Simultaneity of Events: Is It Possible?

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Discussion Overview

The discussion revolves around the concept of simultaneity in the context of relativistic physics, particularly focusing on hypothetical scenarios involving wormholes and the implications for time travel and signal reception. Participants explore the paradox of being in two places at once and the nature of time in relation to these scenarios.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant suggests that traveling through a wormhole to Alpha Centauri and receiving a signal back on Earth raises paradoxical implications about time travel.
  • Another participant mentions that wormholes can create closed time-like curves, referencing the Novikov self-consistency principle as a framework for understanding these scenarios.
  • Several participants express the belief that it is impossible to receive a signal from the past while being in a different location, emphasizing the forward nature of time.
  • One participant draws an analogy comparing the situation to traveling around the globe, suggesting that one can move in one direction and return from another without contradicting the flow of time.
  • Another participant questions the assumption that receiving a signal necessitates being at the point of origin, likening it to sending a letter while traveling elsewhere.

Areas of Agreement / Disagreement

Participants generally disagree on the implications of the scenario, with some asserting that it is impossible to receive a signal from the past while others propose that it could be explained through relativistic concepts. The discussion remains unresolved regarding the feasibility of such situations.

Contextual Notes

Participants express uncertainty about the assumptions underlying their arguments, particularly concerning the nature of time travel and the conditions required for receiving signals across vast distances. There are also references to differing interpretations of time in Newtonian versus Einsteinian frameworks.

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Hi,

A friend of mine asked me something about relativistic physics. It's all hypothetical and I told him it's a paradox that cannot be achieved since you cannot go back in time.

Here's his assumption:

Let's say that you pass through a 'wormhole' to a planet near Alpha Centauri (26 lightyears). You send a signal to Earth and then you get back into your 'ship' from another worm hole.

From your point of view, it took you about 5 minutes to do all that. You are back on Earth 5 minutes after.

26 years later, you receive the signal you sent from Alpha Centauri. That would mean you are on Earth to receive the signal and also on the planet of Alpha Centauri.

My guess is that it is impossible since when you would get back to Earth, you would be traveling backwards in time.

Am I right ?

Oiivier
 
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Wormholes can create close time-like curves.
The same problem exists inside rotating black holes

CTL curve itself is not a contradisction per se, wiki for example novikov self-consistency principle.
 
That's exactly what I think. it's impossible.

You can't go back in time to receive the signal.
 
You don't 'go back in time', you always go forward, but arrive to the past. Like on the globe: you can always go west, but return to the East
 
Dmitry67 said:
You don't 'go back in time', you always go forward, but arrive to the past. Like on the globe: you can always go west, but return to the East

That's my understanding.
 
I don't see how receiving the signal means you are on Alpha Centauri.

It's like I will send you a letter, meanwhile go on a trip around the world, but when you'll receive the letter it will require me to be home.

Maybe I didn't get your question right.
 
That's in a Newtonian world. But in a Einstein world... It can't happen.

elibj123 said:
I don't see how receiving the signal means you are on Alpha Centauri.

It's like I will send you a letter, meanwhile go on a trip around the world, but when you'll receive the letter it will require me to be home.

Maybe I didn't get your question right.
 

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