What is the future of life on Earth and in our Solar System? The Sun is the source of energy for life on the Earth, but it will not shine forever. This lecture looks at the impact of the various stages of the evolution of the Sun on the habitability of the Solar System, with particular emphasis on the continued habitability of the Earth. I will refer to state-of-the-art computer models of the Sun to get is properties at various stages in its past and future life. NOTE: Due to a recorder malfunction this lecture was re-recorded later in the day on 2009 Dec 2, rather than being live from the class room in Smith Laboratory. As such, it is about 10 minutes longer than usual (my pacing is off when not in front of class).