Resumen de Elephant in the room
Clark determines whether a habitable solar system needs a distant giant such as Jupiter. In the search for habitable planets, astronomers thought they knew what to look for: foreign solar systems resembling their own. They were wrong. Their home system, it turns out, is a place of exceptional order, with its neat arrangement of small rocky worlds close to the sun, and far-flung gas giants. When they stare beyond its confines, they come across nothing else quite like it, instead, they consistently find systems where gas giants and rocky planets are mixed together higgledy-piggledy. If they assume that such an arrangement is the upshot of a long history of instability, it severely limits the time that life would have had to get started in most of the cosmos.
