Actually worm holes do exist ( not the star trek variety )

Lets assume a neutron star is traveling past Earth a safe distance.
An adventurer decides to be the first to do a fly by in a space ship with one orbit of the neutron star. During the fly by he determines his clock has slowed due to the intense gravity field he is passing through.
Unfortunately his ship is damaged and stays in orbit two years.
After two years he finally is able to fix his ship and leaves to return home however.... time has passed and the neutron star has traveled one light year from the Earth taking the adventurer with it.
Due to time dilation while he aged two years the Earth has aged 100 years.

The adventurer has experienced a time and space warp.

Somehow a wormhole existing without cause or predictability is a lot more fun then one that follows scientific laws.

If the adventurer was lucky enough the neutron star could have encountered another star which changed its course. Due to the change in course the neutron star may just happened to be passing Earth again at the same time the adventurer is able to leave the orbit around the neutron star.
In this case the adventurer would not experience a distance displacement but only a time displacement into the future.

Unfortunately there is no known way to travel back in time, and although the adventurer may return to Earth he cannot return to his friends which are long dead.