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Vichada Structure
The Vichada Structure is a probable impact structure along the Vichada River in Colombia (Vichada Department), South America. It is most likely the largest impact structure in South America. The structure was discovered in 2004 by Max Rocca, a geologist in Buenos Aires, by examining Landsat imagery. He was supported by a grant from the Planetary Society. The structure consists of a central flat depression surrounded by two concentric rings of hills of approximately 30 and 50 km diameter. The Vichada River anomalously flows around the outer ring of hills. An international team of scientists collected aerial gravity data over the 50 km wide structure and discovered a positive free-air anomaly at the center of the structure, supporting its interpretation as an impact structure.Hernandez, O., et al., 2009, Geophysical evidence for an impact crater in Vichada, northwestern South America, and its economic potential, Earth Sci. Res. J., Vol. 13, No. 2 (December 2009): ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vichada Structure LC08 L1TP 005057 20160118 20170405 01 T1
Vichada may refer to: *Department of Vichada, a subdivision of Colombia *Vichada River The Vichada River ( es, Río Vichada, ) is a blackwater river in the country of Colombia, South America. It flows into the Orinoco River. The eastward course of the Vichada is offset by an impact structure An impact structure is a generally ..., a river in eastern Colombia * Vichada Structure, impact structure in Colombia {{geodis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vichada Structure Skylab G40B091120000
Vichada may refer to: *Department of Vichada, a subdivision of Colombia *Vichada River, a river in eastern Colombia *Vichada Structure The Vichada Structure is a probable impact structure along the Vichada River in Colombia (Vichada Department), South America. It is most likely the largest impact structure in South America. The structure was discovered in 2004 by Max Rocca ..., impact structure in Colombia {{geodis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impact Crater
An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters typically have raised rims and floors that are lower in elevation than the surrounding terrain. Lunar impact craters range from microscopic craters on lunar rocks returned by the Apollo Program and small, simple, bowl-shaped depressions in the lunar regolith to large, complex, multi-ringed impact basins. Meteor Crater is a well-known example of a small impact crater on Earth. Impact craters are the dominant geographic features on many solid Solar System objects including the Moon, Mercury, Callisto, Ganymede and most small moons and asteroids. On other planets and moons that experience more active surface geological processes, such as Earth, Venus, Europa, Io and Titan, visible impact craters are less common because they become ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vichada River
The Vichada River ( es, Río Vichada, ) is a blackwater river in the country of Colombia, South America. It flows into the Orinoco River. The eastward course of the Vichada is offset by an impact structure An impact structure is a generally circular or craterlike geologic structure of deformed bedrock or sediment produced by impact on a planetary surface, whatever the stage of erosion of the structure. In contrast, an impact crater is the surface e ..., called the Vichada Structure. The structure is most likely the largest impact structure in South America. A Target Earth update by Amir Alexander, February 13, 2010, retrieved 25 May 2017 Re ...
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Colombia
Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuela to the east and northeast, Brazil to the southeast, Ecuador and Peru to the south and southwest, the Pacific Ocean to the west, and Panama to the northwest. Colombia is divided into 32 departments and the Capital District of Bogotá, the country's largest city. It covers an area of 1,141,748 square kilometers (440,831 sq mi), and has a population of 52 million. Colombia's cultural heritage—including language, religion, cuisine, and art—reflects its history as a Spanish colony, fusing cultural elements brought by immigration from Europe and the Middle East, with those brought by enslaved Africans, as well as with those of the various Amerindian civilizations that predate colonization. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vichada Department
Vichada Department ( es, Departamento del Vichada, link=no, ) is a department of the Republic of Colombia in South America. Vichada is located in the eastern plains of Colombia, in the Orinoquía Region within the Orinoco river basin bordering the Bolivarian Republic of Venezuela to the north and east. To the north the department also borders with Arauca Department, to the northwest with Casanare Department, to the west with Meta Department, to the southwest narrowly bordering with Guaviare Department and to the south with Guainía Department. The department is the second largest in Colombia and scarcely populated in comparison to other departments. The department was previously a commissary established in 1913. The largest town and capital of the department is Puerto Carreño located in extreme northeastern part of the department and bordering Venezuela. the department is subdivided into four municipalities; Puerto Carreño, La Primavera, Santa Rosalía and Cumaribo. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southern subregion of a single continent called America. South America is bordered on the west by the Pacific Ocean and on the north and east by the Atlantic Ocean; North America and the Caribbean Sea lie to the northwest. The continent generally includes twelve sovereign states: Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Guyana, Paraguay, Peru, Suriname, Uruguay, and Venezuela; two dependent territories: the Falkland Islands and South Georgia and the South Sandwich Islands; and one internal territory: French Guiana. In addition, the ABC islands of the Kingdom of the Netherlands, Ascension Island (dependency of Saint Helena, Ascension and Tristan da Cunha, a British Overseas Territory), Bouvet Island ( dependency ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologist
