Giant Planet Formation

Gas giant planets have to form quickly, in the first few million years before nearly all the gas escapes from a protoplanetary disk. As they accrete gas, they clear out the material in the zone of the disk through which the they orbit, growing at the expense of the disk. You can see this process in action in this animation. The box to the lower left is a profile of the disk density with radius from the star so you get an alternative view of the deep canyon carved by the planet.from Phil Armitage, (http://jilawww.colorado.edu/~pja/planet_migration.html)

The next movie flies you around a gas giant planet near the end of its rapid growth period, to give you an idea of the overall structure. It corresponds to a late period in the movie above. (from Frederic Masset http://www.maths.qmul.ac.uk/~masset/moviesmpegs.html)