February 11

Born in 1548 in Naples, Cataldi studied at the University of Naples before joining the Jesuit order. He is best known for identifying the Mersenne primes 127 and 8191, advancing number theory. Cataldi also wrote treatises on algebra, geometry, and trigonometry that circulated widely in Europe. He made astronomical observations and defended the Copernican heliocentric model. Cataldi corresponded with leading scholars of his time, exchanging ideas on mathematics and astronomy. His work influenced later developments in prime number research and mathematical methods. He died on February 11, 1626, leaving a lasting mark on Renaissance science.

Born on March 31, 1596, in La Haye en Touraine, Descartes studied law before turning to mathematics and philosophy. He developed analytic geometry, bridging algebra and Euclidean geometry. Descartes’s philosophical method, encapsulated in 'Cogito, ergo sum,' established skepticism as a tool for uncovering truth. He wrote key works such as 'Meditations on First Philosophy' and 'Discourse on the Method.' Descartes also made significant contributions to optics and mechanical physics. His dualist view of mind and body shaped centuries of philosophical debate. He died on February 11, 1650, in Stockholm while serving Queen Christina of Sweden, and remains a central figure in Western thought.

Born in 1675 into the noble Maffei family of Verona, Francesco Scipione was known by his title Marchese di Maffei. He conducted pioneering archaeological excavations in Verona and published one of the first detailed studies of Roman ruins. Maffei’s historical research laid groundwork for modern antiquarian methods. As a dramatist, he wrote comedies and tragedies in Italian and Latin that were performed across Europe. He also worked as a literary critic, publishing essays on poetry, drama, and the visual arts. Maffei’s eclectic interests connected scholarly circles in Italy and France. He died on February 11, 1755, remembered as a key figure in the cultural life of the early 18th century.

Born in Paris in 1819, Foucault made significant contributions to experimental physics during the 19th century. In 1851, he unveiled his famous pendulum experiment at the Paris Observatory, providing clear evidence of Earth's rotation. Foucault also measured the speed of light by improving upon Fizeau's method, enhancing understanding of electromagnetic phenomena. His work spanned studies on the gyroscope and the eddy current effect, now known as the Foucault effect. He held the chair of experimental physics at the Collège de France, mentoring future generations of scientists. Foucault's innovative experiments and commitment to empirical evidence cemented his legacy in the history of physics.

Born in 1872 in São Luís, Maranhão, Cruz studied medicine in Rio de Janeiro and furthered his training in Europe. Upon returning to Brazil, he led the federal public health service, implementing campaigns against yellow fever, smallpox, and plague in Rio de Janeiro. He introduced innovative methods such as mosquito control and mandatory vaccination, significantly reducing disease outbreaks. Cruz also founded the Instituto Soroterápico Federal, which later became the Oswaldo Cruz Foundation (Fiocruz), a major center for biomedical research. His rigorous approach to public health laid the foundations for modern epidemiology in Brazil. Cruz's work saved thousands of lives and established a legacy of disease prevention that continues today.

Charles Algernon Parsons (1854–1931) was an Anglo-Irish engineer who pioneered the modern steam turbine. In 1884, he developed a compact and efficient turbine that vastly improved ship speeds and power plant performance. His demonstration vessel Turbinia showcased unparalleled naval speeds and led to widespread naval adoption. Parsons founded the Parsons Marine Steam Turbine Company to produce turbines for military and commercial vessels. His innovations laid the groundwork for the turbine-driven power industry and transformed global energy production. Parsons received numerous honors and his legacy endures in modern engineering and power generation.

Axel Munthe (1857–1949) was a Swedish medical doctor whose practice spanned Paris, Rome, and the Italian island of Capri. He gained international fame with his memoir The Story of San Michele, which blends medical anecdotes with reflections on art and nature. Munthe designed the famous Villa San Michele on Capri and tended to patients from all walks of life, including royalty. He advocated for public health improvements and animal welfare. His writings reveal a compassionate physician with a deep appreciation for beauty and humanity. Munthe's work continues to inspire readers and medical professionals alike.

Ernest Jones (1879–1958) was a Welsh neurologist and the first English-language biographer of Sigmund Freud. He played a central role in founding the British Psychoanalytical Society and served as its president. Jones edited and translated many of Freud's works, making psychoanalytic theories accessible to a wider audience. His clinical practice and writings advanced the understanding of dream analysis and the unconscious. Jones corresponded extensively with Freud and defended psychoanalysis against its critics. His efforts laid the foundation for modern psychoanalytic practice in Britain and beyond.

Born in 1907 in Hamburg, J. Hans D. Jensen studied physics at the universities of Freiburg and Göttingen. He became a professor at the University of Heidelberg, where he pioneered research on the atomic nucleus. In 1963, Jensen shared the Nobel Prize in Physics with Maria Goeppert Mayer for their independent work on nuclear shell theory. His findings advanced the scientific understanding of atomic behavior and nuclear stability. Jensen mentored a generation of physicists and helped rebuild German scientific research after World War II. He passed away on February 11, 1973, remembered as a leading figure in theoretical physics.

Born in Germany in 1894, Alexander Lippisch developed a passion for flight and pursued mechanical engineering. He became a leading glider pilot during the interwar years, setting early endurance and altitude records. Lippisch conducted groundbreaking research on delta wing configurations, influencing post-war jet and supersonic aircraft. After World War II, he continued his work in the United States on experimental rocket-powered planes. His innovations laid the foundation for modern aviation and aerodynamics. He died on February 11, 1976, remembered as a visionary engineer and pilot.

James Bryant Conant was an American chemist, educator, and public servant. He served as the seventh president of Harvard University from 1933 to 1953, modernizing the institution and expanding its scientific research. A pioneer in physical chemistry, Conant made notable contributions to the understanding of reaction kinetics. During World War II, he was instrumental in coordinating American scientific efforts as chairman of the National Defense Research Committee. After the war, he served as the U.S. High Commissioner for Germany, overseeing reconstruction efforts. Conant also advised several presidents on science policy and nuclear issues, shaping U.S. science funding and education. His leadership helped establish the National Science Foundation. Conant remained active in academic and public life until his death in 1978.

Robert W. Holley was an American biochemist who shared the 1968 Nobel Prize in Physiology or Medicine for his work on the structure of transfer RNA (tRNA). Born in Urbana, Illinois, in 1922, he studied chemistry and medicine at the University of Illinois and Cornell University. Holley used enzymatic methods to sequence the first nucleic acid ever deciphered, revealing how tRNA functions in protein synthesis. His pioneering research provided fundamental insights into molecular biology and genetics. After winning the Nobel Prize, he continued his academic career at the Salk Institute and the University of California, San Diego, mentoring a generation of scientists. Holley's work laid the groundwork for advances in biotechnology and understanding of genetic coding. His dedication to teaching and research left a lasting impact on the scientific community.