Medieval Astronomy

A medieval astronomer is pictured in a book on various scientific topics published in Bavaria in the latter half of the 15th century. From the Crawford Collection, Royal Observatory, Edinburgh, http://www.roe.ac.uk/roe/library/crawford/

Key point: Why science largely "marked time" for 1000 years

After the fall of Rome (third to fifth centuries A. D.), much of Greek science was lost to Europe, being only maintained through the flowering of scientific inquiry in the Islamic world. Times were harsh, and scientific inquiry seemed an unaffordable luxury. The Catholic Church  was fighting for its existence and to spread its views, and "pagan" inheritances such as Greek science were scorned.

By the twelfth century, the Church had achieved preeminence and Europe had also become much more prosperous. Scientific thought began to stir, and logically it began where the Greeks had left off.

Aristotle was a pupil in Plato's Academy, then became the tutor of Alexander the Great (when your father is the most powerful king in the world, you can get the best). Although Greek scientists generally wrote about their ideas, Aristotle was particularly influential because he wrote extensive summaries. His writings were sort of an opinionated encyclopedia of Greek physics and astronomy. However, he was a truly great biological scientist, and his writings on that area contained much fundamental science. Portrait of Aristotle, a Roman copy of an original from about 330 B. C., possibly by Lysippos, Alexander the Great's court sculptor. From "Art and Experience in Classical Greece," J. J. Pollitt

Aristotle had such a central role in medieval thought that he was featured in many Renaissance paintings. To the right are Plato and Aristotle, central figures in Rafael's "School of Athens," painted in 1510-11, and to the far right is Rembrandt's "Aristotle Contemplating the Bust of Homer" painted in 1653.  (from http://www.christusrex.org/www1/stanzas/S2-Segnatura.html, and http://www.artchive.com/artchive/R/rembrandt/aristotl.jpg.html)

Aristotle's physics and astronomy were stultifying because he tended to favor explanations that were overly qualitative and "to the point" without abstractions that would allow generalizing the theory and making predictions that could be tested.  

Thus, Aristotle's image of concentric crystalline spheres, and not the Bible's flat domed earth, was the basic form of the universe. The planets still bore the names of the Ancient Roman gods Mercury, Venus, Mars, Jupiter, and Saturn.  Immediately outside the sphere of the fixed stars lay Heaven. God was physically right out there, just beyond the picture of the universe handed down from ancient Greece and Rome. The picture also provided a convenient place to hide Hell, down within and below the earth.

From Dante's (1265-1321) "The Divine Comedy,"from H. & A. Mathai, UN/ESA http://www.seas.columbia.edu/~ah297/un-esa/universe/universe-chapter2.html)

Thus on a clear night in Medieval Europe, a person looking up into the sky would have imagined huge, transparent spheres nested inside each other, encircling the center of the universe, the earth. (painting by Bosch, http://www.ibiblio.org/wm/paint/auth/bosch/delight/) Thomas Aquinas, a prominent 13th century theologian and philosopher blended the Aristotelian and Ptolemaic systems into Christianity -- an earth-centered universe meshed well with the concept of man as God's ultimate creation. Once astronomy had been merged into the doctrines of the Church in this way, astronomical progress became even more difficult because it affected larger questions.

Nonetheless, during the late Medieval period (14th and 15th centuries), many critical issues were raised and improvements suggested. These advances were often in the form of critical commentaries on works of Aristotle; if the commentary ended by saying Aristotle was correct, there seemed to be little controversy, no matter what else had been said along the way!. These critiques sowed the intellectual seeds that would grow and flower during the Renaissance, starting with Copernicus.

Test your understanding before going on

Ptolemy's model, with a central Earth orbited  by planets and the sun, and with the stars on a more distant sphere. (from http://www.uscarom.org/billiard_ball_universe.html)		Case for Copernicus' working copy of his book on the solar system http://www.bj.uj.edu.pl/bjmanus/revol/titlpg_e.html
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