The concept of time travel is largely speculative, and there is no scientific consensus on its feasibility or the potential consequences it may have. However, based on various fictional depictions and interpretations, I can offer you some possibilities.
If we assume that time travel is possible and you were able to go back in time to prevent someone's death, different theories propose different outcomes:
Altering the timeline: According to this theory, if you were successful in preventing someone's death, it would likely create a new timeline or alternate reality where that person continues to live. However, in the original timeline, their death would still have occurred, and the people in that timeline would remember it.
Predestined events: In some theories, events are considered predestined, and any attempts to change them would ultimately fail. In this case, even if you intervened, something else might occur that leads to the same outcome—either the person's death or a different event with similar consequences.
Temporal paradoxes: Time travel can introduce paradoxes, such as the famous "grandfather paradox." If you were to go back in time and prevent someone's death, it could create a paradox because if they didn't die, you wouldn't have a reason to go back in time in the first place. The resolution of such paradoxes is unknown and often leads to speculative explanations or the suggestion of parallel timelines.
It's important to note that these explanations are purely hypothetical and based on fictional ideas about time travel. As of now, time travel remains a topic of scientific and philosophical speculation, and there is no concrete evidence to support its existence or the consequences it would entail.