According to sixth-century-bc Greek poet Hipponax of Colophon, in times of drought, famine, or plague an ugly or deformed person was chosen by the community to be pharmakós, or scapegoat. After being fed figs, barley cake, and cheese, he would be struck on the genitals with the bulbs and twigs of wild plants, led on a procession accompanied by flute, and burned on a pyre. His ashes were thrown into the sea. It is believed that Hipponax, whom Pliny the Elder once called “notoriously ugly,” may have been exaggerating the ritual.

When Albert Einstein visited Beno Gutenberg, a seismologist at Caltech, in 1933, the two strolled around the Pasadena campus while Gutenberg explained earthquake science. Suddenly their wives arrived to inform them there had been a massive earthquake. “We had become so involved in seismology,” recalled Gutenberg later, “that we hadn’t noticed.”

The first mass extinction on earth occurred around 2.5 billion years ago, when a photosynthesizing bacterium appeared and released so much oxygen into the atmosphere that anaerobic life was largely wiped out. This is often called the Great Oxygenation Event, the Oxygen Catastrophe, or the Oxygen Holocaust. 

The opening of a particle accelerator at Brookhaven National Laboratory in 2000 inspired fears that high-speed collisions might launch a chain reaction that could turn the earth into a hyperdense sphere about one hundred meters across. A risk calculation determined this to be unlikely; if the collider were to run for ten years, the chance was no greater than 1 in 50 million. “The word unlikely, however many times it is repeated,” wrote concerned scientists, “just isn’t enough to assuage our fears of this total disaster.”

“Thank the good God we have all got through and the only family that did not eat human flesh,” wrote fourteen-year-old Virginia Reed, a surviving Donner Party member, in an 1847 letter. “Don’t let this letter dishearten anybody and never take no cutoffs and hurry along as fast as you can.” Reed reported being “pleased with California, particularly with the climate.”