Here's why:

* Speed of Light: All electromagnetic waves travel at the speed of light in a vacuum, which is approximately 299,792,458 meters per second (approximately 186,282 miles per second). This includes radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays.

* Other Waves: Other types of waves, like sound waves or water waves, travel much slower than light. The speed of these waves depends on the medium they travel through.

Important Note: While electromagnetic waves travel at the speed of light in a vacuum, they can slow down when they pass through different materials.