Cosmos: A Spacetime Odyssey

Episode 08 - Sisters of the Sun. This episode provides an overview of the composition of stars, and their fate in billions of years. Tyson describes how early human would identify stars via the use of constellations that tied in with various myths and beliefs, such as the Pleiades. Tyson describes the work of Edward Charles Pickering to capture the spectra of multiple stars simultaneously, and the work of the Harvard Computers or "Pickering's Harem", a team of women researchers under Pickering's mentorship, to catalog the spectra. This team included Annie Jump Cannon, who developed the stellar classification system, and Henrietta Swan Leavitt, who has discovered the means to measure the distance from a star to the earth by its spectra, later used to identify other galaxies in the universe. Later, this team included Cecilia Payne, who would develop a good friendship with Cannon; Payne's thesis based on her work with Cannon was able to determine the composition and temperature of the stars, collaborating with Cannon's classification system.

Tyson then explains the lifecycle of stars, being borne out from interstellar clouds. He explains how stars like the Sun keep their size due to the conflicting forces of gravity that pulls the gases in, and the expansion from escaping gases from the fusion reactions at its core. As the Sun ages, it will grow hotter and brighter to the point where the balance between these reactions will fail, causing the Sun to first expand into a red giant, and then collapse into a white dwarf, the collapse limited by the atomic forces. Tyson explains how larger stars may form even more collapsed forms of matter, creating novas and supernovas depending on their size and leading to pulsars. Massive stars can collapse into black holes. Tyson then describes that stars can only be so large, using the example of Eta Carinae which is considered an unstable solar mass that could become a hypernova in the relatively near future. Tyson ends describing how all matter on Earth is the same stuff that stars are made of, and that light and energy from the stars is what drives life on Earth. (from

Episode 08 - Sisters of the Sun

Go to Cosmos: A Spacetime Odyssey Home or watch other episodes:

Episode 01 - Standing Up in the Milky Way
Episode 02 - Some of the Things that Molecules Do
Episode 03 - When Knowledge Conquered Fear
Episode 04 - A Sky Full of Ghosts
Episode 05 - Hiding in the Light
Episode 06 - Deeper, Deeper, Deeper Still
Episode 07 - The Clean Room
Episode 08 - Sisters of the Sun
Episode 09 - The Lost Worlds of Planet Earth
Episode 10 - The Electric Boy
Episode 11- The Immortals
Episode 12 - The World Set Free
Episode 13 - Unafraid of the Dark