Astronotes Armagh Planetarium's Stellar Blog! ... Physicist Gerald Feinberg even gave them a name, tachyons (from the Greek takhus, meaning ?fast?, and the English т?? -on т??meaning ?elementary particle? (yes, really)). ... If they existed tachyons would be really, really bizarre things. ... Not only that, adding kinetic energy to a tachyon would make it slow down, but it would take infinite energy to drop its velocity down to the speed of light! ... Do tachyons exist? ... Reply . ... Astronotes . ...