The movement of electromagnetic radiation with the same velocity in all directions is a fundamental property of electromagnetic waves, as described by Maxwell's equations and the theory of electromagnetism. This property is independent of the presence or absence of boundaries in space or time.
The speed of electromagnetic waves in a vacuum, commonly denoted as "c," is approximately 299,792,458 meters per second (or about 186,282 miles per second). This speed is constant and is referred to as the speed of light. It is a fundamental constant of nature.
According to the theory of special relativity, formulated by Albert Einstein, the speed of light in a vacuum is invariant and is the maximum speed at which any form of information or energy can travel. This means that electromagnetic radiation, whether it's in the form of radio waves, visible light, X-rays, or any other part of the electromagnetic spectrum, will always propagate at this constant speed.
The uniform propagation of electromagnetic waves in all directions is a consequence of the wave nature of electromagnetic radiation. When an electromagnetic wave is generated, oscillating electric and magnetic fields propagate through space, perpendicular to each other and to the direction of wave travel. These fields are self-perpetuating and don't require any physical medium to propagate.
In the absence of any significant obstacles or interactions, electromagnetic waves spread out spherically in all directions, maintaining their velocity and intensity. This behavior is due to the nature of the electromagnetic fields and their ability to influence each other through the laws of electromagnetism.
While space may be vast and seemingly boundless, the velocity of electromagnetic waves remains constant because it is a fundamental property of the electromagnetic field and its interaction with space and time. The absence of boundaries in space does not affect the propagation of electromagnetic waves or alter their velocity.