Planet

A planet is only one type of world which might be chosen as a setting for a geofiction. Moons are another popular setting especially in science fiction. There are many other celestial bodies that could be called a world. Planets make great earth like worlds and are the most popular setting for Geofictions.

IAU Definition of a Planet

 
In 2006 the International Astronomic Union (IAU) changed the definition of a planet. The full resolution was:

RESOLUTION 5A

The IAU therefore resolves that planets and other bodies in our Solar System, except satellites, be defined into three distinct categories in the following way:

(1) A "planet" is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.

(2) A "dwarf planet" is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, (c) has not cleared the neighbourhood around its orbit, and

(d) is not a satellite.

(3) All other objects, except satellites, orbiting the Sun shall be referred to collectively as "Small Solar-System? Bodies".

The eight recognised planets by the IAU are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

Links for Learning

The NineEight Planets
Lunar and Planetary Institute
Solar System Exploration
Pluto and the solar system

Questions for World Builders

These questions can also be applied any type of world.
1. What is the general shape of your planet?
2. How did it become this shape?
3. What is the distance of the planet from the nearest Sun?
4. Does your planet have any moons or other satelites?
5. How old is your planet?
6. How big is your planet?
7. If you disected your planet im half, what would you find beneath its crust?
8. Whare are the core compounds and chemicals that are found in your planets atmosphere.
9. What is the gravity of your planet?
10. Does your planet tilt?
11. If your planet has poles, where are they located?

Fun Projects

1. Map the orbit of your planet around its solar system.
2. Draw a segmented diagram of your planet showing the various layers within.

Image Credit: Lunar and Planetary Institute

 
3. Jot down at least 10 dot points about the creation of your world in scientific terms.
4. Make the shape of your planet out of paper mache.