In the first part of this post I blew your mind with the nature of time itself, well I hope you were able to piece it back together because in our dramatic conclusion I’m going to wrinkle your brain all over again with a breakdown of the real question you want answered: Is it possible to travel through time? So hop in your DeLoreans and buckle your seat-belts because it’s the moment you’ve been waiting for since next week: Mind Blown-Time Part 2 (Back to the Blog Post).
Time Travel has been the subject of speculative fiction for generations, but what you may not realize is that some of the world’s foremost experts in theoretical physics have been interested in the idea for just as long. Work in the area was long relegated to cranks and amateurs but when Einstein developed his Theory of Relativity and sketched out his notion of space-time suddenly time travel was something that serious scientists could begin to talk about without being laughed out of academia. In fact, right now there are several research groups conducting experiments that may someday allow us to emulate Marty McFly.
When talking about time travel it’s important to differentiate between travel to the future and travel to the past. Traveling to the future is simply a matter of manipulating gravity. As discussed in part one of this series gravity affects the passage of time. On Earth, these differences are so small as to be nearly immeasurable, but if you were to head out into the galaxy and do something like say slingshot yourself around a black hole then you could theoretically hurl yourself into the future.
You would just be putting your life in super slow-motion while everyone else barreled forward at regular speed. Depending on the strength of the gravitational pull and how close you got to the event horizon entire eons could pass in the literal blink of your eye. The problem is that this is a one-way trip. You have no way to know what awaits you when you re-enter the normal flow of time and no way to go back if you don’t like what you find when you do. In the end, this method is more a trick of the lights than actual time travel.
Time travel to the past though, that’s the million dollar question. The biggest argument against it is if it were possible then why haven’t we met any time travelers yet? It’s a good argument but far from a conclusive one. The second best argument against it is Einstein’s Theory of Relativity which asserts that time moves in only one direction: Forward. But some scientists say not so fast.
Among the most popular arguments for travel to the past are wormholes, rotating black holes that link two separate points in space-time. If you wanted to travel to the past you would need to either travel through an existing wormhole or use the energy of a neutron star to create your own(definitely easier said than done). So far no one has any idea how to safely traverse a wormhole or how to know what is on the other side of one without actually going through it first, or if wormhole actually exist in reality rather than just in theoretical models; but hey on paper they might just be the closest you’re going to get to hurling yourself into the past.
Another theory about time travel that gets bandied about by theoretical physicists when they’ve had too much to drink involves String Theory. Cosmic strings are these tiny one-dimensional tubes that exist as a byproduct of early cosmic expansion. They’re pretty important to our understanding of the universe but we can delve deeper into that on another occasion. For our purposes today all you need to understand is that those strings have exponentially large amounts of mass, enough to bend space-time around them. If we were able to manipulate two such strings so that they would approach each other on parallel tracks it might just enable us to warp space-time enough to allow travel to the past. But don’t get your hopes up; that kind of technology is a few (ten) thousand years beyond what we are capable of doing now.
Well, there you have it. Time travel to the future? No problem. Time Travel to the past? No solution. Not yet anyway. I hope you enjoyed the second part of our examination of the nature of Time. This has been your regular installment of Mind Blown! Until next Time!….. (Part 3?)