Main Page | See live article | Alphabetical index Aleksander Wolszczan (born 1946) is a Polish astronomer. Educated in Poland he moved in 1982 to USA to work at the Cornell University in Ithaca and Princeton University. Later he became an astronomy professor at the University of Pennsylvania in Philadelphia. Since 1994 he has been a profesor at the University in Torun and a member of the Polish Academy of Sciences (PAN). He carried out astronomical observation in the Arecibo Observatory which led him to discovery of pulsar PSR B1257+12 in 1990. The data analysis gathered thanks to the discovery showed that the pulsar is orbited by two planets with mass 3,4 and 2,8 times that of Earth's mass. Their orbits are 0,36 and 0,47 AU respectively. This planetary system was the first extra-solar system discovered in the Universe whose existence was proved. Wolszczan published his findings in 1992 and 1994. In spite of initial misgivings of some experts today his discovery is regarded fully substantiated. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.