So far it seems that time travel is limited by causality — this means that the effect can never precede the cause — I can’t be full before I start eating.

Therefore, travelling to the future is real, but it is a one-way journey.

Future travel arises from Einstein’s special theory of relativity — the faster we move, the slower our time passes compared to the time of our observers who are at rest (not moving).

Such travel to the future is actually simple — just get into a rocket (it doesn’t have to be a rocket but any means of transport) and fly away quickly.

The faster we move, the slower our time will pass compared to the time on the Earth.

The tricky part is that our speed has to be really fast — to halve our time contrary to the time on the Earth, we would have to move at 70% of the speed of light (it is a lot indeed, for example, rockets go about 0.003% of the speed of light).

The stated principle of time travel is based on the fact that time is relative — that is, it does not flow the same for all people.

This looks strange but it has been proven many times, for example GPS satellites have to consider the relativity of time. Otherwise, their accuracy would decrease by about 10 km after 1 day!

Of course, it is a question of what use would travelling to the future be for us — for example I can think of moving the terminally ill into the future with the expectation that medicine will have a cure for their disease.

But we would definitely need to resolve all debts and health insurance.