2. Our Solar System

4. our solar system is in the Milky Way galaxy composed of the Sun (yellow dwarf) and everything that orbits it –sun is 99.8% of the mass Planets: 0.135% Comets: 0.01% ? Satellites: 0.00005% Minor Planets: 0.0000002% ? Meteoroids: 0.0000001% ? –sun’s gravity keeps the planets in orbit –around 135 satellites are orbiting the planets in our solar system a satellite is an object in orbit around a larger mass Characteristics

5. Formation about 4.6 billion years old –probably began as a nebula-- a large cloud of dust in space –collapsed into a large, rotating, disk- shaped cloud –continued to collapse and the material in the middle became hot and dense (the Sun) –planets begin to form by accretion where particles collide and stick together because of gravity

7. the planets, moons, and asteroids of our solar system orbit the Sun in about the same angle called the ecliptic plane

10. Earth’s temperature tends to be hotter at the equator because the sun’s energy is perpendicular to the earth and therefore more concentrated

11. earth’s seasons are caused by the tilt (23.5º) of the earth on its axis the pole tilted towards the sun is hotter and the days longer –more direct sunlight and higher temperatures

13. The Moon

14. only natural satellite of Earth has no atmosphere gravity is about 1/6 of Earth light comes from the Sun that is reflected off the Moon's surface. moon’s gravity pulls on earth’s water creating high and low tides.

15. phases of the moon –appears to be different shapes depending on its position relative to earth –waxing is when the moon is “getting” bigger –waning is when the moon is “getting” smaller

21. Eclipses occurs when one object moves into the shadow cast by another object –solar eclipse moon blocks out the sun from reaching an area on earth

24. –lunar eclipse earth blocks the sun from reaching the moon