A doctoral student has recently published intriguing new research which has detailed a very simple and elegant design for a time machine. But could it work and is time travel really possible? According to physics professor Gaurav Khanna, from the University of Massachusetts, Dartmouth, the answer to whether time travel works is yes, as we continue to march forward in time from second to second.
But if we wanted to actually propel ourselves much further ahead in time, we would need to either approach the speed of light or travel close to a black hole, so that as time slowed down enough we would be able to jump ahead into the future. However, the big question is whether we could ever build a time machine and go back in time to explore the past. As Science Alert reports, doctoral student Caroline Mallary, who is one of Khanna’s students, has just published the model of a time machine and demonstrated that with the right objects, traveling back in time really is possible.
Describing the theory of time travel, Khanna explained, “Einstein’s general theory of relativity allows for the possibility of warping time to such a high degree that it actually folds upon itself, resulting in a time loop. Imagine you’re traveling along this loop; that means that at some point, you’d end up at a moment in the past and begin experiencing the same moments since, all over again – a bit like deja vu, except you wouldn’t realize it.”
Doctoral Student Just Published a Paper Describing How Time Travel Would Be Possible https://t.co/MP2XPORsL9— ScienceAlert (@ScienceAlert) December 14, 2018
Over the years, many physicists from Stephen Hawking to Kip Thorne have published research on time travel and time machines, and the conclusion appears to be that time loops of the kind that Einstein described are just not possible. Hawking illustrated why this is very succinctly in Chronology Protection Conjecture, which describes how nature has made it so that humans can’t travel backward in time, as if they did so many paradoxes would occur that these humans would almost certainly cease to exist by even performing such an experiment.
To achieve a time loop of the kind described by Einstein, exotic material would be needed, and this exotic material would need to contain negative mass.
However, Mallary believes that her time machine is truly viable, as you do not need any negative mass exotic material to use it. In her time machine, Mallary uses two extremely long cars constructed out of materials which contain positive mass, rather than negative, and these cars have been parallel parked in her paper. As one car rushes forward swiftly, the second car has been left behind, still parked where it was. Once the setup has been properly performed, the space that exists in between these two cars acts as a kind of time loop.
But if you are thinking of building Mallary’s time machine for yourself, you may want to think again, as for time travel to work, each of the two cars in the time machine model must contain infinite density within their centers.
As Khanna noted, “That means they contain objects – called singularities – with an infinite density, temperature and pressure. Moreover, unlike singularities that are present in the interior of black holes, which makes them totally inaccessible from the outside, the singularities in Mallary’s model are completely bare and observable, and therefore have true physical effects.”
As physicists don’t believe that objects like this can be found in nature, Mallary’s time machine unfortunately won’t be able to be tested anytime soon, but it is nice to know that one could be built if such objects could be found and shown to exist in nature.
The new research on building a viable time machine for time travel has been published in Classical & Quantum Gravity.