The generation of an electromagnetic wave from an oscillating electric field is a fundamental concept in electromagnetism explained by Maxwell's equations. Maxwell's equations describe the behavior of electric and magnetic fields and their interplay.
When an electric charge undergoes acceleration or experiences a changing electric field, it creates an oscillating electric field in space. According to Maxwell's equations, a changing electric field induces a magnetic field perpendicular to it, and a changing magnetic field induces an electric field perpendicular to it. This interdependence between electric and magnetic fields gives rise to self-propagating electromagnetic waves.
The oscillating electric field generates a magnetic field, which in turn generates another electric field, and this process continues, resulting in the propagation of the electromagnetic wave. The changing electric and magnetic fields are mutually reinforcing and create a self-sustaining wave that can travel through space.
Unlike mechanical waves, such as sound waves or water waves, electromagnetic waves do not require a medium to propagate. This property of electromagnetic waves is known as their ability to travel through a vacuum. It is a consequence of the fundamental nature of electric and magnetic fields and their interaction.
In a vacuum or free space, electromagnetic waves propagate as transverse waves, where the electric and magnetic fields oscillate perpendicular to the direction of wave propagation. This allows electromagnetic waves to travel through empty space, enabling them to propagate from their source (such as an antenna) to a receiver without the need for a physical medium.
In other words, electromagnetic waves do not rely on the movement of particles or the presence of a material medium for their transmission. This property allows them to travel through the vacuum of outer space and reach us from distant celestial objects, such as stars and galaxies.