Many Worlds: Many Timelines - The Multiverse and Time Travel
Our scientific knowledge and technological achievement has yet to catch up to the limitless dreams of our imaginations. But perhaps just because we have yet to achieve time travel in our universe, in our particular point along the cosmic arrow of time, doesn't mean it isn't achievable... and maybe the key is the universe itself. Are we limiting ourselves to our understanding only of the laws and possibilities of our universe, and leaving out of the equation other realities, other universes, with other laws and forces, paradoxes and limitation, possibilities and potentialities, far beyond our own?
In 2011, quantum physicists at the University of California at Santa Barbara, led by Andrew Cleland and John Martinis, designed a "quantum machine," as they call it, that might one day lead to proof of time travel and parallel universes. Their machine, a tiny little teleporter barely visible to the naked eye, involves making a tiny metal paddle cool to its ground state, the lowest energy state permissible by the laws of quantum mechanics, and then raising it's energy slowly by a single quantum to produce a purely quantum state of motion. And, they even were able to put the device in both states at once, so it vibrated both slowly and quickly at the same time, in another sort of Schrodinger's Cat state of superposition. They posited that we can only see one of these potential states at once, and upon the act of observation, the state then splits into additional universes. Perhaps, there is a plethora of multiple or parallel universes all around us, but we cannot see them.
Wormholes could also be another possibility for teleportation, as physicist Max Tegmark suggested while attending a panel in January of 2008 at MIT to discuss the science behind the movie "Jumper" starring Hayden Christiansen, about a man who can teleport all over the world at will. Tegmark was asked about the science behind the science fiction, and remarked that a wormhole was one possible way of getting something quickly across space-time. However, after admitting that wormholes do appear to be theoretically possible, Tegmark commented that the actual trip would be rather grueling because of the instability of the wormhole. "It could collapse into a black hole, which would be kind of a bummer."
Many scientists look to the possible existence of other levels of reality, or other universes, as a way to make time travel work outside of the restrictions of light speed and paradoxes. Imagine another universe alongside our own where the laws of physics are so completely different, that what is impossible here is mundane and trivial there. Multiple worlds, even, where each is different from the other, or perhaps an infinite number of universes where many would be exactly like our own. Hey, you might even exist in some of them just the way you are right now. In others, you might be rich, famous, handsome or even a cockroach! In fact, perhaps you might even be invisible in one of them!
Parallel universes have long been a mainstay of science fiction films and stories. Parallel universes can exist individually, or grouped together as the "multiverse," and offer the possibility of a totally different reality in which someone, or something, can exist, or hop back and forth between. The laws of nature may be different in one parallel universe as they are in another, and in respect to time travel, would provide multiple versions of the future in which someone could exist, or not exist at all. Light speed limitations may not exist in a parallel universe, and the paradoxes that keep us from traveling back in time would be null and void if we could jump into a different historical timeline.
Theoretically, parallel universes may be the result of a single random quantum event that branches off into an alternative universe. This is the "Many Worlds Interpretation" or MWI, of quantum mechanics, originally formulated by physicist Hugh Everett in 1957, and posits that each time a different choice is made at the quantum scale, a universe arises to accommodate that choice, thus creating infinite new worlds popping up all the time. These new worlds are being constantly created, and could cause problems for a potential time traveler. Physicist David Deutsch wrote in "Quantum mechanics near closed timelike curves" for the 1991 Physical Review, that if time travel to the past were indeed possible, the many worlds scenario would result in a time traveler ending up in a different branch of history than the one he departed from. Deutsch, of Oxford University, is a highly respected proponent of quantum theory, and suggests quantum theory does not forbid time travel, but rather sidesteps it, referring to the traveler's ability to go into another universe, a parallel universe, and avoid the paradox limitations.
Deutsch's idea of parallel universes, the multiverse, or "shadow universes" was described in his interview with the Guardian UK in June of 2010, "David Deutsch's Multiverse Carries Us Beyond the Realm of Imagination." as being "co-incident with, somehow contiguous with, and weakly interacting with, this one. It is a composite, a layer cake, a palimpsest of universes very similar but not quite identical to each other." The number of these shadow universes could be enormous, and Deutsch points to photon experiments that suggest possibly a trillion of them or more. He also suggests that future-directed time travel will essentially only require efficient rockets, and is on the "moderately distant but confidently foreseeable technological horizon." When it comes to past travel, the multiverse might save a time traveler from the pesky Grandfather paradox. He uses an example of a writer who wants to go back in time with a copy of Shakespeare's Complete Works and help the bard complete Hamlet. It can happen, but in the multiverse view, "the traveler has not come from the future of that copy of Shakespeare."
Alternate timelines, each with their own forward arrow of time and their own history, may exist then, allowing time travelers to jump into another version of history and override those pesky paradoxes. Imagine being able to jump into a timeline where you do get your dream of marrying your high school sweetheart, but, finding out she's an evil tramp as soon as you say "I do," you could jump back into your original historical timeline, where you didn't marry her and instead ended up three years later marrying her sister, your true soul mate, and lived happily ever after.
Marie D. Jones and Larry Flaxman are both authors, screen writers, and speakers on science consciousness, metaphysics and the paranormal. They have co-authored several books together.