Men love to wonder, and that is the seed of science.
-Ralph Waldo Emerson
Today is the 205th day of the year; there are 205 pairs of twin primes less than ten thousand. *Number Gossip
Every number greater than 205 is the sum of distinct primes of the form 6n + 1. *Prime Curios
205 is the number of walks of length 5 between any two distinct vertices of the complete graph K_5
594 The Sun was well up (17°) at 6:11 am when totality occurred. On a warm summer's morning it must have got surprisingly cold as totality approached, giving a clue that something unusual was about to happen. At 258 km wide this was an Eclipse with a very wide track and a good duration of over 3 minutes. The Eclipse track traveled into Denmark, Norway, Sweden, Finland, Estonia and Russia. *NSEC
1754 Joseph Louis Lagrange, 18, published his ﬁrst work in the form of a letter in Italian (He was Italian born. Only his great-great-grandfather Lagrange was French, all other ancestors were Italian). A month later he realized that he had rediscovered Leibniz’s formula for the n-th derivative of a product. *VFR
1829, William Austin Burt, a surveyor, of Mount Vernon, Michigan, received a patent for his typographer, a forerunner of the typewriter (U.S. No. 5581X). The Patent Office fire of 1836 destroyed the original patent model. Burt's typographer was a heavy, box-like contraption, made almost entirely of wood. Like today's familiar toy typewriter, the typographer had type mounted on a metal wheel, with a rotating, semicircular frame. By turning a crank, Burt was able to move the wheel until it came to the letter he wanted. Then he would pull a lever, driving the type against the paper and making an inked impression. *TIS
1904 The ice cream cone was introduced at the St. Louis world’s fair.*VFR by some accounts, the ice cream cone was invented by Charles E. Menches during the Louisiana Purchase Exposition in St. Louis. *TIS
1927 The term Eigenvalue first appears in a letter to Nature from A. S. Eddington beginning “Among those ... trying to acquire a general acquaintance with Schrödinger's wave mechanics there must be many who find their mathematical equipment insufficient to follow his first great problem—to determine the eigenvalues and eigenfunctions for the hydrogen atom" *Jeff Miller, Earliest Known Uses of Some of the Words of Mathematics
1962 Tens of millions of people watched a historic broadcast as Telstar beamed live transatlantic video into viewers’ living rooms for the first time. The age of satellite television had dawned.
In homes across Rome, people barely touched their dinners. London’s pubs were packed, but bartenders served nary a drink. Throughout Europe, more than 100 million people huddled around television sets on the evening of July 23, 1962, to tune in to history. With Europeans watching eagerly, a black-and-white image of the Statue of Liberty flickered onto their screens. The picture itself was not particularly noteworthy except for one thing: it was live, via satellite. *History.Com
The first broadcast was to have been remarks by President John F. Kennedy, but the signal was acquired before the president was ready, so the lead-in time was filled with a short segment of a televised game between the Philadelphia Phillies and the Chicago Cubs at Wrigley Field before the President's address.
1995 The comet Hale–Bopp was discovered on July 23, 1995, independently by two observers, Alan Hale and Thomas Bopp, both in the United States. Hale–Bopp's orbital position was calculated as 7.2 astronomical units (AU) from the Sun, placing it between Jupiter and Saturn and by far the greatest distance from Earth at which a comet had been discovered by amateurs. It was discovered at such a great distance from the Sun that it raised expectations that the comet would brighten considerably by the time it passed close to Earth. Although predicting the brightness of comets with any degree of accuracy is very difficult, Hale–Bopp met or exceeded most predictions when it passed perihelion on April 1, 1997. The comet was dubbed the Great Comet of 1997.
1773 Sir Thomas Makdougall Brisbane, (23 July 1773 – 27 January 1860) Baronet British soldier and astronomical observer for whom the city of Brisbane, Australia, is named. He was Governor of NSW (1821-25). Mainly remembered as a patron of science, he built an astronomical observatory at Parramatta, Australia, made the first extensive observations of the southern stars since Lacaille in (1751-52) and built a combined observatory and magnetic station at Makerstoun, Roxburghshire, Scotland. He also conducted (largely unsuccessful) experiments in growing Virginian tobacco, Georgian cotton, Brazilian coffee and New Zealand flax.*TIS
1775 Etienne Louis Malus (23 July 1775 – 24 February 1812) born in Paris. He was the son on the Treasurer of France. His primary interest was mathematical optics. [Ivor Grattan-Guiness, Convolutions in French Mathematics, 1800–1840, p. 473] *VFR He studied geometric systems called ray systems, closely connected to Julius Plücker's line geometry. He conducted experiments to verify Christiaan Huygens' theories of light and rewrote the theory in analytical form. His discovery of the polarization of light by reflection was published in 1809 and his theory of double refraction of light in crystals, in 1810.
Malus attempted to identify the relationship between the polarising angle of reflection that he had discovered, and the refractive index of the reflecting material. While he deduced the correct relation for water, he was unable to do so for glasses due to the low quality of materials available to him (most glasses at that time showing a variation in refractive index between the surface and the interior of the glass). It was not until 1815 that Sir David Brewster was able to experiment with higher quality glasses and correctly formulate what is known as Brewster's law.
