Gravity is the most ubiquitous force in the universe, however there seems to be little agreement on exactly what it is. After centuries of speculation and theory, the most accurate description posed by Albert Einstein is that gravity is a "fictional force". In other words, gravity does not exist on its own but is a collateral effect of something else.
Although relativity strongly supports this conclusion, it does not appear to be a widely understood.
We will correct that here. 😊
For this Gedankenexperiment, there are a few prerequisites. If you are not already familiar with the following, be sure to check out the linked articles first.
When describing gravity using 4-dimensional spacetime, particles tend to move towards larger objects because of the curvature of space. Even though a particle is always moving in a straight line, spacetime itself is curved towards the largest source of time dilation.
This geometric manifold description of gravity is the most common one and particles can be treated dimensionless, however spacetime relies heavily on a strict speed of light limit with difficulty resolving exceptions.
Our preference is to describe time dilation as a radiated field due to a simpler (and equally accurate) description. Additionally, a field-based model is more compatible with quantum mechanics, entanglement, and observations of gravitational propagation delay. Although this is a less frequently used approach, we expect quantum compatible descriptions of relativity will soon become the standard.
Since all particles in motion are wavelike, they possess a dimension. As such, an uneven field of time dilation will cause an uneven rate of speed for the particle wave front.
As the diagram here shows, away from a notable source of time dilation, a particle will move in a straight line. As the particle traverses an area of uneven time dilation, the speed of the wave front is also skewed. This temporal drag is what steers the particle towards the mass which is the effect we call gravity.
Of course describing the "steering" of a single particle may not paint the complete picture of why an object "falls".
In fact, as a particle gets closer to the source of time dilation it slows down. But if we drop an object from some height it accelerates during its descent.
How are both true?
Per our other article, a hadron is essentially a group of fundamental particles bonded together and the particles contained within are all moving at the speed of light (or as close as relativity permits). However, because of this high speed and indeterminate flurry of activity, the assumption can be made that all vectors are being expressed equally and simultaneously causing the intrinsic net velocity of any hadron by itself to be zero.
Although hadrons are believed to contain a finite number of particles, the rapid and indeterminate motion of those particles is such that we can look at it as averages. For example, we can state that at any given moment if 1/2 of the hadron's particles are in the top hemisphere, then 1/2 are in the lower hemisphere. Or if 1/2 of the internal momentum is moving up, then 1/2 is moving down.
If there is a differential time dilation field (slope of a gravity well), this results in the individual particles within the hadron being at a different level of time dilation at any given time. Therefore, the particles in the top half of the hadron are moving faster relative to the bottom half.
One might argue that this still is a balanced state since the average momentum of the hadron could still be geometrically centered.
This might be the case if the faster half of the particle could accelerate the slower half equally, but they don't.
For fundamental particles, time dilation doesn't just slow them down. It sets a firm speed limit that cannot be exceeded "anchoring" them in space. And since the particles in the faster half of the hadron are being deflected down faster than those on the bottom can be deflected up, there is a persistent imbalance to the hadron's net momentum.
We are not pulled to earth by a yet unknown backwards-working force. What we experience as gravity is in fact the fundamental particles in our own hadrons steering each other towards the strongest source of time dilation.