By engaging with all the videos within this series, you will effectively complete a full undergraduate course in astronomy, equipping yourself with the knowledge and skills necessary to navigate the night sky with confidence, learning all the basics and many advanced topics! In the 19th century, the wave theory of light gained prominence, leading to investigations into its propagation mechanisms. This essay highlights pivotal discoveries and theoretical advancements that shaped our understanding of light, focusing on key figures like Michael Faraday and James Clerk Maxwell. The wave theory, which posits light as a wave, became dominant in the 19th century, enabling deeper investigations into light wave propagation. Electromagnetic theories linked electric and magnetic fields with light, expanding scientific discourse. In 1831, Michael Faraday’s discovery of electromagnetic induction marked a significant milestone. He observed that moving a magnet across a wire generated an electric current, suggesting a relationship between magnetic fields and light. Faraday conceptualized light as a disturbance in field lines from electric or magnetic sources, laying the groundwork for electromagnetic theory. Despite limited mathematical training, Faraday’s insights into electric and magnetic fields had a lasting impact. His intuitive grasp of field lines elucidated electromagnetic phenomena, which Maxwell later mathematically formalized. In 1864, James Clerk Maxwell synthesized Faraday’s observations into four fundamental equations of electromagnetism. Maxwell’s equations linked light with electromagnetic waves by predicting the speed of light. They describe the electric and magnetic fields and how they interact. Gauss’s Law describes electric fields, Gauss’s Law for Magnetism explains magnetic fields, Faraday’s Law relates changing magnetic fields to induced electric fields, and the Ampère-Maxwell Law relates electric currents and changing electric fields to magnetic fields. These equations unified electricity and magnetism and provided a foundation for understanding light as an electromagnetic wave. Subsequent research confirmed that light exists in a spectrum beyond the visible spectrum, raising questions about its medium. In the 19th century, scientists sought an ‘ether’ to facilitate light wave transmission. Faraday suggested light doesn’t need a medium, but the quest for evidence continued. Pioneering scientists like Faraday and Maxwell advanced our understanding of light and its propagation. As we delve deeper, we build on their foundational work. In our next lecture, we’ll explore the medium of light propagation and its implications for physics. LightTheory Electromagnetism JamesClerkMaxwell MichaelFaraday Physics ScienceEducation WaveTheory Optics InfraredDiscovery HistoricalPhysics Key themes and topics emphasized include: LightTheory, Electromagnetism, JamesClerkMaxwell, MichaelFaraday, Physics, ScienceEducation, WaveTheory, Optics, InfraredDiscovery, HistoricalPhysics.