Subject: It is said that tachyons travel backwards through time...

Is a tachyon a particle? Comparitively, how big are they? The size of protons 
and neutrons? Have they been proven to exist yet? Can we manipulate them if 
they do exist? Can a tachyon move through space as well as time? If this is so, 
could it theoretically be possible for complicated chaos math to be used to 
move a tachyon in a certain place in space and time, invoke the butterfly 
effect, and proactively affect history? Could the displacement or addition of a 
single particle, in practice, cause large sweeping changes to world history? 
Have we ever tested this theory? Finally, what is a mobius loop?

Re: It is said that tachyons travel backwards through time...