- Gravity forces large masses like planets and stars into spherical shapes.
- A sphere is the most compact three-dimensional shape with the lowest surface area for a given volume.
- Any other shape would be reshaped by gravity into a sphere.
- Less massive bodies experience weaker gravitational force, allowing electromagnetic forces to resist gravity, resulting in non-spherical shapes (e.g., comets, asteroids, humans).
- Stars and planets are not perfectly spherical; they are oblate spheroids. Rotation creates a centrifugal force, causing a bulge at the equator.
- This makes gravity weaker at the equator and stronger at the poles. On Earth, objects fall slightly faster at the poles than at the equator.
Dig Deeper: What are gravitational waves?
