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[[Image:Gfdse5y465.jpg|right|thumb|Johannes Kepler]]

[[Image:Gfdse5y465.jpg|right|thumb|Johannes Kepler]]

'''Johannes Kepler''' (December 27, 1571-November 15, 1630)<ref name=dao>Dao, Christine. "[http://www.icr.org/article/3751/ Man of Science, Man of God: Johann Kepler]." Institute for Creation Research. Accessed March 2, 2008.</ref>, a [[Protestantism|Protestant]] in [[Germany]], was a brilliant mathematician, astronomer, astrologer,<ref>http://www.skyscript.co.uk/kepler.html</ref> and devout [[Christian]] who cited God many times in all of his writings.  He felt it was his Christian duty to understand the creation of [[God]] and the universe, and that God had used a mathematical plan for the universe's design.<ref name=dao/> He also felt that man, being in the image of God, was fully capable of understanding the universe.  Like [[Plato]] and [[Pythagoras]], Kepler felt that God must have created the universe according to a mathematical plan (see [[Cause of the universe]]).

'''Johannes Kepler''' (December 27, 1571 – November 15, 1630),<ref name=dao>Dao, Christine. "[http://www.icr.org/article/3751/ Man of Science, Man of God: Johann Kepler]." Institute for Creation Research. Accessed March 2, 2008.</ref> a [[Protestantism|Protestant]] in [[Germany]], was a brilliant mathematician, astronomer, astrologer,<ref>http://www.skyscript.co.uk/kepler.html</ref> and devout [[Christian]] who cited God many times in all of his writings.  He felt it was his Christian duty to understand the creation of [[God]] and the universe, and that God had used a mathematical plan for the universe's design.<ref name=dao/> He also felt that man, being in the image of God, was fully capable of understanding the universe.  Like [[Plato]] and [[Pythagoras]], Kepler felt that God must have created the universe according to a mathematical plan (see [[Cause of the universe]]).

== Life and career ==

== Life and career ==

Scientists of that time were often opinionated and prone to risk-taking in their theories, and Kepler was no exception. He sacrificed his religious reputation by questioning the "science" of the time, which later forced him to be cut off from orthodox [[Lutheranism]]. Although the loss was great, Kepler was able to become a mathematician and teacher in Graz, [[Austria]], in 1594.<ref name=dao/><ref name=rice/> While at Graz, Kepler wrote his famous ''Mysterium Cosmographicum'', the first forthright and public defense of Copernican [[heliocentrism]].<ref name=nasa/>

Scientists of that time were often opinionated and prone to risk-taking in their theories, and Kepler was no exception. He sacrificed his religious reputation by questioning the "science" of the time, which later forced him to be cut off from orthodox [[Lutheranism]]. Although the loss was great, Kepler was able to become a mathematician and teacher in Graz, [[Austria]], in 1594.<ref name=dao/><ref name=rice/> While at Graz, Kepler wrote his famous ''Mysterium Cosmographicum'', the first forthright and public defense of Copernican [[heliocentrism]].<ref name=nasa/>

In 1600, Kepler left his job at Graz on account of the [[Counter Reformation]]. Unwilling either to convert to Catholicism or to sign the Lutheran Formula of Concord, he decided to leave Graz and travel to Prague.<ref name=nasa/><ref name=rice/> There he became the assistant to [[Tycho Brahe]], court mathematician to Emperor Rudolf II.<ref name=dao/>. Tycho was also making observations on the orbit of the planets. In 1601, Tycho died, and Kepler was named Imperial Mathematician in his place,<ref name=nasa/> the highest ranking in Europe at the time.<ref name=rice/> After reading and studying the data that Tycho had developed and researched, Kepler was able to resolve a nagging problem concerning the motion of [[Mars]], and in particular its apparent [[retrograde motion]] in relation to the [[Earth]]. Kepler went on to calculate Mars' orbit--as an [[ellipse]], not a [[circle]].

