>>9225072Let's say everything in one universe (here timeline) has already a finite amount of everything (matter and energy) since the beginning, it should not contain ever more or less of it, everything will only change to something different over time.
By theoretically time travelling, you take yourself away (matter and energy) from this universe, likewise add yourself on top of another universe (timeline).
Both universes will be now instable, your original universe wants to attract you back through the plane of the multiverses, the other one will try to get rid of your existence or even trades its own overflowing amount of everything with another universes which are also instable to become stable again.
At the end its not only matter and energy, there is information of the parallel universe included too. This information will influence the further developing of the universe which received it from another universe, events which can be repeated will happen again. As living observers we carry information which can be related to something we know to exist or has existed. As an example of time travelling: We travel back in time to save a friend of being killed in an accident, creating already a different timeline (universe) by just being there already. We own the information of our friend's unnatural death, this universe will own it now as well. So if this timeline will play out like the original one and we succeeded in saving our friend, this universe will not let it happen for long, everything needs to be like in your original timeline to go to order again.