An ice giant is type of giant planet composed largely of materials less volatile than hydrogen and helium. It became known in the 1990s that Uranus and Neptune were really a distinct class of giant planet, composed of about 20% hydrogen, compared to the heavier gas giant's 90%. They are thought to lack metallic hydrogen at their cores, instead, mostly heavier elements including supercritical water.
In March 2012, it was found that the compressiblity of water used in ice-giant models could be off one third. The value is important for modeling ice giants, and has a ripple effect understanding of them. Ice giants include Uranus, Neptune, and exoplanets so categorized.
Famous quotes containing the words ice and/or giant:
“When the ice is covered with snow, I do not suspect the wealth under my feet; that there is as good as a mine under me wherever I go. How many pickerel are poised on easy fin fathoms below the loaded wain! The revolution of the seasons must be a curious phenomenon to them. At length the sun and wind brush aside their curtain, and they see the heavens again.”
—Henry David Thoreau (1817–1862)
“Next week Reagan will probably announce that American scientists have discovered that the entire U.S. agricultural surplus can be compacted into a giant tomato one thousand miles across, which will be suspended above the Kremlin from a cluster of U.S. satellites flying in geosynchronous orbit. At the first sign of trouble the satellites will drop the tomato on the Kremlin, drowning the fractious Muscovites in ketchup.”
—Alexander Cockburn (b. 1941)