In 1600, Kepler left his job at Graz on account of the [[Counter Reformation]]. Unwilling either to convert to Catholicism or to sign the Lutheran Formula of Concord, he decided to leave Graz and travel to Prague.<ref name=rice/><ref name=nasa/> There he became the assistant to [[Tycho Brahe]], court mathematician to Emperor Rudolf II.<ref name=dao/> Tycho was also making observations on the orbit of the planets. In 1601, Tycho died, and Kepler was named Imperial Mathematician in his place,<ref name=nasa/> the highest ranking in Europe at the time.<ref name=rice/> After reading and studying the data that Tycho had developed and researched, Kepler was able to resolve a nagging problem concerning the motion of [[Mars]], and in particular its apparent [[retrograde motion]] in relation to the [[Earth]]. Kepler went on to calculate Mars' orbit—as an [[ellipse]], not a [[circle]].

Kepler remained as Imperial Mathematician until 1612, when Rudolf II was deposed.<ref name=rice/> In the next year (1613) he accepted a teaching position in Linz, the last semi-permanent position he ever held. He held this job until 1626, when the pressures of the [[Thirty Years' War]] forced him to leave. Now out of a job and with no salary, he tried in vain to seek employment and to sue for back payment of his salary as Imperial Mathematician.<ref name=rice/> He died in 1630, at Regensburg.<ref name=rice/><ref name=nasa/>

Kepler remained as Imperial Mathematician until 1612, when Rudolf II was deposed.<ref name=rice/> In the next year (1613) he accepted a teaching position in Linz, the last semi-permanent position he ever held. He held this job until 1626, when the pressures of the [[Thirty Years' War]] forced him to leave. Now out of a job and with no salary, he tried in vain to seek employment and to sue for back payment of his salary as Imperial Mathematician.<ref name=rice/> He died in 1630, at Regensburg.<ref name=rice/><ref name=nasa/>

Kepler compared the celestial orbits of the planets with polyphonic harmonies in music. He wrote:{{cquote|Holy Father, keep us safe in the concord of our love for one another, that we may be one just as Thou art with Thy Son, Our Lord, and with the Holy Ghost, and just as through the sweetest bonds of harmonies Thou hast made all Thy works one; and that from the bringing of Thy people into concord, the body of Thy Church may be built up in the Earth, as Thou didst erect the heavens themselves out of harmonies.}}

Kepler compared the celestial orbits of the planets with polyphonic harmonies in music. He wrote:{{cquote|Holy Father, keep us safe in the concord of our love for one another, that we may be one just as Thou art with Thy Son, Our Lord, and with the Holy Ghost, and just as through the sweetest bonds of harmonies Thou hast made all Thy works one; and that from the bringing of Thy people into concord, the body of Thy Church may be built up in the Earth, as Thou didst erect the heavens themselves out of harmonies.}}

==External Links==

==External links==

*[http://www.relativitycalculator.com/Kepler_1st_Law.shtml Johannes Kepler empiricism and mathematics provided the basis for Newton's laws of motion and gravity]

*[http://www.relativitycalculator.com/Kepler_1st_Law.shtml Johannes Kepler empiricism and mathematics provided the basis for Newton's laws of motion and gravity]

*[https://www.relativitycalculator.com/Kepler_2nd_Law.shtml Kepler's 2nd Law ( Equal Areas in Equal Times: Variable - speed model )]

*[https://www.relativitycalculator.com/Kepler_2nd_Law.shtml Kepler's 2nd Law ( Equal Areas in Equal Times: Variable - speed model )]

[[Category:Astronomers|Kepler, Johannes]]

[[Category:Astronomers|Kepler, Johannes]]

[[Category:Lutherans]]

[[Category:Lutherans]]

[[Category:mathematicians|Kepler, Johannes]]

[[Category:Mathematicians|Kepler, Johannes]]