Time Travel and Time Machine is a reality

Astrophysicist Ron Mallett believes he’s found a way to travel back in time — theoretically.

The tenured University of Connecticut physics professor recently told CNN that he’s written a scientific equation that could serve as the foundation for an actual time machine. He’s even built a prototype device to illustrate a key component of his theory — though Mallett’s peers remain unconvinced that his time machine will ever come to fruition.

To understand Mallett’s machine, you need to know the basics of Albert Einstein’s theory of special relativity, which states that time accelerates or decelerates depending on the speed at which an object is moving.

Based on that theory, if a person was in a spaceship traveling near the speed of light, time would pass more slowly for them than it would for someone who remained on Earth. Essentially, the astronaut could zip around space for less than a week, and when they returned to Earth, 10 years would have passed for the people they’d left behind, making it seem to the astronaut like they’d time traveled to the future.

But while most physicists accept that skipping forward in time in that way is probably possible, time traveling to the past is a whole other issue — and one Mallett thinks he could solve using lasers.

Time one or many things?

When we think of time we think of it as just one thing, the ticking of the clock. But time has a number of properties and not all of them vary together, nor are all of the properties of time necessarily continuously present. Some properties can be at zero, null, indeterminate or absent altogether.

Let’s start with an example of a property that has actually been dropped from the concept of time, that of ‘Cyclic Time’. Jump back even a few hundred years and this would not only have been considered a natural property of time but an essential or even fundamental property. Everything in the ancient observable world is cyclic.

Indeed, ‘Simple Harmonic Motion’ is still one of the cornerstones of physics and SHM is seen throughout the physical world. SHM can not exist independently of time, but time can exist without SHM as far as we can tell.

If we can drop SHM from time simply because time can exist without it then what of the other properties that time can live without, at least under some conditions?

At the quantum scale when considering single quantum events we note that there are no components of entropy present. The test for the absence of this property is a hypothetical video of a single interaction or an animation based on the data: could we or anyone else tell if the video clip was being played forward or backward? If not then the entropy property is absent. But what of a spatial extension that contains nothing above the quantum scale? Time is still present in the form of spacetime ~ space isn’t completely flat anywhere so the bit of curvature present needs the temporal dimension to describe it. But there is no entropy. Even the virtual particle, the quantum noise, can proceed in either direction.

So there we have two examples of where entropy, and therefore the arrow of time and even the time line are not present. As with cyclic time, each of those concepts can not exist independently of time, that is, entropy can not proceed independently of time.

The interval is another example, as is change and relative time. So what property of time is essential? There must be at least one property of time present for time to be said to be present, but it doesn’t matter which one. A photon can flit across the universe without accumulating an interval of any duration at all, so change can occur without a local interval.

In our usual experience, all the properties of time, including the cyclic component, are present and so it is an effort to imagine time without even one of the properties. As we probe into the physical world, some properties can be dropped or minimised but no property is always present in all conditions, the closest would be relative time as the observer’s clock ticks on regardless of any philosophical musings and so is readily compared to all other clocks in real and hypothetical conditions.

New Research Shows That Time Travel Is Mathematically Possible

Physicists have developed a new mathematical model that shows how time travel is theoretically possible. They used Einstein's Theory of General Relativity as a springboard for their hypothetical device, which they call a Traversable Acausal Retrograde Domain in Space-time (TARDIS).

BENDING TIME

Even before Einstein theorised that time is relative and flexible, humanity had already been imagining the possibility of time travel. In fact, science fiction is filled with time travelers. Some use metahuman abilities to do so, but most rely on a device generally known as a time machine. Now, two physicists think that it’s time to bring the time machine into the real world — sort

“People think of time travel as something as fiction. And we tend to think it’s not possible because we don’t actually do it,” Ben Tippett, a theoretical physicist and mathematician from the University of British Columbia, said in a UBC news release. “But, mathematically, it is possible.”

Essentially, what Tippet and University of Maryland astrophysicist David Tsang developed is a mathematical formula that uses Einstein’s General Relativity theory to prove that time travel is possible, in theory. That is, time travel fitting a layperson’s understanding of the concept as moving “backwards and forwards through time and space, as interpreted by an external observer,” according to the abstract of their paper, which is published in the journal Classical and Quantum Gravity.

Oh, and they’re calling it a TARDIS — yes, “Doctor Who” fans, hurray! — which stands for a Traversable Acausal Retrograde Domain in Space-time.

FEASIBLE BUT NOT POSSIBLE. YET.

“My model of a time machine uses the curved space-time to bend time into a circle for the passengers, not in a straight line,” Tippet explained. “That circle takes us back in time.” Simply put, their model assumes that time could curve around high-mass objects in the same way that physical space does in the universe.

For Tippet and Tsang, a TARDIS is a space-time geometry “bubble” that travels faster than the speed of light. “It is a box which travels ‘forwards’ and then ‘backwards’ in time along a circular path through spacetime,” they wrote in their paper.

Unfortunately, it’s still not possible to construct such a time machine. “While is it mathematically feasible, it is not yet possible to build a space-time machine because we need materials — which we call exotic matter — to bend space-time in these impossible ways, but they have yet to be discovered,” Tippet explained.

Indeed, their work isn’t the first to suggest that time traveling can be done. Various other experiments, including those that rely on photon stimulation, suggest that time travel is feasible. Another theory explores the potential particles of time.

However, some think that a time machine wouldn’t be feasible because time traveling itself isn’t possible. One points to the intimate connection between time and energy as the reason time traveling is improbable. Another suggests that time travel isn’t going to work because there’s no future to travel to yet.

Whatever the case may be, there’s one thing that these researchers all agree on. As Tippet put it, “Studying space-time is both fascinating and problematic.”

References: ScienceAlert, IOP Science, Phys. Org