Browsing by Author "Hentschel, Klaus"
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Item Open Access Item Open Access "Ausschaltung" oder "Verteidigung" der allgemeinen Relativitätstheorie : Interpretationen einer Kosmologen-Karriere im Nationalsozialismus(1994) Hentschel, Klaus; Renneberg, MonikaAls 1933 die Nationalsozialisten die Macht übernahmen, stand Otto Heckmann als Assistent an der Göttinger Universitäts-Sternwarte noch am Beginn einer Laufbahn in der Astronomie in Deutschland. Als die Alliierten 1945 die Herrschaft der Nationalsozialisten beendeten, war Otto Heckmann Direktor der Sternwarte Hamburg-Bergedorf und ordentlicher Professor für Astronomie an der Universität Hamburg. Dazwischen liegt eine Karriere im Nationalsozialismus. Diese Geschichte endete 1945 ebensowenig wie die Karriere Heckmanns; darum werden wir nicht nur seinem Weg in das -Dritte Reich- nachgehen, sondern auch seinem Weg in die Nachkriegszeit. Uns interessiert daran die Anatomie des Berufungsvorgangs sowie die damit verbundenen Anpassungen und Umdeutungen.Item Open Access Bernhard Bavink (1879 - 1947) : der Weg eines Naturphilosophen vom deutschnationalen Sympathisanten der NS-Bewegung bis zum unbequemen Non-Konformisten(1993) Hentschel, KlausSelected stages in the life and oeuvre of the natural philosopher Bemhard Bavink (1879-1947) are discussed in historical context with particular emphasis on scientiftc issues. Based on materials from the Berlin Document Center, and from his estate located in BielefeId, and supplemented by his unpublished autobiography written between 1941 and 1945 as well as by several of Bavink's papers;appearing in the journal Unsere Welt edited by him from 1920 on, and by certain passages in Bavink's books, this paper presents evidence of his courageous fight during the National Socialist (NS) regime in Germany for what he considered the untainted ,ethos of science' independent of nationality or religion. TItis is the more astonishing since before 1933, Bavink shared right-wing (Deutschnationale) politicaI opinions such as antisemitism with many of his colleagues (Fritz Ringer's Mandarins), and he only gradually realized that the new system, initially welcomed as the end of the unloved Weimar Republic, was much worse than expected. Special emphasis is given to the efforts of NS institutions to gain control over the maverick Bavink and to the reasons why they did not fully succeed in this. Extracts of letters by Planck, Joos, Finkelnburg and others demonstrate that Bavink had a vital role in the efforts of german physicists to resist the intrusion and spread of explicit anti-Semitism and NS racist ideology into their domain. It is illustrated here that it was quite possible to voice and to publish nonconformist opinions, contrary to the widespread view of lhis perlod as a time of drastic ,realignment' (Gleichschaltung) of all branches of public life to the doctrines of the German National Socialist Party (NSDAP). Because of his political ,unreliability' Bavink was prevented from getting a well-deserved chair for natural philosophy in Münster in 1941-43 and had to relinquish editorship of Unsere Welt in 1940, but neither he nor his family suffered any more drastic consequences.Item Open Access Item Open Access Item Open Access Christopher Ray, The evolution of relativity : Bristol ..., Adam Hilger, 1987; [Rezension](1988) Hentschel, Klaus-Item Open Access The conversion of St. John : a case study on the interplay of theory and experiment(1993) Hentschel, KlausGravitational redshift of spectral lines as one of the three early-known experimental implications of Einstein's general theory of relativity and gravitation was intensively searched for by researchers all over the world, but around 1920 most of the contemporary evidence in the sun's Fraunhofer-spectrum conflicted with the predictions of relativity theory. In 1923 the American astrophysicist Charles Edward St. John announced that his own solar spectroscopic data would force him to retreat from his former skepticism concerning the existence of gravitational redshift. This statement was at the time widely interpreted by scientists and journalists alike as the open confession of a rapid conversion of one of the few remaining serious scientific opponents of Einstein's theory. This paper demonstrates that this illusion of a sudden "Gestalt switch" in St. John's evaluation of data can be dissolved by a careful step-by-step account of St. John's research practice between 1917 and 1923. After a fine-grained diachronic report of the development of St. John's interpretation of his and others' data, the second part of the paper consists in a systematic analysis of the heuristics and arguments