What is Johannes Kepler?
{{Infobox scientist | name = Johannes Kepler | image = JKepler.jpg | caption = Portrait of Kepler, 1620 | birth_date = December 27, 1571 | birth_place = [[Weil der Stadt|Free Imperial City of Weil der Stadt]], [[Holy Roman Empire]] | death_date = {{Death date and age|mf=yes|1630|11|15|1571|12|27}} | death_place = [[Regensburg|Free Imperial City of Regensburg]], Holy Roman Empire | field = [[Astronomy]], [[astrology]], [[mathematics]] and [[natural philosophy]] | work_institutions = | nationality = German | alma_mater = [[Tübinger Stift]], [[University of Tübingen]] | doctoral_advisor = [[Michael Maestlin]] | known_for = [[Kepler's laws of planetary motion]]<br />[[Kepler conjecture]]<br />''[[Rudolphine Tables]]'' | prizes = | influences = [[Nicolaus Copernicus]]<br />[[Tycho Brahe]] | influenced = [[Sir Isaac Newton]] | signature = Unterschrift Kepler.svg | footnotes = }} [[File:Brahe kepler.jpg|thumb|220px|Monument of Tycho Brahe and Johannes Kepler in [[Prague]]]] '''Johannes Kepler''' (27 December 1571 – 15 November 1630) was a [[Germany|German]] [[mathematics]] teacher, [[astronomer]], [[optician]], [[natural philosophy|natural philosopher]], [[astrologer]] and [[Lutheranism|Lutheran]] [[theologian]]. He was [[Tycho Brahe]]'s [[apprenticeship|apprentice]]. Tycho Brahe looked at the way the [[planet]]s moved in the sky. Johannes Kepler found a simple way to say how the planets move. Kepler also studied other things like [[SN 1604|Kepler's supernova]]. == How the planets move == A planet moves along a path called an [[orbit]]. Kepler used three laws to say what form the path has and how fast the planet moves # Kepler's first law says that the form of the path is an [[ellipse]], an oval or flattened circle that has two [[focus|centers]]. The Sun is in one of the centers of the ellipse. Before Kepler, astronomers thought that planets moved in circles within circles (epicycles) according to the system of [[Claudius Ptolemy]] with Earth at the middle of the biggest circle/s. # Kepler's second law says how fast