In February 2006, Kaku appeared as presenter in the BBC-TV four-part documentary "Time" which seeks to explore the mysterious nature of time. Part one of the series concerns personal time, and how we perceive and measure the passing of time. The second in the series deals with cheating time, exploring possibilities of extending the lifespan of organisms. The geological time covered in part three explores the ages of the Earth and the Sun. Part four covers the topics of cosmological time, the beginning of time and the events that occurred at the instant of the big bang.