The Water Planet: Origin of Life on Earth
There is no definitive evidence that proves beyond a doubt where water originated. But wherever it came from, water did eventually cover more than two-thirds of Earth's surface. The implications of this for the formation of life on planet Earth were...
The Water Planet: Early Earth
At one time, Earth was a very different planet than it is today. Its atmosphere, in particular, bore very little resemblance to the one that we depend on for the air we breathe. It probably consisted primarily of carbon dioxide and nitrogen gas.
Over the Edge: Exploring the Deep Ocean Floor
Scientists have made great progress in their efforts to map the deepest parts of the ocean. But even with all the new technology that's available, our knowledge and understanding of the deep ocean is far from complete. In fact, we know more about th...
Over the Edge: Hydrothermal Vents
Hydrothermal vents were discovered in 1977. They are sometimes characterized as deep ocean hot springs found thousands of feet beneath the surface. Hydrothermal vents are of great interest because of their circulation processes, as well as for the u...
Over the Edge: Oceanic Ridge System, The
Perhaps the most striking feature that characterizes the deep ocean floor is the vast oceanic ridge system that encircles the Earth along tectonic plate boundaries.
Over the Edge: Undersea Volcanic and Tectonic Activity
For large stretches the deep ocean basin is flat. But seamounts, guyots, island arcs and trenches, all of which result at least in part from tectonic activity, break up the sameness.
World in Motion: Plate Boundaries and Plate Movement
Whether studying earthquakes, volcanoes, or other geologic events, scientists usually focus their attention on plate boundaries and plate movement.
World in Motion: Earthquakes and Plate Tectonics
With the advent of plate tectonics, it's become apparent that episodes of extreme geologic upheaval--like earthquakes--are much more than simply random events.