1. Our Solar System A system of eight planets and many other objects that orbit our sun

2. Inner Planets The 4 solid, rocky planets closest to the sun; Mercury, Venus, Earth, Mars Mercury – 1st planet, moon- like appearance, 450 0 C during the day, -175 0 C at night Venus – 2 nd planet, Earth-like, dense CO 2 atmosphere, 464 0 C avg. temperature

3. Inner Planets (cont.) Earth – 3 rd planet, 150 million km from the sun, or 1 astronomical unit (AU) Mars – 4 th planet, red iron-oxide surface

4. Outer Planets The 4 planets farthest from the sun; Jupiter, Saturn, Uranus, and Neptune Jupiter – 5 th planet, largest in solar system, gas planet composed of liquid hydrogen, helium & some ammonia, methane & water vapor Saturn – 6 th planet, ringed gas planet with the lowest density

5. Outer Planets (cont.) Uranus – 7 th planet, gas planet with rotation axis almost parallel to its revolution plane Neptune – 8 th planet, gas planet similar to Uranus with methane gas giving the blue color

6. Solar System Terms Sphere – a round, three-dimensional object whose surface at all points is the same distance from its center Axis – an imaginary line around which an object spins

7. Solar System Terms (cont.) Rotation – the spinning of an object around its axis Revolution – the orbiting of one object around another, like Earth revolving around the sun Ellipse – an elongated, closed curve; the shape of planetary orbits