Foundational Physics

Classical mechanics is a fundamental branch of physics that describes the motion of macroscopic objects, from projectiles and machinery on Earth to the orbits of planets and stars. Grounded in the principles laid out by Isaac Newton, it utilizes concepts such as force, mass, momentum, and energy to mathematically predict how objects will move when subjected to various influences. This deterministic framework, where the future state of a system can be fully determined from its initial conditions, provides an incredibly accurate model for the everyday world, though its principles are superseded by quantum mechanics at the atomic scale and by relativity at speeds approaching the speed of light.

Thermal physics is the branch of physics that studies the nature of heat, temperature, and their relationship to energy, work, radiation, and the macroscopic properties of matter. It seeks to explain these large-scale phenomena by examining the collective motion and statistical behavior of their microscopic constituents, such as atoms and molecules. The entire field is fundamentally governed by the laws of thermodynamics, which describe how energy is transferred and transformed, and introduce the crucial concept of entropy as a measure of disorder within a system.

Electromagnetism is one of the four fundamental forces of nature, describing the interaction between electrically charged particles through electric and magnetic fields. It unifies what were once considered separate phenomena, revealing that a moving electric charge generates a magnetic field, and a changing magnetic field generates an electric field. Governed by Maxwell's equations, this foundational principle explains a vast range of phenomena, from the propagation of light—which is an electromagnetic wave—to the forces that hold atoms and molecules together, and it forms the basis for modern technologies like electric motors, generators, and all electronics.

Optics and Waves is a foundational area of physics dedicated to the study of disturbances that propagate and transfer energy through a medium or space. It examines the universal principles governing wave behavior, such as reflection, refraction, interference, and diffraction, which apply to everything from sound waves to seismic waves. A primary focus of this field is optics, which specifically investigates the properties and behavior of light as an electromagnetic wave, from its interaction with matter to its application in technologies like lenses, lasers, and fiber-optic communication.

Developed by Albert Einstein in 1905, Special Relativity is a foundational theory of physics that describes the relationship between space and time for objects moving at constant velocities. It is built upon two fundamental postulates: that the laws of physics are the same for all observers in uniform motion, and that the speed of light in a vacuum is constant for all observers, regardless of their motion or the motion of the light source. These principles lead to profound and counterintuitive consequences, including time dilation (moving clocks run slower), length contraction (moving objects appear shorter in their direction of motion), and the famous mass-energy equivalence, expressed by the equation E=mc².

Developed by Albert Einstein, General Relativity is the modern theory of gravitation, which posits that gravity is not a force but a consequence of the curvature of spacetime. In this framework, the distribution of mass and energy warps the four-dimensional fabric of spacetime, and this curvature, in turn, dictates how objects and even light move through it. As a generalization of Special Relativity and a refinement of Newton's law of universal gravitation, it accurately describes large-scale phenomena such as the orbits of planets, the bending of starlight, the existence of black holes, and the propagation of gravitational waves.