What are the characteristics of the 8 planets in the solar system?

Mercury is the closest planet to the sun and has an atmosphere made primarily of oxygen.. Venus has an atmosphere that is over 96 percent carbon dioxide and is the second in the solar system. Earth is filled with landforms and has an average temperature of 58 degrees. Mars is called the red planet and has an average high temperature of 23 degrees Fahrenheit. Neptune, Uranus, Saturn, and Jupiter are all gas planets.