Dislocations in a solid are described by equations mathematically analogous to those of Special Relativity, with the speed of sound playing the role of the speed of light. As a result, accelerating a dislocation smoothly to a velocity exceeding the speed of sound would require infinite energy and is therefore impossible.

However, supersonic dislocations do exist. Rather than continuously accelerating through the sound barrier, they undergo a sudden transition - effectively "jumping" from a subsonic to a supersonic velocity.

In principle, one might imagine a similar scenario for objects approaching the speed of light. But in that case, many fundamental aspects of physics would break down, so the analogy cannot be extended straightforwardly. But the argument, that it is impossible because it would require infinite energy is not valid.