15 May, 2026

Newtonian Physics vs Quantum Mechanics

Special or General Relativity

The distinction between the 3 scenarios is accomplished as follows:

Test Particle

Physicists categorize a test particle based on its velocity and the gravitational field strength it experiences. We distinguish its behaviour across the 3 frameworks as follows:

  1. Non-Relativistic Particle (Newtonian Physics)
    1. Velocity: Much slower than the speed of light (v ≪ c).
    2. Gravity: Weak or treated as a classic absolute force.
    3. Key Behavior: Mass remains constant, and space/time are absolute.
  2. Special-Relativistic Particle (Special Relativity)
    1. Velocity: Approaches the speed of light (v ≈ c).
    2. Gravity: Negligible or absent.
    3. Key Behavior: Exhibits time dilation, length contraction, and relativistic momentum scaling.
  3. General-Relativistic Particle (General Relativity)
    1. Velocity: Can range from slow to light speed (v ≤ c).
    2. Gravity: Strong enough to curve spacetime.
    3. Key Behavior: Follows spacetime geodesics; experiences gravitational time dilation and frame-dragging.