Aerodynamics engineer and mathematician Irmgard Flügge-Lotz was born #OTD in 1903.
She advanced the understanding of aerodynamic pressure on wings and turbine blades, pioneered the theory of discontinuous control systems, and was the first woman named full professor of engineering at Stanford.
Medical physicist and radiologist Edith Quimby was born #OTD in 1891.
One of the founders of nuclear medicine, she developed diagnostic applications for X-rays and radioisotopes. Her research on the penetrating power of radiation established safe levels for its use in treatments.
#OTD in 1609, Galileo Galilei aimed his telescope at the Moon.
While not being the first person to observe the Moon through a telescope (English mathematician Thomas Harriot had done it four months before but only saw a "strange spottednesse"), Galileo was the first to deduce the cause of the uneven waning as light occlusion from lunar mountains and craters. In his study, he also made topographical charts, estimating the heights of the mountains. via @wikipedia
Friends, here is a fun little physics story about satellites and relativity. It’s a day late for an #OTD, but please indulge me.
The Navigation Technology Satellite 2 (NTS-2) was launched into orbit on June 23, 1977, an early step in establishing the GPS NAVSTAR network. It was the first satellite to carry a Cesium atomic clock into orbit! 🧵
Can we productively talk about how many alien civilizations throughout the Milky Way might be actively broadcasting or receiving messages? How would we estimate that?
N ≈ R×fp×ne×fl×fi×fc×L
R = ⭐️ formation rate fp = fraction of ⭐️ with 🌎 ne = 🌎 per ⭐️ on avg that could support life fl = fraction with life fi = fraction of life becoming intelligent fc = fraction that 📡 into 🌌 L = how long they broadcast
Speaking of, the Hubble Space Telescope sent its first image back to Earth #OTD in 1990.
Folks knew right away that something was wrong with the optics, but the problem was eventually corrected.
Ground Image: E. Persson (Las Campanas Observatory, Chile)/Observatories of the Carnegie Institution of Washington Hubble Image: NASA, ESA, and STScI https://mastodon.social/@mcnees/110378772317401238
An #OTD thread from last year, about the scientific contributions of Julius Oppenheimer.
A lot of "common knowledge" about black holes – infinite redshift, the slow progress of an infalling observer from the point of view of a distant spectator – can be traced back to an influential paper Oppenheimer wrote in 1939. https://mastodon.social/@mcnees/110245056828062741
#OnThisDay, 20 Apr 1902, Marie and Pierre Curie refine radium chlorine. The discovery leads to Marie being the first woman to win the Nobel Prize for Physics in 1903.
The Academy originally planned to award only Pierre and Henri Becquerel. Pierre insisted that Marie should also be included.
Biochemist Marie Maynard Daly, who studied correlations between heart attacks and cholesterol, and between smoking and lung disease, was born #OTD in 1921.
She was the first Black woman to receive a chemistry PhD in the US.
Physicist Caroline Herzenberg was born #OTD in 1932. She is known for pioneering early work in Mössbauer spectroscopy, including an analysis of the first samples returned from the moon by the Apollo astronauts.
Image: Herzenberg as Finalist in the 1949 Science Talent Search
Physicist Robert Millikan was born #OTD in 1868. He is best known for the “oil drop” experiment with Harvey Fletcher that measured the charge of the electron, but his next experiment – meant to disprove Einstein's assertion of the reality of quanta – may have been even more important.
Vannevar Bush, an electrical engineer who built one of the first analog computers, was born #OTD in 1890.
He headed the Office of Scientific Research and Development during WWII, proposed what became the National Science Foundation, and devised an early hypertext system.
Pound and Rebka submitted "The Apparent Weight of Photons" to Physical Review Letters #OTD in 1960.
They described the measurement of minuscule gravitational red shifts and blue shifts as photons moved up or down in the Earth’s gravitational field. Einstein predicted this effect in 1911!