The velocity of light in a vacuum does not depend on anything. It is a fundamental constant of nature, denoted by the letter 'c', and is approximately equal to 299,792,458 meters per second.

Here's why:

* Maxwell's Equations: The speed of light in a vacuum is derived from Maxwell's equations, which describe the fundamental relationships between electric and magnetic fields. These equations are independent of any specific reference frame.

* Special Relativity: Einstein's theory of special relativity states that the speed of light in a vacuum is the same for all observers, regardless of their relative motion. This is a cornerstone of the theory.

Important Note: While the speed of light is constant in a vacuum, it does slow down when it travels through a medium like air, water, or glass. This is because the light interacts with the particles of the medium.