What's tachyons actually? is it visible?

Question

What's tachyons actually? is it visible?

Answer 1

Einstein suggested that in another universe it would be possible for all particles to travel in excess of the speed of light, these particles are called tachyons, Because the great man suggested such a thing science had a look at it, experiments were conducted in an attempt to detect one at the fringes of our universe, none were found.

Answer 2

"Tachyon" is the term given to all superluminary particles (that is, particles that travel faster than the speed of light). Tachyons preserve causality (information cannot be sent faster than the speed of light), cannot slow down to the speed of light (they are bounded to speeds > c) and are as of now entirely theoretical and very controversial in physics.

Answer 3

A tachyon is a word for something that doesn't exist as far as we know--a particle that travels faster than the speed of light.  It would absolutely violate causality if such a particle existed.