Crowdscience

Sex is responsible for the large variety of life on earth. Without the two sexes there is no sexual reproduction which means no shuffling of the genetic make-up – and no survival in a changing environment. But why do we have two sexes in the first place and does nature determine your sex? It’s with these questions and more that listener Du from Singapore persuaded the CrowdScience team to investigate the weird and wonderful world of sex. You might think that Nature would have standardised something as important as ensuring the continuation of the species. Far from it – species do sex in many different ways – some stranger than others. Presenter Marnie Chesterton unpicks the zoological oddities of sex and along the way learns about her own sex chromosomes. We also meet an unlikely bird keeper, who is the proud owner of a female duck that is morphing into a male. Will her boyfriend, a male mandarin duck, mind the change?Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.ukPrese

Biometrics are being used everywhere to recognise us. On this edition of CrowdScience we try out the tech that tells us apart. We find out just how unique our irises are and meet a man who can pick people out from a crowd of thousands just by analysing the way they walk. Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.ukPresenter: Anand Jagatia Producer: Marijke Peters(Image: Fingerprints being looked at under a magnifying glass. Credit: Getty Images)

Our planet is getting rather cosy. In just over 200 years, the global population has grown from 1 billion to almost 7.5 billion – and the best estimates suggest it’s going to keep on increasing. But just how far can it go? When will we reach ‘peak human’? That’s what CrowdScience listeners Alan Donaldson and Francoise Brindle want to know: what’s the latest estimate for how many people the Earth can support? It’s a question that’s been bothering some of the world’s greatest thinkers for hundreds of years, and now presenter Marnie Chesterton goes on her own quest for answers. Her journey takes her through the technology and innovation that keeps our growing population alive, and she looks to Dhaka, Bangladesh, to find out what a more densely populated world might feel like. But are there signs that things are already levelling off? And could improving photosynthesis allow populations to grow without destroying the environment?Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.

Mining asteroids, moons or even other planets has remained firmly within the realm of science fiction. But as certain elements become increasingly scarce on Earth, private companies and even nation states are looking to make extra-terrestrial mining a reality. Presenter Marnie Chesterton heads to an Earth-based mine in Scotland to see just how tricky space mining could be, and what possibilities it holds. On the way she discovers what laws govern this new far frontier, and hears from a space prospector who already has designs on key sites for exploration. Could our solar system's asteroids really become self-fuelling gas stations for spaceships?Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.ukPresenter: Marnie Chesterton Producer: Jen Whyntie(Image: Double the Rubble Artist Concept. Credit: NASA)

For most people the idea of chewing on a caterpillar or tucking into a tarantula is pretty unpalatable. Yet according to the United Nations, some two billion people around the world consume insects regularly. This prompted World Service listener Saman from Pakistan to ask the BBC CrowdScience team “are insects a serious food source?”To tackle this question, we head to Burkina Faso in West Africa where shea caterpillars are an important part of the local diet in a place where food security is low and malnutrition is high.Here we follow scientist Charlotte Payne as she tries to crack the tricky science behind the caterpillar’s life cycle and see how local entrepreneur Kahitouo Hien is trying to change lives and reduce malnutrition with edible caterpillars.Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.ukPresenter: Anand Jagatia Producer: Louisa Field(Image: Bowl of cooked Caterpillars. Credit: BBC/Anand Jagatia)

Why do we have so many accents - even when we’re speaking the same language? What's happening in our brains and mouths to make us sound so different from each other? This week’s question from listener Amanda takes CrowdScience to Glasgow in Scotland: home to one of the most studied - and distinctive - accents of English. Along the way we visit a voice coach to try and learn a Texan accent, use ultrasound to see what different sounds look like inside our mouths and find out how a brand new dialect was formed when many accents collided in New Zealand.Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.ukPresenter: Nastaran Tavakoli-Far Producer: Cathy EdwardsNew Zealand Mobile Unit recordings courtesy of Ngā Taonga Sound & Vision(Image: A mouth screaming white letters. Credit: Thinkstock)

Do your joints ache when it's raining? Are you blighted with headaches when the wind picks up? If the answer’s yes then you're definitely not alone. People have been linking their heath to the weather since the time of the Ancient Greeks - but is the effect real?CrowdScience heads for the hills and gets closer to the clouds to have a go at answering this 2,500 year old question. People who believe they’re sensitive to the weather aren’t always taken seriously. But presenter Datshiane Navanayagam hears about the latest ground-breaking experiments that show there's a lot more to it than folklore. And if you've ever wondered why you're particularly prone to aches and pains in the winter, the answer could all be in your genes.Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.ukPresenter: Datshiane Navanayagam Producer: Anna Lacey(Image: Man looking up to grey clouds. Credit: Thinkstock)

