What is the actual shape of the earth? Why is it shaped that way?

The actual shape of the Earth is called an oblate spheroid, or oblate ellipsoid. This means that the planet is mostly spherical but is slightly flattened at the poles and bulges at the equator. While from space the Earth appears nearly round, precise measurements show that its equatorial diameter is about 43km longer than its polar diameter. This bulging at the equator and flattening at the poles gives Earth its oblate shape.

The primary reason for this shape is twofold:

1. Gravity: Gravity pulls all of Earth’s mass toward its center, which naturally tends to form a sphere. This universal attraction is why most large celestial bodies are round or nearly round—the sphere is the most efficient way for mass to distribute evenly around a center.
2. Earth’s Rotation: As the Earth spins on its axis, centrifugal force acts outward, perpendicular to the axis of rotation. This force is strongest at the equator and weakest at the poles, causing material to be pushed outward slightly more at the equator. As a result, Earth has a slight equatorial bulge and is flattened at the poles, leading to its oblate spheroid shape.

Additionally, Earth’s surface features like mountain ranges, ocean trenches, and variations in crust density further contribute to minor irregularities, but these are small compared to the overall size of the planet. If you could cover the planet completely in water, creating an ideal surface called the "geoid," you would see these slight bumps and dips, but the overall shape would still be closest to an oblate spheroid.