1. Topic: Early Astronomy PSSA: 3.4.7.D/S8.A.2.2

2. Objective: TLW explain how the discoveries of early astronomers has changed mankind’s understanding of the universe. TLW explain how the discoveries of early astronomers has changed mankind’s understanding of the universe.

3. MI #1: Ptolemy Ptolemy was an early Greek astronomer (about 140 CE) who compiled a book of all of the astronomical information he could find. Ptolemy was an early Greek astronomer (about 140 CE) who compiled a book of all of the astronomical information he could find. He proposed that the Earth was at the center of the universe and the Sun and other planets revolved around it. He proposed that the Earth was at the center of the universe and the Sun and other planets revolved around it.

4. MI #2: Copernicus In 1543, Nicholas Copernicus published a new theory about the movement of planetary bodies in the universe. In 1543, Nicholas Copernicus published a new theory about the movement of planetary bodies in the universe. Copernicus believed that the Sun is at the center of the universe and that the Earth and other planets orbit the Sun. Copernicus believed that the Sun is at the center of the universe and that the Earth and other planets orbit the Sun. This caused a major revolution in thinking that is often referred to as the Copernican Revolution This caused a major revolution in thinking that is often referred to as the Copernican Revolution

5. MI #3: Tycho Brahe Although Brahe agreed with Ptolemaic Theory, he recorded the most detailed astronomical observations to that time (mid 1500’s) Although Brahe agreed with Ptolemaic Theory, he recorded the most detailed astronomical observations to that time (mid 1500’s) His data aided the work of future astronomers (particularly Johannes Kepler). His data aided the work of future astronomers (particularly Johannes Kepler).

6. MI #4: Johannes Kepler Kepler used Brahe’s data to develop the three laws of planetary motion. Kepler used Brahe’s data to develop the three laws of planetary motion. The most notable of his three laws is that planets orbit the Sun in elliptical (oval) orbits and the Sun is not at the exact center of the orbit. The most notable of his three laws is that planets orbit the Sun in elliptical (oval) orbits and the Sun is not at the exact center of the orbit.

7. MI #5: Galileo Galilei Galileo is credited as being the first scientist to use a telescope to study the stars and planets. Galileo is credited as being the first scientist to use a telescope to study the stars and planets. From his observations, he observed mountains and craters on the moon and discovered four of Jupiter’s moons. From his observations, he observed mountains and craters on the moon and discovered four of Jupiter’s moons.

8. MI #6: Isaac Newton Newton showed that all objects in the universe attract each other through gravitational force. Newton showed that all objects in the universe attract each other through gravitational force. His discovery is known as the Law of Universal Gravitation. His discovery is known as the Law of Universal Gravitation. This law explains why all of the planets orbit the solar system’s most massive object - the sun. This law explains why all of the planets orbit the solar system’s most massive object - the sun.

9. So What….? Real Life Application Understanding early astronomical discoveries is necessary to understand how astronomy has changed over the last 2000 years. Understanding early astronomical discoveries is necessary to understand how astronomy has changed over the last 2000 years. Many of these scientists endured ridicule for their ideas, even though we now consider their ideas simple fact. Many of these scientists endured ridicule for their ideas, even though we now consider their ideas simple fact.