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Scientists can't agree on how fast the universe is expanding – why this matters so much for our understanding of the cosmos
It’s one of the biggest puzzles in cosmology. Why two different methods used to calculate the rate at which the universe is expanding don’t produce the same result. Known as the Hubble tension, the enigma suggests that there could be something wrong with the standard model of cosmology used to explain the forces in the universe. Now, recent observations using the new James Webb Space Telescope are shaking up the debate on how close the mystery is to being resolved.
In this episode, Vicent J. Martínez, professor of astronomy and astrophysics at the University of Valencia in Spain, and his former teacher, Bernard J.T. Jones, emeritus professor of astronomy at the University of Groningen in the Netherlands, explain why the Hubble tension matters so much for our understanding of the universe. Also featuring Lorena Sánchez, science editor at The Conversation in Spain.
This episode was written and produced by Katie Flood with assistance from Mend Mariwany. Eloise Stevens does our sound design, and our theme music is by Neeta Sarl. Gemma Ware is the executive editor. Full credits available here. A transcript will be available shortly. Subscribe to a free daily newsletter from The Conversation.
- Tensión sobre la tensión de Hubble (in Spanish)
- Great Mysteries of Physics: a mind-blowing podcast from The Conversation
- The universe is expanding faster than theory predicts – physicists are searching for new ideas that might explain the mismatch
- Cosmological models are built on a simple, century-old idea – but new observations demand a radical rethink
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How Zimbabwe reached the point of abolishing the death penalty
26:05|Zimbabwe is on the cusp of abolishing the death penalty after its Death Penalty Abolition Bill was approved by the senate on December 12. The bill is now sitting on the desk of Zimbabwe’s president, Emmerson Mnangagwa, a known opponent of the death penalty, waiting for his assent.In this episode, we speak to two experts on the death penalty, Carolyn Hoyle and Parvais Jabbar from the University of Oxford's Death Penalty Research Unit, who explain how Zimbabwe got here and what abolition means for both the country, and the continent. This episode was written and produced by Gemma Ware and Mend Mariwany with sound design by Michelle Macklem. Our theme music is by Neeta Sarl. Full credits for this episode are available. Sign up here for a free daily newsletter from The Conversation.If you like the show, please consider donating to The Conversation, which is an independent, not-for-profit news organisation. And please do rate and review the show wherever you listen.Further reading Zimbabwe’s likely to abolish the death penalty: how it got here and what it means for the continentKenyan prisoners on death row weren’t deterred by the threat of the death penalty: new research findingsWhy the death penalty is losing favour in sub-Saharan AfricaWhy distrust in powerful politicians is part of a functioning democracy
27:41|Surveys suggest that in many western democracies, political trust is at rock bottom. But is it really such a bad thing for people living in a democracy to distrust their government?In this episode, we talk to political scientist Grant Duncan, visiting scholar in politics at City St George's, University of London, about why he thinks a certain level of distrust and scepticism of powerful politicians is actually healthy for democracy. And about how populists, like Donald Trump, manage to use people’s distrust in political elites to their advantage.This episode was written and produced by Gemma Ware, Mend Mariwany and Katie Flood with sound design by Michelle Macklem. Our theme music is by Neeta Sarl. Full credits for this episode are available. Sign up here for a free daily newsletter from The Conversation.If you like the show, please consider donating to The Conversation, which is an independent, not-for-profit news organisation. And please do rate and review the show wherever you listen.Further reading Don’t trust politicians? That may not be such a bad thingWhy people vote for politicians they know are liarsTrusting societies are overall happier – a happiness expert explains whyHow do animals understand death?
26:42|An orca that pulled along the corpse of its baby for 17 days. An opposum that plays dead to fool predators. And a chimpanzee that cleaned the teeth of its dead baby. Observations of behaviours like these suggest animals have a complex relationship with death.In this week’s episode, we speak to Susana Monsó, an associate professor of philosophy at the National Distance Education University in Madrid, Spain, about the different ways animals understand death. This episode was written and produced by Katie Flood with sound design by Michelle Macklem and our theme music is by Neeta Sarl. Full credits for this episode are available. Sign up here for a free daily newsletter from The Conversation.If you like the show, please consider donating to The Conversation, which is an independent, not-for-profit news organisation. And please do rate and review the show wherever you listen.Further readingLos animales entienden la muerte más de lo que se pensabaWhat the grieving mother orca tells us about how animals experience deathElephant calves have been found buried – what does that mean?The story of one Amazon warehouse in the UK that pushed to unionise
32:58|The online retail giant Amazon is known for its resistance to unions. In this week’s episode, we tell the story of what happened at one warehouse in Coventry in the UK when its workers tried to gain official recognition for the GMB union, one of the country’s biggest labour unions.We talk to Tom Vickers, a sociologist at Nottingham Trent University in the UK, who spent weeks observing workers’ efforts to unionise at the warehouse as part of a research secondment with the GMB. And John Logan, a professor of labor and employment Studies at San Francisco State University in the US, explains why some companies, many of them American, are so doggedly anti-union. The episode also includes an introduction from Sarah Reid, business and economy editor at The Conversation in the UK.This episode was written and produced by Katie Flood with sound design by Michelle Macklem and our theme music is by Neeta Sarl. Full credits for this episode are available. Sign up here for a free daily newsletter from The Conversation.If you like the show, please consider donating to The Conversation, which is an independent, not-for-profit news organisation. And please do rate and review the show wherever you listen.Further reading:I spent months with Amazon workers in Coventry before they narrowly voted against unionising. This is what I learnedAmazon still seems hell bent on turning workers into robots – here’s a better way forwardAmazon, Starbucks and the sparking of a new American union movement50 years since the discovery of ancient hominin fossil Lucy in Ethiopia, calls grow to decolonize paleoanthropology
