The Graviton

Duration: 45 minutes
First broadcast: Thursday 24 November 2005

Melvyn Bragg and guests discuss the search for the Graviton particle. Albert Einstein said “I know why there are so many people who love chopping wood. In this activity one immediately sees the results”. Einstein spent the last thirty years of his life trying to find a theory that would unify electromagnetism with gravity, but success eluded him.

The search is still on for a unifying theory of gravitational force and hopes are pinned on the location of the graviton – a hypothetical elementary particle that transmits the force of gravity. But the graviton is proving hard to find. Indeed, the Large Hadron Collider at CERN still won’t allow us to detect gravitons per se, but might be able to prove their existence in other ways.

The idea of the graviton particle first emerged in the middle of the 20th century, when the notion that particles as mediators of force was taken seriously. Physicists believed that it could be applicable to gravity and by the late 20th century the hunt was truly on for the ultimate theory, a theory of quantum gravity.

So why is the search for the graviton the major goal of theoretical physics? How will the measurement of gravitation waves help prove its existence? And how might the graviton unite the seemingly incompatible theories of general relativity and quantum mechanics?

With Roger Cashmore, Former Research Director at CERN and Principal of Brasenose College, Oxford; Jim Al-Khalili, Professor of Physics at the University of Surrey; Sheila Rowan, Reader in Physics in the Department of Physics and Astronomy at the University of Glasgow

http://www.bbc.co.uk/programmes/p003k9ks

Dark Energy

Duration: 45 minutes
First broadcast: Thursday 17 March 2005

Melvyn Bragg and guests discuss ‘dark energy’. Only 5% of our universe is composed of visible matter, stars, planets and people; something called ‘dark matter’ makes up about 25% and an enormous 70% of the universe is pervaded with the mysteriously named ‘dark energy’. It is a recent discovery and may be only a conjecture, but it has been invoked to explain an abiding riddle of the cosmos: if the expansion of the universe is powered by the energy of the Big Bang, then why isn’t the expansion slowing down over time as the initial energy runs down and the attractive force of gravity asserts itself? Scientists had predicted a Big Crunch as the logical opposite of the Big Bang, but far from retracting, the expansion of the universe is actually accelerating…it’s running away with itself.

How do we know that the universe is behaving like this and what’s causing it? If dark energy is the culprit, then what is this elusive, though omnipresent entity?

With Sir Martin Rees, Astronomer Royal and Professor of Cosmology and Astrophysics, Cambridge University; Carolin Crawford, Royal Society University Research Fellow at the Institute of Astronomy, University of Cambridge; Sir Roger Penrose, Emeritus Rouse Ball Professor of Maths at Oxford University.

http://www.bbc.co.uk/programmes/p003k9g5

The Second Law of Thermodynamics

Duration: 45 minutes
First broadcast: Thursday 16 December 2004

Melvyn Bragg and guests discuss the Second Law of Thermodynamics which can be very simply stated like this: “Energy spontaneously tends to flow from being concentrated in one place to becoming diffused and spread out”. It was first formulated – derived from ideas first put forward by Lord Kelvin – to explain how a steam engine worked, it can explain why a cup of tea goes cold if you don’t drink it and how a pan of water can be heated to boil an egg.

But its application has been found to be rather grander than this. The Second Law is now used to explain the big bang, the expansion of the cosmos and even suggests our inexorable passage through time towards the ‘heat death’ of the universe. It’s been called the most fundamental law in all of science, and CP Snow in his Two Cultures wrote: “Not knowing the Second Law of Thermodynamics is like never having read a work of Shakespeare”.

What is the Second Law? What are its implications for time and energy in the universe, and does it tend to be refuted by the existence of life and the theory of evolution?

With John Gribbin, Visiting Fellow in Astronomy at the University of Sussex; Peter Atkins, Professor of Chemistry at Oxford University; Monica Grady, Head of Petrology and Meteoritics at the Natural History Museum

http://www.bbc.co.uk/programmes/p004y2bm

Higgs Boson

Duration: 45 minutes
First broadcast: Thursday 18 November 2004

Melvyn Bragg and guests discuss the Higgs Boson particle. One weekend in 1964 the Scottish scientist Peter Higgs was walking in the Cairngorm Mountains. On his return to his laboratory in Edinburgh the following Monday, he declared to his colleagues that he had just experienced his ‘one big idea’ and now had an answer to the mystery of how matter in the universe got its mass. That big idea took many years of refining, but it has now generated so much international interest and has such an important place in physics that well over one billion pounds is being spent in the hope that he was right. It’s the biggest science project on Earth; the quest to find the ‘Higgs Boson’, a fundamental constituent of nature that – if it does exist – has such a central role in defining the universe that it’s also known as the God Particle.

What is the Higgs Boson? Why is it so important to scientists and how are they planning to find it?

With Jim Al-Khalili, Senior Lecturer in Physics at the University of Surrey; David Wark, Professor of Experimental Physics at Imperial College London and the Rutherford Appleton Laboratory; Professor Roger Cashmore, former Research Director at CERN and now Principal of Brasenose College, Oxford.

http://www.bbc.co.uk/programmes/p004y2b7

The Planets

Duration: 45 minutes
First broadcast: Thursday 27 May 2004

Melvyn Bragg and guests discuss our knowledge of the planets in both our and other solar systems. Tucked away in the outer Western Spiral arm of the Milky Way is a middle aged star, with nine, or possibly ten orbiting planets of hugely varying sizes. Roughly ninety-two million miles and third in line from that central star is our own planet Earth, in thrall to our Sun, just one of the several thousand million stars that make up the Galaxy.

