Julius Bartels (17 August 1899,

Magdeburg Magdeburg (; ) is the Capital city, capital of the Germany, German States of Germany, state Saxony-Anhalt. The city is on the Elbe river. Otto I, Holy Roman Emperor, Otto I, the first Holy Roman Emperor and founder of the Archbishopric of Mag ...

– 6 March 1964) was a German

geophysicist Geophysics () is a subject of natural science concerned with the physical processes and properties of Earth and its surrounding space environment, and the use of quantitative methods for their analysis. Geophysicists conduct investigations acros ...

and

statistician A statistician is a person who works with Theory, theoretical or applied statistics. The profession exists in both the private sector, private and public sectors. It is common to combine statistical knowledge with expertise in other subjects, a ...

who made notable contributions to the physics of the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

and

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

; to geomagnetism and

meteorology Meteorology is the scientific study of the Earth's atmosphere and short-term atmospheric phenomena (i.e. weather), with a focus on weather forecasting. It has applications in the military, aviation, energy production, transport, agricultur ...

; and to the physics of the

ionosphere The ionosphere () is the ionized part of the upper atmosphere of Earth, from about to above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays ...

. He also made fundamental contributions to statistical methods for geophysics. Bartels was the first President of the

International Association of Geomagnetism and Aeronomy The International Association of Geomagnetism and Aeronomy (IAGA) is an international scientific association that focuses on the study of terrestrial and planetary magnetism and space physics. IAGA is one of the eight associations of the Interna ...

(IAGA). With Sydney Chapman, he wrote the influential book ''Geomagnetism''.

Life and career

Bartels was awarded his Ph.D. from

Göttingen Göttingen (, ; ; ) is a college town, university city in Lower Saxony, central Germany, the Capital (political), capital of Göttingen (district), the eponymous district. The River Leine runs through it. According to the 2022 German census, t ...

in 1923, then worked at the

Potsdam Potsdam () is the capital and largest city of the Germany, German States of Germany, state of Brandenburg. It is part of the Berlin/Brandenburg Metropolitan Region. Potsdam sits on the Havel, River Havel, a tributary of the Elbe, downstream of B ...

magnetic observatory as a post-doctorate. In 1928, he was named

professor Professor (commonly abbreviated as Prof.) is an Academy, academic rank at university, universities and other tertiary education, post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin ...

Eberswalde Eberswalde () is a major town and the administrative seat of the district Barnim in Brandenburg in north-eastern Germany, about northeast of Berlin. Population 42,144 (census in June 2005). The town is often called Waldstadt (forest town), beca ...

, teaching

. He became full professor at

Berlin University The Humboldt University of Berlin (, abbreviated HU Berlin) is a public research university in the central borough of Mitte in Berlin, Germany. The university was established by Frederick William III on the initiative of Wilhelm von Humboldt ...

in 1936, and director of the Potsdam Geophysical Institute. From 1931 until the second year of

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

, he was also a research associate at the

Carnegie Institution of Washington The Carnegie Institution for Science, also known as Carnegie Science and the Carnegie Institution of Washington, is an organization established to fund and perform scientific research in the United States. This institution is headquartered in W ...

. He collaborated with Sydney Chapman to publish the two-volume work ''Geomagnetism'', a definitive reference on geophysics. In 1933, Bartels signed the ''

Vow of allegiance of the Professors of the German Universities and High-Schools to Adolf Hitler and the National Socialistic State officially translated into English as the Vow of allegiance of the Professors of the German Universities and High-Schools to Adolf Hitler and the National Socialistic State was a document presented on 11 November 1933 at the Albert Hall in Leipzi ...

''. Following the war in 1946, he became professor in Göttingen. He was also a director at the

Max Planck Institute The Max Planck Society for the Advancement of Science (; abbreviated MPG) is a formally independent non-governmental and non-profit association of German research institutes. Founded in 1911 as the Kaiser Wilhelm Society, it was renamed to the M ...

for Physics of the

Stratosphere The stratosphere () is the second-lowest layer of the atmosphere of Earth, located above the troposphere and below the mesosphere. The stratosphere is composed of stratified temperature zones, with the warmer layers of air located higher ...

