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Earth is the third planet from the ... This water cycle is a vital mechanism for supporting life on land and is a primary factor in the erosion of surface features ...
Earth's crust and mantle, Mohorovičić discontinuity between bottom of crust and solid uppermost mantle. Earth's mantle extends to a depth of 2,890 km (1,800 mi), making it the planet's thickest layer. [20] [This is 45% of the 6,371 km (3,959 mi) radius, and 83.7% of the volume - 0.6% of the volume is the crust].
The Earth's radius is the distance from Earth's center to its surface, about 6,371 km (3,959 mi). While "radius" normally is a characteristic of perfect spheres, the Earth deviates from spherical by only a third of a percent, sufficiently close to treat it as a sphere in many contexts and justifying the term "the radius of the Earth".
Earth's location in the Universe. Universe – all of time and space and its contents.. Observable universe – spherical region of the Universe comprising all matter that may be observed from Earth at the present time, because light and other signals from these objects have had time to reach Earth since the beginning of the cosmological expansion.
Earth scientists often conduct sophisticated computer analysis or visit an interesting location to study earth phenomena (e.g. Antarctica or hot spot island chains). A foundational idea in Earth science is the notion of uniformitarianism , which states that "ancient geologic features are interpreted by understanding active processes that are ...
Landforms are categorized by characteristic physical attributes such as elevation, slope, orientation, structure stratification, rock exposure, and soil type.Gross physical features or landforms include intuitive elements such as berms, mounds, hills, ridges, cliffs, valleys, rivers, peninsulas, volcanoes, and numerous other structural and size-scaled (e.g. ponds vs. lakes, hills vs. mountains ...
Artist's impression of Earth during the later Archean, the largely cooled planetary crust and water-rich barren surface, marked by volcanoes and continents, features already round microbialites. The Moon, still orbiting Earth much closer than today and still dominating Earth's sky, produced strong tides. [104]
In the late 19th and early 20th centuries, geologists assumed that Earth's major features were fixed, and that most geologic features such as basin development and mountain ranges could be explained by vertical crustal movement, described in what is called the geosynclinal theory. Generally, this was placed in the context of a contracting ...