Apparently, all you need is a wormhole, the Large Hadron Collider or a rocket that goes really, really fast. How fast? The fastest manned vehicle in history was Apollo 10. It reached 25,000mph. But to travel in time we’ll have to go more than 2,000 times faster. So…pretty simple actually.
On the fourth dimension:
Travelling in time means travelling through the fourth dimension. To see what that means, let’s imagine we’re doing a bit of normal, everyday car travel. Drive in a straight line and you’re travelling in one dimension. Turn right or left and you add the second dimension. Drive up or down a twisty mountain road and that adds height, so that’s travelling in all three dimensions. But how on Earth do we travel in time? How do we find a path through the fourth dimension?
Let’s indulge in a little science fiction for a moment. Time travel movies often feature a vast, energy-hungry machine. The machine creates a path through the fourth dimension, a tunnel through time. A time traveller, a brave, perhaps foolhardy individual, prepared for who knows what, steps into the time tunnel and emerges who knows when. The concept may be far-fetched, and the reality may be very different from this, but the idea itself is not so crazy.