Scientists have been searching for dark matter for decades, and think there’s six times more of it in the universe than the stuff we can actually see, like stars and planets. But they still don’t know what it is. So how can we be sure dark matter really exists? And why does it matter, anyway? Back in 2018, armed with a boiler suit, hard hat and ear defenders, Marnie Chesterton travelled over a kilometre underground into a hot and sweaty mine to see how scientists are valiantly trying to catch some elusive particles – in the hope of settling things once and for all. Several years on we return to the problem, tackling a few more CrowdScience listeners’ questions about dark matter, and hearing whether we’re any closer to uncovering its mysteries. We’re joined in our quest by Dr Chanda Prescod-Weinstein, physicist and author of The Disordered Cosmos: A Journey into Dark Matter, Spacetime, and Dreams Deferred. With Professor Malcolm Fairbairn, Dr Chanda Prescod-Weinstein, Dr Chamkaur Ghag and Professor Katherine Freese. Presented by Marnie Chesterton Produced by Graihagh Jackson and Cathy Edwards