Why Are Planets Spherical

Many planets have this same unique feature.

It may come to surprise some individuals that earth is not the only planet that is spherical. In fact, all discovered planets to date in our solar system or another, are spherical. Some may state that not all planets are perfectly spherical, which is true, but for the most part all planets are as close to perfect circles as they could be. The main theory as to why planets are spherical depends on who and what you define as the appearance of a planet versus the actual.

However, it is thought that most planets are spherical because gravity compresses planets into a shape that can evenly be distributed due to the gravitational forces that are present within the planet’s mass. Furthermore, if planets had oblong sides or uneven weight distribution, it could possibly throw off their rotation. Therefore, it can be understood that due to the exponentially heavy mass a planet consists of, the only way the planet could be formed is by evenly distributing this mass.

There are however some various forces that cause slight deviations in this perfect sphere. A specific example relating to earth is that every time the earth makes one full rotation, a force known as centrifugal force, creates a slight bulge in the equator. As for other planets in our solar system, the most spherical is Venus, which has an oblateness of about .0002, making it literally almost the concept of a perfect sphere.

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