May 15

Today is Peace Officers Memorial Day. 1618: Johannes Kepler discovered his harmonics law. 1836: Francis Baily observed "Baily's Beads" during an annular solar eclipse. 1863: Frank Hornby, English toy manufacturer who patented the Meccano construction set, was born. 1859: Nobel laureate Pierre Curie, who along with his wife, Marie, discovered spontaneous radioactivity in radium and polonium, was born. 1930: Ellen Church became the first airline stewardess. 1941: Britain's first jet-propelled aircraft, the Gloster-Whittle E.28/39, made its first flight. 1948: Israel was attacked by Transjordan (now Jordan), Egypt, Syria, Iraq and Lebanon only hours after declaring its independence. 1957: Great Britain became the 3rd nation to detonate a nuclear bomb. 1970: President Nixon appointed America's first two female generals: Colonels Elizabeth Hoisington and Anna Mae Mays. 1982: Merle Tuve who first used pulsed radio waves to explore the ionosphere, died. 1992: Robert Morris Page, inventor of pulse radar, died. 2008: Physics Nobel laureate Willis Lamb, who determined fine structure of the hydrogen spectrum, died.