Sunday, December 20, 2009

December 20: Walter Sydney Adams

Walter Sydney Adams
December 20, 1876 – May 11, 1956

Walter Sydney Adams was an American astronomer.

He was born in Antioch, Syria to missionary parents, and was brought to the U.S. in 1885. He graduated from Dartmouth College in 1898, then continued his education in Germany. After returning to the U.S., he began a career in Astronomy that culminated when he became director of the Mount Wilson Observatory.

His primary interest was the study of stellar spectra. He worked on solar spectroscopy and co-discovered a relationship between the relative intensities of certain spectral lines and the absolute magnitude of a star. He was able to demonstrate that spectra could be used to determine whether a star was a giant or a dwarf.

In 1915 he began a study of the companion of Sirius and found that despite a size only slightly larger than the Earth, the surface of the star was brighter per unit area than the Sun and it was about as massive. Such a star later came to be known as a white dwarf.

Along with Theodore Dunham, he discovered the strong presence of carbon dioxide in the infrared spectrum of Venus.

Adams received the Gold Medal of the Royal Astronomical Society (1917), the Henry Draper Medal (1918), the Bruce Medal (1928) and the Henry Norris Russell Lectureship (1947).

The asteroid 3145 Walter Adams and a crater on Mars are named in his honor. The crater Adams on the Moon is jointly named after him, John Couch Adams and Charles Hitchcock Adams.

Saturday, December 19, 2009

December 19: Albert Michelson

Albert Michelson
December 19, 1852 – May 9, 1931

Albert Abraham Michelson was an American physicist known for his work on the measurement of the speed of light and especially for the Michelson-Morley experiment. In 1907 he received the Nobel Prize in Physics. He became the first American to receive the Nobel Prize in sciences.

Michelson was born in Strzelno, Provinz Posen in the Kingdom of Prussia (now Poland). He moved to the United States with his parents in 1855, when he was two years old.

President Ulysses S. Grant awarded Michelson a special appointment to the U.S. Naval Academy in 1869. During his four years as a midshipman at the Academy, Michelson excelled in optics, heat and climatology as well as drawing. After his graduation in 1873 and two years at sea, he returned to the Academy in 1875 to become an instructor in physics and chemistry until 1879. In 1879, he was posted to the Nautical Almanac Office, Washington, to work with Simon Newcomb, but in the following year, he obtained leave of absence to continue his studies in Europe. He visited the Universities of Berlin and Heidelberg, and the Collège de France and École Polytechnique in Paris.

Michelson was fascinated with the sciences and the problem of measuring the speed of light in particular. While at Annapolis, he conducted his first experiments of the speed of light, as part of a class demonstration in 1877. After two years of studies in Europe, he resigned from the Navy in 1881. In 1883 he accepted a position as professor of physics at the Case School of Applied Science in Cleveland, Ohio and concentrated on developing an improved interferometer. In 1887 he and Edward Morley carried out the famous Michelson-Morley experiment which seemed to rule out the existence of the aether. He later moved on to use astronomical interferometers in the measurement of stellar diameters and in measuring the separations of binary stars.

In 1907, Michelson had the honor of being the first American to receive a Nobel Prize in Physics "for his optical precision instruments and the spectroscopic and meteorological investigations carried out with their aid". He also won the Copley Medal in 1907, the Henry Draper Medal in 1916 and the Gold Medal of the Royal Astronomical Society in 1923.

The Lunar crater Michelson is named in his honor.

Friday, December 18, 2009

December 18: Gottfried Kirch

Gottfried Kirch
December 18, 1639 — July 25, 1710

Gottfried Kirch was a German astronomer. He first worked as a calendar-maker in Saxonia and Franconia. He began to learn astronomy in Jena, and studied under Hevelius in Danzig. In Danzig in 1667, Kirch published calendars and built several telescopes and instruments.

In 1686, Kirch went to Leipzig. There, he observed the great comet of 1686, together with Christoph Arnold. At Leipzig, Kirch also met his second wife, Maria Winckelmann (1670-1720), who had learned astronomy from Arnold. In 1688, he invented and charted the now obsolete constellation Sceptrum Brandenburgicum, the Brandenburg Scepter. Later, in 1699, he observed comet 55P/Tempel-Tuttle but this observation was not recognized until later analysis by Joachim Schubart.

