pääplaneetat
Pääplaneetat is a Finnish term that translates to "main planets" or "major planets." In astronomical contexts, it typically refers to the eight planets that orbit the Sun within our solar system. These are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. The term distinguishes these celestial bodies from other objects in the solar system, such as dwarf planets, asteroids, and comets. The classification of a planet is based on specific criteria established by the International Astronomical Union (IAU), which include orbiting the Sun, having sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and having cleared the neighborhood around its orbit. Pääplaneetat are the celestial bodies that meet all these criteria. The concept of pääplaneetat is fundamental to understanding the structure and organization of our solar system and is a common term used in Finnish astronomy education and popular science. It emphasizes the primary bodies that dominate the gravitational landscape around the Sun.