If an immortal, fabricated particle could travel FTL, would it exist in all times, or only the past relative to its present?
This seemed too scifi or hypothetical for physics, so here goes.
Suppose a manipulated quark with 0 mass could travel faster than the speed of light. It's known that the faster you go, the slower time goes for you relative to an outside observer. At 1c, time essentially "stops" and everything outside that the particle sees seems to be standing still in time, while it continues to travel according to its own normal internal time. At 2c, outer time can't really get any slower than 0, so my reasoning is that it must start going backwards.
I am not asserting that my particle can accelerate from 1c to 2c, but rather trying to rationalize what will at > 1c in the first place, which this particle constantly travels at. In that case, wouldn't its vector through spacetime be negative, meaning it is bound to travel ever-backwards in time? Due to the expansion of the universe over time, would the universe would be shrinking for the particle, and all scattered masses of the universe actively unraveling and falling towards a single point in 4 dimensional space? As space compresses, its relative velocity would become slower and slower, until it arrives at the CMB, or if we add its negative time into the equation, the actual beginning of the universe, where negative time starts slowing back towards absolute 0?
If we observed this quark for a planck instant in our world, would we know without a doubt this quark has come from the future, and could we use this knowledge to acquire information from the quark, much like in the movie Interstellar, except these quarks come explicitly from the future rather than morse code from a timeless existence? Or would we not be able to detect its existence at all as it passes through our spacetime?
EDIT: reading the answers and comments so far, I'd like to point out that all or most of you seem to know a lot more about this than I do. To the point that now I am second guessing the validity of my question. 275
In terms of what I deem to be a "good answer," everyone seems to be doing a great job just by providing their thoughts on the matter, even if in some cases your answers are in conflict with one another. I said quark just to give it some validity, as quark is a generic term for subatomic particles, which are the only things I can reasonably imagine to travel FTL in the first place. Tachyons and antiparticles seem to describe this proposed "quark" in more cohesive terms. I'm not up on my spin and colour game so I can't speak for that sort of technical jargon, but it makes sense that they would be inverse if they were travelling backwards in time. I said the particle has 0 mass, because I thought it was a necessary prerequisite for FTL in the first place. It's not important that the particle has 0 mass, it actually helps if it could have mass, because then there is logical recourse for the particle to begin to make observations of its surroundings.
In the spirit of clarifying concrete questions, are tachyons/antiparticles proposed to travel only backwards in time, by some informed schools of thought? Also, how might we go about identifying them and possibly extracting info from them? If you answered these already, of course disregard. Bonus question, do you feel that my interpretation is accurate, where the particle eventually arrives at the beginning of the universe, where its relative velocity, and the progression of time itself approaches absolute 0? If so, then I'm imagining the beginning of the universe, where there is rapid outward expansion of spacetime, energy, and particles, while at the same time, negative spacetime, negative energy, and antiparticles are all rushing towards point 0 to be consumed by a state of timelessness and non-existence. 562