... SUN MOON MERCURY VENUS MARS, JUPITER SATURN . ... Our solar system may have once harbored super-Earths . ... Long before Mercury, Venus, Earth, and Mars formed, it seems that the inner solar system may have harbored a number of super-Earths planets larger than Earth but smaller than Neptune. If so, those planets are long gone broken up and fallen into the Sun billions of years ago largely due to a great inward and then outward journey that Jupiter made early in the solar system's history. ...