“If people would think more of fairies, they would soon forget the atom bomb,” Walt Disney quipped in 1948. President Dwight D. Eisenhower agreed: public fear of the atom bomb was growing, and in 1953 he assured Americans in his “Atoms for Peace” speech that war was not imminent and that nuclear technology had enormous potential for peacetime activity as well. Eisenhower then recruited Disney to produce a television program promoting the “peaceful atom.” In 1957, “Our Friend the Atom” aired on ABC, featuring animated cartoons and narration by Heinz Haber, a scientist who had worked in Nazi Germany and later became a technical consultant for Disney’s Tomorrowland theme park.

In 1783 an English rector named John Michell wrote to the physicist Henry Cavendish of his belief in the possibility of “dark stars,” entities so dense and with such a strong gravitational pull that they could prevent light from escaping them and render them invisible. The Royal Society published his theory the following year, but it would be nearly two hundred years before the term black hole was used to refer to such a phenomenon.

The astronomer and mathematician Thales of Miletus is believed to have been the first ancient Greek scholar to discuss the phenomenon of magnetism. Aristotle notes in On the Soul that Thales held the belief that “the magnet has a soul in it because it moves the iron.” Five and a half centuries later, Diogenes Laërtius concurred with Aristotle, observing that Thales “attributed a soul or life even to inanimate objects.”

Amphetamine salts became popular among soldiers during World War II as a stimulant to counteract fatigue. One study estimates that up to sixteen million Americans had been exposed to Benzedrine by the end of the war. Civilian use increased rapidly after that, especially among upper-middle-class women, who used the drug for appetite suppression and as an antidepressant. In 1962 the pharmaceutical company Smith, Kline & French ran an advertisement targeted toward physicians and featuring a photograph of a female patient. “With your encouragement and Dexedrine Spansule,” the ad proclaims, “she’s losing weight.”

Muscle Shoals, Alabama, site of a huge munitions plant during World War II, had a surplus of ammonium nitrate in 1946. The U.S. Department of Agriculture suggested that the chemical, a primary ingredient in explosives, be used as fertilizer. Industrial production of the resulting synthetic fertilizer led to an explosion in corn yields in the 1950s. A Tennessee Valley Authority representative recounted that “as soon as the need for nitrate explosives fell off, we were ready to convert that to agricultural nitrate.” “We are eating the leftovers of the Second World War,” the environmental activist Vandana Shiva said in a 2005 speech.

Among some species of North American fireflies, females lie in wait for light emitted by males drifting above. A 2022 study found that 96 percent of male fireflies preferred to attempt mating in darkness. No mating occurred in bright artificial light, under which the researchers observed “males crawling directly past or even over females without initiating mating stage one.” The fireflies were “waiting to mate in dimmer conditions,” a New York Times article suggested, “essentially waiting for a night that never comes.”

The Hungarian American physicist Leo Szilard first conceived of the nuclear chain reaction—a crucial milestone in the development of the atomic bomb—on a gray London morning in September 1933 while waiting for a traffic light to change from red to green. “It suddenly occurred to me that if we could find an element…which would emit two neutrons when it absorbed one neutron,” he wrote, this element could “liberate energy on an industrial scale, and construct atomic bombs.” In his book on the history of the bomb, historian Richard Rhodes writes that “as he crossed the street time cracked open before him and he saw a way to the future, death into the world.”