Time travel has been a key component of science fiction for literally hundreds of years. In our reality, or should I say interpretation of it, is time travel actually possible?
Kip Thorne, the most recent Nobel Laureate for physics certainly seems to think so. Thorne theorises that interstellar travel is possible via a wormhole. Thorne worked as an advisor for the Hollywood blockbuster Interstellar and brought this theory to a general audience through the story line of the film.
Our nearest star is Alpha Centauri at a proper distance of 4 light years away. Should a probe from Earth attempt to visit, it would take tens of thousands of years to get there. There are plans to visit this star via the Starshot programme. A micro probe powered by lasers to achieve 1/5 of the speed of light.
Even our most modern probe technology from the Starshot programme would take the probe 20 years to reach this star. So how could we visit there more quickly? If somehow we found a wormhole between here and there.
The broad definition of a wormhole is a tunnel between two points within the galaxy or even outside of it. Should a wormhole entrance be found, this could shorten the time between two points.
I will keep returning to the analogy of a sheet of paper with two circles on it. If you draw a circle on each end of the paper and fold them together until they touch, this is a good representation of the curved nature of the spacetime in which we exist.
The question was asked in the 1980’s, could we actually have a craft enter a wormhole safely and return? It’s one thing finding a wormhole but designing a craft to enter it and see where it leads? I’m no so sure I would volunteer.
The large elephant in the room is the fact that there is no observational evidence that they actually exist.
“We see no objects in our universe that could become wormholes as they age”, Thorne writes in his new book “The Science of Interstellar” (W.W. Norton and Co, 2014).
So the next thought is? Can humanity create an artificial wormhole that can be used as a cosmic highway to take us to different regions of the galaxy? Furthermore can civilisations also use these highways to come and visit us? At the moment I can’t imagine being able to do this given the mass and energy that would be required to warp the space in front of us to travel.
Also, I discussed in a previous post that time travels much more slowly at higher velocities. What may seem a 12h trip for the traveller at the speed of light, 10 or so years will have passed on the Earth. So if you nip to another galaxy for a pint of milk the person waiting for milk in their tea on Earth could be waiting a terribly long time for it.
Maybe time travel for humans is restricted to the boundaries of science fiction. From a personal point of view, would I want to travel given the chance? Probably not.