The Hindu festival of Kumbh Mela is currently underway in India. As part of the event, millions of pilgrims will take a cleansing dip in the confluence of the Ganges, Yamuna and the mythical Saraswati. Inspired by this headline, we splash into a whole bathtub of stories about the science of cleaning. We find out why it’s so important to prevent contamination of other planets and moons, and how space scientists keep things clean.

Next up, we discover how our brains clear out harmful toxins while we snooze.

And is there any truth in the saying, ‘tidy house, tidy mind’?

Finally, Marnie ponders whether it’s possible to be too clean, or if being a bit grubby is okay. Presenters: Marnie Chesterton, with Affelia Wibisono and Andrada Fiscutean Producers: Alice Lipscombe-Southwell, with Dan Welsh, William Hornbrook and Imaan Moin

After the comic malfunctions of a self-driving car, which drove its passenger/prisoner in endless circles, Unexpected Elements rounds its attention on the humble circle. Explore how one man calculated the circumference of the Earth 2,000 years before GPS was invented, then be spellbound by the Magic Circle and the mysterious woman who broke into it. And as we hit the five-year anniversary of the Covid pandemic, we take a look at the cycle of infection and mutation, before asking, 'why don’t we have one antiviral pill that kills them all?' We’re joined by evolutionary psychologist Professor Robin Dunbar, who calculated Dunbar’s number; that is, the maximum number of folks you can hold onto in your circle of friends... five? 500? 5,000? Robin reveals how many REAL friends science says you can have. Presenters: Marnie Chesterton, with Camilla Mota and Phillys Mwatee Producers: Harrison Lewis, with Alice Lipscombe-Southwell and William Hornbrook

Team Unexpected have been digging into their mind palaces to pull on the scientific research that has stuck with them most over the past year. We hear from Professor John Parnell, geologist at the University of Aberdeen, about the role of plankton in forming ancient mountains. How ocean bubbles play a role in climate regulation with bubble physicist Dr Helen Czerski from University College London. Would you know how to measure the size of a bubble? We also participate in some memory sports with Jonas von Essen who is a two-time world memory champion. He helps us construct a mind palace in order to memorise really long strings of digits. Plus we look into the backstory of the human buttocks with science journalist and reporter Heather Radke. She answers the question ‘why do we humans have such large behinds?’ And we hear from Professor Andre Isaacs at the College of the Holy Cross who has filled his chemistry lab with music and dance in order to change perceptions about who can be a scientist. That, plus many more Unexpected Elements.  Presenter: Marnie Chesterton Producer: Jonathan Blackwell and Harrison Lewis with Imaan Moin and Alice Lipscombe-Southwell

Happy New Year! This week, the Unexpected Elements team is reflecting on 2024 and looking forward to 2025 for renewed chances to spot the northern lights while they're at their peak visibility in this current solar cycle, and we recap on cellular regeneration advancements and regulations in embryonic stem cell models. 

We chat to Professor Rene Oudmaijer from the Royal Observatory of Belgium who explains that stars also renew themselves... and this process is key to our lovely planet (and ourselves) existing!  

We also learn all about the potential of bogs and wetlands in the fight against climate change from Professor Christian Dunn of Bangor University. 

With another amazing year behind us, we reminisce about our favourite stories and listener correspondences in 2024. 

And finally, we’re wowed by the regenerative ‘superpowers’ of the magnificent axolotl who has the cellular capabilities to re-grow limbs! 

That, plus many more Unexpected Elements. 

Presenters: Marnie Chesterton and Caroline Steel  Producers: Harrison Lewis, Imaan Moin and William Hornbrook  Sound Engineer: Duncan Hannant

December is a time of celebration, family feuds, and now scientific rivalries. It's also one of the most wasteful months of the year, with festivities in full swing across the globe. No wonder the world is overflowing with rubbish—both literal and metaphorical!

Unexpected Elements dives headfirst into the scientific bin to wallow in waste. Could worms be the unexpected heroes of our plastic pollution crisis? How much garbage have we jettisoned into space? And why is part of our very own genome called "junk DNA"?

But it’s not all rubbish, we’re also talking trash. While celebrations can bring people together, spending too much time with loved ones can lead to tense moments. Rafi Kohan shares expert tips on how to outsmart your opponent during a heated board game debate.

And don’t think trash talk is limited to sports fields. The world of science has its share of drama, too. We’ll explore some of history’s most scandalous squabbles with scientists behaving badly.

Come waste an hour with us on Unexpected Elements!

Presenter: Caroline Steel, with Chhavi Sachdev and Candice Bailey Producers: Harrison Lewis, Imaan Moin, Alice Lipscombe-Southwell, William Hornbrook and Eliane Glaser Sound engineer: Gavin Wong

As news breaks that archaeologists have found the tomb of St Nick in Turkey, we check in on the North Pole Father Christmas, and fact-check his present giving schedule with advanced level physics and a Gant chart.

