Is time travel possible? The problem with time travel is the ‘Time Travel paradox’ which goes something like this. Suppose a person travels back in time before birth and breaks a link in the time chain that led to the traveler’s birth. This problem has been commonly explored by asking the question ‘What if you killed your own grandmother before she first conceived?’ (Why the time travel paradox is never expressed in terms of killing your own mother, I am not sure, but it isn’t). If you kill your grandmother then you would not be born. If you were not born, then you could not travel into the past, in which case you would not kill your grandmother. If you did not travel back in time to kill your grandmother, you would be born causing you to again travel into the past to kill your grandmother…with me so far?
The laws of physics seem to allow the possibility of time travel to take place. Many physicists believe that there would have to be some kind of constraint that would make time travel impossible.
Albert Einstein thought that time travel was a very distinct possibility. His idea was that, theoretically, the closer we come to traveling at the speed of light (186,000 miles per second), the more time would appear to slow down for us in relation to someone who was not moving. He called the slowing of time due to motion time dilation.
Einstein came up with an example to show the effects of time dilation that he called the “twin paradox.” The paradox basically states that there are two twins. One twin travels to a distant location at the speed of light, while the other twin stays on earth. For the twin that traveled, time slowed down, while time stayed constant for the twin that remained on earth. Upon returning the twins were no longer the same age. The twin paradox and time dilation actually supports the theory of time travel into the future.
The twin paradox theory was actually proven in an experiment in 1971. This time experiment used two atomic clocks which started off reading the exact same time. One clock was placed on a jet that traveled around the world at 600 mph, while the other atomic clock stayed stationary. When the jet landed, the clock that had gone around the world was behind by a few billionths of a second.
So what about time travel into the past? The basic features of quantum theory actually allow for the possibility of time travel into the past and that the paradoxes raised by the equations of Einstein’s theory of relativity never come into play. The theory is that quantum objects split their existence into multiple component waves, which follows a distinct path through space-time. Quantum theory allows for time travel, because nothing stops the waves from traveling backwards in time. If you travel back into time using quantum mechanics, you would only see those events that were consistent with the world you left behind.
Time travel is an interesting theory to say the least. I leave you with this thought on time travel. If one day someone knocks on your door and says that they are a distant relative of yours, you might want to think twice before you close the door.