1908 – American chemist and Women’s Army Corps officer Myrtle Bachelder is born.
During World War II, Bachelder enlisted in the Women’s Army Corps (WAC) in November 1942, at the Springfield, Massachusetts headquarters. After spending time in training at military bases in several U.S. states, she received orders assigning her to the Company ‘D’ WAC Detachment of the Manhattan District, United States Army Corps of Engineers. Her secret assignment was to lead a group of 15 to 20 women from the WAC, stationed in Des Moines, Iowa, to Fort Sill, Oklahoma, and from there to Santa Fe, New Mexico. She and the women under her command arrived at Los Alamos, New Mexico on October 21, 1943.
“Manhattan” was the code name for the special military division dedicated to developing an atomic weapon. In the clandestine laboratory at the remote Los Alamos desert site, Bachelder was responsible for the analysis of the spectroscopy of uranium isotopes. Since the uranium-235 isotope is fissile, whereas the uranium-238 isotope is not, Bachelder’s role in the project was a crucial task: to ensure the purity of the sub-critical material, and therefore the nuclear explosion, of the world’s first atomic bombs.
1930 – After confirming its finding with multiple photographs, news of the discovery of Pluto is telegraphed to the Harvard College Observatory.
Pluto was discovered by Clyde Tombaugh in 1930 and was originally considered to be the ninth planet from the Sun. After 1992, its status as a planet was questioned following the discovery of several objects of similar size in the Kuiper belt. In 2005, Eris, a dwarf planet in the scattered disc which is 27% more massive than Pluto, was discovered. This led the International Astronomical Union (IAU) to define the term “planet” formally in 2006, during their 26th General Assembly. That definition excluded Pluto and reclassified it as a dwarf planet.
1969 – After testing the Lunar Module, Apollo 9 returns to Earth.
After launching on March 3, 1969, the crewmen performed the first manned flight of a LM, the first docking and extraction of a LM, two spacewalks (EVA), and the second docking of two manned spacecraft—two months after the Soviets performed a spacewalk crew transfer between Soyuz 4 and Soyuz 5. The mission proved the LM worthy of manned spaceflight. Further tests on the Apollo 10 mission would prepare the LM for its ultimate goal, landing on the Moon. They returned to Earth on March 13, 1969.
2016 – Hilary Putnam, American philosopher, mathematician, and computer scientist, dies.
Putnam has contributed to scientific fields not directly related to his work in philosophy. As a mathematician, Putnam contributed to the resolution of Hilbert’s tenth problem in mathematics. This problem was settled by Yuri Matiyasevich in 1970, with a proof that relied heavily on previous research by Putnam, Julia Robinson and Martin Davis.
In computability theory, Putnam investigated the structure of the ramified analytical hierarchy, its connection with the constructible hierarchy and its Turing degrees. […]
In computer science, Putnam is known for the Davis–Putnam algorithm for the Boolean satisfiability problem (SAT), developed with Martin Davis in 1960. The algorithm finds if there is a set of true or false values that satisfies a given Boolean expression so that the entire expression becomes true. In 1962, they further refined the algorithm with the help of George Logemann and Donald W. Loveland. It became known as the DPLL algorithm. This algorithm is efficient and still forms the basis of most complete SAT solvers.
2016 – Adafruit surpasses 100K Followers on Twitter!
…And now, two years later, we’re still going strong. Follow Adafruit on Twitter here!