The Earth is an oblate spheroid, which means it is roughly spherical in shape but slightly flattened at the poles and bulging at the equator. This shape is caused by the Earth’s rotation, which causes the centrifugal force at the equator to be slightly greater than the gravitational force, resulting in a slight bulging at the equator and flattening at the poles.
It’s important to note that the Earth’s shape is not a perfect sphere, it has a slight flattening at the poles and bulging at the equator. The Earth’s equatorial diameter is about 43 kilometers (27 miles) larger than the diameter measured through the poles. This difference is known as the “oblateness” of the Earth.