In popular, nontechnical use, entropy is regarded as a measure of the chaos or randomness of a system. In thermodynamics, it is the measure of a system's energy that is unavailable for work or of the degree of a system's disorder. Entropy increases during irreversible processes, such as the spontaneous mixing of hot and cold gases. The concept, first proposed in 1850 by the German physicist Rudolf Clausius, is sometimes presented as the second law of thermodynamics, which states what?
E. M. Forster
Back in the day
In 1989, Venezuelan President Carlos Pérez returned to office amid demonstrations and riots sparked by deteriorating social conditions. Three years later, Lieutenant Colonel Hugo Chávez led an unsuccessful coup against Pérez and was jailed as a result. Pérez escaped another coup attempt later that year, but in 1993 he was removed from office on corruption charges and later imprisoned on charges of embezzlement and misuse of public funds. When did Chávez become president?
Born on a day like today
Yahya Khan was the president of Pakistan from 1969 to 1971. As president, he inherited a two-decade old constitutional problem of interethnic rivalry, complicated by economic grievances and the problem of transforming a virtual autocracy into a democracy. He declared martial law, but it failed to curb domestic unrest, and civil war between East and West Pakistan broke out. Pakistan's army was defeated, and Yahya Khan resigned after the establishment of what independent republic in 1971?