Time travel has been a very common topic among Science Fiction writers since the very beginning of the genre. HG Wells was one of the pioneers in the field when he wrote the novel “Time Machine” where an inventor builds a machine that takes him back and forth in time. In Star Trek, there are at least a dozen episodes or more where time travel is involved.
Einstein was one of the first scientists to predict that time travel was a scientific possibility in his theory of relativity. Einstein’s equations determined that time travel into the future was a possibility. Sadly, no one has yet understood completely if there is a mechanism that allows travel into the past (so far, the flux capacitor of “Back to the future” is just another Science Fiction masterpiece). With so much literature about time travel, soon a sub product of it emerged it what many call: the time travel paradox.
Many authors and scientists firmly believe that nature has taken protection in the laws of physics making time travel into the past impossible. This is because such a trip would interfere with the natural flow of time or order in which events occurred. A classic example is the person that travels in time and accidentally kills his/her own father before he/she was born. If this happens, this person would not have been born in the first place and, therefore, incapable of inventing a time machine in the first place. The complexity and scope of the problem is wider and deeper than just a single person’s fate.
For instance, assuming that the time traveler goes back a little further in the past, and accidentally prevents his/her great-great-parents to meet; the consequence is dire not only to the traveler but, most likely, a whole group of persons within his/her family would never exist.
To explain how fragile this time line is, another exercise is needed. In Europe, for a brief period of time, Homo Sapiens (Mankind) has lived together with Homo Neanderthalensis (the famous Neanderthal). Both were so distinct that they are deemed by some Anthropologists to be entirely different species. Many also believe that the more aggressive Homo Sapiens was partially to blame for the extinction of the Neanderthals. If this is correct, it would be mankind’s first in a long line of sad genocides. Being so close to home, it is much more accurate to theorize on what may have happened if the Neanderthals emerged and mankind had failed in the fight for survival. Or, perhaps, if both species share, to this day the planet (many believe that there is a law of nature that somehow forbids to sentient species in sharing the same planet). We also know that Neanderthals were a lot less aggressive and, therefore, some of the bloodshed that happened in our history would never exist with the Neanderthals. Furthermore, Neanderthals showed no signs of organized religion or religious rituals which leads to some theories about the existence of religion (or lack of it) if Neanderthals were alive instead of Homo Sapiens.
Robert J. Sawyer (who also wrote great other novels. Currently, his novel FLASH FORWARD has become a TV series) in his Neanderthal Parallax trilogy devises a parallel universe in which humans were extinct and Neanderthal live in an alternative planet Earth. During a experiment with quantum physics they open a portal to our Earth and manage to travel among worlds. Sawyer uses his novels to show how different both species are and how alien our own world could be had fate favored someone else.
A last example is even more fascinating. For two weeks now South Florida, like most parts of the northern hemisphere, is facing one of the lowest temperatures ever registered in many decades. The human population of South Florida is suffering a lot because residences are just not completely prepared for the cold weather. Nonetheless, another type of resident is suffering even more these days. In Broward and Dade counties Iguanas are dropping from trees to land on the ground. For some of them, the fall is so hard that kills them. This is happening because Iguanas have a mechanism that is triggered every time the temperature is lower than a certain threshold. This mechanism puts them in hibernation as a way to conserve energy while the temperatures are too low. Unlike humans and other mammals, Iguanas rely on exterior heat sources like the sun to support certain functions of their bodies. That is why it is quite common to see them lying somewhere and heating it up before they can move on with their lives. In that sense Iguanas are very similar to the late dinosaurs. Many scientists believe that the extinction of these huge beasts (the dinosaurs) had to do with the impact of an immense meteor that hit the Earth and spread dust on the upper atmosphere blocking the sun. As a result of this event and its consequences dinosaurs could not get important sources of heat and, most important, since plants died due to the lack of sunlight a big portion of the food chain and the ecosystem was destroyed. This event is important because it changed life on earth forever. Thanks to that event lower mammals could evolve and eventually, a group of mammals, ancestors to humans, appeared on the face of the planet and allowed our civilization to exist.
By now the picture is clear, the further we go, the wider are the consequences and possibilities to fundamentally alter reality. Nonetheless, in recent years many have argued that the paradox does not exist at all. When a time traveler alters the past, a a different reality is created allowing the traveler to go back to the unaltered reality left behind.
Regardless of what it is believed to be correct, one thing is certain, an amazing amount of events have to be just perfect and right for us to be us. That small miracle alone is enough reason to celebrate the joy of our existence and that fact that we are all unique.
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