Earth is the third planet from the Sun and the only astronomical object known to harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all of Earth's water is contained in its global ocean, covering 70.8% of Earth's crust. The remaining 29.2% of Earth's crust is land, most of which is located in the form of continental landmasses within Earth's land hemisphere. Most of Earth's land is at least somewhat humid and ... Learn how the Earth is modeled as an ellipsoid with different parameters and datums for horizontal and vertical coordinates. Explore the history and accuracy of the ellipsoid and geoid shapes and their impact on geodesy and cartography. Learn why Earth is not a perfect sphere but an oblate spheroid that bulges at the equator and flattens at the poles. Find out how this affects geographic coordinates, Mount Chimborazo, and Mount Everest. Find out information about the planet Earth, the planet of all life in the Solar System. From its shape, its mass and density, its gravity and magnetism, its atmosphere, hydrosphere, lithosphere to its age, rotation, revolution and precession.
