My book, The Mountain Mystery, is not kind to the great physicist Lord Kelvin. I feel a bit uneasy admitting that in my research on the brilliant fellow, I just could not get comfortable. I wouldn’t have been his friend. And I am quite certain Lord Kelvin would have had no spare change for me, either. I picture him doing his civic duty as an old man, addressing the unwashed masses at one of his Christian Evidence Society rallies, a group that directed its activities towards the “lower grades of society, to save them from infidelity.” At one such meeting, he educated the public on the age of our planet. “Not older than twenty million years,” he told his audience in 1900. By then geologists were daring to disagree.
Lord Kelvin, born William Thomson (1824-1907), would have been rightly heralded as the greatest physicist of his time, perhaps all time, if his time had ended before he turned 50. Some have said that during the first half of his adult life, he could get nothing wrong. Every notion emitted from under his tall black hat carried a deserved air of cleverness. Some go on to say that during the second half of Lord Kelvin’s life, he could get nothing right.
First the shining star. William Thomson (his name while he was still clever) figured out thermodynamics. He understood heat transfer and invented the maths and formulae needed to explain it to others. That second law of thermodynamics – the one that says the universe is winding down and will expire in stark cold entropy? Thank Thomson for that. He worked on electrical signal transmission, helping make long-distant telegraphy possible. He was an engineer and a director of the first trans-Atlantic telegraph cable. Thomson made sense of heat, convection, and conduction. At age 24, he calculated the coldest possible temperature, the state where molecular motion stops and physics becomes bizarre. Other scientists named a new temperature scale for him, the Kelvin scale, with Kelvin’s coldest cold (“absolute zero”) as the base for that particular thermometer. Rather than calling that frozen place minus 273.15 Celsius, it is defined as Zero Degrees Kelvin.
One wishes William Thompson had retired early. Queen Victoria peered him for his loyal opposition to Irish rights and Home Rule, and for his political conservatism. As Lord Kelvin, he droned on and on about things he clearly had not thought much about. By his mid- and later years, he was dismissing X-rays as a hoax and shortly before the Wright brothers great experiment, he was telling the newspapers that flight would never be possible. (“No balloon and no aeroplane will ever be practically successful,” he told Garrett Serviss of the New York Journal in 1902.) On the eve of the great physics revolution kicked off by Einstein, Thomson is claimed to have said, “There is nothing new to be discovered in physics. All that remains is more and more precise measurement.” Physics, thought Kelvin would become a dead science, a place where engineers tinkered with equipment and added a decimal point a decade to already known constants.
In regards to earth science, Lord Kelvin was an unfortunate thorn. He believed the Earth is cooling from an original hot sphere. From his heat conduction calculations, he figured Earth could not be more than perhaps 20 million years old. Likewise the sun. With no knowledge of radiation, fission, or fusion, Kelvin guessed the sun was powered by gravitational collapse. It could not maintain its heat for more than a few million years and must be nearing the end of its reign. But geologists and evolutionary biologists needed a much older planet to explain the slow gradual processes they observed. Hundreds of millions, perhaps billions of years, were required. Kelvin was adamant. Unyielding in his wrongness.
A brave assistant, John Perry, tried to convince Kelvin that mantle convection (a new idea) may be involved in the Earth’s heat distribution. If it was, it could mean the planet was over a billion years old. But Kelvin insisted the globe is a solid homogenous ball of conducting heat, not differentiated into layers and certainly not convecting heat to the surface. Kelvin probably ruined his insubordinate’s career after Perry dared publish the idea in Nature. Had Kelvin given the idea some real thought, he would have hastened the acceptance of plate tectonics and he would have made a final grand contribution to science. Alas, he was by then an old Lord with no new tricks.