Malus is probably best remembered for Malus' law, giving the resultant intensity, when a polariser is placed in the path of an incident beam. His name is one of the 72 names inscribed on the Eiffel tower.*Wik
1854 Ivan Vladislavovich Sleszynski (23 July 1854 in Lysianka, Cherkasy, Kiev gubernia, Ukraine - 9 March 1931 in Kraków, Poland)Sleszynski's main work was on continued fractions, least squares and axiomatic proof theory based on mathematical logic. In a paper of 1892, based on his doctoral dissertation, he examined Cauchy's version of the Central Limit Theorem using characteristic function methods, and made several significant improvements and corrections. Because of the work, he is recognised as giving the first rigorous proof of a restricted form of the Central Limit Theorem. *SAU
1856 Bal Gangadhar Tila (23 July 1856 – 1 August 1920, age 64) Scholar, mathematician, philosopher, and militant nationalist who helped lay the foundation for India's independence. Tilak was a great Sanskrit scholar and astronomer. He fixed the origin and date of Rigvedic Aryans, which was highly acclaimed and universally accepted by orientalists of his time. He founded (1914) and served as president of the Indian Home Rule League and, in 1916, concluded the Lucknow Pact with Mohammed Ali Jinnah, which provided for Hindu-Muslim unity in the struggle for independence.*TIS
1886 Walter Schottky (23 July 1886, Zürich, Switzerland – 4 March 1976, Pretzfeld, West Germany) Swiss-born German physicist whose research in solid-state physics led to development of a number of electronic devices. He discovered the Schottky effect, an irregularity in the emission of thermions in a vacuum tube and invented the screen-grid tetrode tube (1915). The Schottky diode is a high speed diode with very little junction capacitance (also known as a "hot-carrier diode" or a "surface-barrier diode.") It uses a metal-semiconductor junction as a Schottky barrier, rather than the semiconductor-semiconductor junction of a conventional diode. *TIS
1906 Vladimir Prelog (23 July 1906 – 7 January 1998) Yugoslavian-born Swiss chemist who shared the 1975 Nobel Prize for Chemistry with John W. Cornforth for his work on the stereochemistry of organic molecules and reactions. Stereochemistry is the study of the three-dimensional arrangements of atoms within molecules. He authored systematic naming rules for molecules and their mirror-image version, that is, which configuration will be referred to as "dextra" and which will be the "levo" (right or left). Also, by X-ray diffraction, he elucidated the structure of several antibiotics.*TIS
1920 Chushiro Hayashi (July 23, 1920 – February 28, 2010) Japanese astrophysicist who with his coworkers created evolutionary models for stars of mass between 0.01 to 100 times that of the Sun. In 1950, he contributed to the abg (Alpher, Bethe, Gamow) (also see April 1, Events) model of nucleosynthesis in the hot big bang. Hayashi pioneered in modeling stellar formation and pre-main sequence evolution along “Hayashi tracks” (1961) downward on the Hertzprung-Russell diagram until stars reach the main sequence. He and Takenori Nakano studied the formation of low-mass, brown dwarf stars. Hayashi also investigated the formation of the solar system and of the earth and its atmosphere. He retired in 1984. He was presented the Bruce Medal in 2004 for lifetime contributions to astronomy.*TIS
1928 Vera Rubin (July 23, 1928 - ) is an American astronomer who pioneered work on galaxy rotation rates. Her opus magnus was the uncovering of the discrepancy between the predicted angular motion of galaxies and the observed motion, by studying galactic rotation curves. This phenomena became known as the galaxy rotation problem. Currently, the theory of dark matter is the most popular candidate for explaining this. The alternative theory of MOND (Modified Newtonian Dynamics) has little support in the community.
Rubin received the Gold Medal of the Royal Astronomical Society in 1996. She was only the second female recipient of this medal, the first being Caroline Herschel in 1828. The asteroid 5726 Rubin is named in her honor. *TIA
1930 Daniel McCracken, (July 23, 1930 – July 30, 2011) who wrote the first textbook on FORTRAN, was born. A student of mathematics and chemistry, McCracken started working in computers at General Electric in 1951, training workers in using the new technology. Based on this teaching experience, McCracken wrote several important computer programming textbooks, most notably ""A Guide to FORTRAN Programming"" in 1961.*CHM
1932 Derek Thomas "Tom" Whiteside FBA (July 23, 1932–April 22, 2008) was a British historian of mathematics. He was the foremost authority on the work of Isaac Newton and editor of The Mathematical Papers of Isaac Newton. From 1987 to his retirement in 1999, he was the Professor of the History of Mathematics and Exact Sciences at Cambridge University. *Wik
1952 Mark David Weiser (July 23, 1952 – April 27, 1999) American computer scientist and visionary who developed the pioneering idea for what he referred to as "ubiquitous computing," He coined that term in 1988 to describe a future in which PC's will be replaced with tiny computers embedded in everyday "smart" devices (everyday items such as coffeepots and copy machines) and their connection via a network. He said, "First were mainframes, each shared by lots of people. Now we are in the personal computing era, person and machine staring uneasily at each other across the desktop. Next comes ubiquitous computing, or the age of calm technology, when technology recedes into the background of our lives." *TIS
1903 Eduard Weyr (22 June 1852 Praha – 23 July 1903 Záboří) wrote geometrical papers and books mainly in projective geometry and differential geometry. He also worked on algebra, in particular studying linear algebra, matrices and hypercomplex systems.
