By Sally Carpenter

Some time ago I re-watched the “Back to the Future” movie trilogy, of the intrepid Marty McFly journeys in the past and future to correct certain “mistakes” in the time line. The films are highly entertaining and great food for thought. What if time travel was possible? How would humans use—or misuse—that power?

Time travel has long been a subject for the science fiction genre but not so much for mysteries. After all, if the hero could go back in time and actually witness the crime, we’d have swift justice but a very short story.

Just what is “time,” anyway? Is it a man-made construct? Watches, clocks and calendars only measure time but do not create it. And time is not universal. With the various time zones, we are not all “in” the same minute.

Calendar use is not consistent. While most of the world uses the Gregorian calendar, the Orthodox Church still goes by the Julian calendar. In the Jewish calendar, this is year 5777. The traditional Chinese calendar has a leap month rather than a leap day.

If humans achieve space travel, how will they age in space, since time is different on planets with a longer or shorter orbit around the sun than Earth? Are human biological clocks so ingrained that the astronauts will continue to function on a 24-hour rhythm, or will they adapt to their new surroundings?

 Back here on Earth, what would be the practical uses of time travel? Humans could go back in time to correct certain “wrongs”: stop the assassination of Abraham Lincoln; prevent the birth of Adolph Hitler, save communities from natural disasters.

 But if John Wilkes Booth were stopped, would another man have killed Lincoln at a later time? If Hitler was never born, would a man even worse would rise to power, since at that time Germany needed a strong leader to pull the country out of an economic shambles.

 If the good guys had access to time travel, that means the bad guys could use it too. What if a Neo-Nazi prevented Oskar Shindler and many others from rescuing Jews during the Holocaust? What if a criminal made sure John Hinkley or Mehmet Ali Agca succeeded in their assassination attempts (President Ronald Reagan and Pope John Paul II, respectively)?

 Since time travel would be horribly expensive and not all “wrongs” can be righted, who would decide which historical events to change? The government? The millionaires who could afford the equipment? The poor? Victims of violence? Historians?

 What of the ramifications? If John F. Kennedy had not died in Dallas, how much history after that event would change?

Or would time travelers simply go to observe if certain events actually occurred, such as stories in the Bible? What kind of proof could they bring back? Would modern-day cameras and recording devices work in past times? How could one make selfies in first century without anyone noticing?

While this is gist for speculative fiction, it’s doubtful that time travel is possible. Events happen and disappear. While past events are recorded in memories and photographs, one can’t make history happen again. One can’t return 1500 France because 2016 France is occupying that ground. The World Wars are not still being replayed in an alternative universe; at least I hope not.

Attempts to recapture the past usually fail. Promoters tried to recreate the original Woodstock feel-good festival with Woodstock ’94 and ‘99. The first attempt suffered from security breakdown, and ’99 was marred by high vendor prices, violence, rape and fires. The love and goodwill of the original concert got lost in translation.

What your thoughts on time travel? Should humans attempt to change the past or let bygones be bygones? Are there events or choices in your life you’d like to go back and change?