Stories of people visiting the future are not new in fiction. From as far back as Rip Van Winkle, Three Hundred Years Hence, and Looking Backward, authors were telling fantasy stories of people falling asleep for hundreds of years and waking up in the future. But the idea of intentionally traveling through time with the aid of a machine was first introduced in the H.G. Wells novel, The Time Machine (1895).
A time machine could be a means of travel within a wormhole or it could be a machine which facilitates the creation of a closed timelike curve, or both.
Most physicists believe that if a time machine is ever built, traveling forward wouldn’t be a problem; however when it comes to going back in time, the furthest you would be able to go back would be to the day the machine was built.
But if a natural time machine was found, the possibilities would be limitless.
Who could create a time machine?
Machio Kaku (Professor, Theoretical Physics) explains that scientists categorize extra terrestrial civilizations into three categories:
The first can harness the power of a planet; they can control the weather, alter earthquakes, etc.
The second can harness the power of a star; they can ignite stars, detonate stars, etc.
The third are Galactic; they can harness the power of an entire galaxy.
He explains: "Perhaps a galactic civilization would have sufficient energy to play with black holes, to create exotic energy, to find exotic matter throughout the universe by which they could then use it as fuel to create a time machine."