Melvyn Bragg and guests discuss the devastating mass extinctions of the Late Devonian Period, roughly 370 million years ago, when around 70 percent of species disappeared. Scientists are still trying to establish exactly what happened, when and why, but this was not as sudden as when an asteroid hits Earth. The Devonian Period had seen the first trees and soils and it had such a diversity of sea life that it’s known as the Age of Fishes, some of them massive and armoured, and, in one of the icon...
Mar 11, 2021•49 min•Transcript available on Metacast Melvyn Bragg and guests discuss one of the outstanding French mathematicians and natural philosophers of the 18th Century, celebrated across Europe. Emilie du Châtelet, 1706-49, created a translation of Newton’s Principia from Latin into French that helped spread the light of mathematics on the emerging science, and her own book Institutions de Physique, with its lessons on physics, was welcomed as profound. She had the privileges of wealth and aristocracy, yet had to fight to be taken seriously...
Feb 04, 2021•50 min•Transcript available on Metacast Melvyn Bragg and guests discuss solar eclipses, some of life’s most extraordinary moments, when day becomes night and the stars come out before day returns either all too soon or not soon enough, depending on what you understand to be happening. In ancient China, for example, there was a story that a dragon was eating the sun and it had to be scared away by banging pots and pans if the sun were to return. Total lunar eclipses are more frequent and last longer, with a blood moon coloured red like...
Dec 31, 2020•51 min•Transcript available on Metacast Melvyn Bragg and guests discuss Alan Turing (1912-1954) whose 1936 paper On Computable Numbers effectively founded computer science. Immediately recognised by his peers, his wider reputation has grown as our reliance on computers has grown. He was a leading figure at Bletchley Park in the Second World War, using his ideas for cracking enemy codes, work said to have shortened the war by two years and saved millions of lives. That vital work was still secret when Turing was convicted in 1952 for h...
Oct 15, 2020•53 min•Transcript available on Metacast Melvyn Bragg and guests discuss the theoretical physicist Dirac (1902-1984), whose achievements far exceed his general fame. To his peers, he was ranked with Einstein and, when he moved to America in his retirement, he was welcomed as if he were Shakespeare. Born in Bristol, he trained as an engineer before developing theories in his twenties that changed the understanding of quantum mechanics, bringing him a Nobel Prize in 1933 which he shared with Erwin Schrödinger. He continued to make deep c...
Mar 05, 2020•51 min•Transcript available on Metacast Melvyn Bragg and guests discuss the origins of horses, from their dog sized ancestors to their proliferation in the New World until hunted to extinction, their domestication in Asia and their development since. The genetics of the modern horse are the most studied of any animal, after humans, yet it is still uncertain why they only have one toe on each foot when their wider family had more, or whether speed or stamina has been more important in their evolution. What is clear, though, is that whe...
Feb 27, 2020•50 min•Transcript available on Metacast Melvyn Bragg and guests discuss the flow of particles from the outer region of the Sun which we observe in the Northern and Southern Lights, interacting with Earth's magnetosphere, and in comet tails that stream away from the Sun regardless of their own direction. One way of defining the boundary of the solar system is where the pressure from the solar wind is balanced by that from the region between the stars, the interstellar medium. Its existence was suggested from the C19th and Eugene Parker...
Jan 23, 2020•55 min•Transcript available on Metacast Melvyn Bragg and guests discuss what happens when parents from different species have offspring, despite their genetic differences. In some cases, such as the zebra/donkey hybrid in the image above, the offspring are usually infertile but in others the genetic change can lead to new species with evolutionary advantages. Hybrids can occur naturally, yet most arise from human manipulation and Darwin's study of plant and animal domestication informed his ideas on natural selection. With Sandra Knap...
Oct 31, 2019•51 min•Transcript available on Metacast Melvyn Bragg and guests discuss the work and ideas of Dorothy Crowfoot Hodgkin (1910-1994), awarded the Nobel Prize in Chemistry in 1964 for revealing the structures of vitamin B12 and penicillin and who later determined the structure of insulin. She was one of the pioneers of X-ray crystallography and described by a colleague as 'a crystallographers' crystallographer'. She remains the only British woman to have won a Nobel in science, yet rejected the idea that she was a role model for other wo...
Oct 03, 2019•52 min•Transcript available on Metacast Melvyn Bragg and guests discuss how scientists sought to understand the properties of gases and the relationship between pressure and volume, and what that search unlocked. Newton theorised that there were static particles in gases that pushed against each other all the harder when volume decreased, hence the increase in pressure. Those who argued that molecules moved, and hit each other, were discredited until James Maxwell and Ludwig Boltzmann used statistics to support this kinetic theory. Id...
