Famous German astronomer, born in Weil der Stadt, town near Stuttgart, December 27, 1571 and died in Regensburg in November 15, 1630, which enunciated the laws describing the motion of the planets.
Son of a mercenary, Kepler led an unhappy life, marked in his youth by physical illnesses - an unfortunate smallpox irreversibly weakened its view and semiparalizo your hands - and misfortunes family and personal of all kinds, among others to see his mother, who although he/she could save from the bonfire, remained in prison convicted of witchcraft's lifetime. He/She studied University of astronomy in Tübingen, where he/she was master of the Copernican fervent Mostlin. In 1591 he/she began theological studies, intending to order priest, but three years later was offered a position of Professor of mathematics in the Protestant seminar of the Austrian town of Graz and left an ecclesiastical career. Tasks that in Graz was the obligation to collect horoscopes and elaborate the relevant calendar. About astrology, which did not believe but that, however, many times in the course of his life helped her survive, he/she wrote, with bitterness, "philosophers not should criticize so harshly the daughter of astronomy, because it is he/she who nourishes her mother".
In 1596 he/she published Mysterium Cosmographicum, his first work, which embraces undoubtedly the Copernican system, probably more for metaphysical reasons - the Sun, image of God, should be the still Center of system - than physical, and that attempts to relate the periods and the distances of the planets, and thus describe the orbits of the planets as polyhedral figures (cube(, tetrahedron, octahedron, dodecahedron and icosahedron, the so-called five regular platonic bodies) through mechanical reasoning, error which, despite everything, is one of the first attempts to explain the movement of the planets using purely physical causes. Towards 1600 Kepler was victim of the religious persecution of the Protestants and lost his teaching position. Tycho Brahe, who had read the work of Kepler and had favorably impressed him, welcomed him in Prague as an Assistant. Shortly afterwards, a calculation of the results of the theory of Kepler on the orbit of Mars, the master showed Assistant wrong in your assumptions.
Brahe died in 1601, commissioned Kepler who published the results of their measurements of planetary orbits, the famous Tabulae Rudolphinae, result of twenty years of patient observations without the help of telescope that the Assistant he/she published finally in 1627, and that meant a thorough check of the truth of the Copernican system instead of his rebuttal, as its author intended. With the death of Brahe, Kepler also inherited the post of mathematician in the Court of the Emperor Rodolfo II.
In 1604, Kepler published Ad Vitellionem paralipomena, quibus astronomiae pars optica traditur, work in which, among other things, explained the effect of the air on the astronomical refraction, argued about the lunar eclipses and calculated the frequency of passages of mercury and Venus on the Sun disk.
The provision of comprehensive measurements of Brahe Kepler allowed edit in 1609 astronomy Nova, foundational book in the history of Western science, which noted that the difference of about eight minutes of arc existing between the data collected on the motion of Mars and the forecasts of the Copernican theory can be solved if it is assumed that the planets along its own orbit to a non-constant speed. The consequence is the second law of Kepler, called law of areas: "the areas traversed by the radius vector are proportional to times employees to go through them," or, put another way: the straight line which connects any planet with the Sun sweeps equal areas in equal times. As a non-constant speed is acceptable only if the orbits are not circular, it is necessary to then assume the first law: "planets are elliptical orbits that the Sun occupies one of the foci". It should be noted that the movement of the planets is set, in the foreword to this work, as a mere balance of power between central and tangential thrusts of the Sun.
Both laws were discovered in interdependent way around 1605, and various delays postponed its publication until 1609. They are also with clarifications in another work of Kepler, Epitome Astronomiae Copernicae, written between 1618 and 1621.
His first wife, who was suffering from psychiatric problems severe, as one of his five children (his second wife, that had other seven offspring, died also before him, as well as all his children) both died in 1611. That same year a civil war that deposed his protector Rodolfo II of Habsburg, who died a year later broke out. His successor, Matías I, more bellicose promoter of Catholicism as its predecessor, showed by the astronomer interest that is say, the pecuniary compensation - seeking this, so Kepler moved to Linz as Professor at the Regional School, with the custom made extra of the measurement of the district. There he/she published in 1619 Harmonices Mundi, work in which appears the so-called third law of Kepler, which points out that "the revolution times square are proportional to higher orbits shafts hubs". To find this developed all kinds of relationships between the inherited Brahe measures, including Pythagorean harmonic relationships (believed in the so-called music of the spheres). All the work is impregnated with theological, mystical and poetic considerations.
After this work turned in the preparation of tables rodolfinas, so called in memory of who was her protector. However, the pressing economic problems that he/she suffered during his life and persecution suffered by their religious ideas made him take refuge in several German and Austrian cities, and it was in Ulm where in 1627 he/she published finally commissioned inherited by Brahe. These tables, which would have been a tedious enunciation of data, without the addition of Kepler's laws were the essential tool that did advance astronomy several orders of magnitude, and the more accurate tables allowing to infer the position of the planets until the middle of the s. XVIII. It should be noted, finally, that they were only Cookware that used Newton to deduce, through a series of data treatment, the law of gravity.
Kepler died when he/she was not yet at the age of sixty in Regensburg, during a trip undertaken to try and obtain certain amounts of money they owed him.