Tachyon

• Faster-than-light particle existing in normal space (SCE Short Story: "Cold Fusion")
• Capable of penetrating solid objects, intense gravitational fields, or event horizons, allowing for low-resolution scanning in scenarios that would otherwise be nonviable if not defended against or too energetically active for traditional scans (TNG: "All Good Things..."; VOY: "Parallax", "Dreadnought"; SCE Short Story: "Wildfire, Part 1")
• Though native to normal space, FTL properties often lead to interaction with subspace phenomena
  • Pulsed tachyon emissions capable of triggering, disrupting, or accelerating breaches in subspace (TNG: "Descent", "All Good Things..."; VOY: "Coda", "Day of Honor", "Pathfinder"; Destiny)
  • In rare circumstances, natural tachyon emissions from stars can be used to accelerate sublight vessels to warp (DS9: "Explorers")
• Natural side-effect of various forms of spatial or temporal distortion
  • Associated with distortion-based cloaking devices (DS9: "For the Cause", "By Inferno's Light")
    • Tachyon-tachyon interactions lead to prominently detectable signature, leading to application of tachyon beams to cloaking detection late-2360s (TNG: "Redemption II"; VOY: "Flashback"; DS9: "Once More Unto the Breach")
      • Detection method averted by Reman development of cloaking device tuned so as to negate tachyon emissions late-2370s (Star Trek: Nemesis)
  • Common sign alongside chronitons of temporal manipulation or time travel technology (ENT: "Cold Front"; VOY: "Fury", "Endgame")
  • Left by certain obscure types of high-energy transporters (DS9: "Covenant")
• Tachyon interaction with high-energy plasma reactions can lead to drastically increased reaction pressure
  • Can be used to trigger a warp core breach at a distance without proper defenses against plasma contamination (VOY: "Dreadnought", "Day of Honor")
• Extremely high levels of tachyon exposure can be harmful or fatal to living beings (TNG: "Deja Q"; VOY: "Endgame")
• See also
  • Tachyon detection grid