Episode 3 of Seminar sessions is a festive special. Greg and Summer join Royal Holloway’s science fiction duo, Stewart Boogert, Professor of Accelerator Physics and Adam Roberts, Professor of Nineteenth-century Literature  as they ponder Physics and the philosophical conundrum of Santa Claus. Hear their novel dialogue between past, present and future time travel – between the nineteenth-century world view and what we can learn from Dickens’ Christmas Carol and HG Wells, to 21st-century astrophysics and our understanding of black holes, space- time continuum and the Sci Fi of Star Wars, speculating on the all-important secret – how does Santa and his sleigh deliver presents to children across the world in just one night?