(which explains all of special relativity, including time dilation, length contraction, and relative simultaneity) is not a statement for 4d spacetime continuum (since i cannot be used as an independent axis). Einstein & Minkowski made that mistake, and assumed a block universe view in which the past, the present and the future simultaneously coexist! This view is in stark contrast to our everyday experience, as well as with an astonishing number of observations in the whole of science. In fact, an entire book has been written to highlight this fallacy. [The arrow of time: the quest to solve science’s greatest mystery; Peter Conveney, Roger Highfield (Flamingo-an imprint of HarperCollins publishers)].
Again, before I make the incredible claim that our physics appears broken [i.e. the two pillars of modern physics (General Relativity and Quantum Mechanics) appears incompatible] because of our wrong model of the universe, let me shake the mathematical foundation underlying our belief of a (3d) flat universe. We cannot measure the curvature of a 3d (hyper) surface using summation of angles in a triangle. That works for a 2d surface curving in the 3rd dimension. But for our present requirement, we need the sum of solid angles i.e. we need a tetrahedron, and not  a traingle. This has been explained in detail in this paper. The ‘sum of angles of the triangle’ checkup which we had applied to CMB spots is bound to show it is flat! Neither can we measure the curvature of our universe using critical mass/energy density method of General Relativity (General Relativity can measure intrinsic curvature, but not the extrinsic curvature). To see how the conflicting demands of Quantum Mechanics and General Relativity can be easily satisfied, we need the true model of our universe. We must rectify the series of historical mistakes we have made in our mathematics, cosmology and physics. But, for now, let’s come to the title of this paper.
Relativity is inside the light cone phenomena (since nothing can travel faster than light), while Quantum Mechanics is outside the light cone phenomena (allowing instant communications in strongly confirmed ‘quantum entanglement’ experiments, and instant ‘wavefunction collapse’). Both are dictated just by the scale (i.e. whether we use classical/human scale or sub-atomic scale). This recent paper [‘Quantum principle of relativity’; Andrzej Dragan, Artur Ekert, New. J. Phys. 22 (2020) 033098] has shown that every exotic Quantum effect like superposition, entanglement, probabilistic behavior, multiple paths etc. can be explained just by allowing superluminal possibility. The 'inside the light cone' phenomena, and the 'outside the light cone' phenomena together span the entire region within the space and time axes. Only in unison they complete the entire picture. We failed to realize that the same spacetime is getting split into 'space like' and 'time like’ regions based on scale. And the reason behind this is not the magical (?) speed of light. That would have turned both relativity and quantum mechanics into mere branches of electromagnetism. It turns out that the c is the radial expansion velocity of our universe. 
Quantum Mechanics (QM) and Special Relativity (SR) are like two sides of the same coin. But understanding the relation between QM and General Relativity (GR) is a bit tricky, because according to GR, gravity is the warping/curvature of the 4 dimensional spacetime itself. But once we realize that Einstein had mistaken a dynamic 3d hypersheet (composed of fields & particles) moving with velocity c in the 4th dimension in an embedding 4d hyperspace, and had wrongly identified it as 4d spacetime continuum, leading to the wrong ‘block universe’ model, it becomes clear that QM and GR are not really in conflict. It will become clear in the next few paragraphs that GR is an inside view, while this paper presents a divine view (without really challenging the mathematics of GR). This paper does not sacrifice any of the spectacular success of GR and also does not compromise with any of the stunningly accurate predictions of QM. And yet, this paper harmoniously brings QM and GR together (and solves several pressing problems in physics). Just bear in mind that Nature simply cannot afford to make our two greatest theories incompatible. After all, both GR and QM were based on what nature was actually telling us, and nature herself would be accountable for any genuine contradiction (but not for the breakdown of our physics due to our misunderstanding!). For now it is sufficient to realize that SR’s big brother GR only complicates things a bit, but does not become inconsistent with QM altogether. The only difference between the warped spacetime of GR, and the flat spacetime of SR is very similar to the difference between a stretched rubber membrane (RM), with and without a metal ball placed on it. Rather than taking this as an analogy, we should take it quite literally (because the 3d field particle hypersheet or 3d FPHS behave just like a stretched RM). Gravity is not a true force (as correctly guessed by Einstein) but arises due to stretching of this 3d FPHS in the 4th dimension by massive objects. Kindly note that this stretching of the dynamic 3d FPHS also predicts the same gravitational time dilations as predicted by GR (although now it is due to the resolution of temporal component into sin (θ) and cos (θ) components depending on the slope at various points on the stretched 3d FPHS). We don’t need to quantize gravity, as we have already achieved all the necessary quantizations (for Q. Electrodynamics, Q. FlavorDynamics and Q. ChromoDynamics) of the 3d field-particle hypersheet. Unfortunately all modern research towards unifying QM and GR are intensely focused on ‘Quantum Gravity’. The effect of freeing up one dimension is extremely profound. Gravity and (other 3 forces) were fighting unnecessarily. Now gravity gets one extra dimension! Rather than taking the rubber membrane as an analogy, we must take it literally.The RM has already achieved all 3 necessary quantizations. Rather than quantizing gravity, let's just focus on the mechanism which stretches it in the 4th dimension. Let me repeat: gravity is not a true force, and arises due to mere stretching of ‘3d field-particle hypersheet’, and that’s exactly why it is so incredibly weak (hierarchy problem) compared to the three (true) forces of nature. 
