In Our Time: Science Folgen

Melvyn Bragg and guests discuss the age of the Earth. It was once thought that the world began in 4004 BC. Lord Kelvin calculated the cooling temperature of a rock the size of our planet and came up with a figure of 20 million years for the age of the Earth. Now, the history of our planet is divided into four great Eons: the Hadean, the Archaen, the Proterozoic and the Phanerozoic. Together, they are taken to encompass an incredible four and a half billion years. How can we begin to make sense of such a huge swathe of time? And can we be sure that we have got the Earth's age right? Geologists use Eras, Periods and Epochs to further punctuate what's known as 'Deep Time', but can we be sure that the classifications we use don't obscure more than they reveal? With Richard Corfield, Research Associate in the Department of Earth Sciences at Oxford University; Hazel Rymer, Senior Lecturer in the Department of Earth Sciences at the Open University; Henry Gee, Senior Editor at Nature.

Melvyn Bragg and guests discuss the nature and existence of mathematical infinity. Jonathan Swift encapsulated the counter-intuitive character of infinity with insouciant style:“So, naturalists observe, a fleaHath smaller fleas on him that preyAnd these hath smaller fleas to bite ‘emAnd so proceed ad infinitum.”Alas, the developing utility mathematicians put to the idea of infinity did not find the English philosopher Thomas Hobbes quite so relaxed. When confronted with a diagram depicting an infinite solid whose volume was finite, he wrote, “To understand this for sense, it is not required that a man should be a geometrician or logician, but that he should be mad”. Yet philosophers and mathematicians have continued to grapple with the unending, and it is a core concept in modern maths.So, what is mathematical infinity? Are some infinities bigger than others? And does infinity exist in nature?With Ian Stewart, Professor of Mathematics at the University of Warwick; Robert Kaplan, co-founder of The Math Circle at Harvard University and author of The Art of the Infinite: Our Lost Language of Numbers; Sarah Rees, Reader in Pure Mathematics at the University of Newcastle.

Melvyn Bragg and guests discusses the life and ideas of James Clerk Maxwell whose work is not widely known, but whose genius and contribution to the age in which we live is enormous.He took the first colour photograph, defined the nature of gases and with a few mathematical equations expressed all the fundamental laws of light, electricity and magnetism - and in doing so he provided the tools to create the technological age, from radar to radio and televisions to mobile phones. He is credited with fundamentally changing our view of reality, so much so that Albert Einstein said, “One scientific epoch ended and another began with James Clerk Maxwell”. But who was James Clerk Maxwell? What were his ideas, and does this nineteenth century ‘natural philosopher’ deserve a place alongside Newton and Einstein in the pantheon of science? With Simon Schaffer, Reader in History and Philosophy of Science at the University of Cambridge; Peter Harman, Professor of the History of Science at Lancaster University and editor of The Scientific Letters and Papers of James Clerk Maxwell; Joanna Haigh, Professor of Atmospheric Physics at Imperial College London.