- Nicolaus Copernicus (plato.standford.edu)
Nicolaus Copernicus (1473–1543) was a mathematician and astronomer who proposed that the sun was stationary in the center of the universe and the earth revolved around it. Disturbed by the failure of Ptolemy’s geocentric model of the universe to follow Aristotle’s requirement for the uniform circular motion of all celestial bodies. Copernicus decided that he could achieve his goal only through a heliocentric model. He thereby created a concept of a universe in which the distances of the planets from the sun bore a direct relationship to the size of their orbits. At the time Copernicus’s heliocentric idea was very controversial; nevertheless, it was the start of a change in the way the world was viewed, and Copernicus came to be seen as the initiator of what is commonly known as the Scientific Revolution.
- Messier 71 (Wikipedia)
Messier 71 (also known as M71, NGC 6838, or the Angelfish Cluster) is a globular cluster in the small northern constellation Sagitta. It was discovered by Philippe Loys de Chéseaux in 1745 and included by Charles Messier in his catalog of non-comet-like objects in 1780. It was also noted by Koehler at Dresden around 1775. Messier 71 is also known as NGC 6839 and The Bernardo Star, though this identification is very uncertain.
