A viewer asks: “So I take it, that I “can” go back and kill my grandfather and will continue to breathe and leave pollution, etc. But didn’t the act of killing my grandfather create a “new” timeline—one absent my now deceased grandfather? Or did it alter the “same” timeline and I effectively altered the future I came from?”

You are thinking of this in the construct of a paradigm you have created within your own mind or borrowed from elsewhere. In actuality, there is one timeline that is constructed of everything about you. Your grandfather was sharing that timeline, in a sense, by being present in a timeline that served you both. Each of you has a place within this timeline. Sometimes interacting with one another, sometimes not, but the possibility was always there to do so and could be arranged through a free will choice. When someone passes and leaves the physical, the timeline for them ends in that incarnation but continues for the other parties on that same timeline, so his demise would not change your continued presence along that timeline. So you are not going onto another track that is being created by that one act, it is just that the energies of the timeline will be truncated with respect to the grandfather, so there will be no further energy emanating from him and influencing things.