Briefly about tachyons

In the generally accepted picture of the world in which the same Relativity Theory “THAT” rules, the speed of light “C” is considered the speed limit, and the same value is attributed to the speed limit of interaction, the flow of all processes in the universe. The same maintenance asserts the dependence of energy and body mass on speed - the famous equation E = m * c2.

Those. for an object possessing a mass that has reached C, time will simply stop, and mass and energy will become infinite, which you yourself understand is highly undesirable in practice, like any paradox).
Therefore, all particles moving at the speed of light, the general name “luxons”, among them photons, are considered as particles having no rest mass. Simply speaking, with zero mass, because by how much zero you do not multiply, it will remain zero and therefore there will be no paradox. Hooray!
For particles with light velocities, they also found a couple of intricate words “tardions” or “bradyons”, and they were even allowed to have a rest mass, since they do not reach light speeds, which means they do not violate the correct theories ...

But physicists are creative guys, and it is worthwhile for them to decide something firmly, as there is an immediate temptation to refute it. This is in principle understandable, because any theory is not at all an absolute law, but merely an assumption, supplemented by calculations, and to a varying degree confirmed or refuted by practical consideration.
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However, for some mysterious reasons, it is accepted extremely scrupulous to reckon with the Theory of Relativity. And why is it necessary to verify whether new theories correspond to it or the data obtained experimentally ... Despite the fact that this is also just a theory.
Therefore, when in 1967 the American physicist Gerald Feinberg ventured to surprise the world with a new, superluminal particle, he did not bother about it, and immediately mathematically proved that its existence does not contradict THAT at all!

And everyone was happy.
He called this class of particles "tachyons."
Their speed is always faster than light, but for this they have to have some kind of “imaginary” mass (what does this mean, and most importantly, who even the physicist will “wonder”), and the ability to lose speed when absorbing energy, while everything "Normal" particles are accelerated.

All this, of course, had a deplorable impact on tachyons, since I had to admit that their time is flowing backwards, and the fact that tachyons cannot convey information, because this, for example, would violate the principle of causality, and in general cannot interact either with particles of our world, since their speed is higher than the speed of interaction in our universe. They just fall out of our space-time and cause-effect structure!

For this reason, the detection and fixation of such particles seem most likely impossible ... Until a new clever physicist is found, of course!

There is also an interesting attempt to "portray" what a tachyon would look like if it could be seen ...
It is possible to “see” him after the moment of his passing by. The approaching tachyon is invisible, as its image along with the light is delayed behind it. After its close flight, one can observe its forked image, parts of which fly apart in different directions:
one part, in the direction of travel, is the light of a departing tachyon, and the second, against its movement, is gradually flying images of the tachyon, which he left behind while flying to us.
It's funny ...