Good News Everyone!
Time travel is possible!
In VERY Specific Situations…..
Einstein’s theory of relativity is made up of two parts – general relativity and special relativity.
Special relativity says space and time are part of the same thing, known as the space-time continuum, and that time can slow down or speed up, depending on how fast you are moving, relative to something else. Einstein’s Theory of Special Relativity states to travel forward in time, an object would need to reach speeds close to the speed of light. Basically, going back in time would be haaaaaaaaard.
Gravity can also bend time, and Einstein’s theory of general relativity suggests that it would be possible to travel backwards in time by following a space-time path, i.e. a closed timeline curve that returns to the starting point in space, but arrives at an earlier time.
However, doing so would cause you to possibly undo yourself by punching out your grandfather.
But, f*ck paradoxes, we’ve done it anyway!
Scientists from the University of Queensland have effectively made a light particle play tag with itself. Twice:
In the first case, one photon passed through a wormhole and then interacted with its older self.
In the second case, when a photon travels through normal space-time and interacts with another photon trapped inside a closed timeline curve forever.
These simulations are important in studying particle behavior in time-travel without worrying about open paradoxes (fuel, tech, grandfathers, Daleks) that would freak us out. We are still in the theoretical space, but we have other methods to mess with space-time.
So why not go to space?
Time dilation is the principle that occurs within 3,174 kilometers above Earth’s surface, where the effects of increased speed and reduced gravity cancel each other out. The astronauts on the International Space Station actually come back younger due to the speed and place in Earth’s gravitational pull. However, it’s hard to really take advantage of being 30 forever because the effect is miniscule; 100 years for 1 full second.
Despite how far our tech is from sending Bruce Willis to kill the snot-nosed kid from 3rd Rock. There are some interesting tales from the time-space continuum from these possible Marty Mcflys.
Here is an awesome doc by the History Channel on the subject: