This week's entry takes a look at the three minds who advanced the science of astronomy and challenged the norms of the day. This countdown isn't so much about ranking on a scale, but simply listing them. I found it difficult separating the three I list today because they all worked off of each other.
Nicolaus Copernicus, Galileo Galilei, Johannes Kepler
Astronomers, Physicists, Mathematicians
Copernicus was the first astronomer to openly challenge the idea of the geocentric universe. His ideas would be the creation of heliocentric cosmology and is often credited with being the starting point for modern astronomy. Before Copernicus, Ptolemy's geocentric model, which has earth in the center with the sun, moon, planets and stars on spheres which surrounded the earth, was widely accepted as truth. Copernicus' work would result in much controversy long after his death.
Galileo is credited with improving the telescope (invented by Hans Lippershey) and giving it better optical power. With this telescope, he observed and discovered four of Jupiter's moons (Io, Europa, Callisto and Ganymede), which he named after his future patron and his (patron's) three brothers. They would be renamed the Galilean Satellites in honor of the man himself. His Copernican beliefs would eventually land him under house arrest by the church of the time. (If you would like, I will go further into the astronomical [and astrological] belief system of the day and why many astronomers were arrested by the Church. I do not feel that this series is the place to discuss religious and political views of the 17th century. Let me know in your comments.)
Kepler was a German mathematician and astronomer who challenged Galileo's assertion that planetary orbits were perfect circles. He did help to verify Galileo's discoveries with an improved refracting telescope. Kepler noticed that it was impossible for planetary orbits to be round because of anomolies in their orbits. At first, under the eye of Tycho Brahe, he reasoned that Mars' orbit was egg-shaped (with the sun at the center), but all calculations failed. Then he tried to calculate it as an ellipse, and it worked. This results in planetary aphelion (furthest distance from the sun) and perihelion (closest distance to the sun).
I admit that I glossed over much of the story here, but I have mentioned the biggest and most prolific discoveries of each astronomer. All of these men, and others not mentioned are important to next week's entry in the countdown. Thanks for stopping by, I hope you're still interested in learning.