The concept of a time travel machine has always captured the imagination of all, and the occasional Sci-Fi scenario movies. But could it be possible? Of course it is. We’re traveling through time right now, aren’t we? You’re traveling into the future second by second. Or not? Gotcha! That was not what you were thinking. But can we really travel much further into the future? Absolutely! A new paper describes how to build a time machine. Grab your stuff, we’re traveling into time — but we think the past would be fun.
Related media: How To Time Travel
Can You Really Travel In Time?
Let’s get this straight: if Einstein’s theory of special and general relativity predict that space and time are the same thing, (E=mc2), then why can we travel through space but not in time? Thinking of spoilers? Not yet. The new paper which was published in the journal Classical and Quantum Gravity by Caroline Mallary, a doctoral student at the University of Massachusetts, Dartmouth, describes how to build a time machine using a very simple construction.
“I first heard about the notion of time travel when I was 7, … I decided right then that someday, I was going to pursue a deep study of the theory that underlies such creative and remarkable ideas: Einstein’s relativity.” writes Gaurav Khanna, a physics professor also at the University of Massachusetts, Dartmouth, and co-author of the new paper, in an article. “Twenty years later, I emerged with a Ph.D. in the field and have been an active researcher in the theory ever since.”
The theory of classic general relativity predicts the possibility that space is interwoven together with time, such that, a warp in time would eventually warp the fabric of space (and time) to the extent that one has the tendency of changing the other — the result of a time loop. Now imagine you’re traveling through space at the speed of light, you’d be traveling so fast that time seems to be stationary, neither progressing nor regressing. What this means is that, at some point in time, you’d realize that you’re back at a moment in the past and begin experiencing the same moments since, all over again — sort of like a déjà vu you can’t even realize.
This is technically known as closed time-like curves; also known as (you probably guessed it) time travel machines. These time machines are byproducts of the result of the time loop caused by the faster-than-light travel phenomenon, and can help improve our understanding of the universe. Renowned theoretical physicists like Kip Thorne and Stephen Hawking have all proposed similar theories on such models that predicted a time machine.
The Time Travel Paradox
General conclusions for a time travel machine emerged from formal research — including both Thorne’s and Hawking’s — predicts that nature itself forbids such a time loop. To understand this better, Hawking explained it in his book, “Chronology Protection Conjecture,” which essentially says that nature doesn’t allow for changes to it’s past history — this implies that paradoxes can’t happen since time would be working against itself.
The grandfather paradox could help you understand it better. The paradox goes like this: What if you travel back in time and choose to murder your grandparents. This would eventually alter the course of history in a way that a contradiction emerges: In this hypothetical paradox, you would then never be born, therefore you cannot even exist, and thus can’t travel in time. (We believe if you ever time travel you would not think of such a thing). There are even several Sci-Fi novels and movies you’ve probably read or seen that depicts such paradoxes — “Back to the Future” and “Groundhog Day,” are popular examples.
With such a paradox at hand, the physical reality of just normal matter would be affected, since you have to take your entire body through time; and what if you time travel to say yesterday or tomorrow, you’d see your other self (double-ganger) in the past or in the future, which totally sounds bizarre than you’d imagine.
“Depending on the details, different physical phenomena may intervene to prevent closed time-like curves from developing in physical systems,” Khanna writes. “The most common is the requirement for a particular type of “exotic” matter that must be present in order for a time loop to exist. Loosely speaking, exotic matter is matter that has negative mass. The problem is negative mass is not known to exist in nature.”
How To Build A Time Travel Machine
Caroline Mallary, a doctoral student of professor Khanna, and the led author of the new model for the time travel machine in the journal, offers a very simple design of construction. The new model does not even require the so-call “exotic negative mass.” In this model, Mallary proposed the concept of two super long cars — a sort of cosmic wagon built of material that’s positive mass in a parallel setting. One of the wagon travels at a rapid pace forward, while the other stays still. She was able to show that in such a setup, a time loop can be found in the space between the wagons. (This doesn’t sound simple, does it?)
Now, what if you want to build “Mallary’s wagon,” there’s a catch: The model requires that the center of each wagon has infinite density. What this means is that, the wagon must poses a singularity, with an infinite density, temperature, and pressure. Sounds familiar, right? Yes! These singularities are [not] like that of the interior of black holes, which makes it impossible to be seen in the observable universe. But the singularities in Mallary’s model are observable, and therefore should have true physical effects.
“Physicists don’t expect such peculiar objects to exist in nature either,” as Khanna concludes. “So, unfortunately, a time machine is not going to be available anytime soon. However, this work shows that physicists may have to refine their ideas about why closed time-like curves are forbidden.”
Now the spoiler: Hard luck trying to build a time travel machine.
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Written by: Nana Kwadwo, Sun, Mar 31, 2019.