Spheres in Nature and Science
Why are soap bubbles, raindrops, and planets spherical? Surface tension in liquids pulls molecules into the minimal surface area configuration for a given volume: a sphere!
Example: The Volume of Planet Earth
Assuming Earth has an average mean radius of r ≈ 6,371 kilometers:
V_Earth = 4/3 × π × (6,371)³
6,371³ ≈ 2.585 × 10¹¹ km³
V_Earth ≈ 1.083 × 10¹² cubic kilometers (over 1 trillion cubic kilometers)!