was on the “Theory of the Dispersion and Absorption of Helium”.
In April 1885, the University of Kiel appointed Planck as associate professor of theoretical physics. Further work on entropy and its treatment, especially as applied in physical chemistry, followed. He published his Treatise on Thermodynamics in 1897. He proposed a thermodynamic basis for Svante Arrhenius’s theory of electrolytic dissociation.
In 1905, the three epochal papers by Albert Einstein were published in the journal Annalen der Physik. Planck was among the few who immediately recognized the significance of the special theory of relativity. Thanks to his influence, this theory was soon widely accepted in Germany. Planck also contributed considerably to extend the special theory of relativity. For example, he recast the theory in terms of classical action.
Planck’s son Erwin was arrested by the Gestapo following the attempted assassination of Hitler in the 20 July plot. Erwin was hanged at Berlin’s Plötzensee Prison in January 1945. The death of his son destroyed much of Planck’s will to live. After the end of the war Planck, his second wife, and his son by her were brought to a relative in Göttingen, where Planck died on 4 October 1947. His grave is situated in the old Stadtfriedhof in Göttingen.
In 1948, the German scientific institution Kaiser Wilhelm Society (of which Planck was twice president) was renamed Max Planck Society (MPS). The MPS now includes 83 institutions representing a wide range of scientific directions.
*23 April 1858, Kiel, Duchy of Holstein
†4 October 1947, Göttingen, Lower Saxony, Allied-occupied Germany
Max Karl Ernst Ludwig Planck, ForMemRS was a German theoretical physicist whose discovery of energy quanta won him the Nobel Prize in Physics in 1918. Planck made many substantial contributions to theoretical physics, but his fame as a physicist rests primarily on his role as the originator of quantum theory, which revolutionized human understanding of atomic and subatomic processes.
War was common during Planck’s early years and among his earliest memories was the marching of Prussian and Austrian troops into Kiel during the Second Schleswig War in 1864. In 1867 the family moved to Munich, and Planck enrolled in the Maximilians gymnasium school, where he came under the tutelage of Hermann Müller, a mathematician who took an interest in the youth, and taught him astronomy and mechanics as well as mathematics. It was from Müller that Planck first learned the principle of conservation of energy. Planck graduated early, at age 17. This is how Planck first came in contact with the field of physics.
Planck was gifted when it came to music. He took singing lessons and played piano, organ and cello, and composed songs and operas. However, instead of music he chose to study physics.
The Munich physics professor Philipp von Jolly advised Planck against going into physics, saying, “In this field, almost everything is already discovered, and all that remains is to fill a few holes.” Planck replied that he did not wish to discover new things, but only to understand the known fundamentals of the field, and so began his studies in 1874 at the University of Munich.
In 1877, he went to the Friedrich Wilhelms University in Berlin for a year of study with physicists Hermann von Helmholtz and Gustav Kirchhoff and mathematician Karl Weierstrass. He wrote that Helmholtz was never quite prepared, spoke slowly, miscalculated endlessly, and bored his listeners, while Kirchhoff spoke in carefully prepared lectures which were dry and monotonous.
James Clerk Maxwell
*13 June 1831, Edinburgh, Scotland, United Kingdom
†5 November 1879, Cambridge, England, United Kingdom
James Clerk Maxwell FRSE FRS was a Scottish scientist in the field of mathematical physics. His most notable achievement was to formulate the classical theory of electromagnetic radiation, bringing together for the first time electricity, magnetism, and light as different manifestations of the same phenomenon. Maxwell’s equations for electromagnetism have been called the “second great unification in physics” where the first one had been realised by Isaac Newton.
Maxwell was fascinated by geometry at an early age, rediscovering the regular polyhedra before he received any formal instruction. Despite his winning the school’s scripture biography prize in his second year, his academic work remained unnoticed until, at the age of 13, he won the school’s mathematical medal and first prize for both English and poetry.
Maxwell’s interests ranged far beyond the school syllabus and he did not pay particular attention to examination performance. He wrote his first scientific paper at the age of 14. In it he described a mechanical means of drawing mathematical curves with a piece of twine, and the properties of ellipses, Cartesian ovals, and related curves with more than two foci.
He helped develop the Maxwell–Boltzmann distribution, a statistical means of describing aspects of the kinetic theory of gases. He is also known for presenting the first durable colour photograph in 1861 and for his foundational work on analysing the rigidity of rod-and-joint frameworks (trusses) like those in many bridges.
Maxwell died in Cambridge of abdominal cancer on 5 November 1879 at the age of 48. His mother had died at the same age of the same type of cancer.
His discoveries helped usher in the era of modern physics, laying the foundation for such fields as special relativity and quantum mechanics. Many physicists regard Maxwell as the 19th-century scientist having the greatest influence on 20th-century physics.
His contributions to the science are considered by many to be of the same magnitude as those of Isaac Newton and Albert Einstein. On the centenary of Maxwell’s birthday, Einstein described Maxwell’s work as the “most profound and the most fruitful that physics has experienced since the time of Newton”.
