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The movement of water around, over, and through the Earth is called the water cycle, a key process of the hydrosphere.

A hydrosphere (from Greek ύδωρ - hydor, "water" + σφαίρα - sphaira, "sphere") in physical geography describes the combined mass of water found on, under, and over the surface of a planet.

[edit] Other hydrospheres

A thick hydrosphere is thought to exist around the Jovian moon Europa. The outer layer of this hydrosphere is almost entirely frozen, but current models predict that there is an ocean up to 100 km in depth underneath the ice. This ocean remains in a liquid form due to tidal flexing of the moon in its orbit around Jupiter.

It has been suggested that the Jovian moon Ganymede and the Saturnian moon Enceladus may also possess sub-surface oceans. However the ice covering is expected to be thicker on Jupiter's Ganymede than on Europa.

[edit] See also

• Biosphere
• Cryosphere
• Earth's atmosphere
• Lithosphere
• Pedosphere
• Table of Global Climate System Components
• Water Cycle

[edit] References

[edit] External links

Look up hydrosphere in Wiktionary, the free dictionary.

• Ground Water - USGS