Ever since Galileo and Copernicus gave us a scientific model of our own solar system, we have assumed that somewhere amongst the myriad stars there must be other orbiting planets, but it took until 1995 to find one. ‘51 Pegasus A’ was discovered in the Pegasus constellation and was far bigger and far closer to its sun than any of our existing theories could have predicted. Since then 121 new planets have been found. And now it is thought there may be more planets in the skies than there are stars.

What causes a planet to form? How do you track one down? And how likely is there to be another one out there with properties like the Earth’s?

With Paul Murdin, Senior Fellow at the Institute of Astronomy in Cambridge; Hugh Jones, planet hunter and Reader in Astrophysics at Liverpool John Moores University; Carolin Crawford, Royal Society Research Fellow at the Institute of Astronomy in Cambridge

http://www.bbc.co.uk/programmes/p004y25b

Theories of Everything

Duration: 45 minutes
First broadcast: Thursday 25 March 2004

Melvyn Bragg and guests discuss the 30 year search to solve all the biggest questions in physics. At the end of the last century, brave voices were predicting that all the big questions of physics were on the verge of being answered by a Theory of Everything. The disparity between the physics of the very small would finally be reconciled with the very large, and the four forces of nature would finally be united with a single set of equations. It was suggested that with such a theory we might solve the riddle of black holes, unlock the secrets of the Big Bang, probe other universes and even uncover the mystery of travelling through time. But Stephen Hawking, who once said that with a Theory of Everything “we would know the m mind of God”, has changed his mind and now says that it may not be possible after all.

So what are the prospects for a Theory of Everything? Why do we need one? How do we get one? And what would it mean if we did?

With Brian Greene, Professor of Physics and Mathematics at Columbia University and author of The Fabric of the Cosmos; John Barrow, Professor of Mathematical Sciences at the University of Cambridge and author of The Constants of Nature; Dr Val Gibson, particle physicist from the Cavendish Laboratory and Fellow of Trinity College, Cambridge

http://www.bbc.co.uk/programmes/p004y24b

Rutherford

Duration: 45 minutes
First broadcast: Thursday 19 February 2004

Melvyn Bragg and guests discuss Ernest Rutherford. He was the father of nuclear science, a great charismatic figure who mapped the landscape of the sub-atomic world. He identified the atom’s constituent parts, discovered that elemental decay was the cause of radiation and became the first true alchemist in the history of science when he forced platinum to change into gold.

He was born at the edge of the Empire in 1871, the son of Scottish immigrant farmers and was working the fields when a telegram came from the great British physicist J J Thomson asking him to come to Cambridge. Rutherford immediately laid down his spade saying “that’s the last potato I ever dig”. It was. He went on to found a science, win a Nobel Prize and pioneer the ‘big science’ of the twentieth century.

With Simon Schaffer, Professor in the History and Philosophy of Science at the University of Cambridge; Jim Al–Khalili, Senior Lecturer in Physics at the University of Surrey; Patricia Fara, Fellow of Clare College, Cambridge

http://www.bbc.co.uk/programmes/p004y23q

Maxwell

Duration: 45 minutes
First broadcast: Thursday 02 October 2003

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

http://www.bbc.co.uk/programmes/p005491g

The Life of Stars

Duration: 45 minutes
First broadcast: Thursday 27 March 2003

Melvyn Bragg and guests discuss the life cycle of stars. In his poem Bright Star John Keats wrote, “Bright Star, would I were steadfast as thou art”. For Keats the stars were symbols of eternity- they were beautiful and ordered and unchanging – but modern astronomy tells a very different story. Stars, like everything else in the universe, are subject to change. They are born among vast swirls of gas and dust and they die in the stunning explosions we call supernovae. They create black holes and neutron stars and, in the very beginning of the universe, they forged the elements from which all life is made. But how do stars keep burning for millions of years, why do they self-destruct with such ferocity and what will happen to the universe when they all go out?

With Paul Murdin, Senior Fellow at the Institute of Astronomy, Cambridge; Janna Levin, Advanced Fellow in Theoretical Physics in the Department of Applied Mathematics & Theoretical Physics at the University of Cambridge; Phil Charles, Professor of Astronomy at Southampton University.

http://www.bbc.co.uk/programmes/p00548w8

Chance and Design

Duration: 45 minutes
First broadcast: Thursday 13 February 2003

Melvyn Bragg and guests discuss the theories of a grand design in the universe. The late evolutionary biologist Stephen Jay Gould argued that if you re-ran the tape of evolutionary history, an entirely different set of creatures would emerge. Man would not exist because the multitude of random changes that resulted in us would never be repeated exactly the same way. Others disagree, arguing that there is a pattern that points to some kind of direction – even, perhaps, a design, a sense that some things are pre-ordained.

Who were the original proponents of the idea of a grand design? Were they deliberately setting out to find a scientific theory that could sit alongside religious faith? On the other hand, can the concept of contingency – or the randomness of evolution – be compatible with a belief in God?

With Simon Conway Morris, Professor of Evolutionary Palaeobiology at Cambridge University and author of The Crucible of Creation – the Burgess Shale and the Rise of Animals; Sandy Knapp, botanist at the Natural History Museum; John Brooke, Andreas Idreos Professor of Science and Religion at Oxford University

http://www.bbc.co.uk/programmes/p00548td