At birth, the prostate gland is tiny. When testosterone levels rise during puberty, the prostate grows rapidly, doubling in size by age 20. Growth slows down for the next two decades and the prostate usually does not cause problems for many years. Less than 10% of 30-year-old men have an enlarged prostate.
Later scientists called Aristotle the Father of Natural Science because centuries after the ancient scholar's death, his methods formed the basis of the scientific method. Most people in Aristotleâs time believed the earth was flat, but he did not agree. The Greek thinker realized that a lunar eclipse occurred when the earth came between the sun and the moon. The shape of the earthâs shadow, Aristotle observed, was round. If the earth were flat, its shadow would have a much different form. Next, Aristotle considered the position of the North Star. The farther north you journeyed, the closer the North Star seemed to move to the middle of the sky.
The writers of Prentice Hall Earth Science say, on page 213: For thousands of years, most people thought that the earth was flat. But as early as 300 B.C., the ancient Greeks theorized that the earth was round. Yet they still drew maps of a flat earth. As people explored more of the world, they were able to map large areas of it. In 150 A.D., the famous Greek astronomer Ptolemy made maps that included Europe, Africa, and most of Asia.