This week: relief and joy for people in the US, with the news that those who’ve had two doses of vaccine will be allowed to meet up inside with friends and family. The team also discusses the exciting news about how the vaccine might help people with long covid. Things take a turn for the weird when the team explains just how little we know about reality, certainly from a quantum mechanical point of view - but Carlo Rovelli might have an answer. They also explore why cold water swimming is so good for us, they find out how we can use light to power spacecraft, and they celebrate the wondrous sea slug, which has a penchant for chopping off its own head. On the pod are Rowan Hooper, Tiffany O’Callaghan, Clare Wilson, Alison George and Richard Webb. To read more about the stories, subscribe at newscientist.com/podcasts. Our GDPR privacy policy was updated on August 8, 2022. Visit acast.com/privacy for more information.