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Carl Wilhelm Wirtz
Carl Wilhelm Wirtz (24 August 1876 in Krefeld – 18 February 1939 in Hamburg) was an astronomer who spent his time between the Kiel Observatory in Germany and the Observatory of Strasbourg, France. He is known for statistically showing the existence of a redshift-distance correlation for spiral galaxies. Scientific career As already Vesto Slipher in 1912, Wirtz in 1918 observed a systematic redshift of spiral nebulae, which was difficult to interpret in terms of a cosmological model in which the Universe is filled more or less uniformly with stars and nebulae. Wirtz additionally used the equivalent in German of '' K correction''. The term continues to be used in present-day observational cosmology, but Wirtz's observational evidence that the Universe is expanding is not often mentioned. He wrote: In 1922, he wrote a paper where he argued that the observational results suggest, that the redshifts of distant galaxies are becoming higher than more closer ones, which he i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Krefeld
Krefeld ( , ; li, Krieëvel ), also spelled Crefeld until 1925 (though the spelling was still being used in British papers throughout the Second World War), is a city in North Rhine-Westphalia, Germany. It is located northwest of Düsseldorf, its center lying just a few kilometers to the west of the river Rhine; the borough of Uerdingen is situated directly on the Rhine. Because of its economic past, Krefeld is often referred to as the "Velvet and Silk City". It is accessed by the autobahns A57 (Cologne– Nijmegen) and A44 ( Aachen–Düsseldorf– Dortmund– Kassel). Krefeld's residents now speak ', or standard German, but the native dialect is a Low Franconian variety, sometimes locally called ', ', ', or sometimes simply '. The Uerdingen line isogloss, separating general dialectical areas in Germany and neighboring Germanic-speaking countries, runs through and is named after Krefeld's Uerdingen district, originally an independent municipality. History Early history Rec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time Dilation
In physics and relativity, time dilation is the difference in the elapsed time as measured by two clocks. It is either due to a relative velocity between them ( special relativistic "kinetic" time dilation) or to a difference in gravitational potential between their locations ( general relativistic gravitational time dilation). When unspecified, "time dilation" usually refers to the effect due to velocity. After compensating for varying signal delays due to the changing distance between an observer and a moving clock (i.e. Doppler effect), the observer will measure the moving clock as ticking slower than a clock that is at rest in the observer's own reference frame. In addition, a clock that is close to a massive body (and which therefore is at lower gravitational potential) will record less elapsed time than a clock situated further from the said massive body (and which is at a higher gravitational potential). These predictions of the theory of relativity have been repeated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
People From Krefeld
A person ( : people) is a being that has certain capacities or attributes such as reason, morality, consciousness or self-consciousness, and being a part of a culturally established form of social relations such as kinship, ownership of property, or legal responsibility. The defining features of personhood and, consequently, what makes a person count as a person, differ widely among cultures and contexts. In addition to the question of personhood, of what makes a being count as a person to begin with, there are further questions about personal identity and self: both about what makes any particular person that particular person instead of another, and about what makes a person at one time the same person as they were or will be at another time despite any intervening changes. The plural form "people" is often used to refer to an entire nation or ethnic group (as in "a people"), and this was the original meaning of the word; it subsequently acquired its use as a plural form of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1939 Deaths
This year also marks the start of the Second World War, the largest and deadliest conflict in human history. Events Below, the events of World War II have the "WWII" prefix. January * January 1 ** Third Reich *** Jews are forbidden to work with Germans. *** The Youth Protection Act was passed on April 30, 1938 and the Working Hours Regulations came into effect. *** The Jews name change decree has gone into effect. ** The rest of the world *** In Spain, it becomes a duty of all young women under 25 to complete compulsory work service for one year. *** First edition of the Vienna New Year's Concert. *** The company of technology and manufacturing scientific instruments Hewlett-Packard, was founded in a garage in Palo Alto, California, by William (Bill) Hewlett and David Packard. This garage is now considered the birthplace of Silicon Valley. *** Sydney, in Australia, records temperature of 45 ˚C, the highest record for the city. *** Philipp Etter took over as Swiss ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1876 Births
Events January–March * January 1 ** The Reichsbank opens in Berlin. ** The Bass Brewery Red Triangle becomes the world's first registered trademark symbol. * February 2 – The National League of Professional Base Ball Clubs is formed at a meeting in Chicago; it replaces the National Association of Professional Base Ball Players. Morgan Bulkeley of the Hartford Dark Blues is selected as the league's first president. * February 2 – Third Carlist War – Battle of Montejurra: The new commander General Fernando Primo de Rivera marches on the remaining Carlist stronghold at Estella, where he meets a force of about 1,600 men under General Carlos Calderón, at nearby Montejurra. After a courageous and costly defence, Calderón is forced to withdraw. * February 14 – Alexander Graham Bell applies for a patent for the telephone, as does Elisha Gray. * February 19 – Third Carlist War: Government troops under General Primo de Rivera drive through the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astrophysics Data System