In 1700, Kirch was appointed by Frederick I of Prussia as the first astronomer of the Prussian Royal Society of Sciences.

Kirch studied the double star Mizar, and discovered both the Wild Duck Cluster (Messier 11) (1681) and Globular Cluster M5 (May 5, 1702). He also discovered the variability of the Mira variable Chi Cygni in 1686.

The Lunar crater Kirch and the asteroid 6841 Gottfriedkirch are named in his honor.

Sunday, December 6, 2009

December 6: Yoshio Nishina

Yoshio Nishina
December 6, 1890 – January 10, 1951

Yoshio Nishina was the founding father of modern physics research in Japan. He co-authored the well-known Klein-Nishina Formula. He was a principal investigator of RIKEN and mentored generations of physicists, including two Novel Laureates: Hideki Yukawa and Sin-Itiro Tomonaga. During World War II he was the head of the Japanese atomic program.

Nishina was born in Satosho, Okayama and graduated from Tokyo Imperial University in 1918. After graduation, he became a staff member at RIKEN. In 1921 he was sent to Europe for research. He visited some European universities and institutions, including Cavendish Laboratory, Georg August University of Göttingen, and University of Copenhagen. In Copenhagen he did research with Niels Bohr and they became good friends. In 1928 he wrote a paper on incoherent or Compton scattering with Oskar Klein in Copenhagen, from which the Klein-Nishina formula derives.

In the same year he returned to Japan, where he endeavored to foster an environment for the study of quantum mechanics. He invited some Western scholars to Japan including Heisenberg, Dirac and Bohr to stimulate Japanese physicists. He detected what turned out to be the muon in cosmic rays, independently of Anderson et al.

His research was concerned with cosmic rays and particle accelerator development.

In 1946 he was awarded the Order of Culture by the Emperor of Japan.

The Lunar crater Nishina is named in his honor.

Saturday, December 5, 2009

December 5: Werner Heisenberg

Werner Heisenberg
December 5, 1901 – February 1, 1976

Werner Heisenberg was a German theoretical physicist who made foundational contributions to quantum mechanics and is best known for asserting the uncertainty principle of quantum theory. In addition, he also made important contributions to nuclear physics, quantum field theory, and particle physics.

Heisenberg, along with Max Born and Pascual Jordan, set forth the matrix formulation of quantum mechanics in 1925. Heisenberg was awarded the 1932 Nobel Prize in Physics.

Following the war, he was appointed director of the Kaiser Wilhelm Institute for Physics, which was soon thereafter renamed the Max Planck Institute for Physics. He was director of the institute until it was moved to Munich in 1958, when it was expanded and renamed the Max Planck Institute for Physics and Astrophysics.

Heisenberg was also president of the German Research Council, chairman of the Commission for Atomic Physics, chairman of the Nuclear Physics Working Group, and president of the Alexander von Humboldt Foundation.

Heisenberg studied under Arnold Sommerfeld, who was born on this date in 1868. Sommerfeld was a German theoretical physicist who pioneered developments in atomic and quantum physics, and also educated and groomed a large number of students for the new era of theoretical physics. He introduced the fine-structure constant into quantum mechanics.

Friday, December 4, 2009

December 4: Wilhelm Tempel

Ernst Wilhelm Leberecht Tempel
December 4, 1821 – March 16, 1889

Wilhelm Tempel, was a German astronomer who worked in Marseille until the outbreak of the Franco-Prussian War in 1870, then later moved to Italy.

He was a prolific discoverer of comets, discovering or co-discovering 21 in all, including Comet 55P/Tempel-Tuttle, now known to be the parent body of the Leonid meteor shower, and 9P/Tempel, the target of the NASA probe Deep Impact in 2005.

Other periodic comets that bear his name include 10P/Tempel and 11P/Tempel-Swift-LINEAR.

The asteroid 3808 Tempel and the Lunar crater Tempel are named in his honor.