Pluto, discovered in 1930, was once considered the ninth planet in our solar system. In 2006, the International Astronomical Union reclassified Pluto as a dwarf planet because it doesn't meet all ...

(Earth, of course, is the eighth planet, and poor Pluto was demoted in 2006 and is now considered a dwarf planet.) Mars, Venus, Jupiter, Mercury and Saturn should be visible to the naked eye.