Anaxagoras moved to Athens around 480BC, introducing the residents to philosophy and the new idea of science. There he became friends with Pericles, who developed democracy and lead Athens to become an empire.
A New Theory of the Earth, Moon and SunAnaxagoras developed a theory that the moon shines because of reflected light from the "red-hot stone" (the sun). Using this theory, he further explained that Lunar eclipses were caused by the shadow of the Earth. As advanced as this thinking was, it caused Anaxagoras trouble when enemies of his friend, Pericles, had him imprisoned for claiming that the sun was not a god. Anaxagoras also applied geometry to the study of astronomy.
Big Bang & Intelligent DesignAnaxagoras had an advanced view of matter as well, theorizing an infinite number of elements, or basic building blocks. Developing one of the earliest "Big Bang" type theories, he suggested that initially "all things were together" and matter was some homogeneous mixture. Combining science with a theory of "intelligent design," he stated that "nous" ("mind" or "reason") set up a vortex in this mixture which "began in the centre and then gradually spread, taking in wider and wider circles. The first effect was to separate two great masses, one consisting of the rare, hot, dry, called the 'aether,' the other of the opposite categories and called 'air.'
"The aether took the outer, the air the inner place. From the air were next separated clouds, water, earth and stones. The dense, the moist, the dark and cold, and all the heaviest things, collected in the centre as a result of the circular motion, and it was from these elements when consolidated that the earth was formed; but after this, in consequence of the violence of the whirling motion, the surrounding fiery aether tore stones away from the earth and kindled them into stars."
A Remarkable LifePericles saved his friend from prison, but Anaxagoras was exiled from Athens. Returning to Ionia, he began a school at Lampsacus.
One apocryphal story about Anaxagoras relates that when he was asked the meaning of life he replied, "The investigation of sun, moon, and heaven."
Anaxagoras died in Lampsacus, Mysia (now Turkey) 428 BC. The anniversary of his death became a holiday for schoolchildren.