Which type of wave can travel through a vacuum?

The ability of a wave to travel through a vacuum is fundamentally linked to its nature. Electromagnetic waves, such as light, radio waves, and microwaves, do not require a medium for propagation because they are oscillations of electric and magnetic fields. This intrinsic property allows them to travel through empty space, or a vacuum, where there are no particles or matter.

In contrast, mechanical waves rely on a medium—such as air, water, or solid materials—to transfer energy. Mechanical waves, including longitudinal waves (which sound waves are a type of) and surface waves (like waves on water), cannot propagate without a medium present. This is because their movement is contingent upon the interaction of particles within that medium.

Thus, electromagnetic waves uniquely possess the capability to move through a vacuum, setting them apart from other wave types that necessitate matter for transmission.