Electromagnetic waves, which include radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays, are all forms of electromagnetic radiation. These waves are generated by the interaction of electric and magnetic fields, and they travel through a vacuum at a constant speed, known as the speed of light. This speed is approximately 3.00 x 10^8 meters per second (m/s), and it is denoted by the symbol 'c'. According to the theory of relativity, as formulated by Albert Einstein, this is the ultimate speed limit in the universe, and no object with mass can be accelerated to this speed. However, it's important to note that while the speed of electromagnetic waves in a vacuum is a constant, their speed can be affected by the medium through which they are traveling. For example, when light enters water or glass, it slows down, and its speed becomes less than the speed of light in a vacuum. read more >>

Generally speaking, we say that light travels in waves, and all electromagnetic radiation travels at the same speed which is about 3.0 * 108 meters per second through a vacuum. We call this the "speed of light"; nothing can move faster than the speed of light.read more >>