CrowdScience

It took a while before it was officially recognised as a major symptom of Covid-19, but loss of smell has affected up to 60 percent of people who have had the virus. And for a significant portion, smell continues to be an issue for weeks or months after their recovery. So what’s going on and how can you get your sense of smell back? We tend to think of our sense of smell as something universal – if it smells bad to me, it probably does to you but that is not the case for CrowdScience listener Annabel, who wonders why things other people love to sniff, she finds disgusting. Anand Jagatia investigates the science of smell, gets up close to the world’s smelliest plant and finds out if smell training can help those with long-term issues after Covid. Contributors Ellie Byondin, supervisor of the Princess of Wales Conservatory at London’s Kew Gardens Thomas Hummel, University of Dresden Carl Philpott, from the UK’s Norwich Medical School Sissel Tolaas, artist and smell historian based in Berlin Noam Sobel, Weizmann institute of sciencePresented by Anand Jagatia and Produced by Marijke Peters for the BBC World Service

Scales don’t come planet-sized, so answering a question from David in Ghana may require some ingenuity, after all, calculating the weight of the Earth is a huge task. Using a set of weighing scales and a 400 year-old equation, Marnie Chesterton attempts to find out just how much the Earth weighs and is it getting heavier or lighter over time? But how would a planet gain or lose mass? Which tips the scales: meteorites falling from space or gases constantly escaping from our atmosphere? And does the answer have any implications for the future of Earth? Could the atmosphere eventually run out? Contributors: Anuradha TK, former project director at ISRO Matt Genge, geologist at Imperial College London Jon Larsen, researcher at the University of Oslo Anjali Tripathi, astrophysicist Ethan Seigel, journalist and astrophysicistPresented by Marnie Chesterton. Produced by Caroline Steel for the BBC World Service.[Image: Earth on scales. Credit: Getty Images]

They say life is sweet. Well that’s certainly the case for CrowdScience listener Trevor in Poland who wonders why he can’t stop reaching for the cookie jar. He grew up drinking fruit juice with added sugar but wonders whether his genes could be as important as his environment when it comes to his sweet tooth, especially since his wife seem to be satisfied with mainly savoury snacks. The World Health Organisation says added sugar should constitute a maximum of 5% of our daily energy intake because it can contribute to diabetes, heart disease and obesity. But that’s tricky when you consider it’s now in everything from salad dressings, to savoury sauces.Manufacturers have been promoting sugar alternatives for decades but recreating the unique taste and feel of it in the mouth are a challenge. Marnie Chesterton gets to try a brand new innovation – a so-called ‘rare’ sugar that has 70 percent of the sweetness but almost none of the calories. In nature, allulose is found in figs, but one producer has discovered a way to make it in the lab. Does it taste as good as it claims? Whilst switching to alternative sugars and sweeteners may reduce the calories, some researchers claim that tasting sweetness, wherever it comes from, can disrupt the body’s mechanism for regulating blood-sugar levels, increasing the risk for conditions like diabetes.Presented by Marnie Chesterton and produced by Marijke Peters for the BBC World Service

It's a topic that's taboo in many cultures, yet it's also something nearly every woman experiences – on average upwards of 400 times throughout her life: menstruation. Responding to a flood of questions from our CrowdScience listeners, Marnie Chesterton seeks to unpack how periods affect women physically, mentally and societally. Why did humans evolve to have periods when fewer than two percent of mammals share our experience of menstrual cycles? Is it really a good use of our limited energy reserves? What can the little Egyptian spiny mouse teach us about PMS symptoms? We hear why periods may reduce the number of faulty embryos that implant and how more menstrual cycles may even increase our chances of developing certain types of cancer. Finally, as the number of periods a woman has over the course of her life has more than quadrupled since the pre-industrial era, Marnie asks: Do we really still need to have them? Contributors: Dr Nadia Bellofiore, Hudson Institute of Medical Research at Monash University Dr Deena Emera, Buck Institute Lameck Kiula, Jambo for Development Sally King, Menstrual Matters & King's College London Dr Diana Mansour, New Croft Centre & Newcastle UniversityPresented by Marnie Chesterton Produced by Sam Baker and Melanie Brown for the BBC World Service

