Why does faster than light travel violate causality?

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The way I think I understand it, even if we had some “element 0” like in mass effect to keep a starship from reaching unmanageable mass while accelerating, faster than light travel still wouldn’t be possible because you’d be violating causality somehow, but every explanation I’ve read on why leaves me bamboozled.

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Anonymous 0 Comments

Part of why it’s confusing is because causality is, more simplified, cause & effect.

Think of it in terms of say, writing an email and sending it out. If we violate causality, the email would already be sent out before you wrote it.

Another example with sound; bouncing a basketball makes a sound. If we violate causality, then it’d be the other way around, you hear the bounce sound before the ball bounces.

This leads to all kinds of paradoxes – not necessarily as ‘deep’ as the grandfather paradox or other time-travel paradoxes, but still leads to situations that can’t or don’t make sense, *because* they violated causality at some point.

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