1. 23.1 The Solar System

2. The Planets: An Overview Terrestrial planets are relatively small and rocky “Earth like” MercuryVenusEarthMars Jovian planets are huge gas giants JupiterSaturnUranusNeptune

3. Continued… Pluto does not fit into either category (small & cold) Size is the most obvious difference between the terrestrial & Jovian planets The 4 Jovian planets & Pluto are further from the sun they are called outer planets The terrestrial planets that closer to the sun are known as inner planets Density, chemical makeup, & rate of rotation are other ways that the 2 groups differ

5. The Interiors of the Planets TP are dense mostly containing rocky metallic substances & minor amts. Of gases & ices JP contain large amts. of gases & ices The substances that make up the planets are divided into 3 groups: Gases (MP -273 degree Celsius) Rocks (MP above 700 degree Celsius) Ices (Intermediate MP)

6. The Atmosphere of the Planets JP have a very thick atmosphere of hydrogen, helium, methane, & ammonia TP have smaller atmospheres Planet’s ability to retain an atmosphere depends on its mass & temp. (diff. in JP & TP) Moon lacks an atmosphere

7. Formation of the Solar System Nebular Theory – the sun & planets formed from a rotating disk of dust & gases As the speed of the rotating disk increased the disk began to flatten out. Matter became more concentrated in this center, where the sun eventually formed Growth of the planets started as solid bits of matter began to collide & clump together (planetesimals)