Talk:Corpus Gas City/@comment-203.104.11.84-20171114234627/@comment-2602:304:B014:B470:CD9E:C8E:62BB:B4A1-20180806003606

Jupiter is not a failed star that never got big enough or ignited. It didn't form anything remotely like the way a star forms.

Stars form directly from the collapse of dense clouds of interstellar gas and dust. Because of rotation, these clouds form flattened disks that surround the central, growing stars. After the star has nearly reached its final mass, by accreting gas from the disk, the leftover matter in the disk is free to form planets.

Jupiter is generally believed to have formed in a two-step process. First, a vast swarm of ice and rock 'planetesimals' formed. These comet-sized bodies collided and accumulated into ever-larger planetary embryos. Once an embryo became about as massive as ten Earths, its self-gravity became strong enough to pull in gas directly from the disk. During this second step, the proto-Jupiter gained most of its present mass (a total of 318 times the mass of the Earth). Soon thereafter, the disk gas was removed by the intense early solar wind, before Saturn could grow to a similar size.