Richard von Mises was born #OTD in 1883. He worked on mechanics of solids and fluids, and made several contributions to probability theory. The von Mises distribution is the equivalent of the Gaussian for circular variables. en.wikipedia.org/wiki/Richard_v…

Jean-Baptiste Biot was born #OTD in 1774. He is usually remembered for his works on electromagnetism and polarization of light, but he also uncovered the extraterrestrial origin of meteorites, in support of Chladni’s theory. en.wikipedia.org/wiki/Jean-Bapt…

Max Planck was born #OTD in 1858. His postulate that electromagnetic radiation is quantized, introducing the constant that bears his name, is widely acknowledged as marking the birth of quantum theory. en.wikipedia.org/wiki/Max_Planck

Gérard de Vaucouleurs was born #OTD in 1918. A French astronomer who did most of his career in the USA, he was a co-author of the Third Reference Catalogue of Bright Galaxies with his wife Antoinette. en.wikipedia.org/wiki/G%C3%A9ra…

Charles Francis Richter was born #OTD in 1900. His childhood interest in astronomy led him to call « magnitude » the intensity of earthquakes that the scale which bears his name measures. en.wikipedia.org/wiki/Charles_F…

Henri Poincaré was born #OTD in 1854. His contributions were immense, including fundamental advances in topology, dynamical systems, and just stopping short of discovering special relativity before Einstein. en.wikipedia.org/wiki/Henri_Poi…

Carl Friedrich Gauss was born #OTD in 1777. Among his many achievements, astronomers remember that he was able to reconstruct the orbit of Ceres from a very limited data sample, thereby developing the method of least squares. en.wikipedia.org/wiki/Carl_Frie…

Johann Jakob Balmer was born #OTD in 1825. A Swiss mathematician, he is best remembered for the series of spectral lines of hydrogen that bears his name, which is in the visible range of the spectrum. en.wikipedia.org/wiki/Johann_Ja…

Heinrich Gustav Magnus was born #OTD in 1802. A German chemist and physicist, he was a famed experimentalist. The Magnus effect is the deflection of a spinning object moving through a fluid, that was already observed by Newton. en.wikipedia.org/wiki/Magnus_ef…

Alfred Kastler was born #OTD in 1902. He developed the technique of optical pumping to realize the population inversion at work in lasers. Recipient of the 1966 Nobel Prize in physics, he co-founded the LSH (now LKB) with Jean Brossel. en.wikipedia.org/wiki/Alfred_Ka…

#OTD in 2021, the Ingenuity helicopter, brought to Mars with the Perseverance rover, took off for the first ever motorised atmospheric flight on another planet. youtu.be/V5ac3jktME4?si…

Sir Harold Jeffreys was born #OTD in 1891. A British mathematician, geophysicist, and astronomer, he furthered the idea that the Earth’s core is liquid and made major contributions to Bayesian statistics. en.wikipedia.org/wiki/Harold_Je…

Hertha Ayrton was born #OTD in 1854. Known for her works on electric arcs and the physics of sand ripples, she was the first woman to receive the Royal Society's Hughes Medal. Only three others have as of 2024. en.wikipedia.org/wiki/Hertha_Ay…

Jury d’école doctorale, dossiers de candidature au M2 AAIS, à la préparation à l’agrégation, comités de sélection divers… C’est le printemps !