1. CELESTIAL MOTION Outcome #3 – Sun & Solar System

2. ASTRONOMY ASTRONOMY is the study of what is beyond earth (usually called “space”). The UNIVERSE is everything that exists including all matter and energy. We often call the universe “space”.

3. UNIVERSE

4. What is included in “space”: 1.GALAXIES – a huge collection of gas and dust and millions of stars and planets. 2.SOLAR SYSTEMS – a sun and all of the objects that travel around it. 3.STARS – a large collection of matter which emits a huge amount of energy through nuclear fusion. Stars also form patterns called CONSTELLATIONS. 4.PLANETS – a large piece of matter that revolves around a star. 5.MOONS – a piece of matter that revolves around a planet.

5. 6.SATELLITES – an object that travels in orbit around another object. 7.COMETS – a chunk of ice/dust that travels in a long orbit around the sun. 8.ASTEROIDS – a small rocky object in space. 9.METEORS – a streak of light caused by a meteoroid. 10.METEOROID – a lump of rock/metal trapped by earth’s gravity. 11.METERORITE – a meteoroid that has reached the ground.

6. MILKY WAY GALAXY

7. OUR SOLAR SYSTEM

8. MOTION Everything in the universe is moving (stars, planets, meteors, asteriods, moons, etc...) In fact the universe is getting larger even as we sit here!

9. PLANETARY MOTION Planets are constantly in motion. They move in 2 basic ways: – ROTATION – REVOLUTION

10. ROTATION: The spinning of an object around its axis. It is because of Earths rotation we have day & night. The Earth rotates once on its axis every 24 hours. ROTATION

11. REVOLUTION: The movement of one object travelling around another. Earth travels in a counter clockwise direction, relative to the north pole, once a year (every 365.25 days) around the sun. REVOLUTION

12. The Seasons are caused by the combination of the Earths tilted axis (23.45°) and the revolution motion of the Earth. Winter in Northern Hemisphere Fall in Southern Hemisphere

13. GEO-CENTRIC THEORY In ancient times people believed that the Earth did not move. They saw things moving in the sky and assumed they were moving around the earth. PTOLEMY was a Greek astronomer who first wrote about the “EARTH CENTERED UNIVERSE”, also called a GEO-CENTRIC universe. He also believed that the stars were only slightly farther away from Earth than the moon, sun, and other planets.

14. GEO-CENTRIC UNIVERSE

15. RETROGRADE MOTION If you observe and record the position of planets over a number of weeks, you will see that the planet creates an “S” shape in the sky. This is called RETROGRADE MOTION. Ptolemy believed that each planet revolved around a point on its orbit called the EPICYCLE.

16. VIDEOS

17. HELIO-CENTRIC UNIVERSE In 1500 AD, COPERNICUS suggests a solar system with the Sun at the center. It was not until the 1600’s, when GALILEO used the first telescopes, that people began to accept that the sun was the center of our universe.

18. HELIO-CENTRIC UNIVERSE

19. VIDEOS 1.http://www.youtube.com/watch?v=Gmw Ar54L_pM&list=PLD7ED780492E5486 A