The SAO/NASA Astrophysics Data System (ADS) is an online database of over 16 million astronomy and physics papers from both peer reviewed and non-peer reviewed sources. Abstracts are available free online for almost all articles, and full scanned articles are available in Graphics Interchange Format (GIF) and Portable Document Format (PDF) for older articles. It was developed by the National Aeronautics and Space Administration (NASA), and is managed by the Smithsonian Astrophysical Observatory. ADS is a powerful research tool and has had a significant impact on the efficiency of astronomical research since it was launched in 1992. Literature searches that previously would have taken days or weeks can now be carried out in seconds via the ADS search engine, which is custom-built for astronomical needs. Studies have found that the benefit to astronomy of the ADS is equivalent to several hundred million US dollars annually, and the system is estimated to have tripled the readership ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minor Planet Center
The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Function The Minor Planet Center is the official worldwide organization in charge of collecting observational data for minor planets (such as asteroids), calculating their orbits and publishing this information via the ''Minor Planet Circulars''. Under the auspices of the International Astronomical Union (IAU), it operates at the Smithsonian Astrophysical Observatory, which is part of the Center for Astrophysics along with the Harvard College Observatory. The MPC runs a number of free online services for observers to assist them in observing minor planets and comets. The complete catalogue of minor planet orbits (sometimes referred to as the "Minor Planet Catalogue") may also be freely downloaded. In addition to astrometric data, the MPC collects l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeitschrift Für Astrophysik
''Astronomy & Astrophysics'' is a monthly peer-reviewed scientific journal covering theoretical, observational, and instrumental astronomy and astrophysics. The journal is run by a Board of Directors representing 27 sponsoring countries plus a representative of the European Southern Observatory. The journal is published by EDP Sciences and the editor-in-chief is . History Origins ''Astronomy and Astrophysics'' (A&A) was created as an answer to the publishing scenario found in Europe in the 1960s. At that time, multiple journals were being published in several countries around the continent. These journals usually had a limited number of subscribers, and published articles in languages other than English, resulting in a small number of citations compared to American and British journals. Starting in 1963, conversations between astronomers from European countries assessed the need for a common astronomical journal. On 8 April 1968, leading astronomers from Belgium, Denmark, F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomische Nachrichten
''Astronomische Nachrichten'' (''Astronomical Notes''), one of the first international journals in the field of astronomy, was established in 1821 by the German astronomer Heinrich Christian Schumacher. It claims to be the oldest astronomical journal in the world that is still being published. The publication today specializes in articles on solar physics, extragalactic astronomy, cosmology, geophysics, and instrumentation for these fields. All articles are subject to peer review. Early history The journal was founded in 1821 by Heinrich Christian Schumacher,'' Publications of the Astronomical Society of the Pacific'', page 60, v.7 (1895) under the patronage of Christian VIII of Denmark, and quickly became the world's leading professional publication for the field of astronomy. Schumacher edited the journal at the Altona Observatory, then under the administration of Denmark, later part of Prussia, and today part of the German city of Hamburg. Schumacher edited the first 31 issue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Astrophysical Journal
''The Astrophysical Journal'', often abbreviated ''ApJ'' (pronounced "ap jay") in references and speech, is a peer-reviewed scientific journal of astrophysics and astronomy, established in 1895 by American astronomers George Ellery Hale and James Edward Keeler. The journal discontinued its print edition and became an electronic-only journal in 2015. Since 1953 ''The Astrophysical Journal Supplement Series'' (''ApJS'') has been published in conjunction with ''The Astrophysical Journal'', with generally longer articles to supplement the material in the journal. It publishes six volumes per year, with two 280-page issues per volume. ''The Astrophysical Journal Letters'' (''ApJL''), established in 1967 by Subrahmanyan Chandrasekhar as Part 2 of ''The Astrophysical Journal'', is now a separate journal focusing on the rapid publication of high-impact astronomical research. The three journals were published by the University of Chicago Press for the American Astronomical Society ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of Science (journal)
''History of Science'' is a peer-reviewed academic journal that covers the history of science, medicine, and technology. The editor-in-chief is Lissa L. Roberts (University of Twente). It was established in 1962 and is published by SAGE Publications. Abstracting and indexing The journal is abstracted and indexed in Scopus and the Social Sciences Citation Index. According to the ''Journal Citation Reports'', its 2021 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as ... is 1.0371. References External links * SAGE Publishing academic journals English-language journals History of science journals Philosophy of science journals Publications established in 1962 Quarterly journals {{science-philo-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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