As millions more of us move to live in densely populated cities, we almost inevitably face living in closer proximity to our neighbours. Neighbour noise can certainly be a source of annoyance – but could it even be damaging to our health? Increasing evidence suggests that unwanted noise can cause sleep deprivation, distraction and annoyance, as presenter Anand Jagatia finds out. He discovers that noise annoyance has a small but significant impact on our wider health – including our cardiovascular system – but that annoyance is not necessarily down to sound alone. Factors such as perception of the neighbourhood and relationships with our neighbours also play a part. CrowdScience has examined living with unwanted noises before, and we revisit our trip to the acoustics lab at the University of Salford in Manchester, UK. Here, we meet the researchers and engineers investigating the best ways to make our homes more pleasant for our ears whilst still maintaining the ‘buzz’ of city life. Contributors:Contributors: Professor Charlotte Clark, St George’s University of London Professor Trevor Cox, University of Salford Manchester Professor Bill Davies, University of Salford Manchester Dr Mags Adams, University of Central Lancashire (formerly University of Salford Manchester, at time of recording)Produced by Jen Whyntie and presented by Anand Jagatia for the BBC World Service.

You are a star. Literally. You are a carbon-based life form and those atoms of carbon in the molecules that make up your cells were formed by a nuclear fusion reaction at the heart of long dead stars. That goes for the oxygen in your lungs too. And the red blood cells that carry that oxygen to your tissues? They contain haemoglobin, and nestled at the heart of each molecule is an element (iron) formed by a supernova - the fiery explosion at the death of a star. Your body is a walking, thinking museum of some of the most violent events in the universe. This, as CrowdScience host Marnie Chesterton discovers, isn’t as special as it sounds. All of the stuff on the earth - the elements that make clouds and mountains and mobile phones – they all have an origin story. CrowdScience tells that story, starting with the big bang and ending with physicists, creating new elements in the lab. Find out the age of the elements and the distance they have travelled to make their current home on earth. Interviewees: Dr Dorota Grabowska, Professor Andrea Sella, Dr Chris Pearson, Dr Jacklyn Gates (Photo: Neutron star. Credit: Getty Images)

There are over 400,000 species of plant on earth, they’re on every continent including Antarctica. But humans only regularly eat about 200 species globally, with the vast majority of our nutrition coming from just three species. Many of the fruits, leaves and tubers that other plants grow are packed full of toxins that are poisonous to us, and would make us very ill if we ate them. But could we take out the poisons and create new, edible crops? That’s what CrowdScience listener Marija wants to know.Crowdscience dives into this topic, and uncovers the that many crops are poisonous, and why so few plants are eaten globally. Host Anand Jagatia finds that even the modern scientific processes of crop breeding are very slow. But science can now engineer plants at the genetic level by adding, silencing or removing specific genes. This ‘genetic modification’ is hugely controversial but can be highly effective. Anand finds a man who has spent decades making cotton seeds edible by removing the poisons they naturally produce in their seeds. This GM crop could help fend-off starvation. But sometimes introducing poisons can be as important as removing them, as we find in the genetically modified ‘BT eggplants’ in Bangladesh. The new gene makes the vegetable toxic to a major insect pest, so they are much easier to grow. But GM crops are not the perfect solution. They have problems of gene escape, can increase the use of environmentally damaging herbicide, and can be open to monopolisation. In some countries, particularly in Europe, GM crops are hugely controversial. Anand finds out whether these concerns stand up to science and looks at the counterpoint in developing countries in Africa, South Asia and elsewhere, where local farmers like Patience Koku in Nigeria have little time for some of the concerns around GM, particularly as they see poor harvests, poverty and starvation as the more pressing problems. Contributors: Professor Sandra Knapp, The Natural History Museum in London Professor Julie King, Nottingham University Professor Keerti Rathore, Texas A&M University Dr Yousuf Akhond, Bangladesh Agricultural Research Institute Professor Matthew Cobb, University of Manchester Patience Koku, Nigerian Farmer and member of the Global Farmer’s Network Alliance for Science Produced by Rory Galloway and presented by Anand Jagatia for the BBC World Service.Image: Farmer with Fruits. Credit: Arif Hossain, Farming Future Bangladesh.