Quantum Mechanics (QM) and General Relativity (GR) have been spectacularly successful, but limited to their own domains (i.e. for the tiniest and largest scales respectively). The reason for their limitations lies hidden within the words ‘tiniest and largest scales’. Special Relativity is based on constancy of speed of light for any observer. By basing his theory on this postulate, Einstein unknowingly selected a scale: the classical/human scale and above (i.e. astronomical scale), which uses 3 spatial coordinates and one time coordinate. However, for Planck scale objects, there is only one spatial dimension and three temporal dimensions (i.e. nature’s viewpoint prevails). That's exactly why physicists like Dirac and Feynman were so amazed at how finely tuned Quaternions (which uses 1 real number and 3 imaginary numbers and hence best represents 1+3 spacetime structure) are in describing the physics of the very small. Don’t worry if this concept does not make any sense at all right now. Both QM & GR have a common origin, which can be understood only through the correct model of our universe (which is not the presently accepted model). Physics and cosmology are intimately linked. Consequently, our level of understanding of one of them strongly affects our depth of knowledge of the other.
On the one hand, the greatest challenges facing cosmology today are dark matter, dark energy, information loss (paradox) due to singularity inside black hole etc. which are just the relics of our misinterpretation of General Relativity (GR) of physics. GR is mathematically sound, but is based on a faulty assumption of ‘4 dimensional spacetime continuum’, which is a ‘block universe’ view in which there is no distinction between the past, the present and the future!
All those above-mentioned problems magically vanish when we realize that GR is just the viewpoint of a ‘trapped being’, which is an inside view (hence there is no concept of ‘outside’ in GR). That is exactly why GR can’t predict the global structure of the universe, nor can it accommodate ‘external field effect’ (which has now been confirmed to 11 Sigma accuracy in galaxies and galaxy clusters). Don’t worry: we will not require a fifth dimension.
On the other hand, without the correct model of our universe, physics appears to be broken. Quantum Mechanics and General Relativity (which are our two greatest theories in physics, and the two pillars on which our modern physics rests) seem to be utterly incompatible. This incompatibility arises because we straightaway reject nature's point of view, in which superluminal communication is not only possible, but the only possibility (c becomes the lower limit). Relativity and quantum principles are inseparable twins. There are however other serious issues to deal with (like the ‘time problem’ since quantum mechanics require universal and absolute time, whereas general relativity regards the flow of time as malleable and relative) before any meaningful reconciliation of QM and GR are possible. It will be shown that clock time is associated with imaginary number, while absolute universal time is associated with real number. Mathematically, it is not challenging.
But why does the transition from General Relativity to Quantum Mechanics happens with decreasing size scale? That’s because, this is what is happens to spatial and temporal dimensions at different scales:
3+1 (Classical regime) Û 2+2 (Compton regime) Û 1+3 (Planck regime)
Superluminal phenomena (which gives rise to ‘strangeness’ of QM) is not possible in our human scale, since the Minkowskian coordinate system (3+1) we use simply won’t allow velocity greater than velocity of light. However nature uses superluminal communications all the time (which allows Quantum entanglement’s ‘spooky action at a distance’ which challenges Einstein’s causality and relative simultaneity restrictions). Our mistake was to assume that nature will continue to use our 3+1 spacetime even at the smallest scale.
Relativistic Quantum Mechanics uses the Compton scale lying intermediate between (3+1) and (1+3), and has a spacetime dimension of 2+2  as proved by Ord [G.N. Ord; Fractal space-time: a geometric analogue of relativistic quantum mechanics. 1983 J. Phys. A: Math. Gen. 16 1869].
It was a historical mistake to assume that the physics of the very large (General Relativity) and the very small (Quantum Mechanics) are completely decoupled. The largest and the smallest in the universe are tightly linked as highlighted by the ‘large numbers hypothesis (LNH)’ proposed by Hermann Weyl, Eddington, Dirac et al. But due to the unavailability of knowledge regarding the exact size and shape of our universe, those ratios/relations could not be shown to be exact. The aforementioned tight link manifests itself in IR/UV mixing, and also manifests itself in the ‘unnaturalness’ of the mass of Higgs Boson.
We must go back to Special Relativity, where the mistake of 4d spacetime continuum (block universe view) started, and rectify it. The concept of block universe is due to our faulty understanding of relative simultaneity. We have wrongly used the analogy of a ‘loaf of bread’ that can be sliced at different angles. The logic is: if the observers are in motion then the spacetime loaf would be cut at an angle meaning that an observer’s “now” would be significantly different from each other. This analogy leads to the Rietdijk–Putnam paradox (Andromeda paradox) which rather than supporting the viewpoint, actually exposes how ridiculous it is!
A much more appropriate analogy would be the ‘printer cartridge’ analogy. Although the cartridge moves to and fro on an 1d metal rod, still it is able to print any slanting line (of any angle tilt) on a 2d paper, because the paper is moving. It could also do the same if the 2d paper were held still, and the metal rod moved upwards as the cartridge moved sideways.
The equation