How I Visualise Gravity
Rules that influence behaviour
The one fundamental rule in the universe that can be inferred is that of everything wanting least entropy. Symmetry is a byproduct of least entropy, as a symmetric system has least entropy, always.
Everything in the universe wants to remain in the same state (of least entropy). It is the reason why objects keep moving unless stopped, or keep at rest unless moved (that is, inertia). Another way to remain in the same state, is to literally freeze time, essentially, keeping the current state of the universe, hence guaranteeing no increase in entropy. Hence, every object or body in the universe, wants to freeze time for itself, or at least slow down time for itself, so as to have less entropy.
Mass is a universal deterrent for objects, preventing them from moving fast, as making an object with mass move requires energy to be added to the object, thereby increasing entropy. Light does not have mass, hence has no deterrent, and moves as fast as possible (the speed at which an electric field can induce a magnetic field, and magnetic field can induce electric field, vice versa). This is the universal speed limit in the universe, the speed of light is invarient to an observer measured relative to anything. I will explain why speed of light is invarient when measured from any point of reference later.
Where my interpretations come in
Now, the reason why objects want to move as fast as possible is to slow down time. Objects moving faster have time slow down in the objects’ point of view. Why is this?
Our universe has 4 dimensions, 3 in space, and 1 in time. This is what we refer to as spacetime, a 4 dimensional fabric. To better visualise, lets consider a universe where there are 3 dimensions, 2 in space, and 1 in time. Lets consider the x and y axis as space, and z axis as time. Essentially, every object in this 3D fabric has to move at a certain speed in it (we will refer to this certain speed as that object’s speed requirement in the fabric). Objects with more mass move through this 3D fabric at a slower speed than those with less mass. Hence why light, with no mass, moves at c through this fabric, the maximum speed. Why do objects with more mass move slower through the fabric? Its a fundamental property of the universe, just as the speed of propogation of light is.
As stated earlier, objects wish to remain in the same state (least entropy), in other words, they wish to freeze time for themselves. Light can do this. Light moves at the maximum possible speed, c, and hence plotting its movement in this 3D fabric, is a straight line, in the xy plane. It just moves in space, without moving in time (the z axis) at all.
Now consider an object with some mass, it is required to move slower in this fabric than light due to it having mass. It requires energy to make it move fast (increasing entropy) in the space dimensions (xy), in order to account for its ‘speed requirement’ through the fabric being greater than the speed it can possibly move through the xy plane (as it cannot reach c), it moves in the z axis as well (that is, it moves through time, it experiences time).
A heavier object, with more mass, is required to move slower through the fabric, hence if this heavier object was moving at the same speed as the previous object through the xy plane, it needs to move much slower in the z axis to make up the difference in the speed requirement, hence it experiences slower time, or moves through time more slowly.
So essentially, to slow down time, either you need to move very fast in the xy plane so as to use up most of the fabric ‘speed requirement’ in the space dimensions, or you need to be so massive that your fabric speed requirement itself is very low.
Why is c invariant to the observer?
Remember how I said c remains invarient no matter what point of reference you measure it from? As light moves, it experiences no time, (it remains moving on the xy plane at z=0). However, we, measuring it, we move through the fabric, even in the z axis. So consider light starts moving on the x axis from the origin, at z=0. We start at the origin, moving in the z axis (time is passing for us), We measure the speed of light as the diagonal vector between us and the position of light in this fabric. This vector, always increases in length at a constant rate (dictated by c).
Say we were also moving on the y axis, as well as z, the time axis. Some of our fabric speed requirement gets used up due to moving in the y axis, so we move slower through the z axis (time), hence the vector is still increasing in length at the same rate.
This is why why we say c is a universal constant, and even if you measure the speed of light shining from a torch while you yourself are moving at 50% speed of light while holding that torch, you would still measure the speed of light from that torch as being c relative to you.
Why gravity though?
Now, coming to the the actual explanation of why gravity exists. Gravity is not a force, but it is an effect. So far we were considering the z axis in the fabric as being time relative to the object. Now let us consider a fabric with 2 objects, and let us consider that one of the object remains fixed at the origin, this means that we are shifting the time of one of the objects to be relative to the other object. We will also change the z axis from indicating an instance in time, to instead indicating rate of time flow. So if a more massive object A is fixed at the origin, z=0 is rate of time flow for object A, and z=a, a>0 for the another object B, that is less massive than A, hence having a greater rate of time flow. The reason why we are doing this is to visualise a geodesic as a cone/curve in 3D fabric. We will refer to this as the new fabric, and the previously explained fabric as the old fabric.
Essentially, the massive object A curves the 3D fabric, with the sharp end of the “cone” on the object A, and the circle end of the “cone” at a higher z value. This is essentially a 3D cone shaped curve. The reason why this curving occurs has the same underlying reason as why a more massive object has less ‘old’ fabric speed requirement. It has less old fabric speed requirement BECAUSE it curves this new fabric, or it curves this new fabric BECAUSE it has a lower old fabric speed requirement, both are equivalent.
All objects ALWAYS move in a straight line in this new fabric, this is again a fundamental property of the universe. A straight line in a 3D cone/curve is actually a circle when viewed from a 2D perspective (a conic section). Essentially, if object B is moving EXACTLY towards object A in space, of course since it is always moving in a straight line, it will directly fall into the object A, that is, it goes straight down the cone (think of it as a funnel, and you roll a marble into the funnel aiming at the center of the funnel). Now say object B moves into the vicinity of object A, it is moving in a straight line, and that straight line is a circle in the 2 space dimensions, as it moves straight in the 3D cone. Think of rolling a marble into a funnel, but aiming not directly at the center of the funnel, it curves around the edges of the funnel. You rolled the marble in a straight line into the funnel, but when it enters it, it begins to curve and roll around in the funnel (in the vacuum of space, with no influence of other objects, it will infinitely roll around the edges of the funnel). This in a nutshell is an object orbiting another object.
Or you know, you could just ignore my ramblings
Gokul Vasudeva (GokulVSD)
circa after 2 AM on a warm covid night.