What are tachyons? I’m sure you’ve heard of atoms, neutrons, electors, protons, positrons, bosons, leptons and the list goes on and on.
Tachyons are some of the most elusive and fascinating particles in the world, even though we have no proof that they exist. Because if they do exist, they could lead to major change in the way we analyze our universe.
A tachyon is a hypothetical particle that moves faster than light. Now think back to that science lecture your teacher gave your years ago: nothing moves faster than light! That is why most physicists believe it doesn’t exist: it isn’t consistent with the known laws of physics, mainly special relativity and causality.
Let’s assume that the mass of a tachyon isn’t imaginary. Then that makes the energy of the tachyon imaginary. But on the other hand, a regular energy amount means that the mass of the tachyon is imaginary. Neither of these makes sense! If a particle is real, then it must have mass, yet if it does, then it seemingly has no energy, which means that it isn’t doing anything. But we already established that it is doing something because it is moving faster than the speed of light — it makes zero sense.
Let’s just assume energy is real. Because we have to assume one of them. Something interesting to note is that if we assume energy is real, then as the speed of the tachyon goes up, the energy actually decreases. Take a minute to process that. More speed. Less energy. Just as ordinary matter needs an infinite amount of energy to reach the speed of light, tachyons need an infinite amount of energy to get to the speed of light. And speaking of the speed of light, since tachyons travel faster than it, they are actually impossible to see. If you were to observe a tachyon entering and exiting a box, you wouldn’t be able to track it. You would see two images at the same time. One where the tachyon is entering and one where it is exiting.
However, the search for them continues. It will probably continue forever because the applications of a tachyon are endless. Einstein noted that if they exist, they could actually be used to communicate backward in time.
A good argument for tachyons is the reinterpretation principle. It asserts that a tachyon sent back in time can always be reinterpreted as a tachyon traveling forward in time because an observer cannot distinguish between the emission and absorption of tachyons. The attempt to detect a tachyon from the future (and violate the laws of causality) would actually create the same tachyon and send it forward in time (which is causal).
Or the argument that a tachyon CAN have an imaginary mass can also be made through the Standard Model of particle physics. The Higgs boson, a real particle, is supposed to have an imaginary mass in its uncondensed phase, which leads us to believe that other particles can also have an imaginary mass.
There is an infinite number of arguments for and against the existence of tachyons but they get much more complicated and harder to understand. We’ve barely scratched the surface here, so feel free to do your own research!
Photo: Andrzej Wojcicki/Science Photo Library