Einstein’s theories of relativity combined the three dimensions of space with time to create four-dimensional Space-Time. As part of the special theory of relativity, the closer you reach the speed of light, the slower the rate of time so if you could travel at the speed of light you could travel into the future relative to everyone else.
While traveling into the future is possible within the confines of Einstein’s relativistic Space-Time, assuming one could achieve at least almost fast as the speed of light travel, traveling into the past does not seem feasible, particularly due to the paradoxes than can be generated when thinking of time as linear flow that has only one pathway. For example, the “grandfather paradox” is an example of if you could travel into the past and prevent your grandfather from meeting your grandmother. In such conditions, one of your parents would not be born and therefore you would not exist. Another example is the “free lunch paradox” where you invent a new technology – say a time traveling machine – go back in the past and give the plans to your younger self. If you give your younger self the plans to the time machine did you even design / invent it in the first place?
In a more deterministic Universe of Einstein’s Relativity such paradoxes are perplexing. However, as described in the previous article, additional work on Einstein’s equations by others, coupled with additional insights provided by quantum mechanics, have indicated that time is more like a meandering river than an arrow shot into the air. Small inlets that easily break off the main stem of the river and can even flow back into the river further upstream.
A two-dimensional lightcone diagram showing space and time (www.einstein.stanford.edu)
Taking the river analogy a little further, a small inlet that separates from the main stem may be another parallel universe with its own Space-Time. Thus, in the case of the grandfather paradox both occur – there is a Universe where you accomplished your goal and you were never born and there is another where you failed and you were born and there is probably another where you did not even build the time machine in the first place.
In the late 19th and early 20th century, time was generally perceived as always moving forward and in one specific, linear direction. Traveling into the past or future was generally thought of the stuff of science fiction popularized by H.G. Wells in his influential novel The Time Machine, which Lovecraft called “thoroughly entertaining in every detail” (I Am Providence: The Life and Times of H.P. Lovecraft (by S.T. Joshi; 2013). In the novel the narrator can travel into the distant past or future with the aid of a machine or vehicle as it’s called in the novel. Well’s stated in the novel that time is the fourth dimension, which means one would need a timeship to move through it as one would need a spaceship (or plane) to travel the three spatial dimensions. The use of a timeship was a fairly common troupe in science fiction literature in the early 20th century; however, for Lovecraft traveling through time and even space did not require a vehicle.
George Pal in the 1960 movie version of H.G. Wells The Time Machine.
A frequent method of Space-Time travel used by Lovecraft was the exchange of consciousnesses between two entities as demonstrated in “Beyond the Wall of Sleep” and extremely effectively in The Shadow Out of Time. Essentially, the consciousness of an individual is a huge amount of information that is downloaded into the body of another. The Yithians appeared to master this on a species level, where they would avoid destruction by transferring their collective minds into another species from a distant world as well as from a distant time (past or future). In the case of The Shadow Out of Time the Yithians transferred their collective minds into the Cone-Shaped Beings who resided on Earth in the distant past, becoming what was then known as The Great Race.
A member of the Great Race by AJ Jankins (www.hatesnack.com)
By having the consciousness and not the material body travel through time Lovecraft avoids the compilations of removing matter from one time-stream and dumping into another. Essentially, information and not matter travels through time. As has been discussed in previous articles on The Shadow Out of Time such technology may be a possible way for humans to travel through interstellar space and possibly become immortal (The Future of the Mind: The Scientific Quest to Understand, Enhance, and Empower the Mind by Michio Kaku; 2014).
This form of time travel, particularly on a species level, avoids the need for the physical transport of an individual or individuals from one time to another, thus avoiding paradoxes with meeting oneself from a different time. This concept of time traveling and avoiding the paradox of meeting one’s self will be further reviewed in next week’s discussion of “The Silver Key.” Thank you – Fred.