Question: Is it possible to travel in time?

Sam Geen answered on 21 Jun 2013:

Aside from Claire’s answer – maybe. Travelling forward in time is possible with relativity – as you accelerate away from Earth to near the speed of light, you age less quickly that someone on Earth because of an effect called “time dilation”. There’s a science fiction story called The Forever War, where soldiers go off to fight around other stars and come back a few years later to find that society has moved on by hundreds of years because they travelled at near the speed of lightMATOMO_URL

As for time travel backwards, not as far as we know. We can see back in time in the universe because light from billions of years ago and billions of light years away is still just reaching us. Maybe if wormholes were possible they could allow us to time travel, but we don’t know for sure if these exist, or if there’s another way.

* The book is supposed to be explaining using science fiction what it felt like when soldiers came back from the Vietnam War, and found that the war had changed them and people who hadn’t been to war didn’t understand them any more.