No other planet has oceans of water, an oxygen-rich atmosphere, and intelligent life.
Earth is special in many less dramatic respects, too.
These two facts are linked, since Earth's solid surface locks in the heat necessary to force the crust to move. In other ways, however, Earth is just an average planet . It is bigger than four planets in the solar system and smaller than the other four. Two planets, Venus and Mercury , are closer to the Sun, while the other six are farther away. Earth formed about 4.5 billion years ago, and it is still evolving.