On the morning of December 17, 1903, Wilbur and Orville Wright took turns piloting and monitoring their flying machine in Kill Devil Hills, North Carolina. Orville piloted the first flight that lasted just 12 seconds and 120 feet. On the fourth and final flight of the day, Wilbur traveled 852 feet, remaining airborne for 59 seconds. That morning, the brothers became the first people to demonstrate sustained flight of a heavier-than-air machine under the complete control of the pilot. They built their 1903 glider in sections in the back room of their Dayton, Ohio, bicycle shop. That afternoon, the Wright brothers walked the four miles to Kitty Hawk and sent a telegram to their father, Bishop Milton Wright, back home in Dayton:
Through their own research and experimentation, and by studying the attempts of other would-be pilots, the Wright brothers knew that heavier-than-air flight was possible. They corresponded frequently with engineer Octave Chanute, a friend and supporter of their work. On May 13, 1900, Wilbur wrote a letter to Chanute expressing his ambition to fly:
The U.S. Army saw potential in the new technology and signed a contract with the Wright brothers in 1908. Their new Military Flyer was successfully tested in 1909.
The Library of Congress is rich in resources on flight.
On December 17, 1979, President Jimmy Carter walked to Lafayette Square from the White House to participate in the first National Menorah Lighting, in celebration of the Jewish holiday of Hanukkah. Initiated that year by the Washington, D.C. office of the Jewish organization Chabad-Lubavitch, the National Menorah Lighting has since become an annual event. In his Hanukkah remarks, President Carter tied the Jewish wintertime holiday to the triumph of religious freedom over adversity:
This first menorah lighting ceremony included not only the lighting of wax candles in a 36″ sterling silver menorah, but also the lighting of electric “flames” in a 36 foot gold-painted stainless steel menorah that had been under construction for several years. The National Menorah remained in Lafayette Square until 1987 when it was moved to its current location on the EllipseExternal. The President or a representative of the Administration participates in the lighting of the Menorah each year. The Hanukkah (Chanukah) holiday, which is celebrated over eight days, commemorates the rededication of the Second Temple of Jerusalem in 165 BCE, after the Jews, led by Judas Maccabeus, freed themselves from the oppressive regime of Antiochus IV, the Seleucid king, who had desecrated the Temple. Following the Jewish lunar calendarExternal, the start of the celebration varies from year to year. Also known as the Festival of Lights, Hanukkah recalls the Talmudic story of the Temple’s one-day supply of oil miraculously burning for eight days. Hanukkah is celebrated primarily in the home rather than the synagogue, often along with the evening meal, often in the company of friends as well as family. Foods fried in oil such as potato latkes (pancakes) and jelly doughnuts, and games such as dreidel (a four-sided top), are associated with Hanukkah celebrations. In the United States, especially, it has become customary to exchange gifts and children often receive one small gift for each night of the celebration. The Hebraic Section of the Library of Congress has long been recognized as one of the world’s foremost centers for the study of Hebrew and Yiddish materials. Established in 1914 as part of the Division of Semitica and Oriental Literature, it grew from Jacob H. Schiff’s 1912 gift of nearly 10,000 books and pamphlets from the private collection of a well-known bibliographer and bookseller Ephraim Deinard. The section houses works in Hebrew, Yiddish, Ladino, Judeo-Persian, Judeo-Arabic, Aramaic, Syriac, Coptic, and Amharic. Holdings are especially strong in the areas of the Bible and rabbinics, liturgy, responsa, Jewish history, and Hebrew language and literature.
On December 17, 1908, Willard Frank Libby was born on a farm in Grand Valley, Colorado. Libby, a physical chemist, won the 1960 Nobel Prize in ChemistryExternal for his development of the technique known as radiocarbon dating. This technique uses the decay of an unstable isotope of carbon, radioactive carbon-14 (C14), to determine the age of organic materials—anything composed of matter that was once living. Carbon-datable items, generally ranging from a few hundred to 60,000 years old, can be as varied as the sole of an ancient sandal, glacial ice cores, the Dead Sea Scrolls, or mummies from an Egyptian pharaoh’s tomb. Radiocarbon dating has had such a profound impact on many branches of the human sciences—including archaeology, geology, history, geophysics, and preservation—that its discovery has been called “the radiocarbon revolution.” By the 1940s, researchers already knew that when cosmic radiation enters the earth’s upper atmosphere it collides with the gases present there to produce neutron showers. They also knew that a few of these free-floating neutrons are in turn absorbed by nitrogen atoms, which in the process are transformed into C14 (the more common isotope is carbon-12). C14 is unstable and will decay back to nitrogen over time—the emission of beta particles during this second transformation is the process that makes it radioactive. Libby’s achievement was to recognize that C14 moves from the atmosphere to the biosphere through a series of additional steps:
Therefore, Libby concluded, all living organisms contain a small amount of C14. But he also recognized that carbon uptake ceases when an organism dies. Because C14 decays over time, organic items that are no longer living contain increasingly smaller percentages of C14 the older they get. Libby was able to compare the amount of C14 remaining in an item to the amount originally found in the atmosphere to determine that item’s age. During the 1950s, Libby and others built increasingly sensitive Geiger counters to measure the radioactivity of organic objects. Age calculations were based on the half-life of C14: after 5,730 years about 50 percent of the original amount of C14 will still be present in an object. Among the items that Libby tested and successfully dated were prehistoric sloth dung, charcoal from Stonehenge, and the parchment wrappings of the Dead Sea Scrolls. Libby was able to further verify his theory by performing radiocarbon tests on items whose date was already known from other sources. Willard Libby received a PhD in chemistry from the University of California, Berkeley, in 1933 and stayed on to teach there until joining the Manhattan Project when the U.S. entered World War II. Following the war, Libby became a professor of chemistry at the University of Chicago, where he conducted his groundbreaking research; his book Radiocarbon Dating was published in 1952. Libby was appointed by President Dwight Eisenhower to the Atomic Energy Commission in 1954. Shortly before winning the Noble Prize, he returned to teaching and research at UCLA; he died in 1980. With additional research, scientists have continued to refine the techniques of radiocarbon dating. In reality, C14 levels in the atmosphere have been similar, but not fully constant, over time. Changes in the magnetic fields of the earth and sun can affect the intensity of cosmic radiation, while carbon dioxide levels in the atmosphere also fluctuate naturally or due to the burning of fossil fuels. Nuclear weapons testing in the 1950s and early 1960s raised the amount of C14 in the atmosphere to a high of almost twice its natural level. To account for such fluctuations, calibration curves based in dendrochronology (tree ring dating) have been created, going back thousands of years. Developed in the 1980s, accelerator mass spectrometry External (AMS) is a method that separates the atoms of a sample of carbon by atomic weight. This means that the percentage of C14 in a sample can be measured directly, rather than on the basis of radioactive decay. AMS permits the measurement of very small samples, which allows for the dating of museum and library objects without destroying them.
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