The final chapter of the X-Men’s 50th anniversary story dropped last week, concluding the timestream-spanning fracas that was “Battle of the Atom.” Well, really, the issue has always existed and always will exist. Our perception of forward flow is an illusion and all of time exists eternally and simultaneously, just like all of space. That’s if you believe the relativistic arguments of physicists like Brian Greene, Sean Carroll, Adam Frank and Einstein himself. Find out more in this video, taken from the PBS adaptation of Greene’s book, “Fabric of the Cosmos.”
That’s a mind-numbing potential reality that could not only sink trivial things like free will and control over one’s destiny, but it also scuttles a good time travel story. Although really, there aren’t many that make a lot of sense. The tale of the five original X-Men being transported to the present, where they mingle with their current selves, is especially thorny. “Battle of the Atom” hinges on whether they should be sent back or not, ignoring just how impossible that would be. Turns out getting here (now?) was the easy part.
Traveling to the future is possible (kind of), but you probably can’t just pop in out of thin air. From ‘All New X-Men’ #2
Pick Up the Pace
The simplest way to get to the future is to do nothing. We’re all passing “through” time at the same rate when we’re at rest. My kind of journey; one you can take sitting on your ass.
But we’re never truly at rest. The Earth revolves around the Sun at a speed of about 100,000 miles per hour, and the whole solar system itself flies through the galaxy at rates almost 7 times that. Constant velocity, according to Einstein, is the same as being at rest, but the fact we’re changing directions (making revolutions instead of straight lines) makes those motions accelerations. And one thing we know for sure from relativity is objects undergoing accelerations “pass” through time at different “speeds.”
Imagine that space and time are different directions you can travel in, just as if the above x-axis were instead labeled “right” and the y-axis was “forward.” Unless you’re stuck on a railroad track, you don’t have to travel completely right or completely forward. You can take an in-between path, like lines B and C. Similarly in relativity, the greater part of that line in the “space” direction (the faster you’re moving), the slower you naturally move through time. Photons of light, which travel at the universal speed limit, are essentially frozen in time and stay the way they are forever. A person moving on the C trajectory is moving faster than Mr. B (i.e. a greater portion of his overall motion is through space, rather than time) and thus ages more slowly.
Sorry Mr. Traveler, you won’t get anywhere just sitting there. No sooner than the rest of us, anyway.
So that’s the easiest way to travel into the future. Move really fast, turn around and come back. You’ll still be relatively young and everything else will have aged. No time cube required, just a hellaciously powerful rocket and a lot of fuel. Relativity also shows us that the force due to gravity is indistinguishable from an acceleration of equal magnitude. In other words, large gravitational forces can slow the effects of time, too. Watch out for aging actresses hanging out near black holes.
Can’t Go Home Again
Sending someone BACK in time is significantly more difficult, as the future mutants found out when they tried to return their teenage counterparts in Uncanny X-Men #8. But wait, how did THEY do it, then?
‘Battle of the Atom’ #1
Well, if moving really fast slows you down, and moving at light speed stops you in time, than traveling faster than light should take you back in time. Trouble is, scientific laws aren’t like human-written ones. You don’t get a ticket for breaking the cosmic speed limit because you simply can’t. In addition to the slowing of time, extreme speeds also cause an increase in mass, and a theoretical infinite one at light speed. Not happening.
But wait – the rule is that you can’t travel THROUGH space faster than light. What if space ITSELF is being spun around and accelerated? Back to the black hole! Maybe there are some so massive, rotating so rapidly, that they drag spacetime around them, like a spinning top in molasses, so you could achieve faster than light speed through the back door. Entirely theoretical, and you’d probably be torn apart.
Cyclops narrowly avoids being erased from history. From ‘Battle of the Atom’ #1.
And then there are the paradoxes. Killing your grandfather in the past, or killing your younger self, would mean YOU never would have existed to go back and do the deed to begin with. Even if you didn’t have the stomach to kill your grandfather, changing anything before you were born would ensure your never-existence. I’m not just talking about stepping on butterflies. When you consider that every ejaculation contains hundreds of millions of sperm cells, and that half your genetic material comes from just ONE, the tiniest alteration, statistically, would take that swimmer out of the race keep the thing called you from ever being born.
That’s sort of solved if you follow Hugh Everett’s many worlds interpretation of quantum mechanics, in which every physical possibility (every mathematically viable solution to the quantum wave function) is realized somewhere, creating an infinite number of alternate universes. A traveler to the past could just end up in (or start another) one of those other universes. Most physicists don’t ascribe to Everett’s idea, though, and just about everyone agrees it would be impossible to test.
A Glimpse into the Future
I won’t even get into the wonkiness proffered by director Bryan Singer to explain Wolverine’s consciousness being sent back in time in 2014’s Days of Future Past film. He recently told Empire Magazine, “The principle I looked at is this theory that until an object is observed, it hasn’t really happened yet. The time-traveler whose consciousness travels through time I call The Observer, and until The Observer returns to where he travelled from, the result hasn’t occurred yet.”
He’s doing what now? How’s that?
That’s not really how the observer effect works, as anyone or anything can act as an observer, not just the thing performing the action. But we’ll let that one sit for a few months, and revisit it once the film’s released.