Astronomy the Original Science

1. Astronomythe Original Science Chapter 1 Section 1

2. Astronomy Astronomy: The study of the universe, is one of the oldest sciences • Imagine: 5000 years ago. • There are no clocks—no modern calendars. • How could you tell what time it was? • How could you know what day it was? One way to tell the time is to study the movement of the stars, planets, and the moon.

3. Our Modern Calendar • Our Modern calendar is based upon observations of bodies in our solar system. • What is a year? • The time required for Earth to orbit around the sun. • What is a month? • The time required for the moon to orbit once around the Earth • What is a day? • The time required for the Earth to rotate once on its axis

4. Who’s Who in Early Astronomy Ptolemy • 140 CE, Ptolemy, a Greek Astronomer, combined all the ancient knowledge on astronomy he could find. • His ideas became known as the Ptolemaic Theory • Ptolemy believed the Earth was the center of the Universe. • Sun revolves around the Earth • Geocentric Model

5. Ptolemy • Ptolemaic Theory • was supported for over 1,500 years in Europe

6. Copernicus • Made several assumptions: • a. The Earth is NOTat the center of the universe • b. Sun is at the center, everything else revolves around it (Heliocentric) • c. The stars are very far away 1543, a Polish Astronomer named Copernicus revolutionized Astronomy

7. Copernicus • Historical Consequences • Began the Copernican Revolution • Had to wait 150 years for general acceptance • Put on the forbidden book list because it challenged the prevailing view of the Church • Importance was that it challenged the prevailing world picture • Led to further observations to try to disprove.

8. Contributions Galileo Brahe Newton Kepler Hubble

9. Read Pages 4-7 • Complete the following questions on pg 7: • 1,3,6,7 and 8

10. Tycho Brahe’s Model • Made many detailed observations • Earth was in the center • Sun revolved around the Earth • Other planets revolved around Sun

11. Johannes Kepler Three Laws of Planetary Motion • Planets traveled in ellipses around the sun (ovals) • Planets move faster in their orbit when closer to the sun • The time required a planet to orbit depends on its distance to the sun

12. Galileo Improved the telescope Made great observations about our solar system Edwin Hubble Determined that there were other galaxies Determined that Universe was expanding

13. Isaac Newton • Developed the Universal Law of Gravity: Every object in the Universe attracts every other object in the Universe with a force that depends on: • objects’ masses • distance between them