Oblateness refers to the shape of an object that is slightly flattened at the poles and bulging at the equator. This phenomenon is commonly observed in celestial bodies like Earth and Jupiter, which rotate on their axes. The centrifugal force generated by this rotation causes the equatorial region to expand outward, resulting in a shape that resembles a flattened sphere. In the case of Earth, its oblateness is measured by the difference between its equatorial and polar diameters. The equatorial diameter is about 43 kilometers larger than the polar diameter. This slight difference affects various aspects of the planet, including gravity and satellite orbits.