Astronomy is the study of the stars. It is one of the oldest sciences. It is also one of the most complex and thrilling.
Ptolemy was a Greek philosopher who taught the geocentric theory. Geo means earth and centric means center. So what Ptolemy was teaching was that the earth was in the center of the universe and that the stars and the rest of the heavenly bodies were revolving around it. This was the lasting theory until another scientist called Nicolaus Copernicus changed it.
Nicolaus Copernicus (b.1473 d.1543) was a Prussian who invented his own theory to counteract Ptolemy’s. His theory was heliocentricity. Helio means sun and centric is center, as mentioned before. Thus it was the sun in the center of the universe instead of the earth. The Catholic Church didn’t like his theory.
Galileo Galilei was a one of the most famous astronomers, both of his time and ours. He improved the science of the stars by discovering Jupiter’s moons. By this he proved heliocentricity, showing that not all things revolved around the earth.
Johannes Kepler was a German astronomer who advanced this science by publishing a series of books on The Laws of Planetary Motion. He, along with a contemporary named Tycho Brahe, confirmed that the planets moved in oval orbits instead of perfect circles, as was the former belief.
Isaac Newton added to it by forming the Law of Gravitation, which solved the mystery of why the planets stayed in orbit. (more…)