Time travel is one of the most captivating tropes in science fiction, inspiring countless stories of adventures through the ...

A causal loop is a classic time travel conundrum. If you send information to the past – say, you give Albert Einstein the formula E=mc ² before he theorises it himself, then he publishes it and you go ...

Time travel paradoxes like the grandfather problem and causal loops show how the universe may resist changes or trap actions ...