Sunday, February 3, 2008

Aristarchus Sets the Sun in the Middle and Us in Motion

Living in a technology-driven society, we’ve become accustomed to thinking of linear progress in science, a movement from point A, which takes us to point B, then to point C, and so on. We don’t think that steps backward can ever occur. If this were the way knowledge actually was built, the model of a geocentric (or earth-centered) universe would have died during the second century B.C.E.

Far in advance of his peers, Aristarchus of Samos (ca. 310–230 B.C.E.) proposed that the earth is not at the center of the universe or the solar system, but that it orbits the sun while also rotating.

This theory sounds completely reasonable to our modern ears, but it did not sit well with the Greek philosophical establishment, nor with common sense. Why, one might ask, if the earth is orbiting the sun, and spinning on its axis do we not all go flying into space as we would if the earth were a large merry-go-round? Without a theory of gravity (which keeps everything stuck to the surface of the earth as it spins), there was no good answer to this valid question.

One philosopher, Cleanthes the Stoic, went so far as to declare that Aristarchus should be punished for impiety. Maybe if he had been punished, becoming a martyr to his idea, the heliocentric (sun-centered) solar system would have caught on much sooner than it did. But it didn’t. The geocentric model of Aristotle and others held sway for millennia.

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