1930 to 1939
February 18, 1930 - American astronomer Clyde Tombaugh discovers the planet Pluto at the Lowell Observatory in Flagstaff, Arizona. Tombaugh was also known as one of the few serious astronomers to have claimed to sight UFO's.
April 1, 1930 - The population counted in the 1930 census reaches 123,202,624, a 16.2% increase over the past decade. The geographic center of the United States population had reached three miles northeast of Linton in Greene County, Indiana.
August 12, 1930 - Technology moves forward. Clarence Birdseye invents frozen food with his quick-freezing process and patents the concept. Also in 1930, the analog computer, or differential analyzer, is invented at the Massachusetts Institute of Technology in Boston by Vannevar Bush. Bush is also considered a pioneer in the development of the concept for the World Wide Web, with his idea for the memex.
March 3, 1931 - The Star-Spangled Banner, by Francis Scott Key, is approved by President Hoover and Congress as the national anthem. The lyrics of the anthem were inspired during the bombing of Fort McHenry by British ships at the head of Baltimore harbor in September of 1814.
March 17, 1931 - The state of Nevada legalizes gambling.
May 1, 1931 - Construction is completed on the Empire State Building in New York City and it opens for business. On the same day in Aniakchak Caldera, Alaska, a major eruption of the volcano Half Cone occurred, blackening the skies in southwestern Alaska for the next several weeks. (10.54
October 4, 1931 - Cartoonist Chester Gould creates the debut appearance of the Dick Tracy comic strip.
March 4, 1933 - President Franklin D. Roosevelt is inaugurated for the first time. His speech with its hallmark phrase, "We have nothing to fear, but fear itself," begins to rally the public and Congress to deal with great depression issues. His subsequent Fireside Chats, that began eight days later, would continue his addresses with the American public. (1.48) https://www.youtube.com/watch?v=b6KSOaaWqb4
December 5, 1933 - The 21st Amendment to the U.S. Constitution is passed, ending prohibition. (4.56)
June 2, 1935 - The greatest hitter in the history of baseball, Babe Ruth, retires from Major League Baseball. He is among the charter class of players inducted into the Baseball Hall of Fame, in Cooperstown, New York, in 1939. (3.03)
August 14, 1935 - The Social Security Act is passed by Congress as part of the New Deal legislation and signed into law by President Franklin D. Roosevelt. It would begin payouts to retirees within two years. Workers began contributing into the system during the same year, at a rate of 2% of the first $3,000 in earnings, half paid by the employee and half paid by the employer.
August 1, 1936 - The Summer Olympics Games open in Berlin, Germany under the watchful eye of German leader Adolph Hitler, whose policies of Arian supremacy had already begun to take shape. The star of the games was Jesse Owens, a black American, who won four gold at the Berlin 1936 Games. (2.30) https://www.youtube.com/watch?v=mSgx8pzdjWY
February 16, 1937 - Wallace H. Carothers patents the polymer, invented in the Dupont labs.
May 6, 1937 - At Lakehurst, New Jersey, the German airship Hindenburg bursts into flames while mooring. The fire consumes the largest airship in the world, 804 feet long, within one minute, causing the death of thirty-six people. (5.00) https://www.youtube.com/watch?v=CgWHbpMVQ1U
July 18, 1938 - Wrong Way Douglas Corrigan, with his faulty compass, lands his plane in Dublin, Ireland after departing from Brooklyn, New York on a trip to the west coast of the United States.
June 25, 1938 - The National Minimum Wage is signed into law within the federal legislation known as the Fair Labor Standards Act. It established a minimum wage of $0.25 at the time, as well as time and one half for overtime and the prohibition of most employment for minors.
October 30, 1938 - A nationwide scare develops when Orson Welles broadcasts his War of the Worlds radio drama, which included fake news bulletins stating that a Martian invasion had begun on earth. (1.47) https://www.youtube.com/watch?v=nPEn5k55g-o
June 12, 1939 - The Baseball Hall of Fame opens in Cooperstown, New York, home of one of baseball's founders, Abner Doubleday. The first class of inductees included Ty Cobb, Babe Ruth, Honus Wagner, Christy Mathewson, and Walter Johnson.
August 2, 1939 - Albert Einstein alerts Franklin D. Roosevelt to an A-bomb opportunity, which led to the creation of the Manhattan Project. Einstein had arrived as a fugitive from Nazi Germany six years earlier on October 17, 1933.
September 3 1939 - World War II breaks out in Europe when Germany invaded Poland. The remainder of the year would bring chaos and uncertainty across America. The nation will try to remain neutral while supporting the Allied forces of Great Britain, France, and Russia at the same time.
September 5, 1939 - The United States declares its neutrality in the European war after Germany invaded Poland, effectively beginning World War II after a year of European attempts to appease Hitler and the aims of expansionist Nazi Germany.