Whirlpool Galaxy: Messier 51
Messier 51: Whirlpool Galaxy M51a (left) and M51b (right) At 31 million light-years away, Messier 51 is actually two interacting galaxies. In this photo, M51a (the Whirlpool) is the larger spiral galaxy. The smaller companion, M51b, is classified as a dwarf galaxy and is seen at the end of one of the spiral arms of M51a. Before Copernicus and Galileo, people believed that Earth was the center of existence. The sun, the stars and planets revolved around us. After all, that is exactly how it appeared to be (with the exception of a few 'wanderer' planets and occasional passing of comets). With the advent of advanced mathematics and the birth of the telescope, humans made discoveries that led to many realizations; that Earth is not the center of our solar system. The Sun is not the center of our galaxy. Before we were aware of galaxies other than our own, the