How to Invent Everything: A Survival Guide for the Stranded Time Traveler

by Ryan North

The red grapefruit eaten today is a product of a 1950s program in the United States called Atoms for Peace, whose goal was to promote practical uses for nuclear power outside of a wartime context. One of the things Atoms for Peace came up with was the gamma garden, which is exactly as amazing as it sounds. Radioactive material was put in the middle of a garden, around which concentric rings of plants were planted. The plants closest died of radiation poisoning, the plants farthest away were largely unaffected, but the plants in the middle mutated. Some of those mutations were useful, and among them was the modern red grapefruit: a sweeter, atomically induced mutation of the existing red grapefruit, whose flesh often faded to a less-desirable pink. Most red grapefruit today comes from the descendants of those atomically mutated plants.