27:39|It's been 50 years since the American paleoanthropologist Donald Johanson discovered the fossil of ancient hominin 'Lucy' in the Afar region of Ethiopia. The find took the story of human evolution back beyond 3 million years for the first time. Yet, despite largely centring on the African continent as the "cradle of mankind", the narrative of hominin fossil discovery is striking for its lack of African scientists.In this week's episode, Yohannes Haile-Selassie, director of the Institute of Human Origins at Arizona State University in the US, explains why the story of ancient human origins is so western-centric, and why he's calling for the decolonisation of paleoanthropology.This episode was produced by Mend Mariwany with sound design by Michelle Macklem and our theme music is by Neeta Sarl. Full credits for this episode are available. Sign up here for a free daily newsletter from The Conversation.If you like the show, please consider donating to The Conversation, which is an independent, not-for-profit news organisation. And please do rate and review the show wherever you listen.Further reading:‘Deep inside, something told me I had found the earliest human ancestor; I went numb’ – Yohannes Haile-Selassie on his lifetime quest to discover ancient humanityLucy, discovered 50 years ago in Ethiopia, stood just 3.5 feet tall − but she still towers over our understanding of human origins Meet 3-million-year-old Lucy – she’ll tell you a lot about modern African heritageThe controversy over cod fishing in Canada
25:34|For generations, cod fishing was a way of life in Newfoundland and Labrador, the easternmost province in Canada. But in 1992, after cod stocks in the north Atlantic plummeted, the federal government imposed a moratorium on cod fishing. It was to last for 32 years until June 2024, when the government lifted the ban in a controversial decision.In this episode we speak to Tyler Eddy, a research scientist in fisheries science at Memorial University of Newfoundland, to shed light on what’s happened. It's a story that offers a cautionary tale for those politicians trying to balance the complex demands of protecting ecosystems that also support substantial economies.This episode was produced by Katie Flood and Gemma Ware. Sound design was by Michelle Macklem and our theme music is by Neeta Sarl. Full credits for this episode are available. Sign up here for a free daily newsletter from The Conversation.If you like the show, please consider donating to The Conversation, which is an independent, not-for-profit news organisation. And please do rate and review the show wherever you listen.Further reading:The federal government has lifted the moratorium on Northern cod fishing after 32 yearsThe Atlantic: The driving force behind ocean circulation and our taste for codTiny oceanic plankton adapted to warming during the last ice age, but probably won’t survive future climate change – new studyGangsters who leave their gang behind for something new
31:49|What happens when a gangster leaves their life on the street? How do they transition to something new? We find out through the life stories of two people who joined them as young men and came out the other side. Featuring an interview with Gaz, a former gang member in Sierra Leone, and Dennis Rodgers, a research professor at the Graduate Institute in Geneva, Switzerland who leads a global research project on gangs. This episode was produced by Mend Mariwany and Gemma Ware. Sound design was by Michelle Macklem and our theme music is by Neeta Sarl. Full credits for this episode are available. Sign up here for a free daily newsletter from The Conversation.If you like the show, please consider donating to The Conversation, which is an independent, not-for-profit news organisation. And please do rate and review the show wherever you listen.Further reading:Gangs’stories: The Sierra Leonian gangster who gave up violence and drugs for poetryGangs’stories : A glimpse of hard lives around the worldFrom dealing drugs to selling tortillas: the surprising future of former gang membersWhat is motivating Americans as they decide who to vote for
32:27|Amid deep political polarization and extreme campaign rhetoric, the U.S. presidential election on November 5 is likely to be decided by a small number of voters in swing states such as Pennsylvania and Michigan. But why is it so close?In this episode Naomi Schalit, senior politics editor at the The Conversation U.S., speaks to Jesse Rhodes, associate professor of political science at UMass Amherst, who has been surveying Americans on the issues that matter to them, and their concerns as the election approaches. This episode was produced by Katie Flood with assistance from Mend Mariwany. Sound design was by Michelle Macklem and our theme music is by Neeta Sarl. Full credits for this episode are available. Sign up here for a free daily newsletter from The Conversation.If you like the show, please consider donating to The Conversation, which is an independent, not-for-profit news organisation. And please do rate and review the show wherever you listen.Further reading:Why vote for Harris or Trump? A cheat sheet on the candidates’ records, why their supporters like them and why picking one or the other makes senseUS voters say they’re ready for a woman president − but sexist attitudes still go along with opposition to HarrisYes, sexism among Republican voters helped sink Nikki Haley’s presidential campaignOrigins of South Australia’s mysterious pink sands revealed
21:47|Take a walk along a beach in parts of South Australia, and you may come across unusual patches of pink sand. When a team of geologists began analysing samples of this mysterious sand to find out where it comes from, their search took them back through time to a previously undiscovered mountain range in Antarctica. In this episode Sharmaine Verhaert, a PhD candidate in earth sciences at the University of Adelaide, explains how the discovery was made. This episode was produced by Gemma Ware, Katie Flood and Mend Mariwany. Sound design was by Michelle Macklem and our theme music is by Neeta Sarl. Full credits for this episode are available. Sign up here for a free daily newsletter from The Conversation.If you like the show, please consider donating to The Conversation, which is an independent, not-for-profit news organisation. And please do rate and review the show wherever you listen.Further reading:South Australia’s enigmatic pink sand was born in ice-covered Antarctic mountains, new research showsAustralian amber has revealed ‘living fossils’ traced back to Gondwana 42 million years agoThe Anthropocene epoch that isn’t – what the decision not to label a new geological epoch means for Earth’s future