Sugar, seed oils, and avoiding sickness: your health questions answered

Many of us believe that cognitive decline is an inevitable part of ageing, but a new study looking at how our skills change with age challenges that idea. Ian Sample talks to Ludger Wößmann, a professor of economics at the University of Munich and one of the study’s authors, to find out how the team delved into the data to come to their conclusions, and what they discovered about how we can all maintain our faculties for as long as possible. Help support our independent journalism at theguardian.com/sciencepod

The Mars we know now is arid and dusty, with punishing radiation levels. But, as science correspondent Nicola Davis tells Madeleine Finlay, two new studies add weight to the idea that billions of years ago the red planet was a much wetter place. Nicola explains why researchers now think it was once home to sandy beaches, what a study looking into the type of rust on the planet has revealed about its damp past, and what all this might tell us about the former habitability of Mars. Help support our independent journalism at theguardian.com/sciencepod

Madeleine Finlay and Ian Sample discuss three intriguing science stories from the week. From two private moon landings to the controversy over Elon Musk’s continued membership of the Royal Society, and a new study making a link between men’s health and their sperm quality. Help support our independent journalism at theguardian.com/sciencepod

Beavers were once abundant in the UK, but hunting them for their fur, meat and scent oil drove them to extinction. Now they’re back, with the news that the release of beavers into English waterways is to be allowed for the first time in centuries. To understand why this is seen as a huge win for the environment, Madeleine Finlay hears from the Guardian’s environment reporter Helena Horton.. Help support our independent journalism at theguardian.com/sciencepod

When the palaeontologists of the future search for clues to understand how we lived, what might they find? Two scientists exploring this question have suggested that ‘technofossils’ will be our lasting imprint on the Earth. To find out exactly what these are and what they could reveal about our lives, Madeleine Finlay hears from the Guardian’s environment editor, Damian Carrington, and from Sarah Gabbott, a professor of palaeontology at the University of Leicester and one of the scientists behind the new book Discarded: How Technofossils Will Be Our Ultimate Legacy. Help support our independent journalism at theguardian.com/sciencepod