Is Time Travel Possible?
Time Travel has been one of the most elusive concepts of science for several centuries. The concept has been the heart of several movies and novels, famous fiction examples being “The Time Machine” by H.G. Wells and “A Christmas Carol” by Charles Dickens. “The Planet of Apes” is another flick that immediately crosses the mind. Lately, “Interstellar” has only served to step up the ante and prick our imaginations with double the intensity.
One question still persists: “Is time travel really possible?”
What is the Undoing?
It would be safe to start with the bad news first. It would not be possible to travel back in time and say, observe the Great Pyramids being built again. While in the past century, several scientists have suggested that it would be possible to leap forward into the future or backward in time. Sadly, things that ate not as easy as they read. However, the concept has not been proved impossible either.
Most of the scientific research work on time travel, that is being done today, bears proximity to the ground theories laid by Albert Einstein. Also, works of former scientists like Poincare and Galileo have helped. But Einstein’s propositions of theories such as general and special relativity, have left the most groundbreaking clues for our current crop of scientists.
Einstein-Rosen bridge or the Wormhole could be a feasible option. In 1935, Einstein suggested the existence of forms called the wormholes, in collaboration with fellow scientist Nathan Rosen. While none of these forms have been discovered yet, scientists have come up with their own theories of the working of wormholes. Theories by Thorne and Hawking are the most convincing among these. Thorne has actually had a participation in the science behind Interstellar.
With the assumption that wormholes actually exist, Thorne actually suggested that wormholes can be converted into actual time machines. In Einstein’s theory of general relativity, he suggested that a wormhole could be the bridge between space and time, through which two very distant points can be linked with a shortcut. It has been suggested that there are certain wormholes that could function in both the directions. If one end of the wormhole could be accelerated to the speed of light, the direction of travel can be revered. The other end of the hole has to remain still during this. Owing to dilation, the ageing process in the moving mouth can be drastically reduced.
However, this theory of travelling back in time comes with its own lacunae. One of the first caveats to this is that – there are no wormholes! We need to create them. Once that is done, they would only allow people back to the point when they were created. So the wormholes will not lead us to see the Great pyramids being constructed.
Another serious lacuna in the theory of Time Travel with wormhole would be to the scientific challenge to speed up one of the mouths to match the speed of light. In his 1988 paper, Thorne, along with his colleagues, assumed that modern beings will be able to achieve this feat with the help of gravitational or electronic motion. That does not seem possible just yet.
The Good News
Over the last few years, many of the aspects in Einstein’s theory have come true. The most enthralling among these is the effect that is commonly known as time dilation. While the theory has been the basis for several technologies over the past decades, an experiment in 2014 revealed that time dilation is real. Dilation is also the phenomenon that could pave the way for future time travel.
Dilation, or time dilation is the idea that suggests the relatively slow passage of time in a moving clock when compared to a stationery clock. The elapsed time difference is also affected by the gravitational force. With the increase in magnitude of gravity and velocity, a higher time difference can be achieved. Owing to their extraordinary gravitational pull, black holes (like the ones in Interstellar) can produce a great measure of dilation.
Given the dedicated effort of the space program, we have experienced the effect for several years now. This explains why the space station clocks are just a tad slower that the ones on Earth. Owing to the fact that these space stations are affected less by gravity, time seems to fly away more quickly. This also explains why earth’s surface clocks are not absolutely accurate.
GPS satellites offer better examples of time dilation. Smartphone GPS chips work with the help of 24 satellites that keep circling the globe at all times. These satellites encircle the location based on how long it takes information to travel back and forth between the device and satellites.
But the clocks in the satellites are a touch faster owing to the high speed with which they move in the orbits. They lose some microseconds in a day. To adjust the time lapse, scientists employ a complicated equation that tunes the GPS chipset with the satellite clocks. Otherwise, the location data could simply be thrown out of the kilter.
The implication of this could be huge: If you manage to jump into a spaceship that flies at the speed of light and take a tour of the galaxy, by the time you return to earth, a good two-three generations of the human race would have gone extinct. This is exactly what happens in “Planet of Apes.”
The Super Possible
The question persists: Can this extreme be really reached. And will it be also possible to travel back in time through some other procedure?
The answer again rests in the oblivion. The theories by Einstein have largely sidelined the possibility of revisiting the past. But these were theories by one individual. For the wormhole, no one has ever tried it yet and we have no idea on how to build it in space in imminent future.
A better way to delve into the subject is to look for time travelers that are amongst us. A string of zany scientists have tried exactly the same. No success yet, but we are never too far, are we?