In which Stan Muller subs for John Green and teaches you about energy and humanity. Today we discuss the ideas put forth by Alfred Crosby in his book, Children of the Sun. Historically, almost all of the energy that humans use has been directly or indirectly generated by the sun, whether that be food energy from plants, wind energy, direct solar energy, or fossil fuels. Stan looks into these different sources, and talks about how humanity will continue to use energy in the future as populations grow and energy resources become more scarce.