10/29/2014
Differences in the Possibility of Past and Future Time Travel
The possibility of time traveling to the past or future has been extensively explored by physicists and philosophers ever since Einstein first published his theory of relativity in 1905 (Davies 5). Many theories and explanations addressing the senses in which they are physically and metaphysically possible have been developed over the past century in an effort to someday turn theory into reality. This compilation of research has indicated that both past and future time travel are metaphysically possible. However, only future time travel has strong evidence showing that it is physically possible. Therefore, due to the lack of physical evidence supporting the possibility of past time travel, I will argue that there is a significant difference between the way past and future time travel are possible.
First, the theories relating to future time travel are all rooted in Einstein’s idea that time is elastic. More specifically, this idea is known as the theory of special relativity and says that, “the exact duration of time between two specified events will depend on how the observer is moving” (Davies 6). In 1971, Einstein’s first method for time traveling into the future was demonstrated to be physically possible by Richard Keating when he showed that the time on two atomic clocks was slightly different after one clock was flown around the world while the other remained stationary on earth (Davies 8). In effect, the one clock that was flown around the world had time traveled ever so slightly into the future due to its increased speed. That being said, the metaphysical implications of this imply that if an object could reach speeds close to the speed of light, the resulting time warp would then be significant enough to travel a noticeable amount into the future. Furthermore, Einstein later proposed in his general theory of relativity that gravity had a slowing effect on time; also