Tachyoner er hypotetiske " kvasipartikler", der altid bevæger sig hurtigere end lysets hastighed.
Som et tankeeksperiment har
Gerald Feinberg teoretisk antydet at tachyoner kan eksistere. Tachyoner kan teoretisk eksistere, hvis de er skabt med en hastighed over lysets. De kan så bare ikke decelereres ned under lyshastigheden. Tachyoners eksistens er dog stadig en videnskabelig hypotese og er aldrig blevet observeret.
October 21, 1999, scientificamerican.com: What is known about tachyons, theoretical particles that travel faster than light and move backward in time? Is there scientific reason to think they really exist? Citat: "..."Briefly, tachyons are theoretically postulated particles that travel faster than light and have 'imaginary' masses...Tachyons have never been found in experiments as real particles traveling through the vacuum, but we predict theoretically that tachyon-like objects exist as faster-than-light 'quasiparticles' moving through laser-like media. (That is, they exist as particle-like excitations, similar to other quasiparticles called phonons and polaritons that are found in solids. 'Laser-like media' is a technical term referring to those media that have inverted atomic populations, the conditions prevailing inside a laser.)......"We are beginning an experiment at Berkeley to detect tachyon-like quasiparticles. There are strong scientific reasons to believe that such quasiparticles really exist, because Maxwell's equations, when coupled to inverted atomic media, lead inexorably to tachyon-like solutions...", backup