A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, although backgrounds in physics, chemistry, biology, and other sciences are also useful. Field research (field work) is an important component of geology, although many subdisciplines incorporate laboratory and digitalized work. Geologists can be classified in a larger group of scientists, called geoscientists. Geologists work in the energy and mining sectors searching for natural resources such as petroleum, natural gas, precious and base metals. They are also in the forefront of preventing and mitigating damage from natural hazards and disasters such as earthquakes, volcanoes, tsunamis and landslides. Their studies are used to warn the general public of the occurrence of these events. Geologists are also important contributors to climate chan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Landsat Program
The Landsat program is the longest-running enterprise for acquisition of satellite imagery of Earth. It is a joint NASA / USGS program. On 23 July 1972, the Earth Resources Technology Satellite was launched. This was eventually renamed to Landsat 1 in 1975. The most recent, Landsat 9, was launched on 27 September 2021. The instruments on the Landsat satellites have acquired millions of images. The images, archived in the United States and at Landsat receiving stations around the world, are a unique resource for global change research and applications in agriculture, cartography, geology, forestry, regional planning, surveillance and education, and can be viewed through the U.S. Geological Survey (USGS) "EarthExplorer" website. Landsat 7 data has eight spectral bands with spatial resolutions ranging from ; the temporal resolution is 16 days. Landsat images are usually divided into scenes for easy downloading. Each Landsat scene is about 115 miles long and 115 miles wide (or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planetary Society
The Planetary Society is an American internationally-active non-governmental nonprofit organization. It is involved in research, public outreach, and political space advocacy for engineering projects related to astronomy, planetary science, and space exploration. It was founded in 1980 by Carl Sagan, Bruce Murray, and Louis Friedman, and has about 60,000 members from more than 100 countries around the world. The Society is dedicated to the exploration of the Solar System, the search for near-Earth objects, and the search for extraterrestrial life. The society's mission is stated as: "Empowering the world’s citizens to advance space science and exploration." The Planetary Society is a strong advocate for space funding and missions of exploration within NASA. They lobby Congress and engage their membership in the United States to write and call their representatives in support of NASA funding. In addition to public outreach, The Planetary Society has sponsored solar sail ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravimetry
Gravimetry is the measurement of the strength of a gravitational field. Gravimetry may be used when either the magnitude of a gravitational field or the properties of matter responsible for its creation are of interest. Units of measurement Gravity is usually measured in units of acceleration. In the SI system of units, the standard unit of acceleration is 1 metre per second squared (abbreviated as m/s2). Other units include the cgs gal (sometimes known as a ''galileo'', in either case with symbol Gal), which equals 1 centimetre per second squared, and the '' g'' (''g''n), equal to 9.80665 m/s2. The value of the ''g''n is defined approximately equal to the acceleration due to gravity at the Earth's surface (although the value of ''g'' varies by location). Gravimeters An instrument used to measure gravity is known as a gravimeter. For a small body, general relativity predicts gravitational effects indistinguishable from the effects of acceleration by the equivalence p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free-air Gravity Anomaly
In geophysics, the free-air gravity anomaly, often simply called the free-air anomaly, is the measured gravity anomaly after a free-air correction is applied to account for the elevation at which a measurement is made. It does so by adjusting these measurements of gravity to what would have been measured at a reference level, which is commonly taken as mean sea level or the geoid. Applications Studies of the subsurface structure and composition of the earth's crust and mantle employ surveys using gravimeters to measure the departure of observed gravity from a theoretical gravity value to identify anomalies due to geologic features below the measurement locations. The computation of anomalies from observed measurements involves the application of corrections that define the resulting anomaly. The free-air anomaly can be used to test for isostatic equilibrium over broad regions. Survey methods The free-air correction adjusts measurements of gravity to what would have been me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
