Oblateness of the Earth

Oblateness of the Earth

 

a quantity that characterizes the degree to which the earth is flattened in the direction of its axis of rotation, that is, the deviation of the earth’s shape from that of a sphere. The polar oblateness of the earth α is expressed by the equation

where a is the equatorial radius of the earth and b is the polar radius. According to modern findings, α = 1:298.3. With the discovery that the earth is also flattened at the equator, the concept of the equatorial oblateness of the earth was introduced:

where a1 and a2 are the maximum radii of the earth’s equator. According to available data, ∊ = 1:30,000, and the difference between a1 and a2 is approximately 210m.

References in periodicals archive ?
The high area-to-mass spacecraft's orbital evolution behaves strangely under the influence of the solar radiation pressure and the perturbation due to the oblateness of the Earth. Since 1960, there have been observed long-term oscillations of the eccentricity in the satellites' orbital behaviours, like Vanguard and the ECHO balloon.