What type of wave does not require matter to propagate?

Electromagnetic waves are unique in that they do not require a medium to travel through; they can propagate through a vacuum, such as the empty space in the universe. This is because electromagnetic waves consist of oscillating electric and magnetic fields that can generate each other, allowing the wave to move through space even in the absence of matter. This characteristic distinguishes them from mechanical waves, which rely on particles of a medium (like air, water, or solids) to transmit energy and cannot travel through a vacuum. Understanding this distinction is crucial in physics and helps clarify the nature of different types of waves and how they interact with the environment.