PRISONERS OF TIME?

COVER STORY

For centuries, the entangling concept of time has entranced humans. Time has remained constrained to a precept that is abstract in nature and is deeply rooted in the philosophical and scientific arenas alike. The concept of time has been romanticized by literary maestros like Shakespeare, evidenced by the renowned literary play Romeo and Juliet which equates the passage of time to the strength of the force of love. However, physics is logic-driven and renders the romance-induced interpretation of time obsolete.

The comprehension of time has evolved in tandem with the cognitive development of humans, and its logical manifestation has experienced a seismic shift over the passage of millennia. Until the 16th century, the understanding of time was driven by philosophy, demonstrating nuanced scientific grounding. A constellation of academics, including Plato, Aristotle, and Ibn-e-Sina, all proposed a philosophical interpretation of time that associated it with the passage of cosmic events. This school of thought considered time as an entity governed by an abstruse force rather than deeming it a physical quantity.

Newton postulated that time was an absolute physical quantity and rendered a core concept that was affiliated with the omni structured nature of time across the universe. Newton’s theory was a far departure from the philosophical interpretation of time and suggested that absolute time was an extrinsic quantity not driven by the occurrence of any specific event. Newtonian time – acting as an absolute entity and depicting no tandems with space (representation of traversable physical quantities) and the perception or motion of an observer entity – was widely accepted as a logical rationale, but it conflicted with Newton’s theory of absolute and relative time. Newton furthered the principle that humans are unable to perceive absolute time and thus can monitor time solely via tools and techniques, and this led to the subtle concept of relative time.

In 1905, Einstein refuted the Newtonian interpretation of time being an absolute-natured entity and proposed the relativity of time and its perception being intertwined with the motion of an observer. Einstein envisioned that an observant entity depicting motion at a constant speed (non-accelerating reference frame) experiences the passage of time at a different rate as opposed to an observer monitoring time while stationed in a state of non-mobility.

Einstein also proposed the detection of non-simultaneous events by an entity depicting motion in the “non-accelerating reference frame”. One facet of this theory that contrasted the relative nature of all the preceding postulates was the uniformity of expression of principles of physics and speed of light across the manifold reference frames. In short, light travels at a constant speed of 300,000 km per second and the laws of physics depict uniform applicability. To demystify the complexities, one can perceive two twins who are part of an experiment. If one twin travels onboard a spaceship at speeds equivalent to the speed of light, time for him would progress at a receding rate with respect to the reference frame housing the counterpart twin. Upon his return, the twin would have aged significantly less as opposed to his Earth-bound twin.

In 1915, drawing inspiration from Minkowski’s interpretation of the unitary nature of space and time, Einstein proposed the general theory of relativity, which was based on the expression of time within an accelerating reference frame. Einstein proposed that the warping or bending of the fabric of space-time depicting a 4D continuum spatial structure (time being the fourth dimension) by a cosmic body is attributed to the manifestation of the force of gravity. This bending of the space-time fabric architectures the orbit of the surrounding cosmic bodies. For example, the wrapping of the space-time fabric caused by the Sun is responsible for the orbital structures and behaviour depicted by planets of the Solar System. The extent and geometry of space-time is attributed to the energy and mass of the body. This tenet of the theory has been validated by analysing the existence of a strong force of gravity across the premises of a bulky-natured cosmic body like a star and vice versa.

Einstein postulated a radical theory pertaining to the elongation of the passage of time near the vicinity of a supermassive cosmic structure like a black hole due to the extreme warping of space-time. The extreme bending of the fabric affects not only the spatial structures but also the behaviour of time. This is one of the primary reasons why time progressed at a stagnated rate at Miller’s planet featured in the movie Interstellar – the proximity of the planet to the Gargantua black hole that exerted immense gravitational force due to the extreme curvature of the space-time fabric was the source of time-dilation.

Comprehension regarding the unitary nature of time and space expressed in a 4-D coordinate system contradicts with the capability of humans to perceive the 4th dimension of the Minkowski space-time system. Neil deGrasse Tyson has summed up the dilemma associated with traversing the 4th dimension by free will by stating: “We are prisoners of the present, forever transitioning between our inaccessible past and our unknowable future.” In essence, humans can navigate the traversable 3D space dimensions of the Minkowski space-time system but are mandated to charter the time dimension via a pre-stipulated forward direction only. However, physicists have developed hypothetical frameworks empowering humans to embark upon time-traveling expeditions.

Wormholes render an exciting prospect to traverse through diversified timelines and spatial points. A wormhole is a hypothetical structure that was first postulated by Einstein and Rosen in 1935 and was labelled as an Einstein-Rosen bridge that aimed to address the complexities aroused by the concept of singularity. While the ER bridge is non-traversable due to the collapse of the throat under the confluence of gravitational forces, pioneering work in theoretical physics has now enabled the hypothetical development of traversable wormholes. Wormholes encompass two mouths connected via a throat. The mouths can be conceived as two distinct points in the space-time system and the extreme curvature of space-time can forge a tunnel-like structure that connects the two mouths. If one mouth is placed at the periphery of a black hole, then that mouth would experience time dilation, with the counterpart mouth depicting relatively low time dilation behaviour, thus making time travel possible via the throat. Such extreme warping can only be expedited by supermassive structures like a black hole whose gravity can curve the fabric of space-time.

The hypothetical manifestation of a traversable wormhole is ascribed to the postulation of the Morris–Thorne wormhole that addressed the scientific ambiguities associated with the ER bridge. To obviate the collapse of the wormhole structure, the MT wormhole structure incorporates the concept of exotic matter which showcases negative energy or mass to counteract the forces of gravity within the structure of the wormhole. However, our universe is devoid of exotic matter, and such a structure is strictly hypothetical.

The infatuation of the research community with traversing the labyrinth of time has extended to the domain of quantum mechanics too. In a bid to unravel the time-traversal behaviour of a basic unit of quantum information theory, called qubit, the Deutsch CTC (Closed Timelike Curve) was proposed in 1991. This model proposes that a qubit from the future can loop back into its past by traversing through the CTC and interact with its past. However, this model thrives on the concept of self-consistency that warrants the stability of the interacting qubit and permits only those interactions that were stipulated to occur by nature. If the past qubit (CR-Qubit) is warranted to depict a spin of zero but the future CTC-Qubit interacts with the former in such a way that it alters its spin to a state not akin to the pre-postulated one, then the system would block such interactions to prevent paradoxes. This theory and model can be incorporated to facilitate information sharing through different timelines.

I would like to conclude this article with a quotation attributed to Einstein, “The distinction between the past, present, and future is only a stubbornly persistent illusion”. It’s now up to us to unravel the mystic nature of time.