Covid-19 infections in the UK are at an all-time high. But most people in England can no longer access free Covid-19 tests, and the REACT-1 study, which has been testing more than 100,000 individuals since the pandemic began, ended last week after its funding stopped. Martin Mckee, Prof of European Health at the London School of Hygiene and Tropical Medicine, shares his insights on what these changes might mean for ambitions to 'live with the virus'.

This week, the UN's latest Intergovernmental Panel on Climate Change (IPCC) report has unveiled a to-do list of ways to save the planet from climate catastrophe. How do scientists reach a global consensus on climate change amid war, an energy crisis, and a pandemic? Vic Gill speaks to report co-author Jo House, University of Bristol, and Ukrainian climate scientist Svitlana Krakovska who took part in signing off every line of the report while sheltering from the war in Kyiv.

And from our planet's present and future to its ancient past. Scientists working on the Tanis fossil site in North Dakota in the US have dug up a dinosaur's leg, complete with skin and scales. Is this 66-million-year-old fossil, alongside similar nearby victims, the key to unveiling those transformative minutes after the infamous Chicxulub asteroid struck the earth and ended the era of the dinosaurs? BBC science correspondent Jonathan Amos has seen the fossil and speaks with Paul Barrett of London's Natural History Museum about the significance of this un-reviewed new finds.

And from earth to Mars. After a year of analysing audio recordings from NASA's Perseverance rover, scientists have found not one but two speeds of sound on Mars. Trevor Cox, Professor of Acoustic Engineering at the University of Salford, guides us through this sonic wonder, and how sound may become a key tool for exploring distant worlds.

Mars audio credit: NASA/JPL-Caltech/LANL/CNES/CNRS/ISAE-Supaéro