What is the voice inside my head?

The Moon and Earth are drifting gradually further apart. Every year the gap between them increases by a few centimetres. We know that the Moon’s gravity has an important effect on Earth - from controlling the tides to affecting the planet’s rotation - but slowly, imperceptibly, over billions of years, that influence will diminish as the Moon moves away. For CrowdScience listener Tony in the UK that idea poses another question. What if we were to look back in time? What effects did the Moon have when it was closer to Earth? Would it counteract the planet’s gravity more so that, at the time of the dinosaurs, a Brontosaurus would weigh a little less that it would if it existed now? It’s an intriguing question. And, given that it involves both the Moon AND dinosaurs, it’s one that’s got presenter Anand Jagatia really excited! Anand begins his journey on Brighton beach on the South coast of the UK. He’s there to watch the full Moon rise - and get a few insights on Tony’s question - from astronomer Darren Baskill and astrophotographer (and cellist) Ivana Perenic. Anand talks to Darren about the influence of the Moon’s gravity on Earth today. As they stand on the beach, with the sea lapping at their feet, they can certainly see its effect on the ocean tides. But did you know that the Moon also causes tides on the land as well? Every time it’s overhead the ground you’re standing on is higher by a few centimetres. Professor Neil Comins, author of the book What If the Moon Didn’t Exist, explains why the tides are the reason the Moon is moving away from Earth – and it has been ever since it was first formed. And how was it formed anyhow? We turn back time with Prof. Sara Russell from the Natural History Museum in London to discover one of the most dramatic events in the early history of our solar system... when two worlds collided. And, of course, it helps to know what a dinosaur weighed in the first place. Anand turns to paleontologist Nicolas Campione, who’s been puzzling over the most accurate way to calculate the bulk of a Brontosaurus. Contributors: Dr. Darren Baskill, Astronomer, University of Sussex, UK Ivana Perenic, Astrophotographer Dr. Nicolas Campione, Paleontologist, University of New England, Australia Prof. Sara Russell, Cosmic Mineralogist, Natural History Museum, UK Prof. Neil Comins, Astronomer, University of Maine, USAPresenter: Anand Jagatia Producer: Jeremy Grange Editor: Cathy Edwards Production Co-ordinator: Ishmael Soriano Studio Manager: Jackie Margerum(Image: Tyrannosaurus Rex and Spinosaurus in front of the moon - stock photo Credit: MR1805via Getty Images)

18 is the age of majority, or maturity, in most countries around the world. Depending where you live, it might be when you can vote, buy alcohol, or get married. But what's so special about 18 that makes it the beginning of adulthood? CrowdScience listener Lynda didn't feel very mature back then. She recalls a difficult decision that made her wonder what science has to say about when we’re truly grown up. How developed are we, physically, mentally and emotionally, by the age of 18? And how much does this differ between people, or from culture to culture? Presenter Caroline Steel digs around for answers with the aid of neuroscientist Sarah-Jayne Blakemore, biological anthropologist Barry Bogin, and cultural anthropologist Bonnie Hewlett. And even some teenagers. Contributors: Barry Bogin, Emeritus Professor of Biological Anthropology, Loughborough University Sarah-Jayne Blakemore - Professor of Psychology and Cognitive Neuroscience at the University of Cambridge Professor Bonnie Hewlett - Associate Professor, Cultural Anthropology, WSU VancouverPresenter: Caroline Steel Producer: Richard Walker Editor: Cathy Edwards Production Co-Ordinator: Ishmael Soriano Studio Manager: Neva Missirian

