This 15-answer worksheet is designed to accompany Episode 8, Sisters of the Sun, of the documentary television series Cosmos: A Spacetime Odyssey hosted by Neil deGrasse Tyson and follows up Cosmos: A Personal Voyage presented by Carl Sagan. This episode explores the violent cosmic phenomenon of supernovas, which on average occur once per galaxy per century or one billion times per year in the observable universe. The episode pays homage to the discoveries of two female astronomers, Cecilia Payne (voiced by Kirsten Dunst) and Annie Jump Cannon (voiced by Marlee Matlin), and the obstacles faced by female scientists, especially those working in the early 20th century. Payne discovered the chemical composition of stars and that they consist largely of Hydrogen. Cannon developed the first catalog for the spectral characteristics of stars. The episode's title refers to the scientific contributions of the female scientists featured in the episode as well as how their discoveries helped advance our knowledge of the composition of stars. Applies to science, astronomy, physics, history, chemistry, nuclear physics and astrophysics.