In Newtonian physics, the concept of a maximum speed is not explicitly defined. According to Newton's laws of motion, an object can theoretically continue to accelerate indefinitely if a force is applied to it. In this framework, there is no inherent limit on how fast an object can travel.
However, in the theory of special relativity, proposed by Albert Einstein in 1905, a finite maximum speed is introduced: the speed of light in a vacuum, denoted by "c." According to special relativity, the speed of light is the same for all observers, regardless of their relative motion. This principle forms the foundation of many of the theory's profound consequences.
One of the key implications of the finite speed of light is that it sets an upper limit on how fast information, energy, or any causal influence can travel through space. Nothing with mass can reach or exceed the speed of light. As an object with mass approaches the speed of light, its energy and momentum increase significantly, making it increasingly difficult to accelerate further. At the speed of light, an object with mass would require an infinite amount of energy to reach or surpass that velocity.
This limitation on speed has far-reaching consequences in the theory of special relativity, including time dilation, length contraction, and the breakdown of Newtonian notions of simultaneity. It also underlies the famous equation E=mc², which relates energy (E) and mass (m) and demonstrates the equivalence of mass and energy.
In summary, while Newtonian physics does not impose a maximum speed, special relativity introduces the finite speed of light as a fundamental principle, leading to significant changes in our understanding of space, time, and the behavior of objects at high speeds.