Can we really live on Mars? Or exist in a virtual world? And why does movie science sometimes have us shouting at the screen? Our panel of scientists and sci-fi experts reveal all in this special edition of CrowdScience recorded live at the South by Southwest Conference & Festivals in Austin, Texas, USA. To tackle all of our listeners’ questions about science in film, presenter Marnie Chesterton is joined by a team of specialists. Prof Polina Anikeeva is an MIT materials scientist and engineer whose research focuses on developing devices that work directly with the human nervous system. A sci-fi fan, Prof Anikeeva knows just how realistic brain-computer interface movies such as Avatar and The Matrix are. Former NASA astronaut Dr Mae Jemison is a medical doctor, engineer, educator and entrepreneur, and the first African-American woman to go into space aboard the shuttle Endeavour in 1992. She is leading the 100 Year Starship Project, which aims to take humans beyond our solar system by 2112. Prof Cliffor

The human race is getting fatter. But is it our fault? There are a whole host of factors influencing our weight - how many of them can we control?CrowdScience discovers how factors like our environment and our genes can tip the scales in the wrong direction.We visit an apartment complex originally designed for Olympic athletes, to see if people can get fitter just by living there. And from a brand new menu plan for overweight Mumbai police, to hormone injections that stop you getting hungry, CrowdScience asks the experts what we can do if we’ve been dealt a bad hand when it comes to our weight.Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.ukPresenter: Marnie Chesterton Producer: Cathy Edwards(Image: Women and a Man standing next to each other holding hands. Credit: ThinkStock.)

Trees take in carbon dioxide but they also convert some of the toxic gases in our air. How much help can trees give us in fighting air pollution and could where we plant them make an even bigger difference? Crowdscience reports from the side of some busy roads on how canopy coverage may be part of the answer. At a lab in Louisiana one scientist is putting oak leaves through their paces to find out how effective they are at cleaning our air.Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.ukPresenter: Marnie Chesterton Producer: Marijke Peters(Image: Trees in a forest Credit: Julian Stratenschulte/Getty Images)

Our listener Joseph’s question might sound more sci-fi than science show. But as Marnie Chesterton discovers, robots have already entered the realm of medicine and are likely to become more important in the future. A visit to the operating theatre at the University College Hospital in London together with surgeon Caroline Moore reveals that robots take the scalpels out of surgery by letting surgeons treat patients with prostate cancer without having to make a single cut. And chatting to Molly the robot alongside Dr. Praminda Caleb-Sully at Bristol Robotics Laboratory, Marnie discovers that robots could be the helping hand we need to look after a growing elderly population. Machines win when it comes to data-processing. But what about empathy and intuition? Such characteristics would require machines to reach a level of artificial intelligence (AI) which critics say is decades away. The sceptics insist humans will always play a key role in healthcare. But others suggest that not only will AI change everything

A few weeks ago, CrowdScience asked if it pays to be nice. We found that the answer is yes – if you’re a human. But if being social is so great, why aren’t all animals doing it? That’s what our US listener Tony wants to know. After listening to ‘Does it Pay to be Nice?’ he rightly pointed out that cats lead mostly solitary lives - but don’t seem any worse off for it. So why have they taken this path? And are they any less advanced than a social species as a result?Presenter and naturalist Tim Cockerill heads to the rainforests of Madagascar in search of answers. After lots of trekking through the undergrowth, he finds out why so many animals choose group living and what’s different about cats to make them go it alone. But does it matter which way of life an animal takes? Tim discovers that for humans at least, being social has given us much more than we imagine.Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.ukPresenter: Tim Cockerill Producer: Anna Lacey(Photo: Cat lyin

Death is one of life’s few certainties – or is it? To answer listener Pratibha’s question from New Delhi, India, presenter Marnie Chesterton asks medical and scientific experts if there is any evidence that humans could somehow come back into existence after their demise. We start at the end, by asking just what death is – and it turns out to be perhaps surprisingly complicated, especially if cold temperatures are involved. As another listener, Camilla, from Washington DC, USA points out, there are some animals that can become totally frozen over winter and return to life in spring. How does this happen, and could it have implications for the idea of deep-freezing humans – known as cryogenic preservation? Alternatively, if entire bodies might prove difficult to save, could we download our brains’ contents for later reboot instead? It sounds like science fiction, but a global network of scientists are pursuing the goal of cybernetic immortality: uploading our minds to an artificial brain in a robot avatar. Ma

Earth’s surface may be 70 percent water but many places are struggling to access it. We look at a range of water supply options including delivering it by tanker. In Malta we meet a man trying to solve its water problems, with a clever contraption to recycle sewage.Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.ukPresenter: Marnie Chesterton Produders: Cathy Edwards and Marijke Peters(Image: Tanker ship. Credit: Getty)

