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100
Ptolemy is born, time is now A.D.
Ptolemy was born in Greece. He contributed to mathematics, astronomy, and geography. Ptolemy spent 14 years studying the stars and planets, and then wrote Almagest, a book hat stated a detailed theory about the sun, planets, and their moons. Ptolemy thought that, while the planets were moving in elliptical shaped orbits around the earth, they had epicycles, meaning they rotated around an axis. Nobody changed this theory for more than 1,000 years. -
276
Erastosthenes is born in B.C.
Eratosthenes was born in Cyrene, Greece. Eratosthenes became the head libraryan in Alexandria, Egypt. Eratosthenes is best known for calculating the circumference of the earth. He looked at the bottom of a well in Syene, . He calculated the distance between where he was and Alexandria. -
560
Pythagoras is born in B.C.
Pythagoras is one of the earliest known astronomers. He was born in Greece. Pythagoras thought that there was a fire in the center of the earth, and that all other planets and the sun revolved around it. -
Feb 19, 1473
Copernicus is born
Copernicus was born in Poland. He studied mathematics, astronomy, medicine, and law. In 1514, Copernicus chalenged the geocentric theory by writing a paper on the heliocentric theory, or the theory that planets revolve around the sun, not the earth. Later, thbis theory would be proven by another great astronomer. -
Dec 14, 1546
Tycho Brahe is born
Tycho Brahe was born in Denmark. Brahe studied law, but started astronomy when he saw a solar eclipse in 1560. He read Ptolemy's Almagest and then attended science classes at different universities. Brahe created a theory called the Tychonic System. This theory states that the sun and moon revolve around the earth, nand all other planets revolve around the sun. Although he was wrong with the sun, he made the contribution of the theory that all planets revolve around the sun. -
Feb 15, 1564
Galileo is born
Galileo was born in Italy. As a kid, Galileo hated science because he was taught only theories, no facts. Once older, Galileo found that math could prove theories. In 1604, Galileo sparked his intrest in astronomy when he discovered a supernova. Then, in 1609, Galileo was introduced to a small telescope. After finding this toy, he created a larger version of it so that he could have a practical use for it. Galileo discovered Jupiter's moons, and he proved that all planets revolve around the sun. -
Dec 7, 1571
Kepler is born
Kepler was born in Germany. He studied under Tycho Brahe when he was young. Kepler observed the orbits of the planets and correctly guesed their position from the sun. He also made three laws. The 1st law says that the su is the center of the universe and that all planets revolve around it. The 2nd law says that planets move faster when they get closer to the sun. The 3rd law has the mathematical formula used to tell how far a planet is from the sun. -
Newton is born
Newton was born in England. Newton is considered the greatest scientific geinus of all time. He is the person who discovered what gravity was. People knew that something made everything that dropped fall on the ground, but they didn't know what it was or what to call it. Newton tried to figure out, only to have the formula revealed by an apple falling on his head. He also dicovered centrifugal force, the oppisite of gravity. It keeps an object from continuously plowing a hole in the earth. -
Herschel is born
Herschel was born in Germany. At first, he was a music teacher, but he spent his spare time on astronomy and building telescopes. Herschel is known for discovering Uranus. At the time, he named it Georgium Sidus, but the name never stuck. He also discovered the new planet had 2 moons, and that Saturn had an extra 2 moons. -
Aristotle is born in B.C.
Aristotle was born in Greece. He was seventeen when he went to study under Plato, one of the greatest thinkers of all time, in Athens, Greece. Aristotle studied for 20 years before leaving Plato's school. Aristotle contributed the correct theory that planets move in elliptical orbits. -
Hipparchus was born in B.C.
Hipparchus was born in what is now Iznik, Turkey. Hipparchus is known as the Father of Systematic Astronomy. Hipparchus believed that the Earth was the center of the universe, and that all other celestial bodies revolved around it. He determined the longitudes and latitudes of the earth. He also discovered the distance between the sun and the earth, and the distance between the moon and the Earth. -
Eudoxus of Cnidus is born in B.C.
Eudoxus off Cnidus was a scholar interseted in the movement of celestial bodies. He was born in Greece. Eudoxus developed a theory that all planets move in concentric (evenly spaced) circles while revolving around the earth. This theory explained why the sun and stars move across the sky from east to west.
