Nguyen Tan Hung, Hien V. Ho
From Europe to Đại Việt
         On 01-15-2009, UNESCO inaugurated The International Year of Astronomy in Paris to commemorate the 400th anniversary of the day Italian scientist Galileo Galilei (1564-1642) used a telescope to study the universe for the first time (in 1609). On this occasion, we will relate some interesting stories about astronomy in the 17th century, from Europe to Đại Việt ("Greater Vietnam")..

         It was the time when the scientific revolution, in mathematic, physics, astronomy, anatomy and botany, etc took shape and developed rapidly in Europe..

         In astronomy, until then it was accepted that the sun was moving around the earth which stayed still, according to Aristotle's (634-322 BC) and Ptolemy's (90-160?) theories, and in accordance with teaching of the Bible (for example, Joshua blew his ram horn [shofar] to stop the movement of the sun when he destroyed the city of Jericho.) This is geocentrism holding that the Earth is the center of the universe.

         But in the 16th century, a monk, Mikolaj Kopernick (Nicolas Copernicus, 1473-1543) proposed another theory to the effect that the earth was moving around the sun in his De Revolutionibus Orbium Coelestium (1543, shortly before his death, but the work was completed approximately 30 years earlier). This is heliocentrism, or Copernican theory, later confirmed by German mathematician Johannes Kepler (1571-1630) who announced what is known now as Kepler's Laws of Planetary Motion. In the meantime, Galileo used a telescope, secretly applying the Kepler's laws and discovered many celestial events: "the sub-lunar and super-lunar worlds" (les mondes sublunaires et supra lunaires), three small planets next to Jupiter, the spots on the Sun, Venus, etc...

        Please read the rest of the story in THE LANDS OF FREEDOM.