It sounds like a simple question – what is the time? But look closer and you realise time is a slippery concept that scientists still do not fully understand. Even though we now have atomic clocks that can keep time to one second in 15 billion years, this astonishing level of accuracy may not be enough. The complexity of computer-controlled systems, such as high-frequency financial trading or self-driving cars which rely on the pinpoint accuracy of GPS, could in future require clocks that are even more accurate to ensure everything runs ‘on time’. But what does that even mean? As Anand Jagatia discovers, time is a very strange thing. He visits the origins of modern time-keeping at the Royal Observatory in Greenwich and meets scientists at the National Physical Laboratory who have been counting and labelling every second since the 1950s. He meets Demetrios Matsakis, the man who defined time and visits the real-life ‘Time Lords’, at the International Bureau of Weights and Measures (BIPM) in Paris to find out ho

From Chihuahuas to Great Danes, Mexican Hairless to Afghan Hounds, dogs are the most diverse mammal on the planet. There are currently over 500 recognised breeds worldwide with almost every conceivable combination of size, shape, coat, colour and behaviour. But why are there so many different kinds of dog?That's what listener Simon St-Onge in Quebec, Canada wants to know – and CrowdScience has taken up the challenge. Presenter Marnie Chesterton heads to Sweden, a world-class centre of canine research, to sniff around for answers. She finds out how the grey wolf morphed into the vast variety of dogs we have today, and heads out on a moose hunt with one of Scandinavia's most ancient breeds.But are dogs really as different as they seem on the surface? The dog genome is revealing more about man's best friend than ever before – and could now be the answer to understanding both dog and human health.Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.uk(Image: Tika, the Russian-Europ

Modern Martian hunting involves looking for the tiniest evidence of life. But when presenter Marnie Chesterton found out that a scientist she was meant to be chatting to about cleanliness had previously worked for NASA, the topic of space bugs turned out to be too intriguing to ignore, especially when a CrowdScience listener asked us a question on a similar theme. Could Earth's microbes hitch a ride on our missions to Mars and colonise the Martian soil? As the European Space Agency's ExoMars venture gears up to launch a rover in 2020 that aims to find out whether there is, or has ever been, life on Mars, we head to the programme's clean rooms and Mars Yard - a giant planet-simulating sandpit - to find out. Marnie meets space engineers whose job is to prevent microbial contamination of Mars whilst creating robots that can find signs of life on the Red Planet. And she discovers that planetary protection is not all about remote aliens: Could tiny Martians have already arrived here on Earth via a meteoric hitch h

To be healthy you need to be clean – or so we’ve thought throughout human history.The dazzling array of antibacterial products that exploded onto the scene in the 20th century took things to the next level, with their promises of eliminating 99.9% of germs.But could an obsession with cleanliness actually be bad for us? There’s a whole world of microbes out there: some make us sick, but others are essential for our health.How do we tell the difference? Listener Younes’s question gives CrowdScience the chance to sift the good dirt from the bad, with the help of hygiene expert Professor Sally Bloomfield. Along the way we soap up our hands with schoolchildren in Mumbai, get knee deep in mud on an English farm, and find out why snuggling up to a cow might be a good idea.Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.ukPresenter: Marnie Chesterton Producer: Cathy Edwards and Marijke Peters

Is there a killer asteroid with Earth’s name on it? The dinosaurs ruled for many millions of years before coming to their violent end. Will humanity prevail or are we doomed to succumb like the dinosaurs? It’s a question that will keep you up at night. No wonder our listeners Zarin and Pablo wanted to know more.To find out, Anand Jaggtia heads to Denmark to see first-hand the evidence for a giant asteroid impact, written into the rocks at Stevns Klint. And we will hear from scientists at Nasa who are keeping a careful eye out for asteroids on collision course with Earth. Also, we discover that asteroids have a lot to answer for, maybe even our own existence.Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.uk

Why can't we use energy from the waves of the sea to create all the electricity that we need? Listener Michael in Kingston, Jamaica wants to know. Living on a Caribbean island means he’s never far from the might of the ocean – so could it power his house? Presenter Greg Foot heads to one of the world’s leading wave energy test locations, the coast of Cornwall in the UK, to find out. There, he witnesses the challenges of the marine environment, from metre high waves in a giant indoor test tank to being buffeted on a beach where a 25km cable runs beneath his feet to a grid-connected offshore test site. And find out if Greg’s plan to feel the power of the waves first-hand on a research boat works out – in the middle of winter, in the northern hemisphere.Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.ukPicture: Waves, Credit: Oli Scarff/Getty Images