Therefore, ds/dt = i.c
Therefore, every frame of reference reaches the same conclusion. The presence of i clearly shows that everyone is moving with a velocity c in a perpendicular direction to all three x,y and z axis (which is an impossible direction for every observer trapped in this 3d FPHS. Why impossible direction? Well, just try to point your finger towards the future or towards the past. That direction is perpendicular to every direction we can point our finger at). The lack of understanding about i=sqrt(-1) had led scientists to conclude that the velocity is imaginary (and hence discouraged from digging deeper). They simply concluded that our spacetime is very peculiar (hyperbolic), without questioning why this peculiarity arises after all.
But every frame of reference can reach the same conclusion only if the entire 3d FPHS is moving in the same direction. That’s why I emphasized 3d FPHS (instead of 3d space). A 3d space moving through 4d hyperspace doesn’t make any sense! But a 3d FPHS moving (at velocity c) through 4d hyperspace does make sense.
The sharpest minds of the last century had smartly figured out that we are all moving at the velocity c (speed of light) through space-time.  But they failed to reach the correct conclusion, which is: every observer (or every frame of reference) is moving with a velocity c in one single direction (the real-time/universal time direction) irrespective of its location or velocity in the 3d FPHS. We are all travelling at 1079 million kilometers per hour! (That’s right. It is 670.6 million miles per hour). That’s how fast we are all moving through (hyper) space.
If we ignore the dynamic nature of the 3d FPHS (which seems natural to trapped ‘flatlanders’ like us), then our world indeed appears 3 dimensional and Euclidean  ds2 = dx2 + dy2 + dz2 , just as Euclid himself thought. 
As an immediate consequence of making the (4d spacetime vs dynamic 3d FPHS) correction, one dimension got freed up (which we were reserving unnecessarily). Kaluza’s miracle of obtaining Maxwell’s equation in addition to Einstein’s field equations seemed to demand a heavy price: a 5th dimension was required as an embedding space. Actually, 4 dimension is sufficient (and we get electromagnetic phenomena as a bonus!). In fact, the implications of freeing up a dimension is much more profound, and solves the requirement of a fifth dimension popping up everywhere in physics (but stringent limit on the number of dimensions set at four from experiments & observations simply won’t allow that).
Since every star and planets and even ourselves are ultimately made up of particles (which are mere excitations/resonances in the 3d FPHS fields), therefore, every bit of matter is eternally trapped in this 3d FPHS, and is getting dragged with it. Every particle is guided by its own pilot wave generated in widely spread field (as correctly guessed by deBroglie and Bohm) and the collective pilot wave fields create this 3d FPHS. Gravity is not a warping in 4d spacetime, but a stretching of this 3d FPHS (by massive objects) in the 4th dimension. Every normal baryonic matter has a natural tendency to move towards the future (away from the center of the universe). This 3d FPHS behaves just like a stretched rubber membrane, and all massive objects nearby stretch this membrane in a single direction, thus enormously amplifying their collective stretching. This magically solves all dark matter related issues as we will soon see.
We have another piece of the jigsaw puzzle: The 3d HS is also getting stretched (Hubble’s law) as it moves in the 4th dimension. From previous discussion, and this clue, two models of our universe are easily possible: expanding grid model, and hyperballoon model.
Here is another piece of clue which finally nails it: Our universe does have has a Centre (although the Centre does not lie anywhere in our 3d space or 3d FPHS). This can be easily proved:
The Centre of Mass equation is a powerful equation.  In the vastness of our cosmos, we can consider each galaxy (or maybe a galaxy cluster) as a point mass. Even as the number of galaxies tends to infinity, we are still left with a single point center of mass. Simply invoking infinity isn’t going to help us escape from the conclusion that there is indeed a Centre. And what’s more, the above formula works irrespective of the number of dimensions, or whether all the point masses are located on a flat surface, or a curved surface (or even an irregular shaped corrugated surface).
Applying pure logical reasoning we can construct the true model of the universe: an expanding (hyper) balloon universe.
The theoretical Hubble constant value (71.002 km/s/Mpc) matches very well with accepted values (between 69.8 km/s/Mpc and 74 km/s/Mpc).
