Neptune: The eighth planet in order from the sun. It is one of the five outer planets of the solar system. Its two natural satellites are Nereid and Triton.Minor Planets: Small solar system planetary bodies including asteroids. Most asteroids are found within the gap lying between the orbits of Mars and Jupiter.Uranus: The seventh planet in order from the sun. It is one of the five outer planets of the solar system. It has five known natural satellites.Evolution, Planetary: Creation and development of bodies within solar systems, includes study of early planetary geology.Euphausiacea: An order of pelagic, shrimplike CRUSTACEA. Many consume ZOOPLANKTON and a few are predacious. Many antarctic species, such as Euphausia superba, constitute the chief food of other animals.