... what about tachyons? Hypothetical, yes, but does that equate to real, unlikely or impossible?
Yes/No. They're hypothetical, ie, based on an hypothesis, "a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation."
Ergo, no way to know if they're legitimate unless and until observed — like the even more renowned hypothetical construct, the Higgs boson, which is the current Grail sought by particle physicists. CERN probably is the best bet in discovering it.