An apex predator is a killer. Usually large and terrifying, they enjoy the privilege of life at the top of a food chain. Nothing will eat them, leaving them free to wreak carnage on more vulnerable creatures. In biology, it’s a term normally reserved for animals like polar bears, tigers and wolves. But CrowdScience listener Eoin wonders whether there’s a non-animal candidate for apex predator: the car. After all, worldwide, more than 1.5 million humans die on the roads each year, while pollution from traffic kills millions more. And that’s just the impact on us. What are cars doing to all the other species on this planet? Host Anand Jagatia hits the road to investigate. En route, we’ll be picking up some scientists to help answer the question. It turns out to be so much more than a question of roadkill: cars, and the infrastructure built to support them, are destroying animals in ways science is only now revealing. How did the wildlife cross the road? We go verge-side to test four different approaches. And we hear how cars manage to kill, not just on the roadside, but, in the case of some salmon species, from many miles away. Gathering as much evidence as possible, we pass judgement on whether the car truly is an apex predator. Contributors: Samantha Helle - Conservation Biologist and PhD student, University of Wisconsin–Madison Paul Donald – Senior Scientist, BirdLife International and Honorary Research Fellow, University of Cambridge Zhenyu Tian – Environmental Chemist and Assistant Professor, Northeastern University Presenter: Anand Jagatia Producer: Marnie Chesterton Reporter: Camilla Mota Editor: Cathy Edwards Studio manager: Donald MacDonald and Giles Aspen Production co-ordinator: Ishmael Soriano(Image: Illustration of a deer in front of a car - stock illustration Credit: JSCIEPRO/SCIENCE PHOTO LIBRARY via Getty Images)

Many of us experience an inner voice: we silently talk to ourselves as we go about our daily lives. CrowdScience listener Fredrick has been wondering about the science behind this interior dialogue. We hear from psychologists researching our inner voice and discover that it’s something that begins in early childhood. Presenter Caroline Steel meets Russell Hurlburt, a pioneering scientist who devised a method of researching this - and volunteers to monitor her own inner speech to figure out what’s going on in her mind. She discovers that speech is just part of what’s going on in our heads, much of our inner world in fact doesn’t involve language at all but includes images, sensations and feelings. Caroline talks to psychologist Charles Fernyhough, who explains one theory for how we develop an interior dialogue as young children: first speaking out loud to ourselves and then learning to keep that conversation going silently. No one really knows how this evolved, but keeping our thoughts quiet may have been a way of staying safe from predators and enemies. Using MRI scanning, Charles and Russell have peered inside people’s brains to understand this interior voice and found something surprising: inner dialogue appears to have more in common with listening than with speaking. Caroline also has an encounter with a robot that has been programmed to dialogue with itself. Which leads us to some deep questions: is our inner voice part of what makes us human, and if so, what are the consequences of robots developing this ability? Scientist Arianna Pipitone describes it as a step towards artificial consciousness.Featuring: Professor Charles Fernyhough, University of Durham, UK Professor Russell Hurlburt, University of Nevada, Las Vegas, USA Dr Arianna Pipitone, University of Palermo, Italy Presenter: Caroline Steel Producer: Jo Glanville Editor: Cathy Edwards Sound design: Julian Wharton Studio manager: Donald MacDonald Production co-ordinator: Ishmael Soriano(Image: Mixed Race boy looking up Credit: Jose Luis Pelaez Inc via Getty Images)

It would be quite a superpower to regrow entire body parts. CrowdScience listener Kelly started pondering this after a discussion with her friend on whether human tongues could regrow. Finding out that they couldn't, she asked us to investigate the extent of human regenerative abilities. Presenter Alex Lathbridge travels to Vienna, a hotbed of research in this area. He meets an animal with much better powers of regeneration than humans - the axolotl. In Elly Tanaka’s lab he finds out how she studies their incredible abilities – and shows off his new axolotl tattoo.Why can these sweet-looking salamanders regrow entire limbs while we can’t even regrow our tongues? Palaeontologist Nadia Fröbisch has looked into the evolutionary origins of regeneration, and it goes a lot further back than you might think. And in fact, even humans are constantly regenerating, by renewing the building blocks of our bodies: cells. New cells grow and replace old ones all the time – although, in some parts of the body, we do keep hold of the same cells throughout our lives. However, cell turnover isn’t the same as regrowing entire organs or limbs. But can we grow new body parts in the lab instead? We meet Sasha Mendjan, who creates heart organoids using our cells’ innate ability to self-organise. How far off are we from implanting organs, grown from a patient’s stem cells, back into the human body? Contributors: Dr Elly Tanaka, Institute of Molecular Biotechnology (IMBA) Prof Martin Hetzer, Institute of Science and Technology Austria (ISTA) Prof Nadia Fröbisch, Natural History Museum Berlin Dr Sasha Mendjan, Institute of Molecular Biotechnology (IMBA) Presenter: Alex Lathbridge Producer: Florian Bohr Editor: Cathy Edwards Production Co-ordinator: Ishmael Soriano Studio Manager: Bob Nettles

