there never WAS gravity, eg a linear force pushing or pulling things. there is only spacetime (more of a solution, or material) and mass, which is king - and therefore, energy is king.
energy is simply when 'momentum is transferred through a field to other bodies'. energy is a property OF matter. matter HAS energy, and matter can express this energy in various different ways.
energy also comes in FLAVORS, in that many different flavors of events can all result in the same ol 'energy'. one flavor is called mechanical or thermal energy. nuclear, gravitational, etc. but no matter what, energy always just seems to be MASS MOVING AROUND. mass moves, implying distance over time. now 3 variables can be affected by energy, and indeed themselves ARE energy: mass, distance, and time. where distance itself is actually 'distance over time' redundantly (since 1 meter = the distance light travels in 1⁄299792458 second). distance IS space over time: spacetime.
so energy is mass, space, and time. when matter is affected by energy, either its mass, its space or its time can be affected.
the photonfield - a 3D field where its excitations are focal packets of energy called 'photons' that push the field forward in a wave like pattern (similar to how in a wave of water, each water molecule is pushing into the one in front of it, resulting in a forward energy even tho the wave itself has no different mass than before)
just as a photon is a massless surge of energy through the photonfield (magnetic and electric fields), so are gravitational waves massless surges of energy through the spacetime field. the electromagnetic field affects matter via moving (distance over time) particles around based on the particle's charge (an intrinsic value of the matter). similarly, the spacetime field affects matter via moving (distance over time) particles around based on the particles' masses (an intrinsic value of the matter), in the sense that even tho gravitational acceleration moves matter while IGNORING the mass of that matter, it is the matter itself thats curving the spacetime in the first place. this redundancy (the mass bends spacetime, spacetime then moves the mass irrespective of the value of the mass, then the mass re-bends spacetime, then spacetime moves the mass more, etc) is probably why gravity is always an acceleration, not just a velocity.
what else is massless? how gravitational acceleration works. spacetime curvature causes two masses to ACCELERATE towards each other, REGARDLESS of either's mass. they are gaining energy, in a mass-agnostic fashion. energy is king, mass means nothing.
photons are confusing: all energy, but no mass. they are beings of distance=space, and time. their own energy is in the FORM OF space and time - their ability to MODIFY it among others. photons in a box will have zero mass, but not zero energy. e=mc2, so this energy is all in c2 units, aka space and time. but this equation should really just be m=e/c2, because MASS is usually king.
but, no. ENERGY IS KING - as proven by photons. you can have energy without having mass (as w eknow it)
time is just 'how fast things are allowed to move', as a foundational property of the system - but it can change. when space is distorted by mass, the foundational 'rate of time' also changes.
since photons have no mass, they can only control things via space and/or time. perhaps when a photon blazes past something, it exchanges energy with it by giving up some of its time dilation. photons are fast, so their time has slowed down; but if they pass something,
gravity just means "this particular curve of spacetime will have [this effect] on energy". how do you know what spacetime in that location looks like? what is the nature of its 4D shape, aka its geometry? imagine a 3D world of just space, then imagine another, differnt exotic 3D world of space. these two flavors of 3D space are just different geometries. 4D includes space (the distance between things) and time (the rate of things), so different and exotic types of 4D universes would simply differ in how their space looks and how their time looks. the catch is: matter itself (aka energy) CONTORTS the 4D spacetime around it, filling our own universe with myriad pockets of exotically different 4D areas, each different from each other, yet all within the same universe! so spacetime will change based on the position of an energy mass, and the 4D environment gets particularlly bizarre/exotic when two masses are involved (as is always the case in practical physics).
so energy contorts spacetime, which is space (distance) and time (rate). And so, THE NOBLE THREE: energy, distance, and rate - thESE ARE THE 3 FUNDAMENTAL variables of the universe.
