Geoid

GeoidEvery schoolchild knows the answer to the question - which mountain is the highest in the world? Surely it is Mount Everest, or Chomolungma (8848 metres), which is its more modern name. This is true if we count from above sea level. And what if we count from the centre of the Earth? Then the highest point is the Chimborazo volcano located in Ecuador, not far from the equator. Its height is only 6384 metres above the sea level. But this mountain is situated in the right place. The key to the explanation of this surprising fact is in the Earth's shape. Due to revolution the Earth has the shape of a ball flattened at the poles, a so called ellipsoid of revolution. So, the Earth's equatorial radius is 22 kilometres longer than the polar radius. In truth, the Earth's shape is a more complex figure, called geoid by scientists due to existence of the continents, tides and other things like these. A geoid is a figure which reflects the shape of the gravity force potential on the Earth. Geoid is an important notion in geodesy. A geoid is defined as equipotential surface of the terrestrial gravitational field which almost coincides with mean ocean water level and is conventionally prolonged under the continents. In fact scientists are not really interested in the form of the Earth surface. It's much more important for them to know the 'form' of terrestrial attraction. To know how it changes at different places of our planet and thereby see through the earth. To see iron ore, minerals, petroleum. And how about the rockets and satellites speeding on the waves of terrestrial attraction? To calculate their orbits we do need to know gravity sailing directions. And satellites give as good as they get. Studying their movement we learn more precisely how our planet attracts them and how it looks like. Our idea of the Earth's shape keeps changing, but the name stays the same: geoid stays geoid.

Category:

Science & Technology

Tags:

• physics
• research
• unit of measurement

[L0ver80y]

Awesome, very interesting