Modern physics, or also called quantum physics, is an academic discipline that was born from the birth of two theories: the Quantum Theory in 1900 and the Theory of Relativity in 1905 .
See also Quantum Physics .
From the 20th century on, the question of how light propagates was resolved by introducing what we know today as modern physics. During the birth of classical or Newtonian physics, the debate over whether light was a particle or a wave did not find a solid foundation.
In 1900, Max Planck (1858-1947) coined the term quantum ( Latin quantum ) as the minimum energy contained in a particle to explain and measure the radiation found in a dark body.
In this sense, the physicist Max Planck affirmed that light propagates in energy packages and the energy of each package was inversely proportional to the wavelength determined in the Planck constant.
On the other hand, Albert Einstein in 1905, with his Theory of Relativity, postulates that both time and space are relative and verifies that the speed of light is a fundamental constant of nature. In this way, Einstein reinforces Planck’s idea about the propagation of light as energy particles and that these particles are photons that always travel at the speed of light.
See also Speed of light .
For photons to travel at the speed of light, their mass will always be 0 because if a particle is massive it would need infinite energy to move, as postulated by Newton’s First Law of Classical Physics. Therefore, only a massless particle can travel at the speed of light and possess infinite energy, thus defining an electromagnetic field quantum.
See also classical physics .
In this way, the basic postulate of modern physics, also known as quantum mechanics, indicates that the elementary particles that make up matter are endowed with both wave and particle properties.
See also Quantum Mechanics .
The wave-particle duality is, in this way, the fundamental property of nature at the atomic level, defining the bases for modern Physics known as the study of the behaviors, characteristics and radiation of particles at the atomic and subatomic level and not only of everyday objects, field of study of classical physics.