ABSTRACT
The discovery that the earth is 4.5 billion years old is one of the greatest triumphs of twentieth century science. Kelvin’s interest in the age of the earth spanned at least 61 incredibly full years. He first spoke on the topic in 1846 as a 22 year old on his inauguration at the University of Glasgow and returned to the issue many times in later life. The key mathematical physicists to enter the fray were Darwin’s second son George, a brilliant geophysicist, John Perry, a former student of Lord Kelvin’s, and Oliver Heaviside, an eccentric genius who had never attended a university as a student, but who made seminal contributions to mathematics. Numerous estimates by geologists in the latter part of the century had scattered around Kelvin’s 100 million years value and this nice round figure had begun to assume a widespread acceptance, making geologists loath to follow Kelvin on his downward age-spiral.
