Albert Einstein showed that time runs at different speeds in different places – and is just another dimension. Ever since, some scientists have wondered whether we could travel through time to the past or the future. Einstein concluded that you cannot move through time because you would have to travel faster than light, if you travelled faster than light time would stop and you wouldn’t exist.

Albert Einstein

A famous argument against time travel is about killing your grandparents. What if you travelled back in time before your parents were born and killed your grandparents? Then neither you or your parents could have been born, so who killed your grandparents?

In the 1930’s American mathematician Kurt Godel found time travel may be possible by bending space-time. There have been many ideas for bending space-time, including amazing gravity machines. the most powerful benders of space-time are black holes in space.

Stephen Hawking said you cannot use black holes for time travel because everything that goes into a black hole shrinks to a singularity. Others say you might dodge the singularity and emerge safely somewere else in the Universe through a reverse black hole called a white hole.

Stephen Hawking

Mathmatician Carl Sagan thought small black hole-white hole tunnels might exist without a singularity. There might be tunnels such as these linking different parts of the universe, like a wormhole in an apple.

The mathmatics say that a wormhole (which is smaller than an atom) would snap shut as soon as you stepped into it. However, it might be possible to hold it open with an anti gravity machine based on a quantum effect called the Caismir effect.