Curious Cases

What would it take for humans to live permanently on Mars? asks Martin in Weston-super-Mare, UK. The doctors dig into requirements and possibilities of a long-term Martian outpost. We know that many missions to Mars have failed, for a range of reasons – malfunctions, crashes and even a mix-up between imperial and metric units. Getting to Mars – let alone decelerating from 30,000 miles per hour to a safe landing speed in about seven minutes – is not straightforward. Aerospace engineer Anita Sengupta helped land NASA’s Curiosity rover on Mars. She knows first-hand the challenges of putting a robot on the red planet. But getting robots to Mars is an easier proposition than doing the same for humans. Even if we work out how to survive the radiation exposure on the eight-month journey and the pulverising descent, Mars’ surface isn’t easily habitable. Principal investigator for NASA’s Mars Atmosphere and Volatile Evolution Mission (MAVEN) Bruce Jakosky describes the conditions on Mars: Freezing, with an atmosphere containing mostly carbon dioxide and very little water, and subject to annual global dust storms. However, this isn’t deterring space agencies and private companies from researching the challenge. The European Space Agency and Russian Institute for Biomedical Problems focussed on finding out the physiological and psychological tolls by selecting six candidates to spend 520 days in a simulated spacecraft and landing module. Diego Urbina explains the personal challenge of taking part in the Mars500 experiment. Some private company owners have gone even further. As well as making technology based on the current physical conditions, could those constraints themselves be altered? Could Mars be terraformed, or warmed, for easier human survival? Bruce Jakosky shares just what that would take – and compares these requirements with what’s actually available. Presenters: Hannah Fry & Adam Rutherford Producer: Jen Whyntie A BBC Audio Science Unit production, first broadcast on BBC Radio 4 in 2020.

"How many hamsters on wheels would it take to power London?" asks Judah from Virginia in the USA. Rutherford & Fry return with engineering, ethics and economics to answer this electric query.Smart grid engineer Lynne McDonald helps keep the lights on for 8.3 million homes and businesses across London at UK Power Networks. She explains how the kilowatt hours we see on our electricity bills relate to the thousands of gigawatt hours required when thinking about powering the whole of London. In theory, a hamster in a wheel might be able to produce about half a watt of power – enough to run a small LED light bulb. Whilst the doctors argue the case on the resultant practicalities and ethics of even considering such a scenario – as, for example, the required cubic kilometre stack of hamster habitats would cover Canary Wharf – Royal Veterinary College researcher Zoe Davies points out some biological and anatomical home truths. As an expert in biomechanics currently investigating athletic performance in racehorses, she walks Adam through the impossibilities of using pretty much any animal, bird or insect as a source of power. There may be one exception though: humans. Veteran lecturer of undergraduate chemistry for biologists and cycling enthusiast, Andrea Sella discusses whether human power might realistically work. We consider what this or other more realistic sources of renewable energy could mean for the future of our national grid. Presenters: Hannah Fry & Adam RutherfordProducer: Jen WhyntieA BBC Audio Science Unit production for BBC Radio 4, first broadcast in December 2020.

Rutherford and Fry are back in the business of solving your science queries and rooting out the quirks and conundrums of everything that is science!

Is there a point in space where the Sun could heat a burrito perfectly? asks Will. The doctors tackle this and a plethora of other conundrums from the Curious Cases inbox.Featuring expert answers from: Astrophysicist Samaya Nissanke Cosmologist Andrew Pontzen Cognitive neuroscientist Sophie Scott Presenters: Hannah Fry & Adam RutherfordProducer: Jen WhyntieFirst broadcast on BBC Radio 4 in July 2020.

‘Today I learnt that tigons and ligers are what you get when lions and tigers interbreed?!’ surprised listener Jamz G tells the doctors. ‘What determines whether species can interbreed?’ Geneticist Aoife McLysaght studies molecular evolution. She explains the modern definition of a species, built on ideas from Aristotle, Linnaeus and Darwin: a species is a group of organisms capable of interbreeding to produce fertile offspring. Hybrids – such as ligons and tigers – are usually infertile, because their common ancestors long ago diverged into the lions and tigers we know today. However, this definition isn’t absolute, and there are many ways a new species can be formed.Hybrids also offer rich study subjects for scientists. Mathematical biologist Kit Yates discusses why he’s been reading research papers about hebras and zorses (horse x zebra) as their patterns offer insights into how cells spread and develop into organisms, building on a prediction made by codebreaking mathematician Alan Turing.And it turns out that these hybrids are even more intriguing. As speciation and evolution expert Joana Meier explains, hybrids are not always infertile. Hybridisation can lead to successful new species arising, such as in Lake Victoria’s cichlid fish, who it seems have been having a wild evolutionary party for the last 15,000 years. And the picture gets even murkier when we discover that modern genetics reveals our human ancestors successfully mated with Neanderthals. Presenters: Hannah Fry & Adam RutherfordProducer: Jen WhyntieFirst broadcast on BBC Radio 4 in July 2020.

