Science In Action - Betelbuddy and Silk Road Cities

Betelgeuse, one of the brightest and most famous stars in the northern night sky, has varied in brightness with an elusive pattern ever since observations began. Many theories exist as to why it ebbs and flows with apparently two distinct rhythms – one shorter and another around 2000 days long.

But just recently two independent astronomical teams have unveiled papers suggesting the existence of an orbital companion circling the red giant. About the size of our own sun, the “Betelbuddy” may whizz round Betelgeuse, almost skimming its surface, every 2000 days. And why haven’t we seen the Betelbuddy before? Because, from here, it would be a million times fainter than Betelgeuse itself, as one of the authors, and long-time Betelgeuse watcher, Andrea Dupree of Harvard and Smithsonian Centre for Astrophysics explains.

Back here on earth, Omar Yaghi of Berkeley, University of California and colleagues have been designing a new material that can scrub carbon dioxide out of the air in minutes. They have patented this type of Covalent Organic Framework (COF) and are hoping to scale up production such that a few hundred tonnes deployed around our biggest cities could solve our CO2 crisis.

But then what do you do with all those gigatonnes of CO2? Maybe one thing would be to use solar power to convert it into plant food. Robert Jinkerson and colleagues describe in the journal Joule a proposal to transform global food production into “Electro-Agriculture”, growing plants, fungi and algae on acetate made from solar energy. Their proposal would also shrink the global footprint of farming to allow more natural habitat.

And finally, Michael Frachetti of Washington University in St Louis has published an archaeological survey of two lost conurbations in the mountains of southern Uzbekistan that he and colleagues rediscovered in the last few years. He argues that the scale and complexity of these dwelling, and their location over 2000m, way above normal agricultural altitude mean we need to reconsider these stops on what would have been the Silk Road, around 600-1000 CE, perhaps even pointing at a very early industrial economy.

Presenter: Roland Pease Producer: Alex Mansfield with Andrew Lewis

(Image: Orion sink to Kashimayarigadake. Credit: Getty)

Focus on Africa - Ethiopia’s Tigray region’s education system crisis

The crisis in Ethiopia's Tigray region's education system shows little sign of ending two years after the civil war

How crippling national debt in Africa is curbing development under discussion at the IMF and World Bank meetings in Washington DC

Plus the challenge of catching breast cancer early in sub Saharan Africa

Presenter: Audrey Brown Producers: Charles Gitonga, Amie Liebowitz, Patricia Whitehorne and Paul Bakibinga Technical Producer: Francesca Dunne Editors:. Andre Lombard and Alice Muthengi

Focus on Africa - Sudan’s proxy war

Russia's embassy in Sudan has said it is investigating reports that a cargo plane with Russian crew was shot down in Darfur, a key battle ground in the civil war between the army and the paramilitary Rapid Support Forces. Is Russia part of a proxy war in Sudan?

Kenya's all women SWAT squad heads to Haiti

And will the junta in Gabon step aside once a new constitution is adopted?

Presenter: Audrey Brown Producers: Sunita Nahar, Joseph Keen, Alphonso Daniels and Nyasha Michelle in London Technical Producer: Francesca Dunn Senior Journalist: Karnie Sharp Editors: Andre Lombard and Alice Muthengi

Focus on Africa - Kenya returns refugees to Turkey?

The Kenyan government says it deported four Turkish refugees back home. The UN's refugee agency is not pleased

Egypt officially declared 'malaria-free' by the World Health Organization (WHO) after a 100-year long effort.

And why Botswana has never borrowed money from the IMF

Presenter: Audrey Brown Producers Amie Liebowitz, Sunita Nahar, Blessing Aderogba and Paul Bakibinga Technical Producer: Jonathan Greer Editors: Andre Lombard and Alice Muthengi

Focus on Africa - Food poisoning cases rise in South Africa

South Africa's health department say they've begun 'intense' investigations into alleged food poisioning cases especially amongst children. In a recent case six children all under the age of 10 died in Soweto, after allegedly eating food that was poisioned. We hear from a journalist covering the story.

Also why South Africa's relationship with Taiwan is tense - and what sort of relationship does the island share with the rest of the continent?

And why is Mozambique planting around 200 million mangroves?

Presenter: Charles Gitonga Producers: Patricia Whitehorne, Stefania Okereke, Amie Liebowitz, Audrey Brown and Nyasha Michelle in London Technical Producer: Nick Randell Senior Journalist: Karnie Sharp Editors: Andre Lombard and Alice Muthengi

Good Bad Billionaire - Jack Ma: China’s ecommerce CEO

Jack Ma is the king of ecommerce in China. Nicknamed 'Daddy Ma', the former school teacher even appeared alongside martial arts legend Jet Li in a kung fu movie. But how did a scrawny, belligerent child, who was the only person who failed to get hired at his local KFC, become the chairman and CEO of online mega-platform Alibaba? BBC business editor Simon Jack and journalist Zing Tsjeng explain how a crazy trip to America, where Jack had to flee from a conman, ended up introducing him to the internet, which would make him his fortune. Then they decide if they think he’s good, bad, or just another billionaire.

We’d love to hear your feedback. Email goodbadbillionaire@bbc.com or drop us a text or WhatsApp to +1 (917) 686-1176.

To find out more about the show and read our privacy notice, visit www.bbcworldservice.com/goodbadbillionaire

CrowdScience - Why do my armpits smell?

While there is a myriad of deodorants, shower gels and perfumes helping us stay fresh and fragrant today, that hasn’t always been the case. How did humans stay clean in the past, or did they not care so much? And is there an evolutionary reason for human body odour in the first place?

These are questions that CrowdScience listener Sarah has pondered on trips in her camper van, when she wants to keep clean, but washing isn’t always convenient.

In search of answers, presenter Anand Jagatia delves into the sweaty details: where body odour comes from, why some people's armpits don't smell, and whether this heady stink serves any purpose. Could our natural odour really help to attract a partner, or is it just a smelly bacterial by-product?

Anand explores the intriguing mystery of human pheromones, and hears how for hundreds of years, Europeans were terrified of washing.

Contributors: Dr Madalyn Nguyen, Dermatologist Dr Kara Hoover, Biological Anthropologist, University of Alaska Fairbanks Katherine Ashenburg, author, The Dirt on Clean: An Unsanitized History Dr Tristram Wyatt, Department of Biology, University of Oxford

Presenter: Anand Jagatia Producer: Sophie Eastaugh Production co-ordinator: Ishmael Soriano Editor: Cathy Edwards Sound engineer: Emma Harth

(Photo: Girl sweating smelly armpit, Taiwan Credit: PonyWang via Getty Images)