What is Light? Maxwell and the Electromagnetic Spectrum

Since ancient times, humans have been aware of light and often attributed godlike properties to it. However, the true nature of light remained a mystery until the 17th century when figures like Newton and Huygens began to study it.

In the 19th century, James Clerk Maxwell developed classical electromagnetism, describing light as a transverse wave composed of oscillating electric and magnetic fields perpendicular to each other and to the wave's direction of movement.

Like other waves, electromagnetic waves have amplitudes, wavelengths, and frequencies. Different frequencies of these waves produce different kinds of light. Visible light corresponds to certain frequencies, while higher frequencies include UV radiation, X-rays, and gamma rays, and lower frequencies include infrared radiation, microwaves, and radio waves.

All these phenomena are collectively known as electromagnetic radiation and are found on the electromagnetic spectrum. This spectrum encompasses a wide range of wavelengths and frequencies, from radio waves to gamma rays, all of which have technological applications despite appearing dramatically different.

All electromagnetic radiation travels at the speed of light, approximately 300 million meters per second in a vacuum, which is the fastest possible speed in the universe. The product of a wave's wavelength and frequency equals this constant speed.