28: The Dark Side of the Sun

How has the Sun changed over the past 4 billion years?

While the Sun may seem unalterable, it has brightened dramatically over Earth's history, with major implications for our world. Today, we'll meet a team of women who catalogued thousands of stars in the 1800s, play in a galactic ball pit, and puzzle over a cosmic paradox alongside Carl Sagan.

Extra Credit: Watch Cosmos (1980)