Which kinds of motion can classical physics explain well?

In the context of physical science, classical mechanics—often referred to as Newtonian mechanics—is highly effective at explaining and predicting the motion of objects across two primary realms.1

Realms of Application

• Celestial Bodies: Classical physics accurately predicts the motions of stars, planets, and satellites, often thousands of years in advance. While relativity accounts for minor deviations in these orbits, classical mechanics remains sufficient for most practical calculations.1
• Ordinary Objects: Objects on Earth, ranging from large structures like bridges and aircraft down to microscopic sizes, are well-described by classical laws, provided they move at speeds significantly lower than the speed of light.12

Key Principles

Classical mechanics focuses on the interplay of force, mass, and motion, governed by Newton’s laws of motion. It treats bodies as point particles or rigid objects and is deterministic, meaning that if the initial state of a system and the forces acting upon it are known, future motion can be determined.132

It is important to note that classical physics is not applicable to the behavior of matter and electromagnetic radiation at atomic and subatomic scales, which requires quantum mechanics, nor to objects moving at relativistic speeds.12