January 3, 2015.
My conceptual speculation regarding mater and energy, basically everything in the universe--what is everything made of?
I don't think matter in the way that most people think of it as solid material really exists. Long ago we discovered that matter is mostly empty space between atoms. The space is held stable by force fields: gravity, electric fields emanating from protons and electrons, the subatomic strong and weak forces, and possibly more undiscovered forces.
Electromagnetic radiation (EMR such as light), is a stable interaction of electronic and magnetic fields that transports energy through space, all 3 dimensions. Electromagnetic radiation can be stationary in time, the 4th dimension.
Matter appears to be a stable interaction of many force fields that transport energy through time. Matter can remain stationary in space.
There is no small solid particle that makes up matter. At the most fundamental level it's an interaction of energy fields.
Mass is a measure of the gravitational field's resistance to acceleration in space. (October 25, 2020)
Matter can only exist moving through time in the same sense that light can only exist moving through space.
Matter can't stand still in time, nor can it transition from moving forward in time to moving backward in time.
Matter cannot be reflected or refracted in time the way light (EMR) reflects and refracts in space as it interacts with matter.
The previous 2 comments apply to commonly observed physics. Perhaps there are exceptions to those rules in extreme conditions such as black holes or during the formation of the universe.
Since the fundamental force fields of matter are not yet understood, attempts to model the fundamental behaviors of matter are only educated guesses, but that's what the equations of relativity were when Einstein initially proposed them.
This may be similar to what string theory scientists are proposing. I don’t know because I haven’t investigated string theory much.