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Johannes Kepler


Johannes Kepler He was born on December 27, 1571 in southern Germany, which at that time belonged to the Holy Roman Empire, in a town called Weil der Stadt, Swabian region. He was the son of Heinrich Kepler, a soldier, and his wife Katharina, whose maiden name was Guldenmann. His paternal grandfather, Sebald Kepler, was mayor of the city, despite being Protestant (Lutheran) in a Catholic city. This was the time of the Renaissance and the Protestant Reformation.

Because of his fragile body and the poor financial conditions of his family, he was sent to the seminary for his studies. In September 1588 Kepler passed the entrance exam (baccalaureate) from the University of Tübingen, but began his studies there on September 17, 1589, where he studied theology at the Stift seminary. On August 10, 1591, he passed his master's degree, completing two years of study in the arts, which included Greek, Hebrew, astronomy and physics. He began his studies of theology, studying Greek with Martin Crusius, mathematics and astronomy with Michael Maestlin, learning from them about Copernicus, although his master defended the geocentric model of Ptolemy's Almagest. Before completing his studies, Kepler was invited to teach mathematics at the Protestant Seminary (Stiftsschule) of Graz, Austria, where he arrived on April 11, 1594. His work, besides teaching mathematics, which connected with astronomy, also included the district mathematician and calendarist position. Note that at that time, the calendar should predict the weather, saying the best date for planting and harvesting, predicting wars and epidemics and even political events. Kepler did the calendars because it was his obligation, but you had serious restrictions on their veracity, saying, for example, "The heavens cannot do much damage to the strongest of two enemies, nor help the weaker... . " What's more, Kepler used calendars to instigate care, disguised as prognostic, to prevent disease.

In early 1597, Kepler publishes his first book, Prodromus disserationum cosmographicarum continens mysterium cosmographicum of admirabili proportione orbium celestium dequeus coelorum numeri, magnitudinis, motuumque periodicorum genuinis propiis, demonstratum per quinque regular corpora geometrica, whose abbreviated title is Mystery Mysterium of the Universe). In this book he defended Copernicus's heliocentrism, and proposed that the size of each planetary orbit is established by a geometric solid (polyhedron) circumscribed to the previous orbit. This mathematical model could predict the relative sizes of the orbits. Kepler sent a copy to Tycho Brahe, who replied that there were differences between the model's predictions and its measurements. A copy sent to Galileo, eight years older than Kepler, had him send a short letter to Kepler thanking him but saying he had not read it, and saying that he believed in Copernicus's theory.

In September 1598, the Archduke of Austria, Prince Ferdinando of Habsburg, leader of the Catholic Counter-Reformation, closed the school and Protestant church in Graz, and ordered all teachers and priests to leave the city immediately. Kepler was allowed to return to the city as a district mathematician, where he remained until August 1600, when he was definitively expelled from the city for refusing to convert to Catholicism.

In June 1599 Emperor Rudolph II of Bohemia hired Tycho Brahe as court mathematician in Prague. In January 1600 Kepler, then 28, visited him at Benatky Castle, which the emperor had made available to Tycho. Kepler knew that only Tycho Brahe's data could resolve the differences between models and observations. Tycho did not believe the Copernicus model for theological reasons, but also because he believed it was possible to measure the parallax of the stars, which the Copernicus model assumed at infinite distance. The parallax of the stars was not measured until 1838 for the first time by Friedrich Wilhelm Bessel. Kepler had already observed eclipses and even the stars, trying to measure parallax, but his instruments were very rude, and his eyesight very poor.

On October 19, 1600, Kepler, abandoned by his former masters for his convictions in Copernicus's heliocentric theory, and also for his Calvinistic tendencies, not accepting dogma unconditionally, began working for Tycho Brahe in Prague. In September 1601 Kepler returned to Prague after a visit to Graz to settle his father-in-law's inheritance, and Tycho had already installed his instruments, which had been brought from Hveen. Tycho introduced him to the emperor, who hired him as Brahe's assistant. Soon after, on October 24, 1601, Brahe died. Two days later the emperor named Kepler imperial imperial mathematician, succeeding Brahe in the task of calculating the Rudolfine Tables, with the prediction of the positions of the planets.

Kepler immediately began work on calculating the orbit of Mars, and in 1602 discovered the Law of Areas, but could not look at the shape of the orbit. If the orbit were circular, 3 observations would suffice, as 3 points define a circle. The points should be observed in opposition, since in opposition it is irrelevant whether it is the earth or the sun that moves, as the three bodies are aligned. Tycho had observed 10 oppositions of Mars between 1580 and 1600, to which Kepler later added those of 1602 and 1604. Of course any set of 3 observations should result in the same orbit. Since Mars is the most eccentric outer planet, then known, a circle did not look at the observations. Even introducing an equator Kepler could not look at the observations with error less than 8 ', while the accuracy of Tycho's observations were in the order of 1'.

