Early Discoveries
The Egyptians were probably the first to notice that the sun moves completely around the sphere of the fixed stars in approximately 365 days and night. Over time it was also noted that the sky holds not only the sun, moon, and stars, but also five bright planets.
Maps of the stars and their paths and useful calendars were developed by several ancient civilizations such as
the Egyptians, Mayans, Chinese, and the Babylonians.
The ancient Greeks developed many theories about the planetary movements. They believed that the EARTH was the CENTER of the universe and that
all other bodies in the sky moved around it.
That theory remained unchallenged until the 16th century when a Polish astronomer named COPERNICUS wrote a book stating that the SUN, not the earth,
was the CENTER
of the universe and that all the planets and stars moved around it. He was called a mad man, however, and little
attention was given his observations.
In 1609 a young mathematician student named Galileo began to study the sky using a homemade telescope. To his amazement, he discovered
that Copernicus' theories were true. The sun WAS the center of the universe! When he published his notes, he was
tried and imprisoned in his home for the rest of his life by the government
for heresy (going against the current beliefs of the church). Although he was eventually forced
to deny his findings, his theory continued to gain support as more and more scientists examined his work.
Important early work also included the research of two other men. In the late 1500's these two men studied and
reported their findings on planetary movements. Johannes
Kepler formulated the laws
of planetary motion, containing facts about the repetitive orbits
of planets and moons.
Sir Isaac Newton,
who was known for his discoveries of the different effects of gravity on earth, extended his knowledge into space.
He suggested that the same force that kept man, animals, and houses on the earth also helped keep the planets,
stars, moon, and sun in orbit around each other at a constant distance. This ensured that the numerous objects
in space would not float around the universe and collide with each other. His discovery was named the law of universal gravity.
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Questions and comments: [email protected] last revised 7/2005