Frequently Asked Questions
The most-asked questions about planets and dwarf planets.
What is this encyclopedia about?
It is an unofficial, fan-written reference covering all eight recognized planets and the five officially designated dwarf planets in our solar system, organized so casual readers can get accessible overviews without wading through textbook-grade detail.
Who are the main characters I should know first?
The eight planets—Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune—form the core cast, each with its own dedicated entry covering appearance, behavior, and relationships with neighboring bodies.
What's the difference between a planet and a dwarf planet?
A planet must orbit the Sun, be roughly spherical, and have cleared its orbital neighborhood of other debris, while a dwarf planet meets the first two criteria but shares its orbital zone with other objects, which is why Pluto, Ceres, Eris, Makemake, and Haumea sit in a separate category.
Where should a newcomer start reading?
Begin with the Solar System Overview entry for a quick map of everything, then jump to whichever individual planet or dwarf planet entry sparks your curiosity—there is no required reading order.
What happened with Pluto in 2006?
The International Astronomical Union introduced a formal definition of planet that year, reclassifying Pluto as the first recognized dwarf planet, a decision that remains one of the most debated and discussed moments in the community.
How many dwarf planets are there?
Five are currently officially recognized—Ceres, Pluto, Eris, Makemake, and Haumea—though hundreds of additional candidates in the Kuiper Belt and beyond are still under study and may be elevated in the future.
What are the most notable moments covered in the entries?
Highlights include the 2006 reclassification, the New Horizons flyby of Pluto in 2015, the detection of water on Mars, and the ongoing debate over whether objects like Sedna or Gonggong deserve dwarf-planet status.
Do the entries cover moons and rings as well?
Each planet's page includes a section on its major satellites and ring systems, but the encyclopedia's primary focus stays on the planets and dwarf planets themselves rather than cataloguing every single moon.
Is this encyclopedia peer-reviewed or official?
No—it is a fan-written project, so while entries aim for accuracy and cite established sources, the tone and organization reflect community enthusiasm rather than institutional publishing standards.
What makes the outer planets different from the inner ones?
The four inner planets (Mercury through Mars) are small, rocky, and fast-orbiting, while the four outer giants (Jupiter through Neptune) are massive gas or ice worlds with extensive moon families and ring systems, creating two very distinct groups in the solar system.