In 1924 Cornelius Lanczos, a Hungarian-Irish mathematician / physicist discovered an exact solution of the Einstein field equation representing a cylindrical symmetric rigidly rotating configuration of dust particles and its effects on gravitational fields and hence time / timespace. The insinuation is that it represents a closed timelike curve.
A material particle in spacetime, that is "closed", returns to its initial starting point, before restarting its timeline journey to once again return to its initial starting point in perpetuity.
In 1938 Willem Jacob van Stockum, a Dutch mathematician, published a paper which contains the theory based on Lanczoz work that a configuration of rotating matter could have effects on gravitational fields, [van Stockum dust], and hence on time. In this paper, van Stockum was the first to notice the possibility of closed timelike curves, one of the strangest and most unsettling and confusing phenomena in general relativity.
A 1974 paper by Frank Tipler, based largely on van Stockums work speculated on what has been dubbed the Tipler Cylinder. It proposes that a a finite rotating cylinder could also act as a time machine. The basic concept is to take a cylinder and rotate it at incredible speeds. The cylinder itself would have to be immense in length as well extremely dense, a density and length not currently attainable with our current technologies. The spin speed needed, several billion times a second, is also not possible under our current state of technological advancement.
If at some point in the future, if science should overcome the problems cited above, one would theoretically be able to travel time when entering the cylinder. Spacetime should let you emerge thousands or billions of years away, and quite possibly on the other side of the universe from where you began.
As intriguing as it all sounds, I wouldn't suggest getting your hopes up. It is unclear if such a device could exist outside speculative mathematical papers. If it could and someday does, it might require negative mass to function as desired, we are not certain if negative mass even exists. It might also require an infinitely long cylinder.
In a related theory, professor Ron Mallet speculates that “an intense and continuous rotating beam of light [could create the desired time travel outcome]... In Einstein’s theory, space and time are related to each other. That’s why it’s called space-time. So when the black hole spins, it will actually cause time to shift.” Mallets device would use an array of lasers arranged in a cylindrical format to mimic the spacetime-distorting effects of a black hole. “Eventually, a rotating beam of laser lights can be used as a kind of time machine and cause a time warp that will allow us to go back to the past,” said Mallett.
A Naturally occurring time travel device similar to the one proposed in the preceding paragraphs may have already been discovered. At the base of a large spinning sphere we call the planet Earth there is a rotating vortex which allegedly enables time travel. See The South Pole Vortex
Time Travel Mathematically Possible
The Alcubierre drive was theorized by Mexican physicist Miguel Alcubierre in 1994. The hypothetical warp drive envisioned that a spacecraft could achieve faster than light speed travel, basically warp factor 5 and beyond. In the Alcubierre theory, a spacecraft would traverse immense distances by contracting space ahead of it and expanding space behind it which in effect would create a vortex in which a vessel could travel faster than light.. >Full Article
The Chronovisor
The Chronovisor, allegedly allowed for audio-visual access to the past. "The chronovisor did not transport anyone into the past, but captured images from another time period to be viewed on a screen, it supposedly worked using microwave energy that manipulated the frequency of sound and light waves in order to alter how far back in time images were coming from." - Breaking the Time Barrier: The Race to Build the First Time Machine by Jenny Randles
As per its inventor Marcello P. Ernetti, the luminous energy and sound vibrations emanated throughout history are recorded in their environment, the chronovisor he claims capitalized on this phenomena and allowed him to reconstruct the sounds and visions of a specific sequence of events from varying points in History. >Full Article
References
Tipler Cylinder
An Overview and Comparison by Dr. David Lewis Anderson
