Space Questions

I have some deep thought questions. Now, let’s say your friend ([B]), and you ([A]) are on different planets. [A] is on planet Earth, and [B] is on a different galaxy, planet, for example: Andromeda and some planet. Now, from planet Earth [A] can: 1: See the planet [B] is on, and [B]'s people. 2: Be able to notify [B] in a short amount of time (instant, per se). 3: See into the future for a short amount of time. Now, lets say [A] looks into the future and sees that [B]'s planet is going to explode, actually witnesses the reality from Earth (remember we see into the past from Earth). When [A] gets back, [A] states a message: "Your planet is going to explode, leave ASAP." But just as [B] was getting the message the planet exploded. [A] knowing this, and seeing the reality from Earth (seeing the planet still there)--the reality coming towards [A]. Could [A] still message and get a reply from [B] in that reality that’s coming towards him? If so, could [B] be resaved in that reality. This is just one for now. Have fun. Edit: Someone move to GC.

The post is somewhat difficult to understand. First of all, person [A] wouldn't see the planet explode until millions of years after it exploded, but lets say he saw that in the future it would explode. There is no reality coming towards him -- just light. [B] would already be dead. [A] couldn't save [B]. There is no alternate reality. The fact that [A] could still see the planet is due to the lag between what's happening at point [B] and the time it takes light to get here.