Objections which might be raised against this model all fail miserably. Here are some objections:
1) Measured flatness of universe from Cosmic Microwave Background CMB using summation of angles of a triangle. [Already explained that we need a tetrahedron, not a triangle]
2) Accelerated expansion of universe rather than constant rate of expansion. [Explanation: Recent studies using much bigger dataset actually favor universe’s constant rate of expansion over accelerated expansion. Why the illusion of accelerated expansion arises have also been explained. This solves the problem of dark energy: we don’t need dark energy, since we don’t have to account for acceleration.
3) Observable universe is itself 94 billion light years across, and hence entire universe must be much bigger. [This argument fails too].
The radial expansion velocity c of the universe introduces the concept of rest-mass momentum (p=m.c) which greatly simplifies and unifies physics. [Haug E.; Better Quantum Mechanics? Thoughts on a New Definition of Momentum That Makes Physics Simpler and More Consistent. Preprints 2019, 2019010042 (doi: 10.20944/preprints201901.0042.v2)]. In fact, it also explains the origin of rest-mass energy (E=mc2), since the energy (E) and momentum (p) are always related as E=p.c (as shown by the author Haug E.)
From the center of our universe (the point where the Big Bang happened) we have absolute simultaneity as demanded by the Sagnac effect (because the universal time elapsed since the Big Bang is simply a function of universe’s radius), and absolute universal time (as Quantum Mechanics demands. This solves the ‘time problem’ in Quantum Mechanics which stubbornly resisted all attempts to reconcile it with General Relativity).
Physics and cosmology are intimately linked (e.g. conservation laws of Physics arise from symmetry of our universe, as per Noether’s theorem). We can directly see from this simple structure of our universe, why those symmetries (e.g. homogeneity and isotropy) arises in the first place.
We humans experience 3+1 spacetime dimensions, where the 3 spatial dimensions are curved lines (drawn on the surface of a hyper balloon). However each tiniest point in the wall of the balloon universe becomes (1+3) timespace [i.e. Quaternion/superluminal] when viewed from the center of our (hyper) balloon universe, since there is only one real spatial dimension (i.e. the radius of the universe) from the center of the universe to that point. As explained later, temporal dimension is that dimension along which any movement can be ignored. For example, we can easily ignore the tremendous velocity with which we are traveling along the radius of the universe. In a similar manner, nature/universe ignores movement along the wall of the balloon whether we travel to the moon or to the sun or to the Andromeda galaxy, because the moon, the sun, and Andromeda galaxy are all equidistant from the true center of the universe.
As expected, the reconciliation of our two best theories improves every aspect of modern Physics [e.g. ‘Principle of Least Action’ which comes closest to the ‘theory of Everything’ in physics, and from which, all known laws of physics can be derived, arises as a direct consequence of the better model of the universe as proposed in this paper.
The list of achievements in this paper is simply too long to be detailed here in the Abstract (which is already too long. I beg your apology. But this paper concerns our entire universe, and every span of physics and cosmology. I thank you for your patience). For example, the Black Hole information loss paradox also gets resolved.
Thus, a better understanding of imaginary numbers lets us realize that our ‘clock time’ is imaginary. It also explains the true meaning of Wick rotated, Euclidean time (wrongly called ‘imaginary time’) which is so ubiquitous in physics. It becomes crystal clear why Physicists like Dirac & Feynman were so puzzled that ‘imaginary time seems more real than real time’! In fact, many more problems/paradoxes gets resolved together.
From this model, we can see that there are two viewpoints involved. From our viewpoint, locality is absolute, while from the center of the universe viewpoint (nature's viewpoint) simultaneity is absolute. We can finally decipher nature’s deepest secret. Nature does not use two separate rule books, but two different viewpoints. Everything, from the tiniest quark to the Galaxy clusters is telling one single story. Relativity and quantum mechanics both have a common origin. Entire Physics & Cosmology is united.
My aim in this paper is to show that the pillar is the leg of the elephant, the pointed spear is its tusk, the rope is it tail, and the rubbery mattress is its ear.