The inner solar system and outer solar system are divided by the asteroid belt. The outer solar system has four giant gaseous planets and Pluto, a small icy world at the far reaches of the solar system. The four gas giants have all been visited by one or more unmanned spacecraft, but Pluto has never been studied up-close at all.
Related Articles
Read More The Outer Solar System
Astronomy Sections
- Ancient Eyes, Same Sky
- Astronomy As a Science
- How the Universe Came Into Being
- Constellations: Patterns in the Sky
- Navigate the Night Sky
- The Inner Solar System
- The Outer Solar System
- Solar System Wanderers
- A Star Is Born
- Deep-Sky Objects
- Faraway and Far-Out
- First Steps, First Tools
- Telescopes Advanced for Advanced Viewing
- Visit Space Places
- Make Your Own Scientific Discoveries
- Ground-Based and Space-Based Observation
- Robots, Animals, and People in Space
- SETI: Are We Alone?
- How It Will All End
- Constellation List
- Planetary Facts
- Messier's Catalogue
- Web Sites for Amateur Astronomers
- Glossary
- Color Photograph Reference