Explore the fundamental nature and purpose of light in this 15-minute video lecture. Delve into the wave-particle duality of light, its role in the development of relativity and quantum mechanics, and its significance in energy transfer and force mediation. Examine how light is essential for the existence of atoms, matter, and the universe as we know it. Discover the importance of photons in energy exchange processes and information transfer across the cosmos. Learn about black body radiation and gain insights into how light serves as the fundamental currency for energy and information exchange in the universe.