Now used to refer to a convenient principle with a broad application not intended to be strictly accurate in every situation, the term "rule of thumb" first appeared in print in Sir William Hope's The Compleat Fencing-Master in 1692. The phrase is thought to have originated with woodworkers who used the length of their thumbs, rather than rulers, for measurements. However, it is often erroneously claimed that the term originally referred to a law that limited the thickness of what?
Louisa May Alcott
Back in the day
Launched into orbit in 1973, Skylab was the first US space station. It carried a laboratory for studying the human body's adaptation to weightlessness and a powerful solar telescope. Three successive astronaut crews conducted research aboard Skylab for a total of 171 days in 1973–74. Though Skylab was intended to be reused, increased solar activity caused its orbit to degrade faster than expected. In 1979, the 75-tonne station reentered Earth's atmosphere and broke up. Where did the debris land?
Born on a day like today
Guevara was a Latin American revolutionary who developed guerrilla warfare as a tool for revolution. Born in Argentina, Guevara traveled widely in Latin America and became convinced that only violent revolution would end the poverty he witnessed. He joined the Cuban Revolution and became one of Fidel Castro's most trusted aides before leaving to foster revolutions elsewhere. He was killed in 1967 while directing a guerrilla movement in Bolivia. What is the meaning of Guevara's nickname, "Che"?