The collection of water on our planet—in the ocean, the ground, and the atmosphere—collectively forms the hydrosphere, making it a water-world. But as knowledge expands, we've learned Earth is not the only one that would classify as a water-world.
5 - 8
Earth Science, Astronomy, Geology, Oceanography
NASA Blue Marble Photo of Earth
With 71 percent of its surface covered by the stuff, Earth is sometimes called a water-world. This fact is apparent when Earth is viewed from space—so-called "blue marble" pictures.
NASA Goddard Space Flight Center Image by Reto Stöckli with enhancements by Robert Simmon
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October 19, 2023
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