Thomas Clausen (astronomer)

Thomas Clausen

Thomas Clausen (* 16th January 1801 in Snogbæk , community Sottrup , Duchy of Schleswig (today Denmark ); † May 12. ^{. Jul} / 24. May  1885 ^greg. In Tartu ) was a Danish ( Schleswig shear ) astronomer and mathematician .

Like many scientists at the time, Clausen had not completed a regular university course. He was born the son of a poor small farmer in Northern Schleswig, Denmark, and in 1813, still ignorant of reading and writing, came as a herding boy to the pastor and lover of mathematics Georg Holst in the neighboring community of Nybøl (Nübel), who made astronomical observations among other things. Holst made it possible for him to attend school and supported him in acquiring elementary mathematical knowledge . During the school leaving examination, Clausen stood out for his exceptional performance.

Around 1819 he came to Heinrich Christian Schumacher in Altona on the recommendation of Holst and published his calculation of the star coverings of the moon to determine the longitude in the Astronomical News as early as 1823 . From 1824 to 1827 he worked as an assistant at the observatory under Schumacher's direction, where he was able to learn a lot mathematically from Schumacher's assistant Peter Andreas Hansen . During this time there were various disagreements with Schumacher, u. a. because Clausen fell in love with a niece of Schumacher.

In January 1827 Joseph von Utzschneider signed a contract with Clausen for a job in the famous Utzschneider optical institute in Munich. Clausen then renewed his advertising for Schumacher's niece, but received a renewed refusal and ban, which he felt was a very serious offense. Clausen did not leave for Munich until the end of November 1828 and was taken in by Utzschneider. Here, too, there was some inconvenience. In 1833 he fell seriously ill and nothing is known about him from 1834 to 1840. In June 1840, after a long journey on foot from Munich, he arrived back in Altona near Schumacher in a bad state. Gauss previously wrote to Schumacher

“It would be very much to be deplored if his really excellent talent for abstract mathematics were to perish so completely in the withering. Couldn't something be done for him? "

Dorpat observatory

At the Altona observatory he took the position of an observer and in 1840 published a treatise on the memorable comet of 1770 , for which he was awarded the prize of the Royal Society of Sciences in Copenhagen. In 1842 he became an observator under Mädler and in 1865 a professor at the Dorpat observatory . In 1866 he succeeded Mädler in the directorate of the Dorpat observatory, which he held until his retirement in 1872 (it had been postponed for five years in 1867).

Clausen gained his greatest importance as a calculating astronomer. In particular, he dealt with comet orbits . As a mathematician, too, he was extremely good at arithmetic. On November 3, 1826 he wrote to Utzschneider: "Theoretical study of mathematics has always been of greatest interest to me." So he calculated the circle number π with a control calculation to 250 decimal places (series by John Machin and Euler ). In this context he was also interested in questions of number theory; in 1840, independently of Karl Georg Christian von Staudt , he found the sentence today named after von Staudt and Clausen via the denominators of Bernoulli's numbers . In 1853 he further decomposed the number into the prime factors 2 071 723 and 5 363 222 357 and in 1854 the Fermat number into 274177 and 67 280 421 310 721, adding that the last number is the largest known prime number. He also found significant individual results in the field of infinite series . For example, as early as 1830, before Hjortnaes (1953) or Roger Apéry (1978) and Melzak (1973), he gave a rapidly converging series for : ${\displaystyle {\tfrac {10^{17}-1}{9}}}$ ${\displaystyle F_{6}=2^{64}+1}$ ${\displaystyle \zeta (3)}$

${\displaystyle \zeta (3)={\tfrac {1}{2}}\pi \sum _{k=0}^{\infty }{\frac {\binom {2k}{k}}{2^{4k}(2k+1)^{2}}}-{\tfrac {3}{8}}\sum _{k=0}^{\infty }{\frac {1}{{\binom {2k+1}{k}}(k+1)^{3}}}}$

In 1854 he was elected a corresponding member of the Göttingen Academy of Sciences . In 1856 he received the Gauss Memorial Medal and in 1869, together with his colleague Ferdinand Minding, became an honorary member of the St. Petersburg University. Gauss , who was otherwise very poor in praise , had repeatedly valued Clausen's mathematical skills.

Individual evidence

1. ↑ Entry in the baptismal register of the parish of Sottrup , Sønderborg Amt
2. ↑ Entry in the burial register of the university community in Dorpat (Estonian: Tartu ülikooli kogudus)
3. ↑ Holger Krahnke: The members of the Academy of Sciences in Göttingen 1751-2001 (= Treatises of the Academy of Sciences in Göttingen, Philological-Historical Class. Volume 3, Vol. 246 = Treatises of the Academy of Sciences in Göttingen, Mathematical-Physical Class. Episode 3, vol. 50). Vandenhoeck & Ruprecht, Göttingen 2001, ISBN 3-525-82516-1 , p. 59.

literature

• Kurt-R. Biermann : Thomas Clausen, mathematician and astronomer . Crelle Journal, vol. 216, pp. 159-198 (1964).
• Kurt-R. Biermann: Thomas Clausen as an astronomer . Janus, vol. 57 (1970), No. 4, pp. 299-305.
• Kurt-R. Biermann: Genius without a chance: Thomas Clausen, Joseph von Fraunhofer's designated successor . Culture & Technology, Journal of the German Museum, vol. 15 (1991), No. 3, pp. 42-45.

Web links

• John J. O'Connor, Edmund F. Robertson :  Thomas Clausen. In: MacTutor History of Mathematics archive .
• Publications by Th. Clausen in the Astrophysics Data System