One..if he's Copernicus. When Copernicus was born in 1473, the world was still flat, and the sun and planets revolved around the Earth -- at least that was the thinking among the European elite. The idea of geocentric universe, that is, with Earth at the center, was a popular one dating to the second century, when Ptolemy devised an elaborate model of the universe. Ptolemy's arrangement started with a stationary Earth at the center, with the moon, Mercury, Venus, the sun, Mars, Jupiter and Saturn revolving around our planet in that order.
Copernicus changed all that for good. Noting that his observations of the heavens could not always be explained by Ptolemy's model, Copernicus rearranged the universe. The sun must be at the center, he deduced, followed by Mercury, Venus, Earth and it's moon, Mars, Jupiter, and Saturn. (You know the old planetary memory aid: "My very enterprising mother just served us nine pizzas." Of course, Copernicus didn't know about the nine pizzas at that time. After all, Pizza Huts were rare, and telescopes weren't so advanced.)
Copernicus didn't live to see the results of his labor. His earth-moving manuscript was published in 1543, the year be died. Lucky for him, he wasn't around to see that his theory was declared erroneous, if not downright heretical, by the Roman Inquisition.
The consequences of Copernicus. theory were many:
- He expanded the size of the universe. For his model to work, the stars would have to be much farther away than previously thought. Otherwise, they would not appear to retain their fixed position relative to each other.
- He determined, for the first time in history, the relative distances of Earth and planets from the sun.
