This week on the show that brings you the science behind the news, we’re looking at news that China’s population has fallen for the second year running. Worrying news for China’s economy, but would a declining population be a good thing for the planet?The Unexpected Elements team on three continents meet the musical frogs who are having to climb a mountain to keep their populations stable, and dig deep to explore the earth’s declining microbiome and the hope scientists have for the future.As the Africa Cup of Nations continues, we’ll be wondering how you might date a footballer. Not in a romantic sense… we hear about some suspiciously mature youth players and how science can help when the age on a passport isn’t reliable.Marnie will be wondering why Japanese men are shouting their love from a hilltop, and unpicking the recipe for a truly satisfying hug.All that plus a postbag bursting with multilingual puns, and the reason Portuguese speakers have trouble with English doors.Presented by Marnie Chesterton Produced by Ben Motley, with Alex Mansfield, Dan Welsh, Katy Tomsett and Jack Lee

As France's youthful new Prime Minister gets his feet under the desk, we examine how stress and strains can change the way we look. We also ask what the late nights and lack of sleep that go hand in hand with leadership can mean for the health of the human body and we hear how measuring intelligence in young people isn't as straightforward as it might seem.

Could geopolitical tensions around the Red Sea affect research into the region’s heat-resistant super corals? Also on the program, what an ocean that used to lie under the Himalayas can tell us about evolution, the fruit chat continues with the latest chapter in the bananadine saga, and how looking to the past could help create the shipping of the future.

As the new year arrives for much of the world, Marnie and pals look at a few time-related oddities. From the abolition of the leap second, to how some people feel they can actually see time stretching before them, to a festival of lunar-loving worms. On the anniversary of the invention of the word “robot”, we discuss EU AI legislation and its parallels with science fiction of a century ago, regal handedness, Arctic golf courses and the time-capsule of all humanity, stuck to the side of the Voyager Probes.Presented by Marnie Chesterton with Meral Jamal, Andrada Fiscutean, plus Prof Anje Schutze of Texas A&M University Produced by Tom Bonnett, with Alex Mansfield and Dan Welsh

Usually Unexpected Elements looks at the science behind the news, but this week Marnie Chesterton and Caroline Steel are looking back at some of the best bits from our first few months.We’ve got the best from our team of panellists across the globe, including what’s going on in your brain when you speak more than one language, the horrific mating ritual of the bedbug and the science behind our panellist Camilla’s terrible haircut decision.We look back at some of the brilliant scientists we’ve spoken to, with subjects as diverse as whale song, how the entire universe was once the size of a marble, why an archaeologist hasn’t run off with all the gold he’s found and how the jewel wasp turn a cockroach into a zombie.We have ‘Under the Radar’ stories about power outages in South Africa, human ancestors from China, bringing Rhinos back to life in Kenya and how to keep everyone safe from Polar Bears in a place where there’s no phone signal.We reflect on our attempts to find the Coolest Science in the World, and whether it’s possible to pit a hurricane machine against an alternative to antibiotics.And it wouldn’t be a ‘best of’ show without a digest of all the fruit chat from throughout the year.All that plus eating glue for science, our best (or worst?) puns and some singing cows.Presented by Marnie Chesterton & Caroline Steel Produced by Ben Motley, with Tom Bonnett

This podcast explores dark and light topics, including sensory deprivation studies, bioluminescence in ocean creatures, using tilapia fish skin for burn victims, sneezing during sleep, the game of Goalball, and the importance of light in various aspects of life.

On the 75th anniversary of the Universal Declaration Of Human Rights, we look into the phenomenon of caring for things outside of ourselves – whether it’s human rights, the environment, or even odd sports.

After 41 Indian miners were happily rescued last week, Unexpected Elements takes a look at how our futures might lie below the surface.As climate change suggests more of our infrastructures need to be buried safely, and even living spaces could be cooler down there, we discuss future technologies for digging tunnels more safely and cleanly. But tunnelling and boring could go back a long way - more evidence suggests species of dinosaurs used to to live semi-subterranean lives.Tunnelling also happens at the very smallest scales and lowest temperatures, as observed this year by physicists at Innsbruck University. Dr Robert Wild of Innsbruck University in Austria describes quantum tunnelling - a crucial process that belies most chemistry and even the fusion of hydrogen in the sun, and which is increasingly becoming part of our electronic devices.Also, a new technique for monitoring the rapid evolution of the malaria parasite, your correspondence including obscure sports and asteroid fantasies, and a discussion of the difficulties of hiring a panda. Presenter: Caroline Steel, with Philistiah Mwatee and Alex Lathbridge

This week on the show that brings you the science behind the news, inspired by COP28, we’re talking about meetings. Honestly, it’s way more interesting than it sounds. Come to hear about blackworm blobs – a wormy meeting that only happens in stressful situations - and how scientists are taking inspiration from it to design robots. Stay for the stories from nature where species are missing crucial pollination meetings thanks to that global stressful situation that is climate change. And what’s better for the planet, a big meeting that everyone flies to or a telephone conference with no video? In ‘Ask the Unexpected’ we answer a listener’s question about antibiotics - if there are good bacteria in the body, how do they know which ones to attack?Also, OMG it’s the OMG particle – we hear about the tiny but powerful particles that pound the planet from time to time. All that plus your emails about toilets and the rules of Cricket.Presented by Marnie Chesterton, with Chhavi Sachdev and Tristan Ahtone.Produced by Ben Motley, with Alex Mansfield and Dan Welsh.

The cricket world cup has us looking at the science of spitting on cricket balls, particle accelerators, and insect sound engineers.Also on the program, how AI is breaking into e-commerce, why do we get in the middle of the night, and is a fat flightless parrot the world's greatest bird?