Science Weekly

Humans have been wondering why we sleep for thousands of years. Is sleep’s purpose rest and relaxation, memory consolidation or maybe cognitive processing? In the last 15 years, scientists have discovered another possible explanation – waste disposal. In 2012 neuroscientist Maiken Nedergaard’s lab discovered that the brain has its own cleaning process, the glymphatic system, which clears away unhelpful proteins and metabolic byproducts, and only switches on at night. Since that groundbreaking discovery we’ve learned more about what drives this system and, importantly, how it could be impacting dementia. To understand more, Ian Sample talks to Prof Nedergaard about how she made the original discovery and how subsequent work is building a picture of sleep as anything but a quiet and inactive state. Help support our independent journalism at theguardian.com/sciencepod

Last month at Beijing’s half marathon, a robot named Lightning beat the human world record by nearly seven minutes. It’s the latest in a string of AI-powered milestones that have got people wondering whether robots are about to enter our everyday lives, just as chatbots have. And the country leading the charge is China, where the government has pledged to invest more than £100bn in robotics over the next 20 years. To find out how robots are already entering the workforce, and what needs to happen to get them cleaning our homes and weeding our gardens, Ian Sample hears from the Guardian’s senior China correspondent, Amy Hawkins, and from Nathan Lepora, professor of robotics and AI at Bristol University, who researches how robots can achieve human-like dexterity. Help support our independent journalism at theguardian.com/sciencepod

Home red-light therapy devices have exploded in popularity as masks, body wraps and mittens promise to reduce wrinkles, redness and even acne. But do the claims stack up, and what other benefits are scientists investigating? Ian Sample hears from his co-host, Madeleine Finlay, and the consultant dermatologist Dr Jonathan Kentley. Kentley explains how the potential benefits of red light were discovered, how it is thought to interact with collagen in our skin, and what science has to say about its impact on our appearance. Help support our independent journalism at theguardian.com/sciencepod

The US supreme court has preserved nationwide access to mail-order abortion pills – for now. As Carter Sherman explains, the fight to protect this medication is far from over, as a nationwide, near-total abortion ban could be on the horizon. Carter speaks with Dr Angel Foster, co-founder of the Massachusetts Medication Abortion Access Project, who reveals how the legal battle over abortion pills has affected patients across the US – and what could happen next. Help support our independent journalism at theguardian.com/sciencepod

After more than a decade of global consultation, polycystic ovary syndrome – which affects as many as one in eight women – has been renamed. The condition is caused by high levels of androgens, which can lead to symptoms such as excess hair, weight gain and irregular periods. To understand why campaigners wanted it renamed, and what its new name – polyendocrine metabolic ovarian syndrome (PMOS) – could mean for patients, Madeleine Finlay hears from the Guardian’s science correspondent, Nicola Davis, and Rachel, a campaigner from the charity Verity. Help support our independent journalism at theguardian.com/sciencepod