“It offends reason, because nobody knows what “IT” is.”
If by “it” you mean time travel, at some point it would be encumbent upon the Time Travel, and “invisible universe in another dimension” believers to show the slightest shred of observable proof.
Fantastic mathematics are not proof. Because no matter how accurate the equation itself is, there is the basic question as to whether your initial mathematical description of the situation was accurate. The mistaken quantification in the beginning can result in a long and accurate string of equations,, that are simply dead wrong when it comes to describing reality.
Yet instead of search for the mistake when we cannot observe the predicted result. We decide that reality must be invisible. This is right in like with the logic of the Malleus Maleficarum. Those questioning the conclusion are more like Newton and Galileo,, not the other way around. You have it backwards.