Originally Posted by sammi jo
If as you suggest that C has a dependency upon 'an overall gravity field' in the universe...
The speed of light isn't dependent on gravity. What does slow light down is the density of the medium through which light is transmitted. Light travels slower through air than it travels through a vacuum, slower through water than through air, slower still through glass than water. The constant 'c' is more precisely defined as the speed of light in a vacuum
And if so, can technology be created to modify this characteristic of space/vacuum, and therefore allow FTL transmission of information, or even physical objects?
or should I go back and read relativity?
The speed of light is a very different kind of limit than, say, the speed of sound. It's not like you hit a barrier and have trouble moving past it. In fact, if you keep pushing harder and harder, you can travel to any place as arbitrarily quickly as you wish with no limit at all (apart from available energy and how much acceleration you can endure without turning into mush) from your own perspective
on how long it takes to get there.
If you could survive the acceleration and had plenty of energy to burn, you could get from here to the other side of the galaxy in a year, or even a day. You could get back home just as quickly. Funny thing is, however, when you get back home something like 200,000 thousand years will have passed for everyone else on Earth. That's more jet lag than most people want to deal with.
What we'd ideally like is to take that same trip and have to same amount of time pass at home as we experienced while traveling, or at least not have the difference in the two rates of time be so vast. The problem is that anything (be it an actual physical object, or even nothing more the abstract concept of information) traveling from point A to point B faster than the speed of light will appear, from some frames of reference, to arrive at point B before it has left point A. That's not only just weird, but can lead to kill-your-own-grandfather paradoxes. One reason to suspect that faster-than-light travel or communication is impossible is because it seems reasonable to figure that those kinds of paradoxes simply can't happen.
There are a couple of ways to have faster-than-light communication and travel without these paradoxes arising, but you either end up with some fanciful system that can only be implemented at light speed (spend the next 100,000 years creating a grand Cross Galactic Highway, and when you're done, you can thereafter cross this galaxy FTL without those pesky paradoxes), or it could be true that one of the philosophical underpinnings of Relativity is false, that there is a "preferred frame of reference"... and I'm running out of time to make that all make sense right now, so I'll have to leave it at that.