Why Can't Information Travel Faster Than Light Without Breaking Causality?

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Discussion Overview

The discussion revolves around the question of why information cannot travel faster than the speed of light (c) without violating causality. Participants explore the implications of faster-than-light (FTL) information transfer in the context of special relativity, questioning the origins of these ideas and their consequences.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants assert that information cannot travel faster than c due to the implications for causality, referencing special relativity as the foundational theory.
  • One participant explains that if information travels faster than c, it creates scenarios where the same information could be perceived as traveling in reverse order in different reference frames, leading to paradoxes.
  • Another participant emphasizes that losing causality would imply that effects could precede their causes, presenting this as a nonsensical situation.
  • There is a question about the origins of the idea that information cannot exceed the speed of light, with a suggestion that it may be attributed to Einstein.
  • A participant mentions a recent paper that may relate to the topic, although its content is not discussed in detail.

Areas of Agreement / Disagreement

Participants generally agree that faster-than-light information transfer would violate causality, but the discussion includes varying interpretations and explanations of why this is the case. No consensus is reached on the origins of these ideas or the implications of recent research.

Contextual Notes

The discussion relies on the assumptions of special relativity and does not delve into the mathematical details that would clarify the conditions under which these claims hold. The implications of recent research mentioned are not explored in depth.

alpha_wolf
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"Information cannot travel faster than c"
"If information could travel faster than c, we would loose causality"
Just wandering - who came up with these and why? In other words:
1. Why can't information travel at some higher finite speed?
2. Why would we loose causality in that case?

Note that I'm posting here in the relativity forum, since I suspect this has much to do with relativity... Was this Einstein's idea?
 
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It's based on Special Relativity -- information traveling faster than c breaks cause an effect.

The basic geometric cause of the paradox is this: If, in one reference frame, information travels from point A to point B, then there are other reference frames in which the same piece of information travels from point B to point A.

That is, when information is transmitted faster than c, it is impossible to tell the difference between the source and the destination!

With a little care, you can arrange fun paradoxes, such as FTL transmission of information that's "supposed" to from A to B then back to A, but it arrives back at A before it was ever sent! Thus it is said to violate causality -- it violates the "law" cause and effect.
 
alpha_wolf said:
"Information cannot travel faster than c"
"If information could travel faster than c, we would loose causality"
Just wandering - who came up with these and why? In other words:
1. Why can't information travel at some higher finite speed?
2. Why would we loose causality in that case?

Note that I'm posting here in the relativity forum, since I suspect this has much to do with relativity... Was this Einstein's idea?

This may or may not answer your question, but this paper is barely 2 weeks old...

http://physicsweb.org/articles/news/8/11/10/1

Zz.
 
information cannot travel faster then c because we would loose causality...This is a consequence of the special theory of relativity where c is postulated to be constant for all observers. This was an idea from Einstein.

Loosing causlity is not allowed because this is not physical. It means that the consequence of some action can occur before the actual action... Something like you die before you are born...this is crazy talk, wouldn't you say?

marlon
 

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