An attempt to suppress room background noise by adding anti-sound turns into speaker howl if the circuit has an error. A similar glitch occurred with a theory that set out to remove the main cosmic hum — the inexplicably weak dark energy. Calculations show that vacuum energy is colossal, but we see only a tiny surge, accelerating the galaxies rushing apart.
Physicists hypothesized: there is a field that absorbs the excess vacuum energy. The model, however, contained a 'ghost' — a particle with negative energy. Such a guest triggers a chain reaction: processes gain infinite speed, violating causality (the effect arrives before the cause). The universe simply could not have survived even the first moments after its birth.
Worse: the theory added a nonexistent force, squeezing galaxies — astronomers don't hear this false note. The instrument meant to remove the noise itself created a cacophony. The riddle of ordinary physics and the cosmological constant, which once puzzled Einstein, remained unsolved.
A ghost particle in the equations is like a ball that rolls uphill on its own, gaining speed. Such runaway acceleration renders causality meaningless: a shot could ring out before the trigger is pulled.
Even the all-knowing computer from Asimov's 'The Last Question', which defied heat death, could not tame the 'ghost' — such a particle turns time into chaos.