Why do we have two eyes? Two ears? Two arms and two legs? Why is one side of the human body – externally at least – pretty much a mirror image of the other side? CrowdScience listener Kevin from Trinidad and Tobago is intrigued. He wants to know why human beings – and indeed most animals - have a line of symmetry in their bodies. Yet, beyond their flowers and fruits, plants don’t seem to have any obvious symmetry. It seems that they can branch in any direction. Anand Jagatia sets out to find out why the animal kingdom settled on bilateral symmetry as the ideal body plan. And it takes him into the deep oceans of 570 million years ago. Paleobiologist Dr. Frankie Dunn is his guide to a time when animal life was experimenting with all sorts of different body plans and symmetries.Frankie shows Anand a fossil of the animals which changed everything. When creatures with bilateral symmetry emerged they began to re-engineer their environment, outcompeting everything else and dooming them to extinction. Well... nearly everything else. One very successful group of animals which have an utterly different symmetry are the echinoderms. That includes animals with pentaradial - or five-fold - symmetry like starfish and sea urchins. And that body shape poses some intriguing questions... like “where’s a starfish’s head?” Dr. Imran Rahman introduces us to the extraordinary, weird world of echinoderms. To answer the second part of Kevin’s question - why plants don’t seem to have symmetry – Anand turns to botanist Prof. Sophie Nadot. She tells him that there is symmetry in plants... you just have to know where to look! Beyond flowers and fruits, there’s also symmetry in a plants leaves and stem. The overall shape of a plant might start out symmetrical but environmental factors like wind, the direction of the sun and grazing by animals throws it off-kilter. And, while the human body may be symmetrical on the outside, when you look inside, it’s a very different story. As listener Kevin says, “our internal organs are a bit all over the place!” Prof. Mike Levin studies the mechanisms which control biological asymmetry. He tells Anand why asymmetry is so important... and also why it’s so difficult to achieve consistently. Contributors: Dr. Frankie Dunn, Oxford University Museum of Natural History, UK Dr. Imran Rahman, Natural History Museum, London, UK Prof. Sophie Nadot, Université Paris-Saclay, France Prof. Mike Levin, Tufts University, Massachusetts, USA Presenter: Anand Jagatia Producer: Jeremy Grange Editor: Cathy Edwards Production Co-ordinator: Ishmael Soriano Studio Manager: Andrew Garratt(Image: Orange oakleaf butterfly (Kallima inachus) on tropical flower, Credit: Darrell Gulin/The Image Bank via Getty Images)

It's a simple metal box that moves nearly all of our goods around the world. Designed for uniformity and interchangeability, the shipping container has reshaped global trade and our lives in the nearly 70 years since its creation. But listener Paul wants to know if these heavy steel containers could be made with lighter materials to cut down on the fuel needed to transport them, especially when they're empty. Could we make shipping containers a more efficient process and reduce the shipping industry’s sizable greenhouse gas emissions?Host Anand Jagatia travels to Europe's largest port in Rotterdam looking for answers. Speaking to environmental scientists and industry insiders along the way, he takes a look at how the humble container might be modified to once again remake global shipping, from materials, to designs, to how it’s shipped. And thinking outside the box, we explore which innovations might benefit the whole system – from machine learning to new, carbon-free energy sources. For an industry that’s not always quick to change, we speak with the changemakers trying to disrupt the way 90% of the stuff we buy moves, in hope of a greener future.Featuring: Maarten van Oosten - Port of Rotterdam Authority Marc Levinson - historian, economist and author Greg Keoleian - School for Environmental Sustainability and Center for Sustainable Systems, University of Michigan Hans Broekhuis - Holland Container Innovations Trine Nielsen, Flexport Tristan Smith - University College London Elianne Wieles – Deep Sea Carriers, Port of RotterdamPresenter: Anand Jagatia Producer: Sam Baker Editor: Cathy Edwards Production Coordinator: Ishmael Soriano Studio Manager: Steve Greenwood(Photo: Port of Rotterdam, Maasvlakte Deep Sea Carrier Area. Credit: Sam Baker, BBC)

