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:
“Like the water, the Walden ice, seen near at hand, has a green tint, but at a distance is beautifully blue, and you can easily tell it from the white ice of the river, or the merely greenish ice of some ponds, a quarter of a mile off.”
—Henry David Thoreau (1817–1862)
“In frames as large as rooms that face all ways
And block the ends of streets with giant loaves,
Screen graves with custard, cover slums with praise
Of motor-oil and cuts of salmon, shine
Perpetually these sharply-pictured groves
Of how life should be.”
—Philip Larkin (1922–1986)