Adams , Walter Sydney


Adams , Walter Sydney
(1876–1956) American astronomer
Adams was born in Antioch (now in Turkey). He was the son of missionaries working in Syria, then part of the Ottoman Empire, who returned to America in 1885. Adams graduated from Dartmouth College in 1898 and obtained his AM from the University of Chicago in 1900. After a year in Munich he began his career in astronomy as assistant to George Hale in 1901 at the Yerkes Observatory. He moved with Hale to the newly established Mount Wilson Observatory in 1904 where he served as assistant director, 1913–23, and then as director from 1923 until his retirement in 1946.
At Mount Wilson Adams was able to use first the 60-inch (1.5-m) and from 1917 the 100-inch (2.5-m) reflecting telescopes in whose design and construction he had been closely associated. His early work was mainly concerned with solar spectroscopy, when he studied sunspots and solar rotation, but he gradually turned to stellar spectroscopy. In 1914 he showed how it was possible to distinguish between a dwarf and a giant star merely from their spectra. He also demonstrated that it was possible to determine the luminosity, i.e. intrinsic brightness, of a star from its spectrum. This led to Adams introducing the method of spectroscopic parallax whereby the luminosity deduced from a star's spectrum could be used to estimate its distance. The distance of many thousands of stars have been calculated by this method.
He is however better known for his work on the orbiting companion of Sirius, named Sirius B. Friedrich Bessel had first shown in 1844 that Sirius must have a companion and had worked out its mass as about the same as our Sun. The faint star was first observed telescopically by Alvan Clark in 1862. Adams succeeded in obtaining the spectrum of Sirius B in 1915 and found the star to be considerably hotter than the Sun. He realized that such a hot body, just eight light-years distant, could only remain invisible to the naked eye if it was very much smaller than the Sun, no bigger in fact than the Earth. In that case it must have an extremely high density, exceeding 100,000 times the density of water. Adams had thus discovered the first ‘white dwarf’ – a star that has collapsed into a highly compressed object after its nuclear fuel is exhausted.
If such an interpretation was correct then Sirius B should possess a very strong gravitational field. According to Einstein's general theory of relativity, this strong field should shift the wavelengths, of light waves emitted by it toward the red end of the spectrum. In 1924 Adams succeeded in making the difficult spectroscopic observations and did in fact detect the predicted red shift, which confirmed his own account of Sirius B and provided strong evidence for general relativity.

Scientists. . 2011.

Look at other dictionaries:

  • Walter Sydney Adams — Nacimiento …   Wikipedia Español

  • Walter Sydney Adams — (December 20 1876 ndash; May 11 1956) was an American astronomer.Life and workHe was born in Antioch, Syria to missionary parents, and was brought to the U.S. in 1885 [ F.J.M. Stratton. Walter Sydney Adams. 1876 1956. Biographical Memoirs of… …   Wikipedia

  • Walter Sydney Adams — Pour les articles homonymes, voir Adams. Walter Sydney Adams Walter Sydney Adams (né le 20 décembre 1876, mort le 11 mai 1956 …   Wikipédia en Français

  • Walter Sydney Adams — (* 20. Dezember 1876 in Antakya, Türkei; † 11. Mai 1956 in Pasadena, USA) war ein US amerikanischer Astronom. Er war von 1923 bis 1946 Direktor des Mount Wilson Observatoriums in Kalifornien. Adams wurde von einer Missionsangehörigen der Mission… …   Deutsch Wikipedia

  • Adams — /ad euhmz/, n. 1. Abigail (Smith), 1744 1818, U.S. social and political figure (wife of John Adams). 2. Alice, born 1926, U.S. writer. 3. Ansel, 1902 84, U.S. photographer. 4. Brooks, 1848 1927, U.S. historian and political scientist (son of… …   Universalium

  • Sydney — /sid nee/, n. 1. Sir Philip. See Sidney, Sir Philip. 2. a seaport in and the capital of New South Wales, in SE Australia. 2,876,508. 3. a seaport on NE Cape Breton Island, Nova Scotia, in SE Canada. 30,645. 4. a male or female given name. * * * I …   Universalium

  • Walter — /vahl teuhr/ for 1; /wawl teuhr/ for 2, 3, n. 1. Bruno /brooh noh/, (Bruno Schlesinger), 1876 1962, German opera and symphony conductor, in U.S. after 1939. 2. Thomas Ustick /yooh stik/, 1804 87, U.S. architect. 3. a male given name. * * * (as… …   Universalium

  • Adams (Cratère) — Pour les articles homonymes, voir Adams. Adams Localisation Astre Lune Coordonnées 31°  54’ & …   Wikipédia en Français

  • Adams (cratere) — Adams (cratère) Pour les articles homonymes, voir Adams. Adams Localisation Astre Lune Coordonnées 31°  54’ & …   Wikipédia en Français

  • Walter Adams — may refer to:*Walter Adams (economist) (1922–1998), American university professor and president *Walter Robert Adams (1877–1957), Canadian religious leader who served as the Anglican Archbishop of British Columbia *Walter Sydney Adams (1876–1956) …   Wikipedia


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.