Nicolaus Copernicus via Wikipedia

February 19, 1473. Nicolaus Copernicus was born on this date, 540 years ago. Copernicus was a Renaissance astronomer and mathematician. He lived at a time when people believed Earth lay enclosed within crystal spheres at the center of the universe. Can you picture the leap of imagination required for him to conceive of a sun-centered universe? The publication of Copernicus’ book – De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres) – just before his death in 1543, set the stage for all of modern astronomy. Today, people speak of his work as the Copernican Revolution.

If you search on the word “Google” today (February 19, 2013), you’ll find an animated version of a Google Doodle celebrating Copernicus’ 540th birthday. Google uses Google Doodles to showcase holidays, famous birthdays and so on. See the video below, which also features the Copernicus Google Doodle. Thank you to EarthSky Facebook friend Kausor Khan in Hyderabad, India for pointing it out to us.

By the way, Copernicus wasn’t the first to conceive of a sun-centered universe. Early Greek philosophers also spoke of it. It was the Greek philosopher Aristotle, however, who proposed that the heavens were literally composed of 55 concentric, crystalline spheres to which the celestial objects were attached. In Aristole’s model, Earth lay at the center of these spheres. Thus Earth lay – fixed and enclosed – until Copernicus published his version of a heliocentric universe.

Earth-centered model of the universe via Aristotle. In the medieval world, people thought Earth lay enclosed within crystal spheres. Read more about Artistotle’s model of the universe here.

Read more about Copernicus on Wikipedia. He was a cool guy.

Bottom line: Nicolaus Copernicus was born on this date, February 19, 1473. A new Google Doodle celebrates Copernicus’ model of a sun-centered universe.

This Renaissance woodcut is called Empedocles Breaks through the Crystal Spheres.