Johannes Kepler was born on the 27th of December, 1571 in Swabia, a south-westerly area of Germany and died on 15th of November, 1630. He was not always so talented, he was a slow learner and it was only when he studied in Austria that his abilities were truly discovered. He was a mathematician as well as an astronomer and astrologer (although there was no difference between the two professions then as there is now) and he was famous when he was younger for predicting events with amazing accuracy through horoscopes. His most famous was to predict a cold winter with Turkish attacks, it turned out to be true and it boosted his standing in the scientific circles. Although he is most famously known for his 3 laws of planetary motion, Kepler actually worked in optics. He managed to improve the refraction of the telescope to give a clearer, sharper picture; this type of telescope is now called the Keplerian telescope. The first 2 of his planetary laws were published in 1609; he discovered them by studying and analysing Tycho Brahe’s work after he had died in Prague and fitting in both his and Brahe’s data with Copernicus’s. He did not discover his third law until 10 years later in 1619. Kepler’s laws were instrumental for Isaac Newton as well, because Kepler’s laws would only work with the certain conditions, the ones Newton had proposed – the laws of motion and the laws of universal gravitation.
Kepler’s first law is that all planets orbit in an ellipse, around 1 of 2 different foci (a point describing a conic section, one is the sun the other is hypothetical).
Kepler’s second law is that the area of the orbit is equal during periods of equal time.
Kepler’s third law is that the square of the time period of a whole orbit is always proportional to the cube of the semi – major axis in its orbit.
Kepler’s laws were not actually originally his; they were a development of Nicholas Copernicus’s laws, a man who he had always publicly defended throughout his life. Copernicus was a Polish clergyman and he was the first person to believe that the earth was not the centre of the solar system and it made more sense that the earth orbits the sun. People were very resentful of this at first, especially the church who had always said otherwise but Copernicus’s laws were gradually accepted. People like Galileo and Kepler then refined and built upon the laws as they were not entirely correct.
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