Dr Adam Rutherford and Dr Hannah Fry solve more of your everyday mysteries in these five fantastic radio series.

Inquisitive investigators Dr Adam Rutherford and Dr Hannah Fry are back to crack open another batch of baffling cases sent in by the great British public. Using the power of science, they find the surprising solutions to tricky questions such as 'Is anything really random?', 'Why do we have hangovers?', 'Is hypnotism real?' and 'How do you make gold?'

These 29 episodes encompass classic cosmic conundrums - including whether there is intelligent alien life out there, if infinity exists and how wormholes could allow us to time-travel - as well as probing more down-to-earth human quirks like our differing pain thresholds, our attraction to 'bad' foods like chips and chocolate and our varied regional accents. Plus, the duo embarks on a cheery evolutionary thought experiment as they wonder what would happen if humanity became extinct....

Also included is a Valentine's episode about how love affects our brain and a two-part Halloween special on why horror bewitches us so - and it's Rutherford and Fry squared when Stephen Fry joins the show to find out why he struggles to remember faces.

Among the many guest experts aiding the two doctors in their investigations are quantum physicist Jim Al-Khalili, cosmologist Andrew Pontzen, 'The Angry Chef' Anthony Warner, stage hypnotist Ben Dali, psychologist Claudia Hammond, neuroscientist Sophie Scott and Phil Plait, a.k.a. The Bad Astronomer.

Presented by Drs Adam Rutherford and Hannah Fry

Producer: Michelle Martin

Series 11 featuring: Monica Grady, Seth Shostak, Matthew Cobb, Sara Rugheimer, Peter Weyand, Polly McGuigan, Steve Haake, Colva Roney-Dougal, Bill Thompson, Tilly Blyth, Jim Al-Khalili, Irene Tracey, Steve Pete

Series 12 featuring: Janina Ramirez, Mark Thomas, Marina Tyndall, Trevor Cox, Steven Strogatz, Eugenia Cheng, Sean Carroll, Andrew Pontzen, Mark Miodownik, Linda Bartoshuk, Anthony Warner, Sally Adams, Andrea Sella, Adam Rogers

Series 13 featuring: Ben Dali, Wendy Moore, Devin Terhune, Dawn Shaughnessy, Philip Ball, Jim Al-Khalili, Matt Chandler, Wayne Urquhart, Trevor Cox, Zoe Laughlin, Maggie Aderin-Pocock, Sara Russell, Brendan Owens, Neil Comins, Steve Brusatte, Julia Clarke, Al Nelson

Series 14 featuring: Mathias Clasen, Margee Kerr, Claudia Hammond, David Poeppel, Sophie Scott, Brad Duchaine, Frank Close, Andrew Pontzen, Andrew Blum, Helen Willetts, Steven Strogatz, Matthew Cobb, Kate Jones, Phil Plait

Series 15 featuring: Mark Miodownik, Lucie Green, Andrew Pontzen, Dr Helen Fisher, Claudia Hammond, Irene Tracey, Dr Nick Davis, Dr Giulia Poerio, Claire Jones, Jonathan Ball, Wendy Barclay, Carl Philpott. Richard Warren, Heather Massey, Kathryn Jeffs, Jim Al-Khalili, Jennifer Oullette

First broadcast on BBC Radio 4, 3rd-7th September 2018 (Series 11), 21st November-26th December 2018 (Series 12), 3rd April-8th May 2019 (Series 13), 30th October-4th December 2019 (Series 14), 5th February-11th March 2020 (Series 15)