While it is true that spheres are a common shape in the universe, it is important to note that not everything takes the shape of a sphere. The universe is incredibly diverse, and objects come in a wide range of shapes and forms. However, spheres do appear frequently in various phenomena due to a few fundamental reasons:
Gravity: Gravity is a fundamental force that acts on matter, causing it to be pulled inward toward its center. When a sufficient amount of matter is present, gravity pulls it equally from all directions, resulting in a spherical shape. This is why celestial bodies such as planets, stars, and moons tend to be spherical. Gravity acts as a shaping force, compressing matter into a compact, symmetric form.
Surface tension: On smaller scales, surface tension can play a role in shaping objects into spheres. Surface tension is a property of liquids that causes their surfaces to minimize their surface area. This property results in droplets and bubbles naturally forming spheres, as the spherical shape has the smallest surface area for a given volume.
Equilibrium: In many physical systems, objects tend to adopt shapes that achieve the lowest energy state or equilibrium. The sphere is often the most efficient and stable shape for distributing stress evenly across its surface. For example, soap bubbles or water droplets will naturally form spheres due to the balance of internal and external forces.
It is important to remember that these factors are not universal and are subject to specific conditions. The universe contains an immense variety of shapes, including cubes, spirals, irregular forms, and more. The prevalence of spheres can be attributed to the influence of gravity, surface tension, and equilibrium, but they do not encompass the entirety of the diverse structures found in the universe.