There is power in thinking deeply about these concepts, writes Dr. Alan Townsend, author of the moving new memoir This Ordinary Stardust: A Scientist's Path from Sadness to Wonder, which intertwines his scientific and emotional journeys in the aftermath of his wife Diana and four-year-old daughter Neva's brain cancer diagnosis. Townsend, strict scientist that he is, estimates the chance of such a scenario at less than three in a hundred billion.