From: lexfridman
Classical mechanics, a framework for understanding the physical world, was developed by Isaac Newton in the 17th century. This branch of physics is often used to describe the motion of macroscopic objects, from everyday phenomena like throwing a rock to the celestial motion of planets around the sun. However, while classical mechanics has been extraordinarily successful, it also has notable limitations when it comes to explaining certain physical phenomena.
Newton’s Contribution to Classical Mechanics
Isaac Newton’s work on mechanics laid the foundation for classical mechanics, particularly with his formulation of the laws of motion and universal gravitation. Newton’s theories allowed for the prediction of the trajectory of objects and celestial bodies, which have been profoundly influential in science and engineering [00:01:23].
One of the most significant challenges Newton himself encountered was the concept of “action at a distance,” which seemed absurd to him. He pondered over how the Earth could sense the Sun’s gravitational pull 93 million miles away without any physical contact [00:03:10]. Newton admitted that he did not know how gravity worked fundamentally and left it to future generations to address [00:03:19].
Development Beyond Newton: Field Theories
Future generations of physicists, such as Pierre-Simon Laplace, reinterpreted Newton’s law of gravitation into a field theory, enabling a description of gravity without the controversial notion of action at a distance. In Laplace’s reformulation, space was filled with a gravitational field, thereby removing the need for instantaneous action over vast distances [00:03:30].
Albert Einstein’s theory of General Relativity further revolutionized the concept of gravitation, introducing a field theory where gravity was the result of the curvature of spacetime, replacing the concept of gravitational force acting at a distance. This contrasts with Newtonian gravity, where the field was still presumed to have the ability to act across limitless distances [00:04:12].
Limitations of Classical Mechanics
While extraordinarily effective and mathematically robust, classical mechanics was revealed to have limitations. For example, classical descriptions break down at very high velocities approaching the speed of light or on very small scales where Quantum Mechanics dominates. Quantum mechanics, which deals with these small scales, contradicts classical notions by introducing elements such as wave-particle duality and uncertainty, where deterministic predictions of classical mechanics become probabilistic [00:25:48].
Moreover, classical mechanics cannot adequately describe the effects and interactions explained by General Relativity and Quantum Mechanics and General Relativity Connections, such as the behaviors observed in black holes or predictions involving quantum fields [01:01:05].
Conclusion
Classical mechanics remains foundational in physics and engineering for describing and predicting a wide range of phenomena in the macroscopic world. However, its limitations are exposed in extreme environments or at atomic and subatomic scales, necessitating more sophisticated theories like quantum mechanics and general relativity. These developments not only extend our capabilities to predict natural phenomena but also deepen our understanding of the universe’s fundamental principles.