May 23, 2019•52 min•Transcript available on Metacast Melvyn Bragg and guests discuss theories about the origins of teeth in vertebrates, and what we can learn from sharks in particular and their ancestors. Great white sharks can produce up to 100,000 teeth in their lifetimes. For humans, it is closer to a mere 50 and most of those have to last from childhood. Looking back half a billion years, though, the ancestors of sharks and humans had no teeth in their mouths at all, nor jaws. They were armoured fish, sucking in their food. The theory is that...
Apr 11, 2019•49 min•Transcript available on Metacast Melvyn Bragg and guests discuss how members of the same species send each other invisible chemical signals to influence the way they behave. Pheromones are used by species across the animal kingdom in a variety of ways, such as laying trails to be followed, to raise the alarm, to scatter from predators, to signal dominance and to enhance attractiveness and, in honey bees, even direct development into queen or worker. The image above is of male and female ladybirds that have clustered together in...
Feb 21, 2019•49 min•Transcript available on Metacast Melvyn Bragg and guests discuss the remarkable achievement of Aristotle (384-322BC) in the realm of biological investigation, for which he has been called the originator of the scientific study of life. Known mainly as a philosopher and the tutor for Alexander the Great, who reportedly sent him animal specimens from his conquests, Aristotle examined a wide range of life forms while by the Sea of Marmara and then on the island of Lesbos. Some ideas, such as the the spontaneous generation of flies...
Feb 07, 2019•50 min•Transcript available on Metacast Melvyn Bragg and guests discuss the ideas and life of one of the greatest mathematicians of the 20th century, Emmy Noether. Noether’s Theorem is regarded as one of the most important mathematical theorems, influencing the evolution of modern physics. Born in 1882 in Bavaria, Noether studied mathematics at a time when women were generally denied the chance to pursue academic careers and, to get round objections, she spent four years lecturing under a male colleague’s name. In the 1930s she faced ...
Jan 24, 2019•48 min•Transcript available on Metacast Melvyn Bragg and guests discuss the planet Venus which is both the morning star and the evening star, rotates backwards at walking speed and has a day which is longer than its year. It has long been called Earth’s twin, yet the differences are more striking than the similarities. Once imagined covered with steaming jungles and oceans, we now know the surface of Venus is 450 degrees celsius, and the pressure there is 90 times greater than on Earth, enough to crush an astronaut. The more we learn ...
Dec 27, 2018•50 min•Transcript available on Metacast Melvyn Bragg and guests discuss the properties of atoms or molecules with a single unpaired electron, which tend to be more reactive, keen to seize an electron to make it a pair. In the atmosphere, they are linked to reactions such as rusting. Free radicals came to prominence in the 1950s with the discovery that radiation poisoning operates through free radicals, as it splits water molecules and produces a very reactive hydroxyl radical which damages DNA and other molecules in the cell. There is...
Nov 01, 2018•51 min•Transcript available on Metacast Melvyn Bragg and guests discuss the history of real and imagined machines that appear to be living, and the questions they raise about life and creation. Even in myth they are made by humans, not born. The classical Greeks built some and designed others, but the knowledge of how to make automata and the principles behind them was lost in the Latin Christian West, remaining in the Greek-speaking and Arabic-speaking world. Western travellers to those regions struggled to explain what they saw, att...
Sep 20, 2018•52 min•Transcript available on Metacast Melvyn Bragg and guests discuss how some bats, dolphins and other animals emit sounds at high frequencies to explore their environments, rather than sight. This was such an unlikely possibility, to natural historians from C18th onwards, that discoveries were met with disbelief even into the C20th; it was assumed that bats found their way in the dark by touch. Not all bats use echolocation, but those that do have a range of frequencies for different purposes and techniques for preventing themselv...
Jun 21, 2018•51 min•Transcript available on Metacast Melvyn Bragg and guests discuss the discovery and growing understanding of the Proton, formed from three quarks close to the Big Bang and found in the nuclei of all elements. The positive charges they emit means they attract the fundamental particles of negatively charged electrons, an attraction that leads to the creation of atoms which in turn leads to chemistry, biology and life itself. The Sun (in common with other stars) is a fusion engine that turn protons by a series of processes into hel...
Apr 26, 2018•49 min•Transcript available on Metacast In a programme first broadcast on April 12th 2018, Melvyn Bragg and guests discuss the contribution of George Stephenson (1781-1848) and his son Robert (1803-59) to the development of the railways in C19th. George became known as The Father of Railways and yet arguably Robert's contribution was even greater, with his engineering work going far beyond their collaboration. Robert is credited with the main role in the design of their locomotives. George had worked on stationary colliery steam engin...