(today

Max Planck Institute for Solar System Research The Max Planck Institute for Solar System Research (abbreviation: MPS; ) is a research institute in astronomy and astrophysics located in Göttingen, Germany, where it relocated in February 2014 from the nearby village of Lindau (Katlenburg-Lindau ...

) between 1955 and 1964. When, in 1958

International Council for Science The International Council for Science (ICSU, after its former name, International Council of Scientific Unions) was an international non-governmental organization devoted to international cooperation in the advancement of science. Its members ...

, created the

Committee on Space Research The Committee on Space Research (COSPAR) was established on October 3, 1958 by the International Council for Scientific Unions (ICSU) and its first chair was Hildegard Korf Kallmann-Bijl. Among COSPAR's objectives are the promotion of scienti ...

(''COSPAR''), Bartels became chairman of the West-German branch. From 1954 until 1957, he served as first President of the IAGA. Between 1960 and 1963, he was vice-president of the

International Union of Geodesy and Geophysics The International Union of Geodesy and Geophysics (IUGG; , UGGI) is an international non-governmental organization dedicated to the scientific study of Earth and its space environment using geophysical and geodetic techniques. The IUGG is a me ...

Research

Among his contributions was the development of the Kp-index, and he suggested the existence of "M-regions" on the

that resulted in geomagnetic activity. These

coronal holes Coronal holes are regions of the Sun's corona that emit low levels of ultraviolet and X-ray radiation compared to their surroundings. They are composed of relatively cool and tenuous plasma permeated by magnetic fields that are open to interpl ...

were later confirmed by the

Skylab Skylab was the United States' first space station, launched by NASA, occupied for about 24 weeks between May 1973 and February 1974. It was operated by three trios of astronaut crews: Skylab 2, Skylab 3, and Skylab 4. Skylab was constructe ...

mission. Finally he also helped initiate the

International Geophysical Year The International Geophysical Year (IGY; ), also referred to as the third International Polar Year, was an international scientific project that lasted from 1 July 1957 to 31 December 1958. It marked the end of a long period during the Cold War w ...

, which took place in 1957/8. The Bartels' Rotation Number of the Sun based on a regular 27-day cycle is named after him. It is similar to the

Carrington rotation Solar rotation varies with latitude. The Sun is not a solid body, but is composed of a gaseous plasma. Different latitudes rotate at different periods. The source of this differential rotation is an area of current research in solar astronomy. ...

which is based on 27.2753 days.

Awards and honors

* Posthumously awarded the

William Bowie Medal The William Bowie Medal is awarded annually by the American Geophysical Union for "outstanding contributions to fundamental geophysics and for unselfish cooperation in research". The award is the highest honor given by the AGU and is named in honor ...

of the

American Geophysical Union The American Geophysical Union (AGU) is a 501(c)(3) nonprofit organization of Earth, Atmospheric science, atmospheric, Oceanography, ocean, Hydrology, hydrologic, Astronomy, space, and Planetary science, planetary scientists and enthusiasts that ...

. * The ''Julius Bartels Medal'', of the

European Geosciences Union The European Geosciences Union (EGU) is a non-profit international union in the fields of Earth, planetary, and space sciences whose vision is to "realise a sustainable and just future for humanity and for the planet". The organisation has headq ...

Division on Solar-Terrestrial Sciences, was named in his honor. * The crater Bartels on the

is named after him. * The Chree Medal and Prize in 1953

References

* * * {{DEFAULTSORT:Bartels, Julius 1899 births 1964 deaths Scientists from Magdeburg Scientists from the Province of Saxony German geophysicists University of Göttingen alumni German statisticians Members of the German Academy of Sciences at Berlin Members of the Göttingen Academy of Sciences and Humanities Max Planck Institute directors

Life and career

Research

Awards and honors

See also

References