Exoplanets are so diverse that it is difficult to find a universal and convincing classification. Many authors use a classification based on the mass of the object, its distance to the central star and the temperature range derived therefrom as well as the presumed composition. This results in names such as hot jupiter-like planet, mini-Neptune, ocean planet, Earth-like planet, and many more. However, this classification has the disadvantage that it anticipates too many assumed properties and forces the objects into a highly simplified grid. This is well exemplified by 51 Pegasi b: This planet is often referred to as "hot Jupiter," but what similarities actually exist between 51 Pegasi b and the planet we know as Jupiter? One is an already well-measured gas giant in the colder zones of our solar system, the other is an object of similar mass, but in terms of size, composition and weather phenomena, it should be drastically different from Jupiter because 51 Pegasi b receives so much more energy from its star than Jupiter does from the Sun.