Is Time Travel Possible?
Back to the Future, Doctor Who and even in the Marvel Cinematic universe, time travel can be seen almost everywhere we look on our tv screens. We see our protagonist go back in time to explore the wonders of history or to fix a mistake that will lead to an apocalyptic future. But can we take this bit of movie magic and turn it into a reality?
The theory of time travel was first mentioned in H.G Wells novel, 'The Time Machine,’ where our main character travels to the future, to London in the year 802,701 where he finds humanity has split into two different races one subdominant to the other. (I won’t spoil the rest of the book for you, a highly recommended read). This book was pivotal, it planted the idea of time travel into the publics mind and it wasn’t long until scientists started playing with this idea.
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The first scientist to investigate this fantasy of time travel was Ron Mallett, an astrophysicist who devoted his life to exploring the possibility of time travel. Mallet formulated scientific equations and principles that could pave the way for the creation of a time machine.
Mallett's fascination with time travel was sparked at a young age, following the sudden death of his father when he was just 10 years old. His father, a TV repairman, nurtured his son's love for reading and science. One day, Mallett stumbled upon an illustrated version of H.G. Wells' classic novel 'The Time Machine.' This encounter ignited a belief in Mallett that his family tragedy could become a new beginning, setting him on a lifelong journey to understand time. Mallett believes that by creating a loop in time through the bending and twisting of space, it may be possible to construct a wormhole, a tunnel connecting the future and the past. His research took an intriguing turn as he delves into the potential of laser technology in the realm of time manipulation. Mallett proposes the use of a circulating beam of laser light to twist space and time, thus opening the doors to time travel.
Mallett envisions a scenario where a powerful laser creates a circulating beam of light, capable of creating an immensely strong gravitational field that bends and distorts time, (some real Doctor Who shenanigans). By carefully controlling the properties of the laser and its interaction with the surrounding space, he believes it could be possible to create a pathway that allows individuals to journey back into the past.
Building upon his expertise and understanding of laser technology, Mallett has developed a theoretical equation that supports the feasibility of his concept. Through his calculations, he demonstrates that a circulating beam of laser light, with precisely controlled properties, has the potential to act as a gateway to the past.
The Hawking Approach
To me, this seems more like a movie fantasy than an actual reality and I prefer to refer to one of the greatest scientists of the last 100 years for a brief answer to this big question, a more rational approach. Quoting Hawking’s book, ‘Brief Answers to the Big Questions', this is what Hawking has to say on time travel:
Einsteins Theory of General Relativity was a major intellectual revolution that transformed the way we think about the universe. It is a theory not only of curved space but of curved time as well. Einstein interlinked space and time and in a confusing twist of events Einstein wrote a paper that explained that the time and position in space at which one thought an event occurred depended on how one was moving. The time that different observers would assign events would agree if the observers were not moving relative to each other. But would disagree more the faster their relative speed. So one can ask how fast does one need to move in order for the observer to go backward in time relative to the time of another observer.
As it turns out our good friend Einstein also came up with the answer. To travel backwards in time you have to travel faster than the speed of light. Brilliant we can travel back in time to 2015 and put a tenner on Leicester winning the league. Unfortunately in the same paper Einstein explained that for one to travel faster than the speed of light you need an infinite amount of force to accelerate past that point which unfortunately we haven’t quite worked out how to get that, yet….
So if you want to visit ancient Rome, visit your ancestors or warn the Archduke of Austria in 1914 to take a different route all you need is an infinite amount of energy to produce an infinite amount of force. Work that out and you will be traveling through time in no time at all.