The Earth as a Planet - Lecture 1

Explore the Earth's place in the universe through the first of six Christmas Lectures delivered by renowned American astronomer and cosmologist Carl Sagan in 1977. Delve into the history of our understanding of Earth's position in the Solar System, from the Aristotelian geocentric model to the heliocentric model. Discover how advancements in observational tools, from simple telescopes to complex spacecraft, have revolutionized our knowledge of our planet's environment, climate, weather, geology, and biology. Gain unique insights into the scale and geometry of the "pale blue dot" as Sagan uses images and models to illustrate Earth's formation 4.5 billion years ago and its relative place in the cosmos. Learn about the evolution of space science since Sagan's lectures and how it has expanded our understanding of Earth and the universe beyond.