If you have seen the new and misnamed movie, The Theory of Everything, you will learn that Stephen Hawking, just before his ALS disease erupted, mathematically developed the idea of "time" starting at the Big Bang, by mentally running the arrow of time backward to its point-like origin. The singularity idea itself was from Roger Penrose, so the idea of black holes is called the Penrose-Hawking model.
Shortly after Hawking was forced into a wheelchair, but when he still could talk with his own voice, he developed the idea of what we call Hawking radiation. That idea explains how photons leak from black holes (making them not fully black) at their event horizons, eventually emptying the black hole. This radiation is a quantum process that may take many billions of years for supermassive black holes to dissipate.
Dr. Hawking has long been looking for the perfectly simple math equation that clearly explains in detail everything in a theory of everything. Einstein could not find it, nor will Hawking or any others within today's cosmology establishment find that mythical formula. A new paradigm is required.
Once we myopically hypothesize that our/the universe began with a big bang, everything that happens thereafter follows an arrow of time. There is a "beginning," and there is an "after." This tunnel-vision idea requires rejecting the timeless reality of the Multiverse Universe, within which our universe resides. Once the Multiverse is embraced, any beginning within any one universe is just the start of another "local" process within the Multiverse/Universe. The Multiverse is timeless, because there is no one beginning and no one end point; however, there are time arrows within individual universes.
One support for directional time is the Second Law of Thermodynamics. Multiple experiments in closed systems have supported the idea that the past is low entropy (ordered), and the future is high entropy (disordered), a concept known as "thermodynamic time asymmetry." The idea is that there is maximum order (negentropy) at the beginning where heat (and capacity for work) is highest. Over many billions of years the heat of everything diminishes, and thereby we settle into an eternal state of disorder (entropy), or thermal equilibrium, which is the effective death of the universe. In this way, time is the arrow from order to disorder.
Order and disorder are general concepts, whereas entropy is a subset, and is specific: a thermodynamic quantity representing the unavailability of a system's thermal energy for conversion into mechanical work, often interpreted as the degree of disorder or randomness in the system. In this way something that appears to be increasingly ordered, could also be increasingly disordered (entropic), if the energy is less available for work. Up close this idea is weird, but it "makes sense" on a local universal level.
Fortunately, the omnipresent Law of Conservation of Energy and Matter re-energizes every sub-universe at its big-bang creation, so there is no reason for entropy to ever conquer all within the Multiverse. Also, the idea of equating highest heat with highest order is somewhat counterintuitive, but that's how the Second Law works. Again, the question arises as to what came before the very first highest heat/order. This question can only be answered with a god, or cosmic deus ex machina. The next question arises as to how and when that god force got its order above order. The only logical answer would be an unmoved mover beyond motion, and therefore beyond time.
Much error in physics and astrophysics comes from errors of perception. We like to talk of relativity, and Relativity; but there is little fidelity for the need to really think relativistically. We talk of frames of reference, but then also talk about the absolute maximum speed within our universe, "c", the speed of light in a vacuum.
Photons have been hypothesized to have only energy without mass. However, photons are influenced by gravity, and by their passing through, or bouncing off of non-vacuums such as mirrors. A pure energy packet would ignore or penetrate these. Photons appear to have mostly energy, but also some matter/mass. When you understand this simple truth, then you can understand the incompleteness of Einstein's most famous equation: e=mc2.
Newton explained that for every action there is an equal and opposite reaction. An object in motion or rest will stay that way until moved with force. The key to all this is inertial mass, not energy alone. Any "object" without inertial mass is impossible. From a Taoistic understanding of the Law of Conservation of Energy and Matter, mass and energy are interpenetrating and fully interchangeable, but also dual in that they both exist at all times. The two are one. Einstein's idea of energy being equal to mass times the speed of light squared assumes instantaneous acceleration, as there is no explicit acceleration factor in this equation.
The idea of time dilation and time compression follows from this error. The error comes from Einstein's Special Theory of Relativity, where there are TWO INERTIAL FRAMES: that of the object, and that of the observer. Strictly speaking, all objects are always at rest within their self-referential frames of reference. It is only by the perspective of another frame that motion is to or from.
