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tags: #physics #electromagnetism #waves

Light is an electromagnetic wave—a self-propagating disturbance in space with electric and magnetic components. This was the groundbreaking discovery of James Clerk Maxwell in the 19th century.

An electromagnetic wave is created by an accelerating electric charge. This creates oscillating electric and magnetic fields that are perpendicular to each other and to the direction of wave propagation. Once created, the wave is self-sustaining and can travel through the vacuum of space.

Visible light is just a small part of a vast electromagnetic spectrum, which includes:

• Radio waves
• Microwaves
• Infrared
• Visible light (ROYGBIV)
• Ultraviolet
• X-rays
• Gamma rays

All these waves are fundamentally the same phenomenon, differing only in their wavelength and frequency, and they all travel at the speed of light, c. The discovery that light could travel through a vacuum raised a new question: what was the medium that was "waving"? This led to the theory of the Luminiferous Aether.

Reference

Coursera, "Question Reality: Matter"