The assasination of U.S. president John F. Kennedy is one of the most famous conspiracy theories of all time. By official reports, Kennedy was riding in his motorcade down Dealey Plaza in downtown Dallas, Texas when Lee Harvey Oswald shot Kennedy multiple times from the Texas Book Depository, killing him in a matter of seconds before a gathering of Americans on either side of the road.
There is no doubt the murder took place, but the circumstances of the murder, the role of Jack Ruby, and whether or not Oswald had anything to do with the murder are just the tip of the iceberg in the vast library of conspiracy theories. Adding fuel to the fire, we have only one piece of video footage, dubbed the Zapruder film after the operator of the camera, capturing the events. Even so, the Zapruder film fails to catch certain critical moments due to an obstructed view by a road sign during the footage.
If only we could just revisit that moment somehow to observe, we may better understand what really happened that day.
Seeing into the past is not only entirely possible, it's an event we take part in every day of our lives when the right scale is considered. Light is fast, but the universe is large enough to keep us patient for it to arrive. Case in point, the light we see from the sun is eight minutes old. The sun is about eight "light minutes" away from earth.
Astronomers observe this phenomenon noting that any star we observe with the naked eye may already be dead or dying. They are so far away, the light can take millions of years to finally reach us.
The light from the JFK assasination, though nowhere near as bright as a star is itself still traveling through space like an optical film reel. For the same reason we see an older sun, a faraway planet could observe a delayed view of earth on November 22, 1963 with the proper optics.
If only we could find and reach out to such aliens to ask them to take a look for us! If it weren't for the fact no signal we send could outpace light in the first place. But is there another way?
What if a mirror were placed 29 lightyears away from earth, pointed directly at it. The round trip would take 58 years, shining the light of today in 1963 back to Earth. Of course, we would have needed to place the mirror there prior to the assassination. Maybe there is a distant object with a mirrored surface positioned just so that we could peer into a view of the past on Earth?
Following the thought long enough, one quickly runs into some logistical hurdles. 29 lightyears is far away. Earth would appear at so minuscule a size in such a surface, it's doubtful even the best optics could overcome the obfuscation of imperfections in the mirror's surface.
This is to say nothing of how we get an object to 29 lightyears away. The farthest man-made object from earth, Voyager 1, currently drifts at 14.1 billion miles away since its launch in 1977. That's just 0.25% of one lightyear.
This is all sour news for any hope of revisiting another angle of the JFK assassination.
So what is possible?
There is more to think about with regards to a time-reversing mirror perhaps in at shorter distances with more humble results.
But are there other ways to manipulate time satisfactory to the science of present day? Enter the endless philosophical territory. This begins with asking what time really is and whether it is ultimately just an illusion?
Consider what even makes us say that time has passed? At a molecular level, what is different from today versus November 22nd, 1963? Individuals have been born, died, memories are made, the planets are in a different position. Molecularly, energy and matter has just moved around—but a whole lot of it.
This begs the question, if we were to somehow shift the states of all energy and matter in the universe to their exact states from November 22nd, 1963, would we not have accomplished actual time travel into the past?
If we could somehow model the states of energy—all goverened by the laws of physics, determining where they end up in a week, and simply moving them there ("simply"), would we not have accomplished actual time travel into the future?
This puts us in determinism territory which assumes the consequence even of our own thoughts and decisions are goverened by profoundly complex, albeit physically predetermined laws of the universe.
Would we arrive at some enjoyable compromise in the impossible quest for time travel if were were to somehow speed up the natural process of matter and energy state change? What if we lowered the objective by isolating the time warp to a limited three-dimensional region of our liking?
What would it mean anyway if this were to happen? Is the small box of matter whose contents were shifted to a previously identified state flying through time on its own separate timeline?