It's Official: We Were WRONG About the Big Bang

Spacetime is an emergent property of hyper-quantum field excitation interactions and not fundamental, so the universe doesn't have to have always been infinite in order to be infinite now.  Pre the "Big Expansion", space and matter didn't exist, and all energy was in a field state too high for excitations to interact.  Fluctuations in that hyper-dimensional energy field caused some of the energy to drop state into a lower energy level, allowing for the first field excitation interactivity (fundamental particles) to occur, triggering a "cascade" of new space formation and displacement.  The Big Expansion happened "everywhere" because this energy transition literally CREATED spacetime through the newly possible particle stability and subsequent interactions.

This energy transition is still happening in a cascade of entropy, which is what is driving Cosmic Inflation.  Dark energy is just energy emergence at lower field states, increasing the number of field excitations in overlapping quantum fields, and forcing the creation of more space to accommodate them.  

As a result, gravity itself may simply be the result of stable mass essentially being entropically inert and due to its innate stability, taking on a property akin to a sort of "resistance" to Cosmic Inflation.  As new space is made, space occupied by stable matter doesn't expand (or at least, not at the same rate), creating an acceleration gradient proportional to the amount of mass resisting the expansion, rather than to the rate of space creation.  This also explains why gravity is so weak relative to the other forces, but cumulatively powerful in its effects on spacetime.  Earth has enough mass to resist Cosmic Inflation and create an acceleration gradient equivalent to 9.8m/s^2.  Antigravity would work by equalizing or neutralizing the local amount of inflation.  Furthermore,  if warp travel ever became a reality, it would be extremely dangerous technology due to the nature of uneven inflation gradient distribution left behind by moving warp bubbles.  

Lastly, the reason a quantum theory of gravity doesn't exist is that gravity is a characteristic of an energy state that emerges BECAUSE of the emergence capability of matter in the formative hierarchy of matter and energy formulation. Spacetime and energy don't exist in the same way we experience them on the macro, hyper-interactive, classical scale.

Here's a Fun Fact as a side-note:  It is just as impossible to move backward through space as it is to move backward through time.  You are always moving positively along a dimensional vector, and your orientation is irrelevant.  If you walk backward, you're not actually MOVING backward, you're moving forwards while facing backward.  ALL dimensional movement is positive.  In order to move backward through space, you'd have to also move backward through time.  It's like this... all movement in linear spacetime is positive in all dimensions/directions because you are moving away from an origin point.  Time and the relative distance from that origin point go up as you move through spacetime.  In order to move backward, you'd have to move TOWARD an origin point.  Even if you reverse direction and travel directly along the path you were just on, you're not moving backward, you've simply reoriented your origin point to the locus of the change in your direction.