Einstein, when he visited the University of Cambridge in 1922, was told by his host that he had done great things because he stood on Newton’s shoulders; Einstein replied: “No I don’t. I stand on the shoulders of Maxwell.”
Maxwell left the Academy in 1847 at age 16 and began attending classes at the University of Edinburgh. He had the opportunity to attend the University of Cambridge, but decided, after his first term, to complete the full course of his undergraduate studies at Edinburgh.
In October 1850, already an accomplished mathematician, Maxwell left Scotland for the University of Cambridge. He initially attended Peterhouse, however before the end of his first term transferred to Trinity, where he believed it would be easier to obtain a fellowship.
In 1854, Maxwell graduated from Trinity with a degree in mathematics. He scored second highest in the final examination, coming behind Edward Routh and earning himself the title of Second Wrangler. He was later declared equal with Routh in the more exacting ordeal of the Smith’s Prize examination.
With the publication of “A Dynamical Theory of the Electromagnetic Field” in 1865, Maxwell demonstrated that electric and magnetic fields travel through space as waves moving at the speed of light.He proposed that light is an undulation in the same medium that is the cause of electric and magnetic phenomena. The unification of light and electrical phenomena led his prediction of the existence of radio waves. Maxwell is also regarded as a founder of the modern field of electrical engineering.
Susskind was an assistant professor of physics, then an associate professor at Yeshiva University, after which he went for a year to the Tel Aviv University, returning to Yeshiva to become a professor of physics. Since 1979 he has been professor of physics at Stanford University, and since 2000 has held the Felix Bloch professorship of physics.
Susskind was one of at least three physicists, alongside Yoichiro Nambu and Holger Bech Nielsen, who independently discovered during or around 1970 that the Veneziano dual resonance model of strong interactions could be described by a quantum mechanical model of oscillating strings, and was the first to propose the idea of the string theory landscape.
Susskind was awarded the 1998 J. J. Sakurai Prize for his “pioneering contributions to hadronic string models, lattice gauge theories, quantum chromodynamics, and dynamical symmetry breaking.” Susskind’s hallmark, according to colleagues, has been the application of “brilliant imagination and originality to the theoretical study of the nature of the elementary particles and forces that make up the physical world.” Also Susskind was awarded the the 2018 Oskar Klein Medal.
In 2007, Susskind joined the faculty of Perimeter Institute for Theoretical Physics in Waterloo, Ontario, Canada, as an associate member. He has been elected to the National Academy of Sciences and the American Academy of Arts and Sciences.
He is a member of the US National Academy of Sciences, and the American Academy of Arts and Sciences, an associate member of the faculty of Canada’s Perimeter Institute for Theoretical Physics, and a distinguished professor of the Korea Institute for Advanced Study.
Susskind is the author of several popular science books like The Cosmic Landscape, The Black Hole War and The Theoretical Minimum book series.
*20 May 1940, New York City, New York, US
Leonard Susskind is an American physicist, who is a professor of theoretical physics at Stanford University, and founding director of the Stanford Institute for Theoretical Physics. His research interests include string theory, quantum field theory, quantum statistical mechanics and quantum cosmology.
Susskind is widely regarded as one of the fathers of string theory. He was the first to give a precise string-theoretic interpretation of the holographic principle in 1995 and the first to introduce the idea of the string theory landscape in 2003.
Leonard Susskind was born in the South Bronx in New York City. He began working as a plumber at the age of 16, taking over from his father who had become ill. Later, he enrolled in the City College of New York as an engineering student, graduating with a B.S. in physics in 1962.
In an interview in the Los Angeles Times, Susskind recalls a discussion with his father that changed his career path: “When I told my father I wanted to be a physicist, he said, ‘Hell no, you ain’t going to work in a drug store.’ I said, ‘No, not a pharmacist.’ I said, ‘Like Einstein.’ He poked me in the chest with a piece of plumbing pipe. ‘You ain’t going to be no engineer,’ he said. ‘You’re going to be Einstein.'” Susskind then studied at Cornell University under Peter A. Carruthers, where he earned his Ph.D. in 1965.
*12 August 1887, Vienna, Austria-Hungary
†4 January 1961, Vienna, Austria
Erwin Rudolf Josef Alexander Schrödinger was a Nobel Prize-winning Austrian physicist who developed a number of fundamental results in quantum theory. For example in January 1926 he developed the Schrödinger equation provides a way to calculate the wave function of a system and how it changes dynamically in time.
In addition, he was the author of many works on various aspects of physics: statistical mechanics and thermodynamics, physics of dielectrics, colour theory, electrodynamics, general relativity, and cosmology, and he made several attempts to construct a unified field theory. In his book What Is Life? Schrödinger addressed the problems of genetics, looking at the phenomenon of life from the point of view of physics.