Everyone knows about the Big Bang being the beginning of the universe and time - but when and how is it going to end? ask brothers Raffie and Xe from Rome. For this series, with lockdown learning in mind, Drs Rutherford and Fry are investigating scientific mysteries for students of all ages. The doctors sift science from philosophy to find out.Cosmologist Jo Dunkley studies the origins and evolution of the universe. She explains how astrophysical ideas and techniques have evolved to tell us what we now know about our galaxy and far beyond, from the elegant parallax technique to standard candles. This particular distance measure, which uses stars of a known brightness to work out how far away other objects in the universe are, was discovered by American astronomer Henrietta Swan Leavitt in 1912, who worked at the Harvard University as one of several “computers” – women who processed and calculated data and made significant contributions to astronomy.Curious Cases’ universal guru Andrew Pontzen puts this into context. Because the universe is so enormous, it turns out that these measurements are just the first steps on the cosmic distance ladder – a suite of tools that astrophysicists use to determine distances to celestial objects. Scientists know that objects are moving away from us because the wavelengths of light from them get stretched and appear redder in our telescopes – the so-called red shift effect. But having a handle on the distances to and between those objects allows cosmologists to monitor what’s happening to them over time. And it turns out that not only are they getting further apart, indicating that the universe is expanding, but that this process is accelerating. So what might happen in the end? Expansion and then collapse – a big crunch? Expansion into the void – a big freeze, or a big rip? Or what if there is more than one universe – might a new one bubble up with totally different laws of physics that would cause our own to cease existing? It turns out that when dealing with predictions for something involving infinite space and time, the possibilities are largely limited by human imagination alone. Ideas are where science starts, but experiments are required to build evidence confirming or rejecting them as fact. The doctors discuss how gravitational wave detectors and quantum computers might one day provide this.Presenters: Hannah Fry & Adam Rutherford Producer: Jen WhyntieFirst broadcast on BBC Radio 4 in June 2020.

"What’s the point of wasps?" asks listener Andrew, who is fed up with being pestered. For this series, with lockdown learning in mind, Drs Rutherford and Fry are investigating scientific mysteries for students of all ages. Do wasps do anything to justify their presence as a picnic menace?Ecologist Seirian Sumner researches social wasp behaviour and champions their existence. Not only do yellow jacket wasps perform important ecological services as generalist pest controllers of aphids, caterpillars and flies in the UK, they have complex societies and may even perform pollination services, making them more like their better-loved bee cousins than many might think.However, much remains unknown about wasps’ contribution to our ecosystem. Seirian works with entomologist Adam Hart, and together they run The Big Wasp Survey each summer, a citizen science project dedicated to find out more about UK wasp species and their populations. Prof. Hart sets up an experimental picnic with Dr Rutherford to try and attract some native wasps, and discusses why they are so maligned. But in some parts of the world UK wasp species have become a major problem. Just after World War II, having unwittingly chosen some aircraft parts destined for New Zealand as their overwintering home, some wasp queens woke up in the city of Hamilton. With no natural predators or competitors, they quickly established a growing population. Fast forward to today, and by late summer the biomass of wasps becomes greater than all the birds, rodents and stoats in the southern island’s honeydew beech forests. Multiyear nests have been discovered that are over three metres tall and contain millions of wasps. Researcher Bob Brown is digging into wasp nests back in the UK to discover which species keep wasps in check here, and whether they might work as biological control.This causes the doctors to ponder the problems of humans moving species around the planet. Accidental or even well-meaning introductions all too often become invasive. As climate change and urbanisation accelerate, wasps may become more helpful in some ways and more harmful in others.Presenters: Hannah Fry, Adam Rutherford Producer: Jen WhyntieFirst broadcast on BBC Radio 4 in 2020.

Liz Bentley, Chief Executive of the Royal Meteorological society, explains the science of weather prediction. Mark Miodownik discusses the technique of cloud seeding for inducing rainfall, but highlights its unreliable results. The podcast explores the challenges of verifying the effectiveness of cloud seeding and delves into the political implications of manipulating the weather. Additionally, it examines desertification and advancements in desalination technology. Nature versus nurture is also contemplated.

"Why do our tummies rumble - and when they do, does it always mean we are hungry?" asks listener James, aged 12. For this series, with lockdown learning in mind, Drs Rutherford and Fry are investigating scientific mysteries for students of all ages. To get to the bottom of this noisy problem, the doctors tune in to our guts.Geneticist Giles Yeo studies food intake and obesity. He explains the wavy workings of our digestive system, and how those audible rumbles are a sign that digestion is taking place – a phenomenon thought to be onomatopoeically named 'borborygmi' by the ancient Greeks, and explored further in the gruesome 19th century experiments of surgeon William Beaumont. However, tuning in to the gut’s sounds can tell us more than whether we need a snack. Family doctor Margaret McCartney takes us through the process of how and why she and her medical colleagues may use a stethoscope to listen to your abdomen for both particular noises and silence. Microbiologist Barry Marshall has taken medical listening one step further in his Noisy Guts Project. Inspired by microphones used to listen for termites hiding in walls, the Nobel Prize-winning scientist is trialling an acoustic belt, which could be worn to help diagnose and treat Irritable Bowel Syndrome.Presenters: Hannah Fry, Adam Rutherford Producer: Jen WhyntieFirst broadcast on BBC Radio 4 in 2020.

Rutherford & Fry are back with longer duration episodes brought to you from slightly shouty socially distanced studio and bedroom settings.