Johann Rudolf Wolf (7 July 1816 – 6 December 1893) was a

Swiss Swiss most commonly refers to: * the adjectival form of Switzerland * Swiss people Swiss may also refer to: Places * Swiss, Missouri * Swiss, North Carolina * Swiss, West Virginia * Swiss, Wisconsin Other uses * Swiss Café, an old café located ...

astronomer An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...

and

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, mathematical structure, structure, space, Mathematica ...

best known for his research on

sunspot Sunspots are temporary spots on the Sun's surface that are darker than the surrounding area. They are one of the most recognizable Solar phenomena and despite the fact that they are mostly visible in the solar photosphere they usually aff ...

s. Wolf was born in

Fällanden Fällanden is a municipality in the district of Uster in the canton of Zürich in Switzerland, and belongs to the Glatt Valley (German: ''Glattal''). History Fällanden is first mentioned around 820 as ''Fenichlanda''. Geography Fällanden ...

, near Zurich. He studied at the universities of Zurich, Vienna, and Berlin. Encke was one of his teachers. Wolf became professor of astronomy at the

University of Bern The University of Bern (, , ) is a public university, public research university in the Switzerland, Swiss capital of Bern. It was founded in 1834. It is regulated and financed by the canton of Bern. It is a comprehensive university offering a br ...

in 1844 and director of the Bern Observatory in 1847. In 1855 he accepted a chair of astronomy at both the

University of Zurich The University of Zurich (UZH, ) is a public university, public research university in Zurich, Switzerland. It is the largest university in Switzerland, with its 28,000 enrolled students. It was founded in 1833 from the existing colleges of the ...

and the

Federal Institute of Technology ETH Zurich (; ) is a public university in Zurich, Switzerland. Founded in 1854 with the stated mission to educate engineers and scientists, the university focuses primarily on science, technology, engineering, and mathematics. ETH Zurich ran ...

in Zurich. Wolf was greatly impressed by the discovery of the sunspot cycle by

Heinrich Schwabe Samuel Heinrich Schwabe (25 October 1789 – 11 April 1875) was a German amateur astronomer remembered for his work on sunspots. He observed sunspots and made drawings of them from 1825 to 1867 and suggested in 1838 that there may be a ten-year cy ...

and he not only carried out his own observations, but he collected all the available data on sunspot activity back as far as 1610 and calculated a period for the cycle of 11.1 years. In 1848 he devised a way of quantifying sunspot activity. The

Wolf number The Wolf number (also known as the relative sunspot number or Zürich number) is a quantity that measures the number of sunspots and groups of sunspots present on the surface of the Sun. Historically, it was only possible to detect sunspots on t ...

, as it is now called, remains in use. In 1852 Wolf was one of four people who discovered the link between the cycle and geomagnetic activity on Earth. Around 1850, to study the laws of probability, Wolf performed a

Buffon's needle In probability theory, Buffon's needle problem is a question first posed in the 18th century by Georges-Louis Leclerc, Comte de Buffon: :Suppose we have a floor made of parallel strips of wood, each the same width, and we drop a needle onto the ...

experiment, dropping a needle on a plate 5000 times to verify the value of π, a precursor to the

Monte Carlo method Monte Carlo methods, or Monte Carlo experiments, are a broad class of computational algorithms that rely on repeated random sampling to obtain numerical results. The underlying concept is to use randomness to solve problems that might be ...

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HAO "Rudolf Wolf (1816–1893"

Analysis of Wolf's dice data
by

Edwin Jaynes Edwin Thompson Jaynes (July 5, 1922 – April 30, 1998) was the Wayman Crow Distinguished Professor of Physics at Washington University in St. Louis. He wrote extensively on statistical mechanics and on foundations of probability and statistical ...

{{DEFAULTSORT:Wolf, Rudolf 19th-century Swiss astronomers 1816 births 1893 deaths Historians of astronomy University of Zurich alumni Academic staff of the University of Zurich Academic staff of ETH Zurich Members of the French Academy of Sciences

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