Physics and Cosmology

Duration: 30 minutes
First broadcast: Thursday 24 February 2000

Melvyn Bragg examines 20th century physics’ quest for the ultimate theory of everything. Einstein left us with his theory of General Relativity, which explained how gravity works on the scale of stars, galaxies, and the universe itself and Schroedinger left us with the equation that explained the mechanics of the tiny quantum realm. Both theories work to wonderful effect in their own worlds, but (and this is the sticking point) gravity is strangely absent from the quantum realm and planets behave nothing like particles. The enigma for scientists throughout most of the last century is that, as they are currently formulated, general relativity and quantum mechanics cannot both be right. The history of twentieth century physics has been a struggle to find a way to unite them, to find what has become the holy grail of modern physics: The Grand Unified Theory.

With Brian Greene, Professor of Physics and Mathematics, Columbia University and Cornell University; Sir Martin Rees, Astronomer Royal and Royal Society Research Professor in Astronomy and Physics at Cambridge University

http://www.bbc.co.uk/programmes/p00546nx

Duration: 30 minutes
First broadcast: Thursday 30 December 1999

Melvyn Bragg and guests discuss the history of mankind’s attempt to understand the nature of time. At the end of the 19th century, H.G.Wells imagined travelling through time in The Time Machine; “The palpitation of night and day merged into one continuous greyness; the sky took on a wonderful deepness of blue, a splendid luminous colour like that of early twilight; the jerking sun became a streak of fire, a brilliant arch in space”.

When he was writing we thought time was unbending and universal and counted out by Newton’s clock. A hundred years later we have had Einstein and relativity, quantum theory, and atomic clocks, but in the third millennium, is mankind any closer to understanding what time really is?

What, in short, do we know about time itself? A Greek philosopher thought that time was a figment of the imagination and there are contemporary physicists who go a long way to agreeing with him. Newton’s views on time were bent by Einstein. The ancient skills of astronomy once ruled the known world and skill in time usage could be said to be enthroned as a master craft in our day. “But at my back I always hear time’s winged chariot hurrying near and yonder all before us lie deserts of vast eternity” – Marvel wrote that of love, but it could be our epigraph for time.

With Dr Neil Johnson, theoretical physicist at the Clarendon Laboratory, Oxford University and Royal Institution Christmas Lecturer 1999 on the subject of Time; Lee Smolin, cosmologist and Professor of Physics, Pennsylvania State University

http://www.bbc.co.uk/programmes/p005465z

Duration: 30 minutes
First broadcast: Thursday 20 May 1999

Melvyn Bragg examines the history of what we know about the origins of the universe. Some four hundred years ago in Rome, one Giordano Bruno was burnt at the stake for his belief in other inhabited worlds – it’s a possibility which has fascinated scientists, writers, artists and the general public for centuries – and any consideration of the origins of life and matter on other planets, and indeed this one, inevitably raises huge questions. Do other worlds exist? How did our planet come into existence? How can we know anything at all about the origins of life and matter so many billions of years ago, and how has our thinking on these – amongst the deepest of questions – changed over the 20th century? Are we any closer to knowing whether other worlds exist and how our own planet came into being? And does the knowledge we have about these things change our perception of ourselves and our position in the universe?

With Professor Sir Martin Rees, Astronomer Royal and Royal Society Research Professor in Astronomy and Physics, Cambridge University; Professor Paul Davies, theoretical physicist and Visiting Professor at Imperial College, London

http://www.bbc.co.uk/programmes/p00545j9