interestingly, gravity is not a velocity, its an acceleration. meaning, somehow, its adding energy - the object is going faster and then even MORE faster. E=mc2, and since the mass isnt changing, and energy is increaing, that means c2 must be the one causing the increase, and since its units are distance2/time2, either distance (space) is increasing, or time (the rate of things) is decreasing, which means time is slowing, meaning theres potential energy being built up inside the object since the rate of things is now slower so more energy is sitting on the left side of the reaction, waiting to pass to the right side. AND/OR, spacetime becomes more and more stretched as you approach a massive object, meaning space itself, the distance of things, is increasing. making space itself wider somehow could increase overall energy, perhaps by the fact that increasing the radius bw two objects will increase the force of gravity bw them. since space and time are inextricably linked, it must be that distance is increasing AND time is decreasing at the same time, together, and in such a way that overall E is still increasing simply exponentially ^2.
as this object slides down a very curved spacetime, it gains exponential energy because space is stretching (more potential energy generated between any two points in space since raidus increased), AND because time is slowing (slower rate of things, so more stored potentnial energy waiting to be spent per unit time).
perhaps the true sources of energy are space itself and time itself. space, if its the case that there is inherent potential energy between any two given points of empty space, and as space stretches, these imaginary points grow farther apart, increasing their potential energy - like an elastic tension, or rubber band. similarly, as time (the rate of things) slows, potential energy increases - similar process, where since the the distance between two points in TIME is now farther, that same elastic energy is increasing. think of the light box, or an 'interval' in spacetime where its two events separated in time. if you slow time, then matter must move farther to complete a full cycle/carry on at a rate, so potential energy increases.
the elastic energy principle: there seems to be a strange inherent principle in the universe: that when one thing is moved away from another thing (whether two points in space, or two different rates of time where a slower time has particles needing to travel farther distances), a potential energy is generated. an elastic tension. but why?? is it just because? well, potential energy is being stored up, almost as if entropy is decreasing, as if energy is being put into a chemical bond that can be broken later and harvested. as things stretch, this potential energy builds up and radiates outward as dark energy, which expands the universe exponentially. entropy is decreasing as the objects fall down spacetime curves (potential energy being generated and stored as space and time are stretched), and its radiating outwards to the rest of the universe causing an overall increase in entropy.
it could be THIS VERY elastic force that is supplying the energy for acceleration here. as energy becomes stretched in both space and time, its radiuses of ALL types and forms are increasing, creating a RUNAWAY EFFECT where more stretching leads to more energy leads to more acceleration, as the masses continue to move ever-down the spacetime curve until finally meeting their end (probably at a blackhole somewhere millions of years down the line), its like, as energy increases, spacetime is stretched, and this very stretching generates a spontaneous, hot friction that exudes outwards. this 'increased potential energy between things, generally'
so energy is simply generated by the process of 'a thing changing its position', whether its changing its position in space, or in time. energy is generated as things fall naturally down a slide that compels them downwards, gently with ease. a universe filled with energy is inherently always falling inwards towards itself, down the spacetime curve of masses attracting each other... but as spacetime stretches, it generates the radiating friction energy which causes the expansion of the universe constantly, for as long as matter is allowed to fall inwards down its gradient, which will be "forever" or "as long as two energy piles exist".
energy is constantly attracting each other. massive energy balls curve spacetime around them, and other energy balls fall inwards down a gradient in response, on a huge scale. compare two sources of energy in two different 4D spacetimes: as energy travels through space OR travels through time, the farther it goes, the more energy is generated (somehow).
"energy travling down a spacetime gradient will inherently increase itself because of the stretching of things, both distance and time itself"
everything is accelerating. WHYz? because energy inherently stretches spacetime, and as spacetime stretches energy is inherently generated (a potential energy, via particles having to travel longer/farther to do things, but its a REAL energy, realized as spacetime itself expanding outwards. as if potential energy on the spacetime level is kinetic energy in the IRL level).
Einstein realized the fact that we dont notice we are accelerating while sitting on earth, therefore gravity is indistinguishable from acceleration, so it must be one. whereas velocity is a constant: it doesnt change, just as an object at rest doesnt change, aka inertia, aka an object with constant velocity will only ever stay in that state, and another perspective is the object is at rest while everything is just moving around it (relativity).