Air-conditioning, refrigeration, and superconductivity are just some of the ways technology has put cold to use. But what is cold, how do you achieve it, and how cold can it get?
The two-part special follows the quest for cold from the unlikely father of air-conditioning, the court magician of King James I of England in the 17th century, to today's scientists pioneering superfast computing in the quantum chill near absolute zero—the ultimate extreme of cold at minus 273.15 C (minus 460 F).
Part One, "The Conquest of Cold," opens in the 1600s when the nature of cold and even heat were a complete mystery. Are they different phenomena or aspects of some unified feature of nature? Are they added to a substance or qualities of the substance itself? The experiments that settled these questions helped stoke the Industrial Revolution, which exploited such fundamental insights as that heat always flows from hot to cold.