Today in history @ 26 Apr

Famous birthdays

a. American ornithologist, naturalist, and painter John James Audobon (b. 1785). He was notable for his extensive studies documenting all types of American birds and for his detailed illustrations that depicted the birds in their natural habitats. His major work, a color-plate book entitled The Birds of America (1827–1839), is considered one of the finest ornithological works ever completed. Audubon is also known for having identified 25 new species.

b. Former Indian film actress Minoo Mumtaz (b. 1942).

c. American physicist and seismologist Charles Richter (b. 1900). He developed the scale that bears his name and measures the magnitude of earthquakes. 

Before Richter’s work on earthquake magnitude, the only way to rate an earthquake was to use the Mercalli scale established in 1902. The Mercalli scale classified earthquakes from 1 to 12 depending on the amount of damage that occurred to people and buildings. Richter’s scale was instead an absolute measure of an earthquake’s intensity. It is not a physical scale, but rather a mathematical calculation. 

He authored two textbooks that are still used as references in the field and are regarded by many scientists as his greatest contribution, exceeding the more popular Richter scale. 

Famous death anniversaries

a. One of India's greatest mathematical geniuses Srinivasa Ramanujan (d. 1920). He made substantial contributions to the analytical theory of numbers and worked on elliptic functions, continued fractions, and infinite series. 

One cannot read the history of Ramanujam without reading the contribution of Prof. G H hardy, the professor at Cambridge who made him famous, got him to England, collaborated and improved his rawness and was instrumental in the award of FRS.

He left a number of unpublished notebooks filled with theorems that mathematicians have continued to study. G N Watson, Mason Professor of Pure Mathematics at Birmingham from 1918 to 1951 published 14 papers under the general title Theorems stated by Ramanujan and in all he published nearly 30 papers which were inspired by Ramanujan's work. Hardy passed on to Watson the large number of manuscripts of Ramanujan that he had, both written before 1914 and some written in Ramanujan's last year in India before his death.

b. German philosopher and principal founder of phenomenology, Edmund Husserl (d. 1938). He has made important contributions to almost all areas of philosophy and anticipated central ideas of its neighbouring disciplines such as linguistics, sociology and cognitive psychology.

c. German theoretical physicist Arnold Sommerfield (d. 1951). He is known for introducing the azimuthal quantum number (2nd quantum number) and the spin quantum number (4th quantum number). He also pioneered the X-ray wave theory and introduced the fine-structure consonant.

He did not get a Nobel Prize. Some of his doctoral and other students who won atleast 1 Noble Prize were Wolfgang Pauli, Werner Heisenberg, Petr Debye, Herbert Kroemer, Hans Bethe, Walter Ludwig Kessel, Max Lave and John Bardeen. It is said, only J. J. Thomson's record of mentorship is comparable to his.

d. German chemist, engineer and Nobel Laureate in Chemistry Carl Bosch (d. 1940). He was a pioneer in the field of high-pressure industrial chemistry and founder of IG Farben, at one point the world's largest chemical company.

Other notable events

a. 1514 Copernicus makes his 1st observations of Saturn.

b. 1954 Mass trials of Jonas Salk's anti-polio vaccine begin; the first shot is delivered in Fairfax County, Virginia; more than 443,000 children receive shots over three months.

c. 1954 "Seven Samurai", Japanese film directed by Akira Kurosawa, starring Toshiro Mifune, is released.

d. 1994 Physicists announce first evidence of the top quark subatomic particle.