Yes! It’s a success! Guys, it worked!
This week, I move on from psychology for a while to discuss a purely theoretical and utterly paradoxical Hollywood science phenomena- Time Travel.
Now, theoretically speaking, time travel is possible. This all ties back to my column on space, oddly enough. In that column, I talked about something called time dilation. Time and space are linked together- they are one fabric. You’ve probably heard the phrase “space-time continuum” in media before, that’s what they’re referring to. So, when you travel through space you are also traveling through time. This seems natural to us because the time we travel through is the time it takes to travel. But it goes deeper than that.
Two things warp space-time: mass and velocity. Super-huge things and super-fast things can actually bend space-time. You actually feel this effect all the time- this is what causes gravity. The physical mass of planets, asteroids, moons, stars, etc. actually bend the fabric of space-time. It’s like a stretching out a blanket and putting a rock in it. If you roll a ball in that duvet, it’ll start to orbit around the rock. That’s why the earth orbits the sun. Now, the bend in the space-time continuum (called a gravity well) caused by the earth or our sun isn’t anything really serious, but as stars get more massive, they create greater and greater gravity wells. Things like white dwarfs, neutron stars, and black holes (all dying/dead supermassive stars) create gravity wells strong enough to perceptively warp time.
Black Holes are theoretical constructs, which means we haven’t ever observed one. This is primarily for two reasons: One, space is just really balls-ass huge. When you see something, it means that the particle of light (photon) has come from a light source (the sun, a light bulb, etc.) bounced off an object, and entered our eye. Now, photons travel at the speed of light, which is effectively instantaneous here on earth. But out in space, where distance is measured in lightyears (the distance light travels in a year). That photon can take thousands or even millions of years to reach our planet to be observed. This is how we can tell how old our universe is. We look for the furthest thing possible, thus if we can see a nebula 13 billion light-years away, we know that the universe must be AT LEAST 13 billion years old, since those photons have been travelling for 13 billion years.
And two, the gravity well of a black hole is so intense that at a point (the “Event Horizon”), the gravitational forces are so strong that even light cannot escape it- hence why it’s called “black.”
Now, light is able to go the speed it does because photons are nearly massless, but if you got something with more mass to start going that fast, you’d warp the very fabric of space-time. Still have that stretched out blanket from the last example? Imagine pushing that rock across it really fast, the blanket will get bunched up in the front and stretched out along the back. This is what you’d be doing to space-time. Generally speaking, the faster you go, 1. The heavier you get, and 2. the slower time passes (for you). If you wanted to be able to feel the difference, you’d have to be going super-duper fast- like 99.999999999998% of the speed of light. But at that speed, one second to you would be about 10 years for your buddy on earth. At slower speeds, though, precise atomic clocks can detect differences here on earth.
NASA confirmed this with two atomic clocks synchronized on the ground. One of them was put up into an X-15, the fastest goddamn thing we have ever made. It’s a rocket-propelled jet capable of going 6 times the speed of sound. It took one flight, came back down and the two clocks were off by a fraction of a millisecond.
So, assuming you could get something quick enough, you could travel forward in time, sort of. You wouldn’t really be traveling through time, you’d just be aging super slowly comparative to the norm and time wouldn’t feel like it’d have passed.
Time Dilation is basically the core of what the classic military sci-fi book The Forever War is about. A young man leaves for an interstellar war across the galaxy using FTL drives and comes back to find the earth aged thousands of years, everything and everyone he knew dead, and the human race so foreign he no longer belongs to their species.
If you wanted to actually travel through time, you’d need to use wormholes. Wormholes, or Einstein-Rosen Bridges, are another theoretical construct that would allow one to travel from one point in space-time to another much further/later point instantaneously. For example, still got that blanket? Good, now fold one corner onto the other and poke a pin through. That pin just space-time traveled. That’s what a wormhole is in a nutshell- a tunnel through folded-over space-time. Now, the fabric of space-time is actually folded over in some other higher dimension beyond the 3 that we can see (they go pretty much all the way up to ten, here’s a neat video explaining them).
Passing through a wormhole would send you not only to somewhere else in the galaxy, but someWHEN else in time. Stargates (from the movie/series) are wormholes. However, they only adhere to the space aspect of the travel, not the the time. Though I suppose that’s good, otherwise MacGyver would return to an earth unlike anything he knew. That’s because wormhole time travel is pretty much one way- forward. Traveling to the past is pretty much best left to Back To The Future and Primer. Primer is the first movie made by the creator of Upstream Color which is about time travel.
Two of the core mechanics about their use of time travel are that 1. You cannot go back to a point in time in which the time machine was not on, and 2. You have to stay in the time machine for however long you want to go back in time (if you wanted to go back in time 2 hours, you gotta be in the machine for 2 hours). This kind of time travel isn’t really possible in any sense of the word but it does make for a good drama and science fiction. Be warned, though the film is incredibly complex. It takes a few graphs just to figure out what the hell is going on. But it’s a fantastic movie and certainly a Grade-A mindfuck.
Well, that’s it for this week, if you don’t mind I’m going to attempt to travel back in time to the beginning of this article.
Be sure to join me again next week as I discuss science tropes in the media. And be sure to check out my other column, where I review dumb-ass action films every Monday: Mindless Action Mondays
Have a science-related question? Ask it!
If I don’t know the answer, I’ll find someone who does.