Question

What is Tachyon?

Answer 1

tachyon, hypothetical subatomic particle whose velocity always exceeds that of light.

Answer 2

A tachyon or tachyonic particle is a hypothetical particle that always travels faster than light. Physicists believe that faster-than-light particles cannot exist because they are not consistent with the known laws of physics. If such particles did exist they could be used to send signals faster than light. Wikipedia

Answer 3

tachyon (/ˈtækiɒn/) or tachyonic particle is a hypothetical particle that always travels faster than light. Physicists believe that faster-than-light particles cannot exist because they are not consistent with the known laws of physics.[1][a] If such particles did exist they could be used to send signals faster than light. According to the theory of relativity this would violate causality, leading to logical paradoxes such as the grandfather paradox.[1] Tachyons would exhibit the unusual property of increasing in speed as their energy decreases, and would require infinite energy to slow down to the speed of light. No verifiable experimental evidence for the existence of such particles has been found.

Tachyon

Because a tachyon would always travel faster than light, it would not be possible to see it approaching. After a tachyon has passed nearby, an observer would be able to see two images of it, appearing and departing in opposite directions. This double-image effect is most prominent for an observer located directly in the path of a superluminal object (in this example it is a sphere, shown in transparent grey). Because the tachyon arrives before the light, the observer sees nothing until the sphere has already passed, after which (from the observer's perspective) the image appears to split into two—one of the arriving sphere (to the right) and one of the departing sphere (to the left) Details information Wikimedia :https://en.m.wikipedia.org/wiki/Tachyon