In Our Time: Science

Melvyn Bragg and guests discuss prime numbers: 2, 3, 5, 7, 11, 13, 17 … This sequence of numbers goes on literally forever. Recently, a team of researchers in Missouri successfully calculated the highest prime number - it has 9.1 million digits. For nearly two and a half thousand years, since Euclid first described the prime numbers in his book Elements, mathematicians have struggled to write a ru...

Melvyn Bragg and guests discuss artificial intelligence. Can machines think? It was a question posed by the mathematician and Bletchley Park code breaker Alan Turing and it is a question still being asked today. What is the difference between men and machines and what does it mean to be human? And if we can answer that question, is it possible to build a computer that can imitate the human mind? T...

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 gra...

Melvyn Bragg and guests discuss the unique properties of asteroids. They used to be regarded as the 'vermin of the solar system', irritating rubble that got in the way of astronomers trying to study more interesting phenomena. It was difficult or even impossible for an observer of asteroids to book time using the world's best telescopes, because they were regarded as unspectacular objects that cou...

Melvyn Bragg and guests discuss the rise of the mammals. The Cenozoic Era of Earth's history began 65 million years ago and runs to this day. It began with the extraordinary 'KT event', a supposed asteroid impact that destroyed the dinosaurs, and incorporates the break up of Pangaea, the enormous landmass that eventually formed the continents we know today. It is known as the 'Age of the Mammals',...

Melvyn Bragg and guests discuss the history of magnetism. Pliny the Elder, in his Historia Naturalis, tells a story of a legendary Greek shepherd called Magnes who, while guiding his flock on Mount Ida, suddenly found it hard to move his feet. The nails of his sandals held fast to the rock beneath them, and the iron tip of his crook was strangely attracted to the boulders all around. Magnes had st...

Melvyn Bragg and guests discuss the KT Boundary. Across the entire planet, where it hasn't been eroded or destroyed in land movements, there is a thin grey line. In Italy it is 1 cm thick, in America it stretches to three centimetres, but it is all the same thin grey line laid into the rock some 65 million years ago and it bears witness to a cataclysmic event experienced only once in Earth's histo...

Melvyn Bragg and guests discuss Renaissance Mathematics. As with so many areas of European thought, mathematics in the Renaissance was a question of recovering and, if you were very lucky, improving upon Greek ideas. The geometry of Euclid, Appollonius and Ptolemy ruled the day. Yet within two hundred years, European mathematics went from being an art that would unmask the eternal shapes of geomet...

Melvyn Bragg and guests discuss perception: how the brain reacts to the mass of data continually crowding it. Barry Stein's laboratory at Wake Forest University in the United States found that the shape of a right angle drawn on the hand of a chimpanzee starts the visual part of the brain working, even when the shape has not been seen. It has also been discovered that babies learn by touch before...

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...

Melvyn Bragg and guests discuss the history of Alchemy, the ancient science of transformations. The most famous alchemical text is the Emerald Tablet, written around 500BC and attributed to the mythical Egyptian figure of Hermes Trismegistus. Among its twelve lines are the essential words - “as above, so below". They capture the essence of alchemy, that the heavens mirror the earth and that all th...

Melvyn Bragg and guests discuss the Cambrian period when there was an explosion of life on Earth. In the Selkirk Mountains of British Columbia in Canada, there is an outcrop of limestone shot through with a seam of fine dark shale. A sudden mudslide into shallow water some 550 million years ago means that a startling array of wonderful organisms has been preserved within it. Wide eyed creatures wi...

Melvyn Bragg and guests discuss the mind/body problem in philosophy. At the start of René Descartes' Sixth Meditation he writes: "there is a great difference between mind and body, inasmuch as body is by nature always divisible, and mind is entirely indivisible. For when I consider the mind, or myself in so far as I am merely a thinking thing, I am unable to distinguish many parts within myself; I...

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...

Melvyn Bragg and guests discuss the extraordinary mind of the psychiatrist Carl Gustav Jung. In 1907 Sigmund Freud met a young man and fell into a conversation that is reputed to have lasted for 13 hours. That man was the Swiss psychiatrist Carl Gustav Jung. Freud is celebrated as the great pioneer of the 20th century mind, but the idea that personality types can be 'introverted' or 'extroverted',...

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 ma...

Melvyn Bragg and guests discuss the dawn of the age of electricity. In Gulliver's Travels, published in 1726, Jonathan Swift satirised natural philosophers as trying to extract sunbeams from cucumbers. Perhaps he would have been surprised, or even horrified, by the sheer force of what these seemingly obscure experimentalists were about to unleash on society. Electricity soon reached into all areas...

Melvyn Bragg and guests discuss the emergence of the world’s first organic matter nearly four billion years ago. Scientists have named 1.5 million species of living organism on the land, in the skies and in the oceans of planet Earth and a new one is classified every day.  Estimates of how many species remain to be discovered vary wildly, but science accepts one categorical point – all living matt...

Melvyn Bragg and guests discuss the history of the most detailed number in nature. In the Bible's description of Solomon's temple it comes out as three, Archimedes calculated it to the equivalent of 14 decimal places and today's super computers have defined it with an extraordinary degree of accuracy to its first 1.4 trillion digits. It is the longest number in nature and we only need its first 32...

Melvyn Bragg and guests discuss Renaissance obsession with Magic. In 1461 one of the powerful Medici family’s many agents carried a mysterious manuscript into his master’s house in Florence. It purported to be the work of an ancient Egyptian priest-king and magician called Hermes Trismegistus. When Cosimo de Medici saw the new discovery, he ordered his translations of Plato to be stopped so that w...

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 thou...

Melvyn Bragg and guests discuss the history of the number between 1 and -1, which has strange and uniquely beguiling qualities. Shakespeare’s King Lear warned, “Nothing will come of nothing”. The poet and priest John Donne said from the pulpit, “The less anything is, the less we know it: how invisible, unintelligible a thing is nothing”, and the English monk and historian William of Malmesbury cal...

Melvyn Bragg and guests discuss a problematic notion which can be an emotional condition, a syndrome, an extreme or over-reaction, or the physical signs of trauma. The term ‘hysteria’ was first used in Greece in the 5th century BC by Hippocratic doctors. They were trying to explain an illness whose symptoms were breathing difficulties and a sense of suffocation, and whose sufferers were seen chief...

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 fin...

Melvyn Bragg and guests discuss the interpretation of dreams. Over a hundred years ago, Sigmund Freud declared confidently, “The interpretation of dreams is the royal road to a knowledge of the unconscious activities of the mind”. He was writing in his famous volume, The Interpretation of Dreams and his ideas made a huge impact on the century that was to follow. However, despite the cultural influ...