Vaccine scientist Katrina Pollock answers some of the biggest questions about covid-19 vaccines: when are we going to get one, and when will life go back to normal? A clinician at Imperial College London, Katrina is working on both the Imperial mRNA vaccine trials, and the AstraZeneca-Oxford vaccine trials. She discusses vaccine safety, and the finding in trials that a low-dose of the AstraZeneca vaccine caused a bigger immune response. Also on the podcast, science writer Stuart Clark explains why the unusually fast expansion of our universe might require a rethink of Einstein’s general theory of relativity. We discuss China’s Chang’e 5 mission to bring back samples of moon rocks for the first time in over 40 years. We also hear about the startling finding that nematodes produce ‘milk’ for their young, and explain why president-elect Joe Biden is providing renewed hope for tackling the climate crisis. On the pod this week are Rowan Hooper, Cat de Lange, Leah Crane and Donna Lu. 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.