Why is every event in spacetime limited to our present point

[quantumfunction]

Yes, he does. The events are timelike separated so all observers agree on their order.

This is a quote about simultaneity in general from a previous post and timelike and spacelike separation.

In my post and diagram it shows that events do happen in order. JFK doesn't walk out of the airplane before the plane lands or get assassinated before the Cuban Missle Crisis.

These events happen in order.

There's no force or mechanism that says these events have to happen the same way for observer B as they happened for observer A because the event(JFK assassination) is outside the future light cone of observer B.

So many paths can occur at this point. Sometimes we will take the less probable path, sometimes we will take the most probable path. There's many paths that lead to JFK assassinated/not assassinated, we may have even taken a less probable path. This doesn't mean observer B has to take the same path as observer A.

 

[Nugatory]

So many paths can occur at this point. Sometimes we will take the less probable path, sometimes we will take the most probable path. There's many paths that lead to JFK assassinated/not assassinated, we may have even taken a less probable path. This doesn't mean observer B has to take the same path as observer A.

Not only does B not have to take the same path as A, they must necessarily take different paths. (The only way they could be following the same path is if they start at out at the same location at the same time at rest relative to one another and never accelerate or decelerate). However, if you draw their worldlines (which you still haven't) and identify the event on A's worldline which is in B's "now" and vice versa, you will find that there is no way of configuring the worldlines that do not lead to the same outcomes along both worldlines.

 

[Nugatory]

because the event(JFK assassination) is outside the future light cone of observer B.

As you've drawn the diagram, the assassination event is within the future light cone of B. The diagrams that you posted in #4 and #20 may confusingly not make it look that way, but future light cones extend all the way to the top of the page and keep on going (and past light cones extend all the way to the bottom of the page and keep on going) and you'll want t show this in your diagram as well.

Now consider the point that is the base of B's future light cone in your diagram. That point is a moment when B said "now!", and as well as the past and future light cones it also defines a surface (the plane in the diagram in your post #4) that is B's now at that moment. Where does that plane intersect A's worldline?

 

[timmdeeg]

I must confess, I don't like explaining physics using the context of JFK's assassination.

 

[PeterDonis]

There's no force or mechanism that says these events have to happen the same way for observer B

Yes there is. As Dale already pointed out, and I pointed out even before that, events that are timelike separated occur in the same order for all observers.

because the event(JFK assassination) is outside the future light cone of observer B

This is false, and it has been repeatedly pointed out to you that it is false.

We can't have a useful discussion if you refuse to accept correction when you make false statements. Thread closed.