Jovian planets, the planets Jupiter, Saturn, Uranus, and Neptune. They are all larger and more massive than the earth. Since they rotate faster, they are more flattened at the poles than are the terrestrial planets. They are all less dense than the earth. Jupiter and Saturn, which are classified as gas giants, are composed predominantly of hydrogen and helium. Uranus and Neptune, which are ice giants, are composed predominantly of somewhat heavier elements, such as oxygen, carbon, and nitrogen.
The Columbia Electronic Encyclopedia, 6th ed. Copyright 2012, Columbia University Press. All rights reserved.
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