In 1911, Schrödinger became an assistant to Exner. At an early age, Schrödinger was strongly influenced by Arthur Schopenhauer. As a result of his extensive reading of Schopenhauer’s works, he became deeply interested throughout his life in colour theory and philosophy. In his lecture “Mind and Matter”, he said that “The world extended in space and time is but our representation.”
In the first years of his career Schrödinger became acquainted with the ideas of quantum theory, developed in the works of Max Planck, Albert Einstein, Niels Bohr, Arnold Sommerfeld, and others. This knowledge helped him work on some problems in theoretical physics, but the Austrian scientist at the time was not yet ready to part with the traditional methods of classical physics.
In 1920 he became the assistant to Max Wien, in Jena, and in September 1920 he attained the position of ao. Prof. (associate professor) in Stuttgart. In 1921, he became o. Prof. (full professor), in Wrocław. In 1921, he moved to the University of Zürich.
In 1927, he succeeded Max Planck at the Friedrich Wilhelm University in Berlin. In 1933, Schrödinger decided to leave Germany because he disliked the Nazis’ antisemitism. He became a Fellow of Magdalen College at the University of Oxford. Soon after he arrived, he received the Nobel Prize together with Paul Dirac.
His position at Oxford did not work out well; his unconventional domestic arrangements, sharing living quarters with two women, were not met with acceptance. In the midst of these tenure issues in 1935, after extensive correspondence with Albert Einstein, he proposed what is now called the Schrödinger’s cat thought experiment.
On 4 January 1961, Schrödinger died of tuberculosis, aged 73, in Vienna.
He paid great attention to the philosophical aspects of science, ancient and oriental philosophical concepts, ethics, and religion. He also wrote on philosophy and theoretical biology. He is also known for his “Schrödinger’s cat” thought experiment.
Between 1906 and 1910 Schrödinger studied at the University of Vienna under the physicists Franz S. Exner and Friedrich Hasenöhrl. He received his doctorate at Vienna under Hasenöhrl. He also conducted experimental work with Karl Wilhelm Friedrich “Fritz” Kohlrausch.
Early in his life, Schrödinger experimented in the fields of electrical engineering, atmospheric electricity, and atmospheric radioactivity, but he usually worked with his former teacher Franz Exner. He also studied vibrational theory, the theory of Brownian movement, and mathematical statistics.
He also formulated an empirical law of cooling, made the first theoretical calculation of the speed of sound, and introduced the notion of a Newtonian fluid. In addition to his work on calculus, as a mathematician Newton contributed to the study of power series, generalised the binomial theorem to non-integer exponents, developed a method for approximating the roots of a function, and classified most of the cubic plane curves.
Newton was a fellow of Trinity College and the second Lucasian Professor of Mathematics at the University of Cambridge. He was a devout but unorthodox Christian who privately rejected the doctrine of the Trinity.
Unusually for a member of the Cambridge faculty of the day, he refused to take holy orders in the Church of England. Beyond his work on the mathematical sciences, Newton dedicated much of his time to the study of alchemy and biblical chronology, but most of his work in those areas remained unpublished until long after his death.
Politically and personally tied to the Whig party, Newton served two brief terms as Member of Parliament for the University of Cambridge, in 1689–1690 and 1701–1702.
He was knighted by Queen Anne in 1705 and spent the last three decades of his life in London, serving as Warden (1696–1699) and Master (1699–1727) of the Royal Mint, as well as president of the Royal Society (1703–1727).
Newton died in his sleep in London on 20 March 1727.
*25 December 1642, Woolsthorpe-by-Colsterworth, Lincolnshire, England
†31 March 1727, Kensington, Middlesex, Great Britain
Sir Isaac Newton PRS was an English mathematician, physicist, astronomer, theologian, and author (described in his time as a “natural philosopher”) who is widely recognised as one of the greatest mathematicians and most influential scientists of all time and as a key figure in the scientific revolution.
His book Philosophiæ Naturalis Principia Mathematica, first published in 1687, established classical mechanics. Newton also made seminal contributions to optics, and shares credit with German mathematician Gottfried Wilhelm Leibniz for developing the infinitesimal calculus.
In Principia, Newton formulated the laws of motion and universal gravitation that formed the dominant scientific viewpoint until it was superseded by the theory of relativity. Newton used his mathematical description of gravity to derive Kepler’s laws of planetary motion, account for tides, the trajectories of comets, the precession of the equinoxes and other phenomena, eradicating doubt about the Solar System’s heliocentricity.
He demonstrated that the motion of objects on Earth and celestial bodies could be accounted for by the same principles. Newton’s inference that the Earth is an oblate spheroid was later confirmed by the geodetic measurements of Maupertuis, La Condamine, and others, convincing most European scientists of the superiority of Newtonian mechanics over earlier systems.
Newton built the first practical reflecting telescope and developed a sophisticated theory of colour based on the observation that a prism separates white light into the colours of the visible spectrum. His work on light was collected in his highly influential book Opticks, published in 1704.