To take ANY mass at all, and accelerate it to ANY non-zero speed, in ZERO TIME, you will need an INFINITE AMOUNT OF ENERGY. The reason that the speed of light in a vacuum is always "c" is precisely due to (1) the amount of mass in a photon, (2 ) the force launching that photon, and (3) the duration of the launch. That duration's time is expressed as "T." Within Einstein's formula, photonic acceleration duration is T=1, so it is not written.
Instantaneous equals zero time, or zero T. Infinite time of acceleration equals infinite T. Zero rate of acceleration over infinite time requires zero force. Instantaneous acceleration requires infinite force. So, how is "c" the speed of light?
The speed of light is a function of the time of acceleration of a photon as it stretches and pops from its source, times the mass of the photon itself. The force can be derived from these two. Depending on your perspective, that force can be great, or minimal. After all, a single photon does not have much mass, but the top end speed is achieved in almost zero time, so the force to accelerate even one photon is relatively large.
Each photon (or gluon) is composed of a string of YY particles, which individually are three orders of magnitude smaller than gravitons. Gravitons vibrate, and at a certain frequency they release each photon string. The frequency-related type of light energy is dependent on the number of YY particles in each photon. Short strands populate the areas above ultraviolet. Longer strings populate lower frequencies associated with waves below infrared. The speed of "c" is nevertheless the same for all released YY strings, due to the identical elasticity of each YY particle. Each stretched particle snaps away from its graviton base at the same rate, and they all snap away together at the same rate.
Therefore, the proper formula is not e=mc2. The proper formula is e=mc2/T. Einstein's original formula assumes a particular acceleration to get to "c" in a vacuum, which operates over a very short time, so here T=1. If we write the new formula with the force and time needed to launch a photon, it would be e=mc2/1. That, of course, is the same as e=mc2.
Many "time-related" things flow from this simple truth:
(1) Billions of dollars have been spent on CERN's large hadron collider (LHC) because the electro-magnetically powered "gun" protons are in a different inertial frame from the targets. An increasingly large force must be used to propel massive protons nearly instantaneously to their target. The giant accelerator just sits there in its inertial frame, as with each new pulse of energy it tries to accelerate protons ever faster. If the "proton bullets" were photons, then the force needed for each would be much less. A perfect example is the recent invention at the DOE's Berkely National Lab of a table-sized laser photon accelerator producing more acceleration energy than the giant LHC.
(2) Special Relativity's narcotic lure is the idea that time itself changes with speed approaching "c." Time does indeed APPEAR to do this, from the observer's frame of reference. This is precisely because doppler-shifted light coming to us from the receding object in the other frame also must accelerate, but it can only move toward us at its launch speed from within that launch inertial frame. The amount of doppler shift is "c" minus the object's speed away. Thus the appearance of time and shape shifting. This is an illusion. Remember that the object at any point of time within its own moving frame is at rest (see Zeno's "paradox of the arrow.")
(3) A corollary of the above is what would happen when what we are looking at continues to accelerate. There is absolutely nothing (no vertical wall of time) stopping a slow acceleration of any object over a long period, such as a nuclear pulse-powered spaceship. That means such a ship could accelerate at, say, 1g (the rate we accelerate to the Earth from where we stand). Eventually the ship would go faster than light could travel to or from it vis-a-vis the original point of origin on Earth. That is, the approaching "c" is exceeded by the retreating object. In other words, the spaceship would eventually vanish from us, while not really vanishing at all.
All this movement, within the currently popular theory, implies that we on Earth would get older, and the residents of the space craft would age normally. However, an equal return trip, with equal g-forces, would reverse the apparent time differences. Net result is no change in our ages between the two original frames of reference -- we the observers, and they the travelers. (From their perspective, we could be the travelers, and they could be the observers. The math works in both directions.)
The bottom line is that time is not a metaphysical concept. It merely describes motion between at least two frames of reference. It can be very local, or it can be inter-galactic, even inter-universal. At the inter-universal we enter into the greatest realm of traveling photons, gravitons, and YY particles. Gravity itself is not metaphysical. It simply measures the motion of gravitons between frames of reference, however distant.
NONE of these motions necessitates multiple dimensions beyond the basic four (l,w,h, and duration). None of these inter-universal flows generate branes, worm holes, or other popular exotic phenomena. From a Universal perspective all motions in the Multiverse cancel out each other, so that net Universal time does not change, even while there are myriads of inter-frame time arrows. Universal time is "time above time," precisely where an unmoved mover would reside.