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One of the most significant results of space exploration concerns our view of Earth and the dynamics of how the planet changes.
Now, "for the first time in all of time man has seen the Earth from the depths of space---seen it whole and round and beautiful and small." With satellite photography Earth is seen literally from a new point of view and geology is perceived and understood in a new planetary perspective.
Small-scale features such as fluvial valleys, coastlines, and deserts, are directly or indirectly the products of the atmosphere and energy from the Sun.
All this knowledge about Earth is of utmost importance to planetary studies because it is the conceptual basis by which other planetary bodies are investigated.
How then are we able to determine the structure and composition of Earth, or any planetary body?
The evidence comes largely from studies of the physical characteristics of the planet itself---its density, the way in which it transmits seismic (earthquake) waves, the nature of its magnetic field---and from comparisons with meteorites.
Most large-scale features such as the continents, ocean basins, mountain belts and volcanoes are the result of Earth's internal heat.
High-standing continents began to form at this time and were not recycled back into the mantle.
As the planet cooled, modern-style plate tectonics developed by about 2.5 billion years ago.
They are created and modified by a distinctive tectonic style called plate tectonics that reflects the style of convection in the upper mantle.
Deep mantle convection is driven by mantle plumes like those on other planets. Liquid water is stable at the surface of Earth and forms deep oceans.