Plus, prepare for stories of reindeers high... despite their apparent immunity to their favourite hallucinogenic mushroom treats. And we burrow into Santa’s iconic beard to find any microbial magic that lives there.

And yet more reindeer magic, this time the mysteries of their amazing body clocks, which they seem to be able to switch on and off at will... AND we reveal Rudolf the red nose reindeer’s big secret. You’ll never hear that song in the same way again

Presenter: Marnie Chesterton, with Phillys Mwatee and Camilla Mota Producers: Emily Knight, Alice Lipscombe-Southwell and William Hornbrook Sound engineer: Searle Whittney

This week, a banana sold at auction for $6.2 million dollars. Well, not quite… it’s actually a piece of conceptual art and it’s WAY more than just a banana. There’s also some duct tape. In response to this most bananas of auctions, the Unexpected Elements team are going bananas for bananas! We investigate the science of slipping on a banana-skin. Is it just ‘cartoon physics’ or are they actually a slip-hazard? And did you know your breakfast banana might be… radioactive? Also, can Romanian ethical hackers succeed where the police have failed? We look at the computer sleuths tackling real life missing persons cases. We find the answer to why toads have evolved such dangerous skins, and yet more bananas, as we look at the pros and cons of the Ethiopian False Banana. Why hasn’t this hardy plant conquered the world? Presenter: Marnie Chesterton, with Andrada Fiscutean and Christine Yohannes Producers: Emily Knight, Alice Lipscombe-Southwell and William Hornbrook Sound engineer: Searle Whittney

This week we’re looking at a political agreement that will hand back sovereignty of the Chagos Islands to Mauritius. In the 1970s, the UK removed the entire Chagossian population to make way for a US military base. The islanders have been fighting for their right to return ever since. If deal can be agreed, the islanders are hoping they will have the chance to go home.

And this got us thinking about all things home-related.

First up, we discover the intriguing reasons why you can’t smell your own home, then we take a closer look at our homes and all the creatures that live there, before finding out about the ‘home scars’ created by limpets.

Next we hear from Dr Nadescha Zwerschke, a scientist who spent time on Rothera research station in Antarctica. She reveals how she made this isolated outpost feel like home.

Also, we reveal that global talks to agree a reduction in plastics have collapsed, which could have an impact on all our homes from a pollution perspective.

And finally – a type of pasta that would be no good for your homecooked recipes.

Presenter: Marnie Chesterton, with Tristan Ahtone and Godfred Boafo Producer: Alice Lipscombe-Southwell, with Harrison Lewis and William Hornbrook Sound engineer: Gavin Wong

It’s Black Friday! Everyone is camping in the street, staying up all night for the very best deals around. And Unexpected Elements are joining in.

We take a look at the huge underground trade of vital resources...not run by criminals but fungi.

Then it is onto illegal animal trade and the 300 pets who got a terrible deal, strapped to a man’s chest as he tried to make it through airport security.

Have you ever asked a pigeon for advice when gambling? We hear from a professor of psychology about why you should not.

And finally, the story of Lee Sedol, the world’s best player of the board game Go, who was challenged by Google to a game worth one million dollars.

Presenter: Caroline Steel, with Phillys Mwatee and Christine Yohannes Producers: Emily Knight, Harrison Lewis, Imaan Moin and William Hornbrook Sound engineer: Searle Whittney

Headlines that Canadian uranium deposits could make it a nuclear superpower has the Unexpected Elements team musing on all manner of superpowers.

Tardigrades are an obvious candidate – boil them, freeze them, irradiate them in space, these adorable creatures are almost indestructible. We also meet Dr Deep Sea, Joseph Dituri, from the University of South Florida, who lived under water for 100 days and swears by it as a boost for our health.

As the leader of the free world goes on an Amazon jungle tour, we talk tiny frogs, giant frogs and radiation tolerant frogs.

We also hear how cancer survivors may have a secret superpower and how we’ve co-opted plants superpowers for medicines.

Presenter: Marnie Chesterton, with Camilla Mota and Affelia Wibisono Producers: Imaan Moin, Harrison Lewis and Dan Welsh Sound engineer: Gavin Wong

It’s been 24 years since the release of Ridley Scott’s Gladiator, which left audiences captivated by the story of Maximus the gladiator, played by Russell Crowe. Now, Gladiator II is hitting the cinemas, so this week we enter the arena to take a look at some gladiatorial science.

We hear about an angry little fish that fights off its rivals in mouth-to-mouth combat, we discover how humans have looked to nature to design better armour, and we find out about the perfume that Julius Caesar would have worn.

We also speak to Dr Chris Nowinski, a former WWE professional wrestler who's now a pioneering neuroscientist. He’s leading some research into how to prevent concussions in sport, and is co-founder of The Concussion Legacy Foundation.

That, plus many more Unexpected Elements.

Presenter: Marnie Chesterton, with Christine Yohannes and Chhavi Sachdev Producers: Alice Lipscombe-Southwell, Dan Welsh and Imaan Moin Sound engineer: Dyfan Rose