Before Ferdinand Magellan proved Earth was round by sailing west from Europe to the Philippines in the east, the shape of our home planet was one of mankind's greatest mysteries. Early civilizations had extraordinary ideas about Earth's profile -- ideas based mostly on myth. As centuries passed, certain individuals endeavored to replace these ideas with conclusions based on observation and reason. And while these conclusions weren't always correct, they contributed to a deeper understanding of our world.
The ancient Greeks possessed some of the best scientific minds of their time. With pioneers such as Pythagoras and Aristotle in their dynasty of geniuses, theirs was a culture that used only their eyes and intellect to recognize Earth's round shape. Ardent travelers, they observed the North Star lower in the night sky in southern Egypt than they did in northern Greece. They noticed that when ships approached the mainland, the first part to appear above the horizon was the sail. But their most compelling evidence came from the moon. During lunar eclipses, they saw a rounded shadow cast upon the surface of the full moon. Each of these phenomena is proof of a round Earth, but millennia would pass before this became common knowledge.
When science was a new and controversial area, political and religious leaders upheld the belief that Earth was flat and at the center of the universe. Those who said otherwise were often persecuted and, in some cases, killed. But brilliant thinkers persisted, and, eventually, science prevailed.
We know now where our ancestors had it wrong. Earth is not Frisbee-flat. And while we call it "the globe," it is not a true sphere. It's actually an oblate spheroid, a ball-like figure with slightly flattened surfaces at its north and south poles. Today, astrophysicists are revisiting the round versus flat debate but with a new topic: the shape of our universe.science - bookclub
First Published April 5, 2012 9:30 AM