The Earth is not a perfect sphere, but it is approximately spherical in shape. It is best described as an oblate spheroid, which means it is mostly spherical but slightly flattened at the poles and bulging at the equator.
Due to the Earth's rotation, it experiences a centrifugal force that causes the equatorial region to slightly bulge outward. This bulge results in the Earth's shape resembling a flattened sphere rather than a perfect sphere.
Measurements and observations from various sources, including satellite data, geodesy, and measurements of the Earth's gravitational field, support the conclusion that the Earth is an oblate spheroid. However, when examining the Earth on a smaller scale, such as local topography or surface features, variations from this shape can be observed.
It's important to note that the Earth's shape is complex and influenced by various factors such as gravitational forces, rotation, and geological processes.