(Purcell, Edward Mills (1912–1997
(Purcell, Edward Mills (1912–1997
American physicist at Harvard who shared with Felix Bloch (at Stanford) the 1952 Nobel Prize in Physics for his independent work on the nuclear magnetic moment, discovering nuclear magnetic resonance (NMR) in solids. Purcell was also the codiscoverer, with Harold I. Ewen, in 1951, of the 21- centimeter line of hydrogen.
In a lecture delivered at Brookhaven National Laboratory, in 1960, Purcell attacked the notion that intersteller travel would ever be possible, arguing that radio signals were probably the best way of establishing contact with other intelligent races. A similar discouraging outlook for flight between the stars was expressed by Pierce and Von Hoerner.
(Barnard, Edward Emerson (1857–1923
(Barnard, Edward Emerson (1857–1923
One of the greatest observational astronomers of his time, and discoverer of Jupiter's moon Amalthea and the nearby star that now bears his name - Barnard's star -. Born into poverty in Nashville, Tennessee, Barnard began work in a photographic studio when he was only nine. He became a brilliant amateur astronomer, discovering 10 comets before the age of 30.
In 1887, Barnard joined the staff of Lick Observatory and used the new 36-inch Lick refractor to discover Amalthea and the first comet to be found by photography, both in 1892. In 1895 he moved to the University of Chicago's not-yet-completed Yerkes Observatory and helped test the great 40-inch refractor following its installation
Barnard spent 28 years as an astronomer at Yerkes using the giant refractor as well as the 10-inch Bruce wide-field telescope, built specially for him, to measure star positions and to pioneer wide-field photography for studying the structure of the Milky Way. He discovered the star, subsequently named after him, with the largest known proper motion, and numerous dark clouds and globules.
(Morgan, William Wilson (1906–1994
(Morgan, William Wilson (1906–1994
American astronomer who, with Philip Keenan (1908–2000) and Edith Kellman (1911–2007), introduced stellar luminosity classes and developed the Morgan-Keenan classification of stellar spectra. With Donald Osterbrock and Stewart Sharpless he demonstrated the existence of spiral arms in the Galaxy using precise distances of O and B stars obtained from spectral classifications. Morgan helped originate the UBV system of magnitudes and colors, and, with Nicholas Mayall, developed a spectral classification system for giant galaxies. After three years of undergraduate study at Washington and Lee University, Morgan joined the staff of the Yerkes Observatory, where he spent his entire career, including three years as director. While at Yerkes he earned bachelor's and doctoral degrees at the University of Chicago. Eschewing theory, his research focused on morphology – the classification of objects by their form and structure.
Friedrich Georg Wilhelm Struve
Friedrich Georg Wilhelm Struve
Born: 15-Apr-1793
Birthplace: Altona, Germany
Died: 23-Nov-1864
Location of death: St. Petersburg, Russia
Cause of death: unspecified
German-Russian astronomer, the son of Jacob Struve, was born at Altona on the 15th
of April 1793. In 1808 he entered the university of Dorpat (Yuriev), where he first
studied philology, but soon turned his attention to astronomy. From 1813 to 1820 he
was extraordinary professor of astronomy and mathematics at the new university and
observer at the observatory, becoming in 1820 ordinary professor and director. He
remained at Dorpat, occupied with researches on double stars and geodesy until 1839,
when he removed to superintend the construction of the new central observatory at
Pulkowa near St. Petersburg, afterwards becoming director. Here he continued his
activity until he was obliged to retire in 1861, owing to failing health. He died at St.
Petersburg on the 23rd of November 1864.
Struve's name is best known by his observations of double stars, which he carried on
for many years. These bodies had first been regularly measured by William Herschel,
who discovered that many of them formed systems of two stars revolving around their
common center of gravity. After him John Herschel (and for some time Sir James South)
had observed them, but their labors were eclipsed by Struve. With the 9.5" refractor
at Dorpat he discovered a great number of double stars, and published in 1827 a list of
all the known objects of this kind (Catalogus novus stellarum duplicium). His micrometric
measurements of 2714 double stars were made from 1824 to 1837, and are contained
in his principal work, Stellarum duplicium et multiplicium mensurae micrometricae (St.
Petersburg, 1837). The places of the objects were at the same time determined with
the Dorpat meridian circle (Stellarum fixarum imprimis duplicium et multiplicium
positiones mediae, St. Petersburg, 1852). At Pulkowa he redetermined the "constant of
aberration", but was chiefly occupied in working out the results of former years' work
and in the completion of the geodetic operations in which he had been engaged during
the greater part of his life. He had commenced them with a survey of Livonia
(1816-19), which was followed by the measurement of an arc of meridian of more than
3.5° in the Baltic provinces of Russia (Beschreibung der Breitengradmessung in den
Ostseeprovinzen Russlands, 2 vols. 4to, Dorpat, 1831). This work was afterwards
extended by Struve and General Tener into a measurement of a meridional arc from the
north coast of Norway to Ismail on the Danube (Arc du méridien de 25° 20' entre le
Danube et la Mer Glaciale, 2 vols. and 1 vol. plates, 4to, St. Petersburg, 1857-60).