Over the last several decades, a great deal of pop-culture has been influenced by the
idea of time travel. Doctor Who, Back to the Future, and Donnie Darko are all prime examples - and each one has a different spin on how time travel could be achieved.
Unfortunately, the concept remains one that is firmly rooted in the realms of
fiction, and we do not yet have access to a TARDIS, or a modified Delorean, or a weird demonic rabbit thing to guide us through the space-time continuum.
However, that could be set to change in the future.
Ethan Siegel, an astrophysicist at Lewis & Clark College, believes that time travel might not be so impossible after all. And, according to him, "The place to start is with the physical idea of a wormhole."
In layman's terms, a wormhole is a warp in space-time. It's usually explained in TV shows and movies using the visual metaphor of a piece of paper with a line drawn down the middle; under normal circumstances, time moves in a linear fashion from the beginning point, along the line, to the endpoint. But, if the paper is folded over, and a "wormhole" is poked through, the two separate points of the timeline become linked, and, theoretically, a person can travel from one to the other without following the normal linear rules.
Siegel explains how a wormhole could be formed:
"In our known Universe, we have tiny, minuscule quantum fluctuations in the fabric of spacetime on the smallest of scales ... A very strong, dense, positive energy fluctuation would create curved space in one particular fashion, while a strong, dense, negative energy fluctuation would curve space in exactly the opposite fashion."
If these two curved regions met, they would create a wormhole.
He goes on:
"If this negative mass/energy matter exists, then creating both a supermassive black hole and the negative mass/energy counterpart to it, while then connecting them, should allow for a traversable wormhole.
"No matter how far apart you took these to connected objects from one another, if they had enough mass/energy – of both the positive and the negative kind – this instantaneous connection would remain."
Based on this principle, it should be possible for somebody to enter a wormhole at one point in time, and exit at a completely different one.
"If, 40 years ago, someone had created such a pair of entangled wormholes and sent them off on this journey, it would be possible to step into one of them today, in 2017, and wind up back in time at the mouth of the other one... back in 1978," Siegel says.
However, there is a problem.
"If, 40 years ago, someone had created such a pair of entangled wormholes and sent them off on this journey, it would be possible to step into one of them today, in 2017, and wind up back in time at the mouth of the other one... back in 1978. The only issue is that you yourself couldn't also have been at that location back in 1978; you needed to be with the other end of the wormhole, or traveling through space to try and catch up with it."
Basically, if time travel is ever going to be possible, it will have to be a one-way trip.
However, this would apparently also prevent the 'grandfather paradox' (whereby, if you travel back in time and kill your grandfather, you then negate your own existence, which in turn prevents you from going back and killing your grandfather).
According to Siegel:
"Even if the wormhole were created before your parents were conceived, there's no way for you to exist at the other end of the wormhole early enough to go back and find your grandfather prior to that critical moment."
Honestly, I don't entirely understand it, but this guy seems to know what he's on about.