used by St. John pro and contra gravitational redshift.Item Open Access Item Open Access Item Open Access Item Open Access Einstein's attitude towards experiments : testing relativity theory 1907 - 1927(1992) Hentschel, KlausContrary to the widespread Einstein legend, it is demonstrated that in many cases he was extremely curious about certain experimental results and that he could hardly wait for the moment when tests which he had suggested were actually done by skilled observers. I will show that this was the case whenever these empirically testable effects were closely linked to his newly proposed fundamental principles which still lacked empirical support, focussing on the examples of gravitational redshift (linked to the equivalence principle between gravitational and acceleration fields), of light deflection (linked to mass-energy equivalency and the curvature of space-time), and of interferometric experiments (linked to the two axioms of the special theory of relativity).Item Open Access Item Open Access Einstein, Neokantianismus und Theorienholismus(1987) Hentschel, KlausDie Stellungnahmen der Kantianer lassen sich klassifizieren gemäß der verfolgten Argumentationsstrategie angesichts von Ergebnissen der Relativitätstheorien, die den Ausführungen Kants zu widersprechen schienen. Im größeren Teil der Reaktionen werden Immunisierungsstrategien verfolgt, die darauf hinauslaufen, daß die Kantischen Anschauungsformen "Raum" und "Zeit" mit den durch die Relativitätstheorie beschriebenen Eigenschaften der physikalischen Raum-Zeit als Maßräumen nichts zu tun haben sollen. Andere Vertreter des Neukantianismus entwickelten Revisionsstrategien, bei denen jeweils einige der Kantischen Setzungen als voreilige Identifikationen der Bedingungen der Möglichkeit von Erfahrung mit speziellen Voraussetzungen der Newtonschen Mechanik interpretiert wurden, die dank der durch die Relativitätstheorie gewonnenen Einsichten nur durch andere Bestimmungen ersetzt werden müßten.Item Open Access Der Einstein-Turm : Erwin F. Freundlich und die Relativitätstheorie; Ansätze zu einer "dichten Beschreibung" von institutionellen, biographischen und theoriengeschichtlichen Aspekten(1992) Hentschel, KlausDer Einstein-Turm wurde von den Zeitgenossen einhellig als das Symbol eines "neuen Zeitalters" aufgefaßt, ganz im Gegensatz zu den in der Anwendung historisierender Stilarten wie z.B. romanischer Bogen schwelgenden Bauten des Astrophysikalischen Observatoriums, gleichfalls auf dem Telegraphenberg in unmittelbarer Nachbarschaft des Einstein-Turmes. Einsteins Relativitätstheorie ebenso wie das nach ihm benannte Turmteleskop wurden weithin als Bruch mit der Tradition verstanden, übrigens unter der für solche Phasen revolutionären Umschwungs typischen Verkennung der gleichsam subkutanen historischen Kontinuitäten.Item Open Access Item Open Access Erwin Finlay Freundlich and testing Einstein's theory of relativity(1994) Hentschel, KlausThis article covers aspects of the life and career of ERWIN FINLAY FREUNDLICH, the first German astronomer to consider seriously Einstein's theory of relativity and gravitation. In doing so, he made himself so unpopular among his colleagues that nothing less than Einstein's powerful intercession was necessary for him to be able to continue his research on the experimental verification of this theory.Item Open Access Grebe/Bachems photometrische Analyse der Linienprofile und die Gravitations-Rotverschiebung : 1919 bis 1922(1992) Hentschel, KlausAn effort of proponents of relativity theory to find evidence for the so-called gravitational red-shift of spectral lines as one of the experimental consequences of Einstein's generalized theory of relativity is reconsidered with reference to hitherto unpublished documents. It is shown how much interest Albert Einstein in fact took, around 1920, in the data analysis of Leonhard Grebe and Albert Bachem, who tried to explain why most earlier efforts to find the gravitational red-shift had failed. They carefully measured the line profiles of the spectral lines both in the sun's Fraunhofer lines and in pressure-independent laboratory comparison spectra. Then they rejected all lines with strong neighbouring lines which could cause apparent shifts of the line centres; the remaining seven well-isolated lines showed the gravitational red-shift with acceptable accuracy. Nevertheless, their claim to have successfully isolated the relativistic effect never convinced the astrophysicists of their day - the reasons for the scientific community's scepticism, contrasted against the enthusiastic group of Einstein sympathizers, are also discussed.Item Open Access Item Open Access
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