Here's why:

* Light is electromagnetic radiation: It travels in the form of oscillating electric and magnetic fields. These oscillations create waves.

* Light doesn't need a medium: Unlike sound waves, which need a medium like air or water to travel, light can travel through the vacuum of space.

* Speed of light: Light travels at a constant speed of approximately 299,792,458 meters per second in a vacuum.

While light is the most well-known example, other forms of electromagnetic radiation, like radio waves, microwaves, X-rays, and gamma rays, also travel in waves through space.