

Planets are celestial bodies located within solar systems across the Universe. Current definitions by the International Astronomical Union define a planet as a body that is in orbit around the Sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibirum (nearly round) shape, and has cleared the neighborhood around its orbit or within another system.
The Earth's solar system consists of eight planets. (A former ninth planet, Pluto, was reclassified as a dwarf planet in 2006, and reclassified again as a plutoid -- celestial objects that lie within the solar system's Kuiper belt -- in 2008.)
The planets in Earth's solar system have long been a subject of fascination for humans, in part because they appear as bright "wanderers" among the traditional stellar constellations. Many of them have been named after mythological gods, and fantastic stories have been written about them through history. One of the most prominent appearances in art during the beginning of the 20th century was Gustav Holst's The Planets, a symphonic suite inspired by the celestial bodies.
Extraterrestrial Planet Index
- Crayon: home of Tee Hee, an alien featured in the Sesame Street Live shows Big Bird and the ABCs and Sleeping Birdie
- Cute-tron: home of Commander Bunny.
- Enormous: Super Morphin Mega Monsters
- Gazoob
- Gortch: referred to in one sketch as being another planet.
- Jupiter: after taking a trip to the moon, Selma Worm plans to lay eggs on Jupiter.
- Koozebane
- Lactosia: home of Moo-ing and his henchman.
- Malamaroo: a planet inhabited by an alien named Alvin.
- Mars
- Mayonnaise: a planet inhabited by the Mayonasians, who lack energy in the mornings.
- Neptune
- Planet G0N0
- Planet Grover: discovered and christened by Grover in The Adventures of Grover in Outer Space.
- Paltroon: planet of leaf people in The Muppet Show Comic Book: The Four Seasons #3.
- Planet Poobatron: home of the Poobs and the closest galactic neighbor of Planet Koozebane
- Saturn
- Thra: the world of The Dark Crystal
- Wheel Planet: unnamed planet in The Adventures of Rowlf in Outer Space, in which every person, place, and object is on wheels, rolling to stay within the view of the sun.
- Zircon: Celestial body around which Lothar and Othmar the Grouches' home orbits
- Zucchini: visited by Elmo in his book Elmo Rides a Spaceship to Somewhere in Space (episode 3990)
References
- In the Muppet Kids book The Trouble with Twins, Skeeter creates a model of the planets using fruit, but it rots before the science fair.
- In the 1983 book People in Your Neighborhood, Guy Smiley is a science teacher, teaching about the planets.