The potential implications and consequences of time travel, if it were possible, are a subject of much debate and speculation among physicists and philosophers. The concept of time travel raises various paradoxes and challenges that have not yet been definitively resolved.
One of the most famous paradoxes is the grandfather paradox, where a person travels back in time and kills their own grandfather before their parent is born, thereby preventing their own existence. This paradox, among others, highlights the potential for logical inconsistencies and contradictions that could arise if time travel were possible.
These paradoxes have led some to argue that time travel, if achievable, would be inherently impossible or that the universe would somehow prevent paradoxes from occurring. For example, the Novikov self-consistency principle suggests that any actions taken in the past would be constrained to ensure that they are consistent with the current timeline, avoiding any paradoxes.
On the other hand, other theories and interpretations propose that time travel could lead to the creation of parallel timelines or multiple universes, where any changes made in the past would result in the creation of a new timeline diverging from the original. This idea is similar to the many-worlds interpretation in quantum mechanics, where every possible outcome of an event exists in a separate universe.
Ultimately, the implications of time travel, including whether it would "break" the universe, are still a matter of speculation and theoretical exploration. As of now, time travel remains purely hypothetical, and our understanding of the fundamental laws of physics is not yet sufficient to provide a definitive answer to these questions.