In 1605 Kepler discovered that the orbit was elliptical, with the sun in one of the foci. These results were published in the Astronomia Nova in 1609. In 1604 Kepler completed Astronomiae pars Optica (Ad Vitellionen Paralipomena, Quibur Astronomiae Pars Optica traditur), considered the fundamental book of optics, where he explained the formation of the image in the human eye, explained how It works an obscure chamber, discovered an approximation to the law of refraction, studied the size of celestial objects and eclipses. On October 17, 1604 Kepler observed the new star (supernova) in the constellation Ophiucus, near Saturn, Jupiter, and Mars, which were nearby, in conjunction.

The star competed with Jupiter in brightness. Kepler immediately published a small paper on her, but two years later published a treatise describing the gradual decay of luminosity, color, and considerations of the distance that placed her along with the other stars. In 1610 Kepler read the book of Galileo's discoveries using the telescope, and wrote a long supporting letter published as Dissertatio cum Nuncio Sidereo (Conversation with the Sidereal Messenger). In August 1610 he used a telescope given by Galileo to the Duke of Bavaria, Ernst de Cologne, to observe Jupiter's satellites, publishing Narratio de Observatis Quatuor Jovis Satellitibus (Jupiter's Observation of the Four Satellites). These treaties gave great support to Galileo, whose findings were denied by many. Both works were republished in Florence. Kepler also studied the laws governing the passage of light through lenses and lens systems, including magnification and image reduction, and how two convex lenses can make larger and more distinct, though inverted, objects, the principle of the astronomical telescope. He also studied Galileo's telescope, with a converging lens as an objective and a diverging lens as an eyepiece. These studies were published in the Dioptrice in 1611.

In 1612, with the death of Emperor Rudolph II, who had abdicated on May 23, 1611, Kepler accepted the position of mathematician and teacher at the district college in Linz. There published the first work on the chronology and the year of the birth of Jesus, in German in 1613 and, expanded, in Latin in 1614: Of summer Anno, that aeternus Dei Filius humanam in Utero benedictae Virginis Mariae assumepsit (About the True Year in which the Son of God assumed human nature in the womb of the Holy Virgin Mary). In this paper Kepler demonstrated that the Christian calendar was in error for five years, since Jesus was born in 4 BC, a currently accepted conclusion. The argument is that in 532 AD Abbot Dionysius Exigus assumed that Christ was born in the year 754 of the city of Rome, corresponding to the year 46 of the Julian calendar, defining it as year one of the Christian era. However, several historians have claimed that King Herod, who died after the birth of Christ, died in the 42nd year of the Julian calendar. Thus the birth had occurred on 41 of the Julian calendar.

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Between 1617 and 1621 Kepler published the 7 volumes of the Epitome Astronomiae Copernicanae (Compendium of Copernican Astronomy), which became the most important introduction to heliocentric astronomy, and a widely used textbook. The first part of the Epitome, published in 1617, was placed in the Index of Books Forbidden by the Catholic Church on May 10, 1619. The Catholic Church's prohibition of works on the heliocentric model began because Galileo wrote his book Siderius. Nuncius (Heavenly Message) in 1610, arousing the interest of the people. The reason for the prohibition was that in the Old Testament Psalm 104: 5 of the Bible, it is written, "God has laid the earth upon its foundations, that it may never move."

In 1619 Kepler published Harmonices Mundi (Harmony of the World), in which he derived that the heliocentric distances of the planets and their periods are related by the Third Law, which states that the square of the period is proportional to the cube of the average distance from the planet to the sun. The law was discovered by Kepler on May 15, 1618.

Pursuits
In 1615-16 there was a witch hunt in his native region, and he defended his mother in a case in which she was accused of witchcraft. The lawsuit lasted until 1920 when it was released. The year 1618 marked the beginning of the Thirty Years' War between the Protestant Reformists and the Catholic Counter Reformation, which devastated the region of Germany and Austria. Kepler's position worsened as the Catholic Counter Reformation increased the pressure on Protestants in Upper Austria, of which Linz was the capital. Since Kepler was a court official, he is exempt from the decree banning all Protestants in the province.

At this time Kepler was printing the Tabulae Rudolphinae based on Tycho Brahe's observations and calculated according to his elliptical orbits. These tables included the position of the planets and eclipse calculations. When a rebellion occurred and Linz was taken, the print shop was burned, and with it much of the print edition. Kepler and his family left Linz in 1626. His family stayed in Regensburg while he moved to Ulm to print the Tabulae Rudolphinae, finally published in 1627. These tables proved to be accurate for a long time, bringing general acceptance to the heliocentric system.

Although Kepler's name is linked to astrology, he says: "My celestial bodies were not the birth of Mercury in the seventh house square Mars, but Copernicus and Tycho Brahe; without their observations, all I could bring to light would be buried in darkness. "

Kepler then joined his family in Regensburg, but moved to Sagan in July 1928 as a mathematician of the Emperor and Duke of Friedland. On one trip, he was stricken with an acute illness in Regensburg, Germany, where he died on November 15, 1630.

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