Ian Sample and science correspondent Hannah Devlin discuss some of the science stories that have made headlines this week, from a new theory challenging the existence of dark matter to an alarming study about the possible impact of microplastics on our health and a glimpse of a ‘waterworld with a boiling ocean’ deep in space. Help support our independent journalism at <a href="https://www.theguardian.com/sciencepod">theguardian.com/sciencepod</a>