Farther out in the nascent Solar System, 5 AU from the Sun and beyond, planetesimals coalesced to form a number of bodies with masses about 5–10 times that of Earth. Why such large bodies formed in the region beyond the terrestrial planets remains an unanswered question. Located in a much colder part of the accretion disk, these planet-sized objects formed from planetesimals containing volatile ices and organic compounds in addition to rock and metal. In a process astronomers call core accretion–gas capture, mini accretion disks formed around these planetary cores, capturing massive amounts of hydrogen and helium and funneling this material onto the planets. Four such massive bodies became the cores of the giant planets—Jupiter, Saturn, Uranus, and Neptune