Weyr published Differential calculus in 1902. This led to controversy with a young mathematician J V Pexider who sharply criticised Weyr's textbook. Jindrich Beèváo and Ludek Zajièek give an interesting account of this episode in a paper in the book .*Math.info website
1916 William Ramsay (2 October 1852, Glasgow, Scotland - 23 July 1916 (aged 63)
High Wycombe, Bucks., England) died. Ramsay was a British chemist who discovered the four gases neon, argon, krypton and xenon. He also determined they belonged with helium and radon to form a family of gases called the noble gases. This discovery would earn him the 1904 Nobel Prize in Chemistry.*Science History
1932 Alberto Santos-Dumont (July 20, 1873 – July 23, 1932) was a Brazilian aviation pioneer, deemed the Father of Aviation by his countrymen. At the age of 18, Santos-Dumont was sent by his father to Paris where he devoted his time to the study of chemistry, physics, astronomy and mechanics. His first spherical balloon made its first ascension in Paris on 4 July 1898. He developed steering capabilities, and in his sixth dirigible on 19 Oct 1901 won the "Deutsch Prize," awarded to the balloonist who circumnavigated the Eiffel Tower. He turned to heavier-than-air flight, and on 12 Nov 1906 his 14-BIS airplane flew a distance of 220 meters, height of 6 m. and speed of 37 km/h. to win the "Archdecon Prize." In 1909, he produced his famous "Demoiselle" or "Grasshopper" monoplanes, the forerunners of the modern light plane. *TIS
1964 Samarendra Nath Roy or S. N. Roy (11 December 1906 – 23 July 1964). He was well known for his pioneering contribution to multivariate statistical analysis, mainly that of the Jacobians of complicated transformations for various exact distributions, rectangular coordinates and the Bartlett decomposition. His dissertation included the Post master's work at the Indian Statistical Institute where he worked under Mahalanobis. To commemorate his Birth Centenary an International Conference on "Multivariate Statistical Methods in the 21st Century: The Legacy of Prof. S.N. Roy" was held at Kolkata, India during December 28–29, 2006. The Journal of Statistical Planning and Inference published a special Issue for celebrating of the Centennial of Birth of S. N. Roy*Wik
1964 W. W. Rogosinski died. *VFR He wrote on Fourier Series with G.H. Hardy
1993 Florence Nightingale David, (August 23, 1909 – July 23, 1993) also known as F. N. David was an English statistician, born in Ivington, Herefordshire, England. She was named after Florence Nightingale, who was a friend of her parents.
David read mathematics at Bedford College for Women in London. After graduation, she worked for the eminent statistician Karl Pearson at University College, London as his research student. She calculated the distribution of correlation coefficients, producing in 1938 her first book, Tables of the correlation coefficient.
After Karl Pearson died in 1934, she returned to the Biometrics laboratory to work with Jerzy Neyman where she submitted her last four published papers as her PhD thesis. During World War II, David worked for the Ministry of Home Security. In late 1939 when war had started but England had not yet been attacked, she created statistical models to predict the possible consequences of bombs exploding in high density populations such as the big cities of England and especially London. From these models, she determined estimates of harm to humans and damage to non-humans This included the possible numbers living and dead, the reactions to fires and damaged buildings as well as damages to communications,utilities such as phones, water, gas, electricity and sewers. As a result when the Germans bombed London in 1940 and 1941, vital services were kept going and her models were updated and modified with the evidence from the real harms and real damage.
David became head of the Statistics Department at the University of California at Riverside in 1970.*Wik
2012 Sally Kristen Ride (May 26, 1951 – July 23, 2012) was an American physicist and a former NASA astronaut. Ride joined NASA in 1978, and in 1983 became the first American woman—and then-youngest American, at 32—to enter space. In addition to being interested in science, she was a nationally ranked tennis player. Ride attended Swarthmore College and then transferred to Stanford University, graduating with a bachelor's degree in English and physics. Also at Stanford, she earned a master's degree and a Ph.D. in physics, while doing research in astrophysics and free electron laser physics.In 1987 she left NASA to work at Stanford University's Center for International Security and Arms Control.
Sally Ride died on July 23, 2012 after a 17-month battle with pancreatic cancer. US President Barack Obama called her a "national hero and a powerful role model" who "inspired generations of young girls to reach for the stars."*Wik
*CHM=Computer History Museum
*FFF=Kane, Famous First Facts
*NSEC= NASA Solar Eclipse Calendar
*RMAT= The Renaissance Mathematicus, Thony Christie
*SAU=St Andrews Univ. Math History
*TIA = Today in Astronomy
*TIS= Today in Science History
*VFR = V Frederick Rickey, USMA
*Wik = Wikipedia
*WM = Women of Mathematics, Grinstein & Campbell