The concept of a multiverse encompasses various speculative theories and hypotheses, so the specific nature of timelines and their relationship between different universes within a multiverse can vary depending on the proposed model. However, I can provide you with a general understanding.
In some multiverse theories, each universe within the multiverse may have its own separate timeline, meaning that the events and progression of time in one universe would not be synchronized or aligned with those in another universe. In this scenario, each universe would have its own unique history and timeline of events.
Other multiverse theories suggest the possibility of parallel universes that share similar or even identical timelines up to a certain point but then diverge due to different quantum or macroscopic events. In these cases, there might be universes that started with the same initial conditions and history as ours but have since developed differently, leading to alternate timelines or outcomes.
It's important to note that the concept of a multiverse is still speculative, and there is currently no conclusive empirical evidence supporting its existence. It is an area of active scientific and theoretical exploration, and different theories propose different mechanisms for the existence and nature of multiple universes.
Ultimately, the specific nature of timelines in a multiverse, and whether they are aligned or divergent, would depend on the specific multiverse theory under consideration. As our understanding of the universe evolves and scientific investigations progress, we may gain more insights into the nature of the multiverse and its potential implications for timelines and their relationships across different universes.