Final answer:
Electromagnetic waves can travel through empty space, distinguishing them from mechanical waves that require a medium. This is a primary reason why we can observe light from distant stars and galaxies.
Step-by-step explanation:
The correct answer to the question is A) True. Electromagnetic (EM) waves, unlike mechanical waves such as sound or earthquake waves (seismic waves), can indeed travel through the vacuum of space. Mechanical waves require a medium, like air or water, to travel through. However, electromagnetic waves are self-propagating; they are generated by oscillating electric and magnetic fields that can move through space without the need for any medium. This phenomenon is one of the unique properties of electromagnetic radiation.
It was once believed that a substance called the "aether" was necessary for light to travel through space, but this concept is now known to be false. Electromagnetic waves can travel through a vacuum at a constant speed, often denoted as "c," which is approximately 3 × 10⁸ m/s. This fundamental characteristic enables electromagnetic waves, which include radio waves, microwaves, infrared waves, visible light, ultraviolet waves, X-rays, and gamma rays, to reach us from astronomical distances without the need for any intervening medium.