In the first of today's lessons, I started by quizzing Jared on what he had learned the day before regarding the structure of atoms, and how our understanding has progressed. We then reviewed the first stages of a star's life (birth in a molecular cloud, the fusion of hydrogen into helium for about 10 billion years for a star like our Sun). At the end stages, when the star has consumed all its fuel, it becomes unstable and puffs out into what we call a red giant. In 5 billion years, when our Sun will become a red giant, it will encompass Earth's orbit. Following this period, the outer layers of the star will vent into space, and the star enters the stage we call a planetary nebula. We looked at some images of different planetary nebulae, and discussed how the elements formed in the fusion processes inside stars are now contributing to the interstellar medium.