Light is an electromagnetic wave, and it propagates through space by oscillating electric and magnetic fields. This wave-like behavior of light can be described by Maxwell's equations, which are fundamental equations in classical electromagnetism. According to these equations, changing electric fields create magnetic fields, and changing magnetic fields create electric fields. This reciprocal relationship allows the electromagnetic wave to propagate through space.
Light also exhibits particle-like behavior, which is described by quantum mechanics. In quantum theory, light is composed of discrete packets of energy called photons. Each photon carries a specific amount of energy, and its behavior can be described by wave-particle duality.
When light is emitted or absorbed by matter, it behaves as though it is made up of individual particles (photons). For example, in the photoelectric effect, photons interact with electrons in a material, causing the electrons to be ejected. The energy of the ejected electrons depends on the energy of the individual photons involved in the interaction.
However, when light propagates through space, its wave-like properties become more apparent. The wave nature of light allows it to exhibit interference and diffraction phenomena, similar to other types of waves. This is why we observe phenomena such as interference patterns in double-slit experiments or the bending of light around obstacles.
The wave-particle duality of light is not a contradiction but rather a fundamental aspect of quantum mechanics. Light can exhibit both wave-like and particle-like behavior depending on the experimental context. In space, light primarily behaves as an electromagnetic wave, propagating through the vacuum without the need for a medium. The distance between particles in space does not impede the propagation of light waves. Instead, the electric and magnetic fields of the wave interact with charged particles (such as electrons) that may be present in space, causing various phenomena like absorption, scattering, or reflection.