Why is the speed of light constant?

[TheDarkestOfAngels]

Why should light travel in the way that it does? What characteristic of spacetime is the root cause of relativistic consequences? The entire argument of relativity is that time, mass and length are relative to observers frames of reference. So something about the act of moving at relatively very high speeds causes spacetime to react in a way that light travels the same speed for both perspectives.

Light travels the way it does because it does not have mass and anything without mass always travels at the speed of light. Gravity even travels at the speed of light even though it isn't so much a 'force' as it is a bend in space-time due to a massive object or whatever.
From what I understand, it's not a characteristic of space-time, but rather energy and matter or at least both.
I'm not sure if this answers your question, but this is the best answer I can give short of researching it myself.

Gravity has proven to 'bend' spacetime, and light will react to this curvature. My thoughts are that perhaps its the motion of the gravity wells that causes the relativistic effects, gravity is thought to travel at the speed of light, but so little is known about the mechanisms of gravity that I wonder what unknown effects it might have.

We actually know quite a bit about gravity but what we don't know is how massive objects cause gravity, exactly and the biggest frontier of 'shrug-shoulders' isofar as gravity is concerned is quantum gravity or gravity on the scale of atoms and light waves.

I have read papers theorizing gravity as a manifestation of a higher spatial dimension, but I'd like to hear responses to this. Since increased mass implies increased gravitational effects, and gravity may be associated with higher spatial dimension is mass an indicator of the effects that 4th dimensional motion has on our perception? (I know, the logic here is very faulty, but its the line of thinking I went through to try and disprove) And could the relative movement of two bodies in this higher dimension have the consequences of relativistic effects? I know this is borderline philosophical, but I'd like to hear theoretical contradictions to this idea as I'm not as well versed in this as I'd like to be.

There are a lot of theories about gravity's precise cause but unfortunately, the key to that understanding will probably have to wait until we discover the higgs boson, discover that the higgs boson isn't real, or something about quantum gravity will unlock, I think the answers you're seeking, but this is at the edge of physics research, as far as I understand it and right now there are more questions than answers for the time being.

I share your desire to understand more about it myself, but that'll have to wait some years I suppose.