When listener Watum heard about the Titan submersible implosion in the news in 2023, a question popped up in his mind: if a machine that we specifically built for this purpose cannot sustain the water pressure of the deep ocean, how do fish survive down there? In this episode, we travel with marine biologist Alan Jamieson to the second deepest place in our oceans: the Tonga trench. Meanwhile, presenter Caroline Steel speaks to Edie Widder about the creatures that illuminate our oceans, and travels to Copenhagen to take a closer look one of the strangest deep sea creatures and its deep sea adaptations. But even fish have their limits! Scientist Paul Yancey correctly predicted the deepest point that fish can live, and it all comes down to one particular molecule. So is there anything living beyond these depths? Well, there is only one way to find out… Contributors: Prof Alan Jamieson, University of Western Australia Luke Siebermaier, Submersible Team Leader, Inkfish Dr Edie Widder, Ocean Research & Conservation Association Peter Rask Møller, Natural History Museum of Denmark Prof Paul Yancey, Whitman College Presenter: Caroline Steel Producer: Florian Bohr Editor: Martin Smith & Cathy Edwards Production Co-ordinator: Ishmael Soriano Studio Manager: Steve Greenwood(Image: Deep-sea fish - stock photo, Credit: superjoseph via Getty Images)

CrowdScience listener Azeddine from Algeria has had bad handwriting since he was a child. In fact, it was so untidy that, when he later became a chemistry lecturer, his university students complained that they couldn’t read his lecture notes. That was when he decided he had to do something about it. And it got him wondering… why do some of us have very neat handwriting while other people’s is almost unreadable? Why do his sisters all write beautifully when his natural style is quite the opposite? Presenter Alex Lathbridge – who admits that his handwriting isn’t always the tidiest – sets out to answer Azeddine’s question. He explores the different factors which determine how well we write. How much of it is inherited? What part does family and education play? And what’s actually going on in our brains when we apply pen to paper? Alex talks to anthropologist Monika Saini in Delhi who has analysed writing styles within families and in different regions across India. She tells him about the genetic and cultural factors which seem to influence our handwriting. We also hear from neuroscientist Marieke Longcamp who uses MRI scanning to find out which parts of our brains are involved when we write by hand. She’s looked at what’s happening in the brains of people who write in more than one script – for example in French and Arabic, like Azeddine. Another neuroscientist, Karin Harman James, has been looking at the link between learning something by writing it down compared to typing it on a tablet or laptop. And Alex meets handwriting tutor Cherrell Avery to find out if it’s possible to improve your writing – even as an adult. Contributors: Cherrell Avery, Handwriting Tutor, London, UK Dr. Monika Saini, National Institute of Health and Family Welfare, Delhi, India Prof. Karin Harman James, Indiana University, USA Prof. Marieke Longcamp, Aix Marseille Université, France Presenter: Alex Lathbridge Producer: Jeremy Grange Editor: Cathy Edwards Production Co-ordinator: Ishmael Soriano Studio Manager: Emma Harth

In many languages across the world, all nouns are classed as either male or female, or sometimes neuter. The English language, however, only signals gender in its pronouns - he, she, it or they. For inanimate objects, gender just crops up in occasional examples like ships or countries, which, for some reason, are deemed female. This lack of gender in English intrigued CrowdScience listener Stuart, since the other languages he knows all highlight whether something is male or female. Did English ever have gender, and if so, where did it go? Presenter Anand Jagatia dives into some Old English texts to uncover the idiosyncrasies of its masculine and feminine nouns, and learns why these gradually fell out of use. But why do other languages assign gender to nouns – male, female, and sometimes many more categories too? And does this affect the way we think?Contributors: Andrew Dunning, Curator of Medieval Manuscripts, Bodleian Library, Oxford University Rachel Burns, Departmental Lecturer in Old English, Oxford University Suzanne Romaine, Professor of Linguistics, Hawaii Ida Hadjivayanis, Senior Lecturer in Swahili, SOAS University Angeliki Alvanoudi, Sociolinguist, Aristotle University of Thessaloniki Amy Bahulekar, Writer, MumbaiPresenter: Anand Jagatia Producer: Eloise Stevens Editor: Cathy Edwards Production Coordinator: Ishmael Soriano