Most of this I figured out a long time ago, for example, the fact that Einstein was right about relative motion, but, wrong about mass increasing at the speed of light. Since inertia is caused by mass, there is no inertia at the speed of light, and no acceleration to the velocity of light speed. While we may say mass is relative to velocity what we are really talking about is inertia.
Last night though, I had an epiphany and here is a teaser.
So....time travel is relative. What does that mean? The classic example Einstein used is a person sitting still on a train that is traveling past a person who is sitting still at a station. Neither is moving, yet, the relative motion between them makes it look to each of them as if the other is moving.
Now usually this is where someone might say that when the person at the station appears to be moving it is an illusion caused by the motion of the train.
This is wrong.
The truth is that the train station is moving relative to the observer on the train. Motion is always relative to the observer.
As is time.
For example, suppose I go forward in time to 1914. From my relative position I am moving forward in time, my watch would continue to tick forward.
However, from a different observation point, it may appear that time traveled backwards around me as I continued to move forward in time. While some people say time travel is impossible, even though we currently travel in time at a constant rate and in a constant direction, the reality is that the momentum we have in time remains constant because while we continue to travel forward in time, our position in time relative to someone else's position in time is different.
Einstein wrote: "It is not clear what is to be understood here by "position" and "space." I stand at the window of a railway carriage which is travelling uniformly, and drop a stone on the embankment, without throwing it. Then, disregarding the influence of the air resistance, I see the stone descend in a straight line. A pedestrian who observes the misdeed from the footpath notices that the stone falls to earth in a parabolic curve. I now ask: Do the "positions" traversed by the stone lie "in reality" on a straight line or on a parabola? Moreover, what is meant here by motion "in space" ?"
We tend to conceive of fixed points from which we determine motion. For example, we may consider the Earth to be revolving about the sun, from an observation point on the sun. From an observation point on Earth, the sun is moving and we are stationary.
The truth is, both are true depending on the point of observation. There is a third perspective which Einstein did not consider in this example and that is the perspective of the rock, which remains motionless until assaulted by the Earth moving at a vector in opposition to and at a velocity consistent with the Train. Were we to plot the motion of the Earth and the train in relation to the observation point on the rock we would have a very different perspective on the motion of the train and the Earth, however, both of these would be describing identical motions such that as the train moved up and away, the Earth would move up and toward the rock.
Now, suppose time were to travel backwards. Where in space would I be if I remained stationary? (this is hypothetical, since in reality, momentum would remain constant and my motion forward in time and space would remain constant, if we consider my existence to be a fixed point in time, at any particular moment in time, but, not in space)
I would be in the same place, but, the Earth moves relative to its axis, and relative to the sun. The sun is moving relative to the center of the galaxy. The galaxy is moving relative to the center of the universe. If time goes backwards around me just for a minute, then I would be about 9,000 miles away from where I was on Earth before time moved relative to me. Gravity maintains my position relative to the center of the planet at any particular moment and since I was born on the planet, my relative motion is consistent with the motion of the planet and we typically do not feel any inertial effects. There is an inertial effect however, and the wind proves this since wind is simply air moving in response to inertia related to the rotation of the Earth.
Now this is where Einstein messed up, because, he believed that as velocity increases, mass increases until it becomes infinite and as mass becomes infinite, gravity becomes infinite and, well, bye. The entire universe becomes a black hole. Huh?
Now anyone who followed me this far without retreating to, "yeah, but this is all an illusion", might begin to realize that, were we sitting on a photon with the sun speeding away from us at the speed of light and the Earth speeding towards us at the speed of light we would not be experiencing an increase in mass, since we don't, and since gravity remains constant, from our point of observation, sitting on a photon. Neither the Earth nor the sun became a black hole, their mass did not become infinite as they suddenly experienced the instantaneous transition from stationary to light speed.
See, we keep thinking of fixed points or coordinate systems in space time, but, there aren't any fixed points and the Earth, as well as everything on it is moving at the speed of light already, relative to the observation point of a photon created on the sun, which is also moving at the speed of light away from the photon. The concept of the fixed point is an illusion, not the relative motion. The relative motion is real.
So..... which objects are experiencing time dilation and expansion to infinite mass?
Wouldn't you like to know :-) God, I love it when I understand.