The “Geography” of the Solar System

1. The “Geography”of the Solar System

2. Five types of objects orbit the Sun: • Planets, that have enough mass (and thus gravity) to… • be spherical • clear their orbits of other objects of similar size. • They are also “differentiated” or layered • Dwarf Planets, that have enough mass (and gravity) to… • be spherical • But not enough to clear their orbits • They are also “differentiated” or layered • 3. Comets, Icy objects that melt as they near the Sun forming “tails” 4. Minor Planets or Asteroids, rocky objects that have too little mass to make themselves spherical. 5. Meteoroids, even smaller rocky objects

3. Plutoids Most dwarf planets are similar to Pluto. They are called Pluroids They orbit in the Kuiper Belt and in composition resemble comets. (Although exactly what gas the ice is varies) They Include: Pluto Eris Makemake and Haumea Some such as Sedna, Quaoar, Orcus and Varuna await a further observation

4. Ceres One Dwarf planet does have a composition similar to Earth…Ceres It was once considered an asteroid it orbits in the asteroid belt between Mars and Jupiter at 2.77 AU It is between 909 & 975km in diameter.

5. The Inner the Solar System Closer to the Sun than Jupiter (< 5 AU) is the… Inner Solar System It consists of silicate & metal objects with no or a thin atmosphere such as the terrestrial planets, asteroids & Ceres

6. The“Outer” Solar System From 5 AU to about 30 AU is the “Outer Solar System It consists of Giant Planets with thick atomspheres (Gas Giants) Ans a few Icy Asteroids

7. The Kuiper Belt From 30-1000 AU is the Kuiper Belt, Ring shaped it is similar to the asteroid belt but populated by Thousands (millions?) of Icy objects like Comet nuclei and Plutoids

8. The Truly Outer Solar System From 55 AU to 100,000 AU is a spherical cloud of Comet nuclei and Plutoids Numbering in the millions…. The Oort Cloud