Explore the mysteries of the early Universe in this captivating lecture on cosmic microwave background radiation. Delve into the origins of the oldest light in the Universe, emitted just 400,000 years after the Big Bang, and discover how it contains the seeds of cosmic structures. Examine the development of the Big Bang Theory, key discoveries in cosmology, and the unexpected results from measuring the Universe's expansion. Learn about the Hubble tension in modern cosmology and potential solutions from new observations. The lecture covers topics such as redshift, infrared telescopes, Project Echo, Telstar, and the groundbreaking work of scientists like Vesto Slipher, Edwin Hubble, and Penzias and Wilson. Gain insights into why we can only observe the cosmos in the past and how the James Webb Space Telescope contributes to our understanding. Conclude with a Q&A session to further explore these fascinating concepts in astrophysics and cosmology.