Planetenklassen
Planetenklassen is a term used in astronomy to categorize planets based on their physical characteristics. This classification system helps astronomers understand the diversity of planetary bodies within our solar system and beyond. The primary distinction is often made between terrestrial planets and gas giants. Terrestrial planets, like Earth, Mars, Venus, and Mercury, are rocky, dense, and have solid surfaces. They typically possess a metallic core and a silicate mantle and crust. Gas giants, such as Jupiter and Saturn, are much larger and less dense, composed primarily of hydrogen and helium. They lack a well-defined solid surface and are characterized by their massive atmospheres and extensive ring systems. Uranus and Neptune are sometimes referred to as ice giants, a subcategory of gas giants, due to their higher proportion of heavier volatile substances like water, ammonia, and methane compared to Jupiter and Saturn. Beyond these broad categories, further subdivisions and refinements exist, considering factors like planetary mass, orbital characteristics, and the presence of moons or an atmosphere. This system aids in comparative planetology, allowing for the study of planetary formation, evolution, and the potential for life.