Celestial mechanics planetary positions, using geometrical or arithmetical techniques, and contemporary discussions of the physical causes of the planets' motion. Johannes Kepler (1571–1630) was the first to closely integrate the predictive geometrical astronomy, which had been dominant from Ptolemy in the 2nd century to Copernicus, with physical concepts to produce a "New Astronomy, Based upon Causes, or Celestial Physics" in 1609. His work led to the modern laws of planetary orbits, which he developed using his physical principles and the planetary observations made by Tycho Brahe. Kepler's model greatly improved the accuracy of predictions of planetary motion, years before Isaac Newton developed
Stars and planetary systems in fiction with most writers of his era, his settings did not extend beyond the Solar System, and so his work is not found in this article. Planetary systems (mostly hypothetical or imaginary) of real stars appearing in fiction are: In 2011 three Super-Earths were confirmed in orbit around 82 Eridani (HD20794). Barnard's Star is a red dwarf of apparent magnitude 9 and is thus too dim to be seen with the unaided eye. However, at approximately 6 light-years away it is the second-closest stellar system to the Sun; only the Alpha Centauri system is known to be closer. Thus, even though