This is due to gravity, which pulls equally in all directions. As a planet forms from dust and gas, gravity pulls this material towards the center, creating a roughly spherical shape.
However, planets are not perfectly spherical. They are slightly oblate, meaning they are flattened at the poles and bulging at the equator. This is due to the centrifugal force caused by the planet's rotation.
Here's a breakdown of how oblate the planets in our solar system are:
* Most oblate: Saturn is the most oblate planet in our solar system due to its fast rotation and low density.
* Second most oblate: Jupiter is also quite oblate for similar reasons to Saturn.
* Least oblate: Mercury and Venus are the least oblate, likely due to their slower rotation rates.
So, while all planets are spherical, they vary in how much they deviate from a perfect sphere.
