<p>Arthur Holmes (January 14, 1890 - 20 September 1965) was a British geologist and geophysicist who made significant contributions to the understanding of Earth's geology and geochronology. He is best known for his work on the age of the Earth, which he estimated to be around 1.6 billion years old.</p><p></p><p>Holmes began his career as a field geologist, working on mapping and studying the geology of the British Isles. In 1913, he joined the faculty of Imperial College London, where he began to focus on the study of Earth's history. He developed the technique of using radioactive isotopes to date rocks and minerals, which became a key tool in the study of geochronology.</p><p></p><p>In the 1920s, Holmes proposed the concept of convection in the Earth's mantle, which he believed was responsible for the movement of continental plates. His ideas were initially met with skepticism, but they have since been widely accepted as a key mechanism for plate tectonics.</p><p></p><p>In the 1930s, Holmes published a book, "The Age of the Earth" where he estimated the Earth's age to be around 1.6 billion years old, which was significantly older than previous estimates. His estimate was based on the study of radioactive isotopes in rocks and minerals and was a major breakthrough in the field of geochronology.</p><p></p><p>In recognition of his contributions to the field of geology, Holmes was awarded the Wollaston Medal, the highest award of the Geological Society of London, in 1944. He was also made a Commander of the Order of the British Empire (CBE) in 1952.</p><p></p><p>Arthur Holmes's contributions to the field of geology were groundbreaking. His work on the age of the Earth and the concept of convection in the Earth's mantle were major milestones in the understanding of Earth's history and geology. His ideas and techniques continue to shape the field of geology and his legacy will continue to inspire and guide future generations of geologists.</p><p></p><p></p>