People have always been interested in time travel, from ancient myths to the new series of Doctor Who. Whilst the model used in much of science fiction (the huge machine beeping and whirring us back to the stone-age) is not realistic, physics suggests that time travel of a certain kind may be possible.

According to Einstein’s theory of General Relativity, we can jump forwards in time simply by travelling close to the speed of light. If someone could attain a high enough speed then they would leap hundreds of years into the future, whilst only travelling for a short time. Alas, rockets capable of such speeds do not currently exist, but you can experience time travel on a minute scale simply by climbing a tall building. As you are further from a source of gravity, time will run slightly faster at the top than the bottom.

It is said that looking to the stars is like looking back in time, but going into the past is a more controversial topic than to-the-future time travel. Wormholes offer the most promise. These would act as tunnels through space, allowing us to enter in one time and emerge at an earlier one.

Unfortunately, there is no evidence that these structures actually exist, and even if they did, they would be unlikely to be large enough to allow a human traveller through. Nonetheless, it is exciting to know that physical theories allow for the prospect of time travel.