Have you taken classes to learn a new sport or musical instrument or a language? It’s hard work! Why is it that as children we effortlessly absorb new skills and we don’t as adults? That’s what 50-something listener Gary Grief wondered about playing guitar. Do you need to play more frequently as an adult to attain the same level of expertise? Does the 10,000-hours theory still apply? Presenter and budding tabla-player Anand Jagatia embarks on a musical journey to discover what neuroscience can tell us about muscle memory and learning. Do musicians and sportsmen share the same challenges? By understanding what’s happening in the brain, can we learn how to learn better? With tabla-teacher Satvinder Sehmbey, neuroscientist Dr Jessica Grahn, viola-player Dr Molly Gebrian and sports scientist Prof Yannis Pitsiladis. Presented by Anand Jagatia Produced by Dom Byrne for the BBC World Service[Image: Adult and Child learning Piano. Credit: Getty Images]

When eating a blackberry one day, CrowdScience listener Charles got a tiny seed stuck in his teeth. That got him wondering: why are seeds the size they are? Why does a blackberry have dozens of tiny pips, while a peach has one huge stone right in the middle?Plant seeds have been around for hundreds of millions of years, so they’ve had plenty of time to shapeshift into wildly different forms: from dust-like orchid seeds to giant coconuts. This evolution has been a long and intricate dance with wind, water and animals; we ask how different kinds of seeds might respond to today’s environmental threats and rapidly changing ecosystems.And we go in search of the world’s biggest seed, the coco de mer: native to just two remote islands in the Indian Ocean and weighing up to 18kg, how did this seed evolve to be so much bigger than any other? With Professor Angela Moles, Dr Si-Chong Chen, Marc Jean-Baptiste, Dr Frauke Fleischer-Dogley and Dr Wolfgang Stuppy.Presented by Marnie Chesterton Produced by Cathy Edwards for the BBC World Service[Photo: Different sized fruit seeds. Credit: Getty Images]

Most of us don’t like to dwell on our toilet habits, but this week Crowdscience has gone down the drain to discover what wastewater can tell us about our health.It’s been more than a year since scientists across the globe started to track the spread of Covid-19, with help from home test results and hospital data. Marnie Chesterton investigates the latest tool in their arsenal: sewage. Listener Kevin has heard how human waste can be monitored to check for virus levels, and wants to know if it can also be used to stop the disease in its tracks? Although the coronavirus has been discovered in people’s poo, so far there’s little indication it’s actually being spread through the water system. But by taking regular samples from different parts of cities, authorities are now able to accurately predict a local peak weeks before the population shows signs of sickness, then take immediate measures to alert them. In Detroit we hear how environmental engineer Professor Irene Xagoraraki used this method to detect a rare strain of Herpes which doctors didn’t even know was a potential problem. Marnie also talks to Professor Nick Thomson from the Wellcome Sanger Institute, who sequenced the genome of the bacteria that causes cholera, to understand how it has crisscrossed the globe. He discovered that the pandemic currently devastating Yemen actually originated in Asia. It’s a discovery that has changed how the WHO is thinking about this killer disease and could have important implications for vaccination programmes. But our effluent can also pose environmental problems, and Professor Andrew Johnson from the UK’s Centre for Ecology and Hydrology explains there are now as many as 300,000 chemicals that could threaten natural habitats. While authorities try to test each one individually, he’s concerned they may have different effects when they mix in wastewater, and current monitoring systems don’t take this into account. Not only that, but some of these substances contain silver nanoparticles, which Professor Juliane Filser tells us stick around in soil for ever, threatening organisms and bacteria at the base of the food chain. Presented by Marnie Chesterton and Produced by Marijke Peters for the BBC World Service.[Image: Sewage outlets. Credit: Getty Images]