It is a question that has vexed philosophers and scientists for centuries; 'What is Time?' Exactly how is our past, present, and future connected by that arrow of cause and effect that we call Time? Is time simply another dimension, just like the dimensions of space we know? Can you run time backwards just as easily as it runs forward, just as left-to-right can swap for right-to-left? If other universes exist, then what is time like in them: could their Time be different from ours? And we'll probe the biggest question about time: Is our future determined? Do we exercise free will? Or, is time merely a dream?

• Geoffrey Sharp

• Morgan Freeman