Thomson, William

The Englishman William Thomson, 1st Baron Kelvin (1824 - 1907), son to a teacher of mathematics and engineering, was a mathematician, mathematical physicist, and engineer.

In 1848, he published a paper on an absolute thermometric scale and, in a footnote, he derived the value of -273 °C for absolute zero.

He investigated the earth's cooling to make an inference of its age. In 1897, he ultimately settled on an estimate that the earth was 20 - 40 million years old, which is two orders of magnitude too small.

He lent his name to the Kelvin temperature scale and the kelvin, the unit of temperature.