Gravity and Time

Here's my abstract: Time is a function of Gravity versus the expansion of the universe.

Let me explain:

Gravity is the least understood and weakest of the known fundamental forces of nature. While we perceive gravity as a powerful force, one that keeps us anchored to the surface of our planet, all it takes to prove its weakness as a force is to try to lift something, anything. The chemical energy in your cells is converted into into mechanical energy, which easily defies the propensity of an object to be attracted to a nearby gravity well. Lifting a pen or a cel phone proves how weak gravity is.

However, like all the mysterious things in the universe, gravity is dichotomous. While over the short range and the small scale gravity wouldn't even be noticed when compared to electromagnetism, over the large and extremely large scale, it becomes one of the most dominant forces in the universe. It's almost as if gravity were a diffuse force, objects interacting within its infinitely vast influence.

When you think of gravity as being everywhere, then you are no longer able to defy it by picking something up; it takes a rocket to break the surly bonds of the Earth, and even then you're still in the grasp of the sun, then the galaxy. In this way, gravity is perhaps the most patient of forces; almost nothing has ever escaped the Earth in her six-billion-year history. Even the collision event that created the moon only managed to push it into orbit, and only the probes of the Voyager program have ever come close to escaping the Sun. Except for those cases, Earth's gravity has you, forever.

(Most physicists, Einstein notably, may tell you that the universe is a soft rubber sheet where things generate gravity wells proportional to their mass, or they may tell you that gravity is an exchange of graviton particles propagated at the speed of light. Neither model of gravitation is particularly relevant to this discussion, and it's not relevant which is being thought of, only the fact that gravity exists.)

The future of physics, I think, can be found in gravity. The more we're able to precisely pin down what exactly causes it, the more we'll be able to manipulate it as we have electromagnetism.

It shames me that I can't pin down the exact thing I'm thinking about on google, but I recall once, long ago, hearing about a series of mathematical transformations that turned an equation describing time into one describing gravity, and vice versa. It was touted as an oddity, but the more I thought about it, the more it seemed like a very subtly profound concept, and gravity and time are nothing if not subtle.

The universe is expanding. Thanks to NASA's Spitzer telescope, we just now discovered the exact rate by which the universe expands (about 74km/s/Mpc). Fighting this expansion, however, is the force of gravity. We know this because galaxies are flying apart from one another in all directions, not themselves expanding concurrently with the universe. Gravitation fights the expansion of the universe.

The expansion of the universe is touted as accelerating, that is, the rate by which the universe is flying apart is speeding up. It's on this point that I disagree.

As the universe expands, there is necessarily more space. The new space also has the nature of expansion built within it. With more space, you have more expansion, and in that way it appears that galaxies are moving away from each other at an increased rate.

My main thought is about the interaction between gravity and the expansion of the universe. Let's say that the fabric of the universe is a treadmill, and to represent its expansion, you have your reference object, something sitting on its plastic housing, and another object on the belt itself. Let the objects be galaxies for a moment; there is nothing to connect them, so as the expansion of the universe takes place, they move further apart.

Now, connect the two objects by a lanyard or a string. The universe is still expanding as the belt rolls on, but the objects remain still in relation to each other; let the stationary object be the Sun, and the one dragging on the belt be Earth. The expansion of the universe is an external force acting against gravitation, however, over relatively short distances, all the other fundamental forces dominate it, making it difficult to perceive.

Gravity is keeping them together, but, something interesting is happening; energy is being expended.
As any elementary physics student knows, you have to account for all the energy of a system. We know that the universe is expanding, but over the scale of a single galaxy, gravity is strong enough to overcome it. (Incidentally, I'd like also to propose that galaxies have a maximum size, and the reason they're that big is because any further out, gravity can't overcome expansion.) Obviously, it would take what appears to us to be inconceivable amounts of energy to spark the expansion of space, but that energy isn't really accounted for, given that gravity is pulling against it over the galactic scale.

So, where does all that energy go?

I posit that the 'friction' created by gravity pulling against expansion is expressed as time.

Time is another poorly-understood facet of nature. We generally hear that time is a dimension, separate from the well-known three spatial dimensions, but it's left at that. The thing no one ever points out, though, is that moving in spatial dimensions require energy. Why, then, should the temporal dimension be any different? Even if you can only move in a single temporal dimension, it follows that there should be some kind of temporal energy required to do so.

I simply propose that time is an expression of gravity's universal pull against the expansion of the universe.

At relativistic speeds, time slows down; relatively speaking, the faster you go, the slower time goes. This is proved every day by communication satellites, which require calibration on their internal clocks to account for their increased speed when compared to objects on the ground. Why should this be? Why should time slow down, the faster you go? How does that relate to my position?

As something travels at great speed, its perception of time slows, yes, but it also changes length. Obviously, if you're the one traveling at near light speed, you notice neither the time nor the length dilation, and the reason for this is that the faster you go, the longer it takes for light to move around in relation to you. If you're in a spaceship traveling at .99999 light speed, the light reflecting off of the aft bulkhead toward the fore viewscreen will take a much longer time to get there, but the passenger within the spaceship won't notice anything different.

If gravity also travels at the speed of light, then traveling near the speed of light must also be effected by the propagation of gravity, just as it is by light.

I further posit that gravity propagates at the speed of light, and because time dilation is linked directly to the speed of light, so too must gravity's propagation be linked to the perceived progression of time.

In closing, I hope this thought experiment reaches someone, anyone. I hope that it makes someone think. If I could have understood calculus in college, maybe I could prove this with math. Failing that, I'll leave the idea to anyone who wants to try to work it out on paper.