Electromagnetic waves can travel through space without the need for a medium because they are composed of oscillating electric and magnetic fields. Unlike mechanical waves, such as sound waves or water waves, which require a medium (like air or water) to propagate, electromagnetic waves do not rely on a material medium for their transmission.
According to Maxwell's equations, changing electric fields generate magnetic fields, and changing magnetic fields generate electric fields. This continuous interplay between electric and magnetic fields allows electromagnetic waves to propagate through space.
In the absence of a medium, electromagnetic waves can travel through the vacuum of space at a constant speed, known as the speed of light, which is approximately 299,792,458 meters per second. This speed is a fundamental constant of nature and is denoted by the symbol "c."
Electromagnetic waves can travel through a variety of media as well, such as air, water, glass, or other substances, but in space, they can travel unhindered due to the absence of a material medium. This property enables electromagnetic waves, including visible light, radio waves, microwaves, X-rays, and gamma rays, to propagate through the vacuum of space and reach us from distant celestial objects like stars, galaxies, and other astronomical phenomena.