It’s a mystery that has long puzzled researchers. Why can’t we remember our early childhood experiences? Freud called the phenomenon infantile amnesia, and for many years scientists have wondered whether it’s a result of failure to create memories or just a failure to retrieve them. Now new research appears to point to an answer. To find out more, Ian Sample talks to Nick Turk-Browne, a professor of psychology at Yale University.. Help support our independent journalism at theguardian.com/sciencepod

Dark energy, the mysterious force powering the expansion of the universe, appears to be weakening over time, according to a major cosmological survey that has thrown the laws of modern physics into doubt. Ian Sample tells Madeleine Finlay how this new finding could shed light on the ultimate fate of the cosmos, and Saul Perlmutter, who won a Nobel prize for his work proving the universe is expanding, describes how the new development could upend assumptions about how this mysterious force operates. Help support our independent journalism at theguardian.com/sciencepod

Before billionaires dreamed of setting up communities on Mars, the ocean was seen as the next frontier in human habitation. Reviving this dream is Deep, a project backed by an anonymous millionaire to the tune of more than £100m that aims to establish a ‘permanent human presence’ under the sea from 2027. Guardian Seascape editor Lisa Bachelor visited the project just outside Chepstow on the Welsh border, and tells Madeleine Finlay what scientists hope to learn about the ocean by spending extended periods living underwater. Help support our independent journalism at theguardian.com/sciencepod

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

In his first month in office the US president has thrown science in the US into chaos, delaying projects and casting the future of research funding and jobs into doubt. To understand everything that has happened in the month since he took office and what its impact could be, Madeleine Finlay hears from science editor Ian Sample and Prof Harold Varmus, a Nobel prize winner and former director of the National Institutes of Health under Bill Clinton. Help support our independent journalism at theguardian.com/sciencepod

Science editor Ian Sample joins co-host Madeleine Finlay to discuss some of the most intriguing science stories of the week. From a concerning rise in hospital diagnoses of constipation in children, to research suggesting that the environment is far more important for ageing and longevity than our genes, and how squeaks from genetically engineered mice are providing insight into how human language may have emerged. Help support our independent journalism at theguardian.com/sciencepod