# Equatorial Bulge

An equatorial bulge is a difference between the equatorial and polar diameters of a planet, due to the centrifugal force of its rotation. A rotating body tends to form an oblate spheroid rather than a sphere. The Earth has an equatorial bulge of 42.72 km (26.54 mi): that is, its diameter measured across the equatorial plane (12,756.28 km (7,926.38 mi)) is 42.72 km more than that measured between the poles (12,713.56 km (7,899.84 mi)); in other words, anyone standing at sea level on either pole may be 21.36 km closer to the earth's centrepoint than if standing at sea level on the equator. To get the Earth's mean radius, these two radii must be averaged.

An often-cited result of Earth's equatorial bulge is that the highest point on Earth, measured from the center outwards, is the peak of Mount Chimborazo in Ecuador, rather than Mount Everest. But since the ocean, like the Earth and the atmosphere, bulges, Chimborazo is not as high above sea level as Everest is.

### Other articles related to "equatorial bulge, equatorial":

Equatorial Bulge - Mathematical Expression
... a small amount of flattening, is approximated by where and are respectively the equatorial and polar radius, is the mean radius, is the angular velocity, is the rotation period, is ...
Stellar Rotation - Physical Effects - Equatorial Bulge
... See also Equatorial bulge Gravity tends to contract celestial bodies into a perfect sphere, the shape where all the mass is as close to the center of gravity as possible ... But a rotating star is not spherical in shape, it has an equatorial bulge ... an equilibrium shape, in the sense that the effective gravity in the equatorial region (being diminished) cannot pull the star to a more spherical shape ...

### Famous quotes containing the word bulge:

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Walt Whitman (1819–1892)