Apr 12, 2018•50 min•Transcript available on Metacast Melvyn Bragg and guests discuss the pioneering scientist Rosalind Franklin (1920 - 1958). During her distinguished career, Franklin carried out ground-breaking research into coal and viruses but she is perhaps best remembered for her investigations in the field of DNA. In 1952 her research generated a famous image that became known as Photograph 51. When the Cambridge scientists Francis Crick and James Watson saw this image, it enabled them the following year to work out that DNA has a double-he...
Feb 22, 2018•50 min•Transcript available on Metacast Melvyn Bragg and guests discuss fungi. These organisms are not plants or animals but a kingdom of their own. Millions of species of fungi live on the Earth and they play a crucial role in ecosystems, enabling plants to obtain nutrients and causing material to decay. Without fungi, life as we know it simply would not exist. They are also a significant part of our daily life, making possible the production of bread, wine and certain antibiotics. Although fungi brought about the colonisation of the...
Feb 15, 2018•49 min•Transcript available on Metacast The octopus, the squid, the nautilus and the cuttlefish are some of the most extraordinary creatures on this planet, intelligent and yet apparently unlike other life forms. They are cephalopods and are part of the mollusc family like snails and clams, and they have some characteristics in common with those. What sets them apart is the way members of their group can change colour, camouflage themselves, recognise people, solve problems, squirt ink, power themselves with jet propulsion and survive...
Feb 01, 2018•47 min•Transcript available on Metacast In a programme first broadcast in 2017, Melvyn Bragg and guests discuss Gauss (1777-1855), widely viewed as one of the greatest mathematicians of all time. He was a child prodigy, correcting his father's accounts before he was 3, dumbfounding his teachers with the speed of his mental arithmetic, and gaining a wealthy patron who supported his education. He wrote on number theory when he was 21, with his Disquisitiones Arithmeticae, which has influenced developments since. Among his achievements, ...
Nov 30, 2017•49 min•Transcript available on Metacast In a programme first broadcast in 2017, Melvyn Bragg and guests discuss the development of theories about dinosaur feathers, following discoveries of fossils which show evidence of feathers. All dinosaurs were originally thought to be related to lizards - the word 'dinosaur' was created from the Greek for 'terrible lizard' - but that now appears false. In the last century, discoveries of fossils with feathers established that at least some dinosaurs were feathered and that some of those survived...
Oct 26, 2017•48 min•Transcript available on Metacast In a programme first broadcast in 2017, Melvyn Bragg and guests discuss why some birds migrate and others do not, how they select their destinations and how they navigate the great distances, often over oceans. For millennia, humans set their calendars to birds' annual arrivals, and speculated about what happened when they departed, perhaps moving deep under water, or turning into fish or shellfish, or hibernating while clinging to trees upside down. Ideas about migration developed in C19th when...
Jul 06, 2017•51 min•Transcript available on Metacast Melvyn Bragg and guests discuss enzymes, the proteins that control the speed of chemical reactions in living organisms. Without enzymes, these reactions would take place too slowly to keep organisms alive: with their actions as catalysts, changes which might otherwise take millions of years can happen hundreds of times a second. Some enzymes break down large molecules into smaller ones, like the ones in human intestines, while others use small molecules to build up larger, complex ones, such as ...
Jun 01, 2017•49 min•Transcript available on Metacast Melvyn Bragg and guests discuss the life and work of Louis Pasteur (1822-1895) and his extraordinary contribution to medicine and science. It is said few people have saved more lives than Pasteur. A chemist, he showed that otherwise identical molecules could exist as 'left' and 'right-handed' versions and that molecules produced by living things were always left-handed. He proposed a germ theory to replace the idea of spontaneous generation. He discovered that microorganisms cause fermentation a...
May 18, 2017•51 min•Transcript available on Metacast Melvyn Bragg and guests discuss the life and ideas of Wolfgang Pauli (1900-1958), whose Exclusion Principle is one of the key ideas in quantum mechanics. A brilliant physicist, at 21 Pauli wrote a review of Einstein's theory of general relativity and that review is still a standard work of reference today. The Pauli Exclusion Principle proposes that no two electrons in an atom can be at the same time in the same state or configuration, and it helps explain a wide range of phenomena such as the e...
Apr 06, 2017•48 min•Transcript available on Metacast Melvyn Bragg and guests discuss the high temperatures that marked the end of the Paleocene and start of the Eocene periods, about 50m years ago. Over c1000 years, global temperatures rose more than 5 C on average and stayed that way for c100,000 years more, with the surface of seas in the Arctic being as warm as those in the subtropics. There were widespread extinctions, changes in ocean currents, and there was much less oxygen in the sea depths. The rise has been attributed to an increase of ca...
Mar 16, 2017•50 min•Transcript available on Metacast 
