61st Annual Meteoritical Society Meeting 5006.pdf

G. C. LICHTENBERG AND THE “LUNAR VOLCANISM.” W. Czegka, Karlsbader Ring 7, D-68782 Brühl, Baden, Germany ([email protected])

Although Robert Hooke concluded in his 1665 [6]. A few days later he was able send a letter to Her- work Micrographia that the craters on the were schel [7] (see [8] for a description of his relationship caused by lunar volcanos, detailed observation on lu- with Herschel). In this letter he made detailed mor- nar craters in context with volcanism did not begin phological comparison between the Vesuvian caldera until the 1770s or 1780s. It was first discussed by and : “Ich glaube überhaupt daß alle G. C. Lichtenberg, who reported in two publications Ringe mit dem Punkte in der Mitte [see Fig. 1, top] [1,2] about an observation he had made in 1775 with a eingestürzte ungeheure Berge sind und daß der Punckt telescope during his stay in Oxford. in der Mitte durch dieselbe Krafft entstanden ist, die den grosen Berg aufwarf. Denn würcklich sieht der Vesuv von oben betrachtet [see Fig. 1, center] etwas so aus A ist der jetzige Vesuv, B sein Crater mit dem kleinen Kegel in der Mitte, C und D sind der Monte Somma und der Ottajano, die gewiß die Wurtzel des alten Vesuvs sind, denn man findet bey E Lava, die unmöglich von dem jetzigen Vesuv herrühren kan, denn sie müste vorther Thal F angefüllt haben [see Fig. 1, bottom]. Also ABC war der alte Vesuv , dieser stürzte ein und ließ die Wurtzeln CFE und ADE ste- hen nach und nach entstund der neue Vesuv E G der nun in seinem crater wieder den kleinen neuesteb Ve- suv H hat” [7]. Lichtenberg transfers the development of the Ve- suv caldera in the principle of actualism to the lunar surface when he stated that “daß die meisten Berge im Monde Vulkane, oder wenigstens durch eine Krafft hervorgebracht seyn, die der Richtung der Schwere entgegenwürckt” [7]. Within a few years, volcanic activity on the Moon was reported in Germany by J. Bode, F. X. von Zach, Fig. 1. “Aerial-photograph”-type sketches of a lu- and J. Schroeter, all in personal and scientific con- nar crater (above) compared to “aerial” and land- nection with Lichtenberg. In 1795 W. Olbers, a friend scape-type sketches of Mount Vesuvius. Letters are of Chladni and Lichtenberg, conceived the idea that explained in the text. meteorites were lunar volcanic ejecta [9]. References: [1] Lichtenberg G. C. (1778) Göt- Just as Herschel did 12 years later, Lichtenberg ob- tinger Taschen-Calender für 1779. [2] Lichtenberg served a fiery glow on the Moon that he interpreted as G. C. (1781) Göttingsches Magazin der Wissen- volcano activity. Even in his first publications, he schaften und Litteratur, 2, 26–33. [3] Hamilton W. made morphological comparisons between terrestrial (1772) Observations on Mount Vesuvius, Mount Etna volcanos (Mount Etna and Mount Vesuvius) and ob- and Other Volcanoes of the Two Sicilies. [4] Joost U. served craters on the Moon. Lichtenberg got his de- and Schöne A. (1990) Briefwechsel III (=BW). [5] tailed knowledge about the two terrestrial areas from Lichtenberg G. C. (1787) Letter from Chr. Girtanner, his edition of Tobias Mayer’s lunar atlas and Hamil- 21.05.1787 (BW 1527). [6] Lichtenberg G. C. (1787) ton’s Vesuvian monography [3]. Letter to C. F. Hindenburg , 01.06.1787 (BW 1531). On May 21, 1787 (before Herschel’s publication), [7] Lichtenberg G. C. (1787) Letter to F. W. Herschel, Lichtenberg received a letter from Chr. Girtanner 04.06.1787 (BW 1533). [8] Czegka W. (1997) Mete- [4,5] concerning Herschel’s observations of volcanos oritics & Planet. Sci., 32, A33–A34. [9] Czegka W. on the Moon, which Girtanner witnessed on May 18, (1994) Aufschluss, 45, 111–123. 1787. Herschel had reported similar phenomena in 1783. Lichtenberg was enthusiastic. He immediately reported Herschel’s observations to C. F. Hindenburg