Jakob Karl Ernst Halm

Jakob Karl Ernst Halm , also Jacob Karl Ernst Halm (born November 30, 1866 in Bingen am Rhein , † July 17, 1944 in Stellenbosch ) was a German-British astronomer who worked mainly in Scotland and South Africa.

Live and act

Halm studied at the universities of Giessen , Berlin and Kiel , in Kiel he received his doctorate in mathematics in 1890 with a thesis on linear differential equations . He began his scientific career in 1889 as an assistant at the Strasbourg observatory . In 1895, at the invitation of the astronomer Royal for Scotland Ralph Copeland, he moved to the Royal Observatory Edinburgh , founded in 1894 , where he worked for twelve years and made a name for himself as an astronomer. Among other things, he published a series of articles on observations of comets and then increasingly devoted himself to solar research , such as the study of the influence of solar activity on the earth. He was one of the first astronomers who could precisely determine the rotational speed of the sun and the radial speed of stars with a special spectroscope ( spectroheliograph ). For his work on Spectroscopic Observations of the Rotation of the Sun and Some Further Results obtained with the Spectroheliometer , he was awarded the Makdougall-Brisbane Prize of the Royal Society of Edinburgh for the period 1904-1906. In 1904 he was elected a Fellow of the Royal Society of Edinburgh. In 1906 he became a member of the Royal Astronomical Society . He had been a British citizen since 1901.

On the recommendation of Sir David Gill and Frank Dyson , he became chief assistant to the then newly appointed director of the Royal Observatory at the Cape of Good Hope Sydney Samuel Hough in 1907 . Halm remained the observatory's chief scientist until his retirement twenty years later. In South Africa he was instrumental in the progress of astronomy at the beginning of the 20th century. Initially, he was involved in a project initiated by Gill to determine the mean distance between the earth and the sun and then devoted himself to the systematic survey of the southern starry sky using astrophotographic methods, which was also started by Gill . His investigations included the systematic determination of the radial velocity of the brightest stars in the southern sky, and he identified a third in addition to two known stellar streams (discovered by Kapteyn ). He played an important role in proving the existence of an interstellar medium and was the first to propose a mass-luminosity relationship for stars. His assumptions about an expanding earth and the galactic redshift in a static universe, expressed in two publications from 1935, proved scientifically unsustainable.

In addition to his scientific work, Halm played an important role in the institutional development of astronomy in South Africa, and he was active in several scientific societies and associations, such as the Royal Society of South Africa and astronomical associations. After his retirement in 1927, he settled on a farm in Stellenbosch and taught astronomy at the University of Stellenbosch for a few years . When the South African Union under Prime Minister Jan Christiaan Smuts joined the Allies in World War II , Halm ended his membership in the Royal Astronomical Society in 1940.

Fonts (selection)

• J. Halm: On spectroscopic observations of the rotation of the sun . In: Astrophysical Journal . tape 22 , 1905, pp. 150-153 , doi : 10.1086 / 141252 .
• SS Hough, J. Halm: A spectroscopic determination of the systematic motions of the stars . In: Monthly Notices of the Royal Astronomical Society . tape 70 , no. 1 , 1909, p. 85-103 , doi : 10.1093 / mnras / 70.1.85 .
• J. Halm: Further considerations relating to the systematic motions of the stars . In: Monthly Notices of the Royal Astronomical Society . tape 71 , no. 8 , 1911, pp. 610-639 , doi : 10.1093 / mnras / 71.8.610 .
• JKE Halm: Present-day problems of astronomy . In: Journal of the Astronomical Society of South Africa . tape 1 , no. 6 , 1925, pp. 163-184 .
• JKE Halm: An astronomical aspect of the evolution of the earth . In: Journal of the Astronomical Society of South Africa . tape 4 , no. 1 , 1935, p. 1-28 .
• JKE Halm: On the theory of an “expanding universe” . In: Journal of the Astronomical Society of South Africa . tape 4 , no. 1 , 1935, p. 29-31 .

literature

• Willy Jahn:  Halm, Jakob Karl Ernst. In: New German Biography (NDB). Volume 7, Duncker & Humblot, Berlin 1966, ISBN 3-428-00188-5 , p. 569 ( digitized version ).
• IS Glass: Jacob Karl Ernst Halm (1866–1944) . In: Monthly Notes of the Astronomical Society of South Africa . tape 73 , no. 1–2 , 2014, pp. 14-23 ( online [accessed January 27, 2020]).
• H. Spencer Jones: Obituary Notices: Jakob Karl Ernst Halm . In: Monthly Notices of the Royal Astronomical Society . tape 105 , no. 2 , 1945, p. 2-3 .
• Hartmut Frommert: Halm, Jacob Karl Ernst . In: Thomas Hockey, Virginia Trimble et al. (Ed.): The Biographical Encyclopedia of Astronomers . Springer, 2007, ISBN 978-0-387-31022-0 , pp. 467 , doi : 10.1007 / 978-0-387-30400-7_575 .
• Straw. Jacob Karl Ernst. In: S2A3 Biographical Database of Southern African Science. National Council of S2A3, accessed April 9, 2020 . 

Web links

• Short biography in the Biographical Database of Southern African Science
• Publications in the Astrophysics Data System

Individual evidence

1. ↑ Jakob Karl Ernst Halm in the Mathematics Genealogy Project (English)
2. ↑ J. Halm: Spectroscopic Observations of the rotation of the Sun . In: Transactions of the Royal Society of Edinburgh . tape 41 , no. I , 1904, p. 16 .
3. ^ Awards of the Keith, Makdougall-Brisbane, Neill, and Gunning Victoria Jubilee Prizes from 1827 to 1906. Makdougall-Brisbane Prize. In: Transactions of the Royal Society of Edinburgh, Volume 45, Appendix, pp. 930-931. Biodiversity Heritage Library, accessed April 9, 2020 . 
4. ^ Fellows Directory. Biographical Index: Former RSE Fellows 1783–2002. (PDF file) Royal Society of Edinburgh, accessed April 10, 2020 . 
5. ↑ Helge Kragh: Expanding Earth and Static Universe: Two Papers of 1935 . 2015, arxiv : 1507.08040 .