Time travel was once the holy grail of science fiction, but scientists have now shown that time travel into the future is theoretically possible – so why not backwards? If we can use the quirks of physics to move into the future “faster” than we’d get there anyway, could it be possible to move into the past? And if time travel in either direction became possible, what would it do to our world… and ourselves? 

Emma Kennedy asks Jim Al-Khalili, famed for The Life Scientific and professor of theoretical physics at the University of Surrey, and Nikk Effingham, professor of philosophy at the University of Birmingham, about our days of future past. 

Buy Nikk’s book Does Tomorrow Exist?: A Debate through our affiliate bookshop and you’ll help fund Why? by earning us a small commission for every sale. Bookshop.org’s fees help support independent bookshops too. 

Check out Jim’s Radio 4 show The Life Scientific. 

WHY? is presented by Emma Kennedy. Produced by Eliza Davis Beard. Audio production and theme music by Jade Bailey. Managing editor: Jacob Jarvis. Group editor: Andrew Harrison. Artwork by James Parrett. Additional music is from Artlist.io. WHY? is a Podmasters Production. 

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