Light is both visible and elusive, quietly shaping the course of human history. From the earliest flickers of firelight in prehistoric caves to today’s lightning-fast data transmissions, our journey with light is a story of discovery, imagination, and innovation.

By tracing the steps of this journey, we can uncover how our understanding of light has evolved—revealing not only the progress of science, but also the brilliance of human curiosity.

From Flame to Mirror: The First Step of Ancient Civilization

In prehistoric times, the first light source humans came into contact with was fire. The ancient Egyptians used sun worship to explain the mysterious power of light, while ancient Chinese bronze mirrors and magnifying glasses showed the initial application of light reflection and focusing by the ancients.

Ancient Greek philosophers Plato and Aristotle tried to explain the nature of light. Plato believed that vision originated from the "visual rays" emitted by the eyes, while Aristotle believed that light was a phenomenon that propagated in a transparent medium. Although these early thoughts were not accurate, they provided a valuable starting point for later generations.

The Golden Age of Arab Wisdom: The Rise of the Science of Light

In the Middle Ages, scholars in the Arab world brought about major breakthroughs in the field of optics. In the 11th century AD, Ibn al-Haytham (Alhazen) published the Book of Optics, which first proposed the idea that light enters the eye from an object, and studied reflection and refraction through experimental methods. He also used the principle of the dark camera to explain the imaging process, laying the groundwork for the birth of modern cameras.

His work not only challenged the views of ancient Greece, but also established the foundation of experimental science for optics, becoming an important bridge for the scientific revival during the Western Renaissance.

From Newton to Huygens: The Debate on the Nature of Light

In the 17th century, Newton discovered through prism experiments that white light can be decomposed into a rainbow-like color spectrum, and proposed the theory that light is composed of particles. This theory has far-reaching influence and also triggered a dispute with Huygens' view that "light is a wave".

Although there was a lack of experimental tools to support the wave theory at the time, Thomas Young's double-slit experiment in the early 19th century proved the wave nature of light through interference phenomena, which made people gradually accept that light is neither a pure particle nor just a wave, but a more complex existence.

Electromagnetic waves and the quantum revolution: Unveiling the dual identity of light

In the 19th century, James Maxwell proposed that light is a type of electromagnetic wave, belonging to the same spectrum as radio waves and itself. This theory links light with other natural phenomena and provides a theoretical basis for the development of wireless communication and radar technology.

In the early 20th century, Einstein proposed the concept of photons with the help of the photoelectric effect, proving that light has the dual nature of particles and waves at the same time. This theory gave birth to quantum mechanics and provided the foundation for modern technologies such as lasers, fiber-optic communications, and semiconductors.

Contemporary technology: the future illuminated by light

Today, we use light not only for illumination, but also for transmitting information, treating diseases, and driving energy. From fiber-optic communications to laser surgery, from solar panels to LED lights, humans have transformed the power of light into tools in life.

More cutting-edge fields such as quantum optics, super-resolution imaging, and photon computing are redefining the relationship between humans and light. For example, quantum communication uses the state of photons for ultra-secure transmission, which may subvert the existing Internet structure.

Light, never-ending exploration

From the torches in the hands of the ancients to the quantum lasers in modern laboratories, light has always accompanied the progress of human civilization. It not only illuminates the darkness, but also illuminates the boundaries of our cognition of the world.

We are far from exhausting all the secrets of light. In the days to come, light may continue to open the door to the universe, consciousness, and a new era of technology for us. We are willing to continue to pursue the footsteps of light with everyone and walk into the unknown world that is always bright.

A Visual History of Light

Video by The Atlantic