We're about to head into some fairly dense scientific territory and one of the strangest mysteries of all, the Big Bang. The big question for this segment is, why shouldn't I panic? [MUSIC] It's often at this point in Big History courses, online or in the classroom, that people's heads feel like they are about to explode from all the new and overwhelming detail, and some pretty out there concepts about the beginning of all existence. A topic as massive and mysterious as the Big Bang can feel quite mind boggling for people who are visiting the topic for the first time. All I can say is, keep calm and carry on. You do not need to become a Nobel Prize winning physicist to explore big history. You won't be doing mathematical equations, in this course, and you won't have to memorize all the technical details the first time you watch a video. Big History provides a framework for knowledge, which can be fleshed out by later studies. But the important thing is to see how all the knowledge fits together into one unified narrative. The other point is that you can see the significance of the Big Bang, and all the other thresholds of complexity, by seeing how they relate to the wider story. Just like you don't need to be a technical expert at constructing and using a 15th century longbow, to study its wider historical significance to the Hundred Years War. Lots of French knights with bits of wood sticking out of them, and a couple of decades with an English King of France, you won't be needing a PhD in Astrophysics, to develop your understanding of the role of cosmology in the enfolding tale of 13.8 billion years. Big History provides a story, people of different backgrounds take different things away from that story. So don't let the fact that you may have been terrible at science in school scare you off. In fact, Big History has a knack for making science heavy topics accessible to everyone, if it is given its proper chance. So relax. Don't worry. Enjoy the next set of lectures where we explore the cosmos, from the beginning of everything to the formation of the tiny rock we call home. [MUSIC]