why are planets round?

Gepubliceerd op 22 juli 2023 om 12:00

Have you ever wondered why planets are round? Well, they are born in disks around young stars. These disks consist of gas, dust, and leftovers that remain when a star is formed. But why do planets have a round shape? Let's discover together why protoplanetary disks are the birthplaces of round planets.

How disks around stars form:

When a new star is born, a large cloud of gas and dust collapses due to gravity. As this happens, the gas begins to rotate, similar to a spinning top. This rotating gas forms a flat disk around the young star, much like a pancake on a plate.

The round formation of planets:

The round formation of planets has everything to do with the way matter behaves in the protoplanetary disk. The disk consists of a vast number of particles attracted to each other by gravity. Due to this gravitational attraction, the particles start to clump together and gather.

Balance between gravity and rotational motion:

Within the protoplanetary disk, there is a balance between the gravitational attraction and the rotational motion of the gas and dust. The rotating motion of the material pushes it outward, while gravity pulls it back towards the center. This creates an equilibrium, allowing the material to distribute evenly throughout the disk.

Growth into a round shape:

As the planets in the protoplanetary disk begin to grow, this balance between gravity and rotational motion remains significant. The larger aggregates of matter also maintain their round shape because of this balance. This means that as a protoplanet grows, it develops its own gravity and eventually takes on the form of a sphere.

Round planets in the universe:

The round shape of planets, therefore, results from the equilibrium between gravity, pulling towards the center, and centrifugal forces caused by the rotational motion. This ensures that matter is evenly distributed across the surface of the planet, resulting in a spherical structure. Other objects in the universe, such as moons and asteroids, can also assume round shapes if they are large enough to overcome their own gravity and become spherical.