Until the End of Time: Mind, Matter, and Our Search for Meaning in an Evolving Universe

by Brian Greene

of all the innumerable processes, life on planet earth leverages one and only one energy mechanism: a specific sequence of electromagnetic chemical reactions in which electrons engage in a downward-directed sequence of jumps, starting with food or water and ending with the clutching embrace of oxygen. How and why did this energy extraction process become life’s go-to mechanism? No one knows. But the universality, like that of the genetic code, speaks again, and strongly so, to the unity of life. Why do all living things power themselves in the same way? The immediate answer is that all life must have descended from a common ancestor, a single-celled species that researchers believe likely existed around four billion years ago.