Planet

Earth's closest planet on average isn't Venus but Mercury. Bigger orbits spend longer on the far side of the Sun, so average distance grows. Mercury's tiny orbit keeps it near every planet. Earth–Mercury averages 1.04 AU, Earth–Venus 1.14 AU. The "Whirly Dirly Corollary."

Pluto hasn't completed a full Orbit around the sun since its 1930 discovery. With an orbital period of about 248 years, it will finish its first lap in 2178. Counting from its 2006 demotion as a Solar System Planet, it will complete a full orbit in 2254.