As science and technology progress we are understanding time and its relation to the universe much deeper than ever before. There are apparently “portals” in the universe that, well, we’re not sure what is on the other side of them, but it might be another universe, or a connection to another part of the universe. Apparently, there is some way of approaching the speed of light and somehow space will curve in front of the vehicle traveling through space. I’m not an astrophysicist, so please excuse my rather dim perception of some of these astrophysical science theories. If you want to believe that time travel is still possible, stop reading now, because I’m going to destroy your belief in it. I won’t go into event/horizon, black holes or string theory. There is a much more sensible and logical explanation of why no one has traveled from the future back in time.
For exhibit one, I give you the North Sentinel Island. I’m reasonably sure that none of you, dear readers, have ever heard of it. If you Google it, and why wouldn’t you, the first sentence reads: “North Sentinel Island is one of the Andaman Islands, which includes South Sentinel Island, in the Bay of Bengal. It is home to the Sentinelese who, often violently, reject any contact with the outside world, and are among the last people worldwide to remain virtually untouched by modern civilization. As such, only limited information about the island is known.” I left the links in the quote, for those of you who are interested in this tribe.
OK, so there’s this island where everyone is forbidden to visit. There have only been a few visitors, and the results were quite tragic. What has happened when modern visitors have any close association with the Sentinelese, is that the Sentinelese die very quickly, in a matter of days. The reason for this is that the Sentinelese have not had any substantial contact with humans from the outside world for centuries, or even thousands of years.
For exhibit two, you must understand that all of us are walking test tubes of bacteria and viruses that are no longer a threat to our health. These viruses and bacteria have evolved over the centuries (sorry to have to tell you folks that do not believe in evolution) and we have become immune to them. The same thing happened with the settling of North America, when the indigenous populations were exposed to the European diseases, they had no immunity, and, as medicines that could address the diseases were not available, thousands of the indigenous tribespeople got sick and died. Nothing, at that time, could stop it, other than the Europeans not getting anywhere near the indigenous tribes, and that wasn’t going to happen.
Now we have someone from the future travel back in time. Unless the time travelers are wearing a space suit, all of those viruses and bacteria that they are carrying with them, that they are immune to, that have evolved over the centuries, are going to infect anyone in the past to where they have traveled. In a model almost identical to the indigenous North American tribes being attacked by the Sentinelese, the highly evolved viruses are going to attack the people who come in contact with the time travelers. The results will make the Great Plague look like a case of the sniffles. The evolved viruses will assault the unevolved population will attack the immune systems of the people of the past and wipe them out by the millions, with nothing to stop them. Any contact, even so much as shaking hands, will transmit viruses that will kill the population of the earlier time with impunity. It would be almost impossible to stop the deaths from the infection, even with the most sophisticated of drugs, because even a vaccine with a watered-down virus would more than likely still be a fatal infection. No doubt there would be some that survive, but very few. The very young, infants, and the very old (or what was considered old at that time) whose immune systems would be vulnerable, would perish quickly. I am sorry to dismantle your idea about traveling back in time, but the results on the population would be devastating. Traveling forward in time has the same problem, in that your immune system could not fight off the highly evolved viruses to which the future humans would be immune. They might be able to create a vaccine for you, but I wouldn’t count on it.
In the same way, the astronauts who landed on the moon, in case you do not remember, were quarantined on a ship out in the ocean for several days before they were allowed to have contact with people from earth. There was a fear, and rightfully so, that there could be viruses on the moon to which we earthlings would have no resistance. It turned out not to be the case, but had any of those astronauts taken ill, I’m pretty sure those ships they were on would have stayed out in the ocean until things could get settled. The possibility of an alien virus was too great a risk, when a short quarantine could have addressed the issue, as it did.
Unfortunately for all of the UFO believers, this same theory applies to extraterrestrials. If extraterrestrials are even remotely similar to us, there would be a distinct probability that they would be carrying bacteria and viruses that our immune systems would not be able to fight off. That’s the reality of it. Space and time have a menace that we don’t want to admit to, and that menace is that our immune systems are our greatest weakness. Captain Kirk and Mr. Spock might have been transported to alien worlds, but the viruses that they carried would have quickly decimated the populations of those worlds. I’m sorry to bring all of this pessimism to those wonderful ideas about time travel and space exploration. It’s always the little things that gum up the works. In this case, little things, microscopic things, spell doom to organisms that cannot resist microbial life forms that infect and kill us.
NASA has a team that work on this, and, in case you didn’t know it, we are very careful that we do not bring with us any viruses that could infect, and decimate, any population with which it comes in contact.
Remember to get your flu shot this year, as the flu virus develops immunity to the old vaccine. The regeneration and evolutionary cycle of a virus is exponentially faster than that of humans. New generations of viruses come about in months. It is called survival of the fittest, and the newly born menace, the cycle of survival that Charles Darwin spoke of in “The Origin of the Species.” The older viruses died off, and the vaccine-resistant virus survives to wreak havoc upon the human population. Even now, penicillin-resistant viruses have evolved and are threatening pretty much all of humanity. Other than that, pull that dusty version of “The Time Machine” off the bookcase and enjoy reading what can never come about. That’s why it’s called fiction.