“By exchanging the burning-coal idea for the notion of nuclear fusion, science was really trading an amazing wrong idea for an amazing right one. Given the total power emitted by the Sun, which delivers nearly a kilowatt of energy to each square yard of Earth’s sunlit surface every second, and the formula E = mc2, it’s easy to calculate how much of the Sun’s body gets continuously consumed and turned into light. The truth is a little disconcerting: the Sun loses four million tons of itself each second.”