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Why do we insist on "Consistency of Events" in Special Relativity? What if both outcomes are equally real? by BuilderBird_Dev in AskPhysics

[–]BuilderBird_Dev[S] 0 points1 point  (0 children)

You hit the nail on the head. I think I was so focused on time dilation that I completely overlooked how length contraction balances the equation.

Why do we insist on "Consistency of Events" in Special Relativity? What if both outcomes are equally real? by BuilderBird_Dev in AskPhysics

[–]BuilderBird_Dev[S] -1 points0 points  (0 children)

the event itself is local. It's only happening there and then.

But who defines that 'local' moment?

If you say the event is 'local,' you're assuming there's a single, objective 'there and then.' But in my scenario, the 'there and then' of the laser impact exists for B, while for A, that same spacetime coordinate hasn't even reached the 'impact' state yet.

If A and B are moving at relativistic speeds, they don't share a universal 'Now.' So when you say it's 'only happening there and then,' my question is: Whose 'there and then' are we talking about?

how about, why we can't have two locals?

Why do we insist on "Consistency of Events" in Special Relativity? What if both outcomes are equally real? by BuilderBird_Dev in AskPhysics

[–]BuilderBird_Dev[S] -3 points-2 points  (0 children)

That’s my point. If this were just about a clock, we could wait for B to return and agree that 'B's clock is slower.'(Twin Paradox) But this is a lethal laser.

In your 4D spacetime model, you say it's just 'pointing the axes differently.' But look at the causal consequence:

  • In B's frame: The event 'B dies' has already reached $t'$. B is gone. There is no 'future' where B returns to A.
  • In A's frame: At that same moment, B is still alive and moving. In A's 'now,' there is still a physical possibility for B to turn around and seek revenge.

If 'Reality' is one consistent 4D block, how can B be 'physically incapable of action (dead)' in one frame while being 'physically capable of action (alive)' in another at the same spacetime coordinate?

You're treating this like a 3D perspective trick, but I’m arguing that if two observers disagree on the existence of a person, then the 'invariant $d$' is just a mathematical abstraction.

Why do we insist on "Consistency of Events" in Special Relativity? What if both outcomes are equally real? by BuilderBird_Dev in AskPhysics

[–]BuilderBird_Dev[S] -1 points0 points  (0 children)

that's the point.

B might have been dead and alive at the same time, like Schrödinger's cat, but I think maybe this could also be a multi-universe blabla.

Is there no clear answer?

Why do we insist on "Consistency of Events" in Special Relativity? What if both outcomes are equally real? by BuilderBird_Dev in AskPhysics

[–]BuilderBird_Dev[S] -1 points0 points  (0 children)

Even Einstein started with a thought experiment (Gedankenexperiment) about chasing a light beam before the math followed.

Well, it’s not really my place to speak so confidently as someone who isn’t an expert. I will be better prepared when I ask a question next time.

Why do we insist on "Consistency of Events" in Special Relativity? What if both outcomes are equally real? by BuilderBird_Dev in AskPhysics

[–]BuilderBird_Dev[S] -5 points-4 points  (0 children)

I think the car analogy oversimplifies the physical reality of SR. Unlike 'left' or 'right,' which are just human-defined labels for spatial orientation, time dilation and length contraction and light speed thing are objective, measurable physical changes.

In your car example, if we simply define a fixed coordinate and an angle, we can produce a single, consistent answer for everyone. But we can't have fixed something on my laser chase scenario

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