Jack Eylores, age 11, of Glendale, Ariz., for his question:
WHAT DID COPERNICUS DO?
Nicolaus Copernicus was a Polish astronomer who is considered to be the founder of present day astronomy. Copernicus is the man who developed the theory that the earth is a moving planet and that it circles the sun.
He was born in what is now Torun, Poland; in 1743. His name as we know it is the Latinized form of Mikolaj Kopernik.
Before Copernicus became interested in astronomy, the scientists of his time accepted the theory that Ptolemy had formulated 1,400 years before: that the earth was the center of the universe and that it had no motion at all. Scientists then also believed that all the observed motions of the heavenly bodies were real.
Copernicus came to doubt Ptolemy's theory. He believed that the earth moves rapidly through space and that man does not sense this motion because he travels with the earth. He also believed that what man sees in the heavens is affected by the earth's motion. Real motions in the heavens, Copernicus said, must be separated from apparent motions.
In 1530 Copernicus put his thoughts together and in 1543 they were published in a book called "Concerning the Revolutions of the Celestial Spheres." In the publication he demonstrated how the earth's motions could be used to explain the movements of other heavenly bodies.
Copernicus' theories also laid the foundations for the telescopic discoveries of Galileo, the planetary laws of Johannes Kepler and the gravitational principle of Sir Isaac Newton.
A graduate of the University of Krakow, Copernicus was appointed a canon of the cathedral in what is now Frombork, Poland. The income from this position supported him for the rest of his life. He was able to receive a doctor's degree in law and also study medicine in Italy.
Copernicus' ideas were not accepted at once. Only after years of conflict and struggle did man finally consent to relinquish the belief that the earth was the center of the universe.
On the moon you'll find two very conspicuous craters. One is called Tycho, and was named for Tycho Brahe, the great Danish astronomer. The other crater is called Copernicus.
The crater Copernicus is about 55 miles in diameter. Located a little east of the central line of the moon, it is very bright and has a tremendous system of rays that extend out from its edges for hundreds of miles in all directions.
Copernicus, the astronomer, decided that Ptolemy, the great Egyptian astronomer, had believed the earth was fixed and the sun moved around. it from his observation, of the Great Dipper moving slowly, night after night, around the North Star.
Copernicus understood that it was the earth's turning on its own axis which gave this effect of movement to the sun.
Copernicus died in 1543, the year his famous book was published.