Once the planet finished forming, these heavy, solid bits of material fell into the center of the planet, as illustrated in figure B. The heavy elements of the planet made up a much smaller portion of the planet than the gaseous elements. The amount of gas and ice which make up Neptune depended upon where Neptune was in the primordial cloud.

Eventually, the heavy, solid material at the center solidified into a core, as illustrated in figure C.

Leftover heat from this process of Neptune's forming may still influence the motions in Neptune's atmosphere.

As the planets drew material from the solar cloud, bits of heavy rock collected inside the forming planet, as shown in figure A.

Once the planet finished forming, these heavy bits of rock fell into the middle of the planet, as illustrated in figure B.

As shown in the picture, the gas part of the planet is much bigger than the rocky part. That is because the amount of gas and ice which came to Neptune in the beginning, depended upon where Neptune was in the original solar cloud.

Eventually, the heavy, rocky material at the center became a core, as illustrated in figure C.

Leftover heat from this process of Neptune's forming may still influence the motions in Neptune's atmosphere.

As the planets drew material from the solar cloud, bits of heavy rock came to where the planet was forming, as shown in figure A.

Once the planet finished forming, these heavy bits of rock fell into the middle of the planet, as illustrated in figure B.

As shown in the picture, the gas part of the planet is much bigger than the rocky part. That is because the amount of gas and ice which came to Uranus in the beginning, depended upon where Neptune was in the original solar cloud.

Eventually, the heavy, rocky material at the center became a core, as shown in figure C.